Building a small solar power system, want product recommendations and to talk out some ideas

for weeks i have been over thinking the set up of a small solar power setup i am about to dive into.
i started off with the ideas of small, simple, minimalist and very importantly - cheap, although i have gone back and forth now a dozen times from extremely simple to a bit more complicated and expensive and elaborate, and if maybe i should just go for it.
to be clear though my idea of just go for it is....still a very very simple and cheap system, relative to what most people think of for going solar.
ive lived off grid with very small solar, but things have gotten more complicated now, and if anything i would prefer my creature comforts again so i want a bigger better system for this time.
but the technology and offerings are much better, and even relatively speaking - cheaper. now theres way too many options though, which gets me going in circles trying to figure out what to get.
so as far as total load i want to plan for - its nebulous, i can adjust my self to what i can get going on, i am very familiar with extreme minimalism and can adapt to what i can get.

still i have always come back round to start small, and simple ish...as simple as solar can be! anyway, and plan to later work it out with adding on and expanding later once i have it somewhat going.
and i feel like until i dive in and just start making it happen - i cant i figure out all the bazllion questions and concerns i have now. i need to hone in on what parts i am going to use, what set up i will use, and that will influence what i need later.
now after looking up stuff and products and systems and everything! days and days and weeks of reading here and there -- i am getting ready to purchase at least the beginning components.
i'd like some feedback, some product recommendations if anyone has them, and just general  help with brainstorming this.

so here is where i am at --
potentially 400-800 watts of panels - i want to get bifacial panels 100w? 200w even just 400w or whatever else, one big one
and then maybe even invest in a mounting system, or just make my own.

to start off - ground mount them, maybe figure something better later.
example -- https://www.amazon.com/gp/product/B0C99J2WRZ
or -- https://www.amazon.com/gp/product/B0CW17P4NX

although i may end up looking around for other options. actually i could get some free panels in california, but the task of shipping them seems ridiculous.
but at this point may be thinking to buy new, and to buy these bifacial ones for the snow in upstate new york.

potentially 24V or even 48V system...although originally i was going to do 12V and again - simple.
and this will be hooked up to a stationary RV - which does have 12V appliances and receptacles, making me think i should maybe just stick with the simple 12V
then again this system would be eventually used in a different function, and moved to not be on an RV.

a good MPPT controller could be had for 120-180$ and maybe that is worth the splurge - rather than the super basic cheap, middle price type of thing i would usually go for. this is one thing i am looking for recommendations of products and companies.
maybe because it is such an important thing i should even try to get a really top notch one, even more than that-  or maybe some other option, something that could serve some other function and function stack...like my understanding is many portable power station, aka solar "generators" or even fancy inverters have charge controllers and BMS and other more complicated systems. can i use something like this instead?

i have been looking at these -- https://www.amazon.com/gp/product/B0CPY3QNP4
and -- https://www.amazon.com/gp/product/B01MSYGZGI

I think i am looking for 2 - or 3 - lithium LifePO4 batteries -- another thing i would like recommendations for.  
one i would like to integrate into the RVs battery compartment and converter, that i have many questions about can i switch this to lithium or should i just get a (used or new?) lead acid.
such as -- https://www.amazon.com/gp/product/B09BQVVTHH
or -- https://www.amazon.com/gp/product/B0BQ7PHWSK
and this is intriguing -- https://www.amazon.com/gp/product/B0CTC4S54H
or even the more expensive types that get more recommendations.

then an inverter, which that seems like the easiest and one of the cheapest so i will probably get anything that looks ok for 2000watts/ maybe 3000watts.

now heres where it gets tricky, and my brain has been saying from the beginning this is how i should do it, and to figure it out. even though its much more complicated.

i want to run two separate tiny systems. additionally - theres already a subsystem of RV wiring in the catalina.
one will be the panels, to controller --> to two (or more later) lithium batteries  (100AH ? 200AH? even bigger?) --> to an inverter. i would plug the main RV shoreline plug to the inverter.
then replace and upgrade the battery that is connected to the RV, that gets fed by the main plug in (or pigtail, but i dont think i can or should use this? the pigtail?)

the other -- i would like to get a unit like this ---> https://www.amazon.com/gp/product/B0CKWTHM8K

or this -->https://www.amazon.com/gp/product/B0CG3D72QC

have it inside the Catalina RV and be able to connect/ disconnect it. i could use this as standalone, to shut off the other system and let it recharge with no load, or in combination with the other system for quick high draw power uses (electric kettle/RV low watt microwave or my mini shop vac). and use it for my laptop and screen/phone/ etc.
and also have other options for taking it elsewhere for a top up charge to supplement the tiny solar.

some of my questions are where would i connect it ? to the last battery? to the charge controller?? a second line straight from the panels?
i believe these have their own internal BMS and controllers and such, and wouldnt need the charge controller, could be a direct second line from the panels or batteries.

i would like to snake the wiring into the RV somehow so that theres an easy way to connect and disconnect it... and i also want a built in way to turn everything off, or to turn part of it off (as the heat and water heater both have a small electric start need, for propane appliances).
some other questions and concerns are - about the cold. maybe that should steer me away from the Life PO4 batteries, but i have a plan to use geothermal properties, and dig a big hole in the ground between the RV and panels. to submerge the lithium batteries into a box dug down -- 3 -4 feet down, maybe get "heated batteries" or buy some small heating pads that run on DC and could be made into a little battery box nest inside the underground battery hole..
that and again - have built in easy ways to shut it off, for cold weather and for extended times i will be away, and to switch between the battery/ inverter set up and the power station.

or maybe i just set up the first system, and call it good, resist the temptation to buy that solar generator.
it has been the idea i come back to, the first idea i had, and it is the way i want to proceed, though.
two tiny systems, redundancy and flexibility.
thoughts?
recommendations?
constructive criticism even

Batteries are the big money part of a solar system and part of that is the short lifespan compared to the other parts.

This article lays out the option of using direct solar and avoid the battery (mostly) by using electric when it is produced and also charging machines and such that have their own battery (mobile, laptop, powertools, ... ).
https://solar.lowtechmagazine.com/2023/08/direct-solar-power-off-grid-without-batteries/
&
https://solar.lowtechmagazine.com/2023/12/how-to-build-a-small-solar-power-system/

tamara dutch wrote:Batteries are the big money part of a solar system and part of that is the short lifespan compared to the other parts.

This article lays out the option of using direct solar and avoid the battery (mostly) by using electric when it is produced and also charging machines and such that have their own battery (mobile, laptop, powertools, ... ).
https://solar.lowtechmagazine.com/2023/08/direct-solar-power-off-grid-without-batteries/
&
https://solar.lowtechmagazine.com/2023/12/how-to-build-a-small-solar-power-system/

since i lived on very small scale solar for quite a few years, i am definitely familiar with the peak time power splurge, for me it was like oooo the sun is shining bright, time to make a smoothie! which a blender smoothie was out of the question usually-- otherwise would totally depleat my battery bank. but in those peak times you can try to time your high energy draws.
or other weird habits i got into with small scale solar. like grinding all my coffee at that time, or any other task i had that required that peak power. because thats power that would be somewhat wasted....the peak sunshine power when system was at 100% and still tons of sun - thats the time to get any high power chores or tasks done.

living with small scale solar, maybe with any scale solar does definitely make it very clear what things are necessary and what may not be worth the solar bank draw.but yeah its a good take, but i still want a system with 2-4 battery bank. also theres quite a few little things i need set up right for my work. i have and may get some varities of smaller battery options, and rethink my appliances and things. with an RV the things are already set up for low power situations, so theres direct 12V stuff and even a 12V (direct current) receptacle in catalina. so i will work out some other small subsystems, i already have some back up battery gizmos for phone and laptop and small draws. probably get more of that sort of thing later to minimize use on the main system (s).

Although I haven’t been there in a few years, I really like the service and products at MWANDS …Missouri Wind and Solar. I would contact them

John F Dean wrote:Although I haven’t been there in a few years, I really like the service and products at MWANDS …Missouri Wind and Solar. I would contact them

thanks thats an interesting source. i like the larger watt panels they have.
https://windandsolar.com/vsun-550-watt-monocrystalline-solar-panel-bifacial/
and this -- https://windandsolar.com/trina-solar-410w-bifacial-mono-solar-panel-remanufactured/
and the combiner and charge controllers look interesting too -- https://windandsolar.com/70-amp-pwm-solar-charge-controller/
and all the mounting stuff.

i saw this simple mount that i liked -- https://www.currentconnected.com/product/integra-rack-ir-30-frame-individual-frame/?ref=wpc
but really the mounting stuff seems like one of the last things i can figure out .

seems like a good deal with those larger watt panels. less panels and more watts. with 1-2 of those, rather than 4 or 6 i have thought about.
although those higher watt panels are they better for 48V systems?

i was thinking to go up to a 24V system. i suppose in my two systems maybe even that one system or subsystem is 12V (as the RV is 12V stuff)
but panels and battery 24V or even 48V. ???

on my - maybe i should just go for it - wish list, and a totally different idea -- i am interested in this product --
https://signaturesolar.com/eg4-6000xp-off-grid-inverter-split-phase/?ref=cPwLcVc0SW-BjN

detailed here -- https://www.youtube.com/watch?v=6alau_7t5NM&ab_channel=DIYSolarPowerwithWillProwse

but this feels like  way more than what i am currently working on. but theres a lot of things i like about it, as far as i understand it - with charge controller/ split phase/ flexibility/ inverter all bundled. so in my mind this could be a very simple - more than i need - but something i could grow into -- with just batteries, or single server rack battery, and panels and skip all the rest of the stuff i was talking about .

and that may have better use later, when i could grow into this system, with more panels and more battery.

Comment #1.  I would not go with a 12V system simply because so many of the direct drive things need at least 24 volt system.  The more things you can directly drive without an inverter the lower your overall cost and the greater your efficiency.

#2  Be very careful doing your homework mppt systems.  A review about 18 months ago tested something like 40 different ones that claimed it and nearly all of the cheap and mid levels systems were simple pwm systems in spite of the claims for being mppt.

#3 in my thinking I have been looking at recharge cycle life expectancy and because battery life is based on number of cycles I have been looking at super capacitor banks as my primary daily use one since if they are kept cool they can have a half million cycle life expectancy.   Way lower power density so a battery bank is still needed but should reduce the number of cycles needed.  Problem is needing a charge controller designed to balance all factors.  Hadn't found one yet.

C. Letellier wrote:Comment #1.  I would not go with a 12V system simply because so many of the direct drive things need at least 24 volt system.  The more things you can directly drive without an inverter the lower your overall cost and the greater your efficiency.

#2  Be very careful doing your homework mppt systems.  A review about 18 months ago tested something like 40 different ones that claimed it and nearly all of the cheap and mid levels systems were simple pwm systems in spite of the claims for being mppt.

yes thats why i am trying to crowd source some recommendations, especially with the charge controller. i think the ones i have been looking at are ok, but if there is something thats really great that someone else knows, well maybe i want something better. i also think i want to eventually grow out the system and expand. so i am trying to get things that are maybe more than i need, use big wires, higher watts than i am going to start with -- so this can all be useful when i hopefully eventually set up a better system with more panels and watts.
i also like these all in one type bundled things. thats an MPPT bundled with an inverter...and that appeals to me. i'm finding theres some lower end things like this. so because the charge controller/ battery charger/ and inverter all bundled - its much simpler, although some of them look a bit confusing in the wiring, i think i could figure it out. but yeah this is another rabbit hole! .

C. Letellier wrote:
#3 in my thinking I have been looking at recharge cycle life expectancy and because battery life is based on number of cycles I have been looking at super capacitor banks as my primary daily use one since if they are kept cool they can have a half million cycle life expectancy.   Way lower power density so a battery bank is still needed but should reduce the number of cycles needed.  Problem is needing a charge controller designed to balance all factors.  Hadn't found one yet.

that seems like a bit complicated and experimental. i did just go down that rabbit hole a bit, and now not really sure about that, but my thoughts are -- maybe one of these all in one bundled MPPT charge controller /inverter units might be able to integrate that capacitor idea? most of them go very high in watts, like 6k systems and up to like 12k watts and insanely huge amounts. seems like maybe those super high capacity ones with built in MPPT might work with the high capacity of the super capacitor?
just a thought, not sure about that, actually just a random guess.

for those i have been looking at the lower end -- 3k - 4.5k or whatever...but like that one above most of them are super high capacity.

i guess that one above doesnt charge your battery bank until you have a LOT of power coming in for panels, or from the grid...so that would be a good system if you have the grid connect - not for grid tied, but a system where the grid is available. so you could use grid power to charge the battery and having whole house power for black outs etc...or if you want to have a HUGE array of panels.

but the ones i am looking at are similar but much smaller capacity. not sure any of them are good or whatever, so i dont know any specific one is good  to post.
but just maybe that might work with your capacitor idea.

I'll agree that skipping 12V completely is a good idea.  My very first solar system was 12V and I was very happy to get rid of it.  Too little capacity for what I wanted in run.  Today I am VERY happy with my 24V and 48V systems.  My 48V home system can run my 240VAC well-pump.

Definately go with an MPPT charge controller.  PMW is cheaper, but you are forced to use solar panels in the right voltage range.  With MPPT, the controller acts as a transformer, bringing raw high-voltage solar down to battery charging voltage.  The BIG advantage of MPPT is the the extra volts gets converted into extra amps.  The MPPT controller will allow you to utilize larger high-voltage residential panels, which are dirt-cheap right now.  You might get 500W of HV residential panels for the same cost as one single 100W 12V panel.  You also loose less power running the power over distances.  The higher the voltage, the lower the net resistance of the wire.

The warnings though about fake MPPT controllers though are very real.  Dishonest overseas sellers market cheap controllers with a MPPT logo on them.  A simple way to tell the fakes from the real controller is shipping weight.  The sophisticated electronics inside the MPPT controllers are quite heavy, so if you see a controller with a shipping weight of ~ 6lbs, it's likely to real.  If the weight is only 6oz, it's likely to be fake.

The problem with the new All in One (AiO) systems is that they are all made overseas with marginal components barely appropriate for the design.  I've heard that some of them are actually made of recycled components pulled off of scrapped electronic boards.  The American and European designed stuff is much higher quality.  You mentioned the Epever 4210.  I'd consider that the bottom level of where quality components start.  Don't buy Renogy though.  It's actually an Epever product that has the Renogy label put on it.  So you are paying extra just for the brand.  Look at Epever, Midnight, MorningStar, Outback, Samlex, Schneider, and Victron for quality components.

Don't buy panels retail via Amazon or whatever.  Shipping all that glass buts a big price premium into the cost.  Shop locally, with cash and carry pickup.  Helped a neighbor get 240W panels last week off of Craigslist for 40$ each.  He drove his pickup over to pick them up.

Lastly, the inverter.  If you are going to run anything with an electric motor, get a sine-wave inverter.  Motors will overheat and prematurely fail if they are run on a modified sine-wave inverter.

Here's what you can put together not too expensively.....
four 250W residential panels, ~160 to 200$  (wire them 2S2P if using the Epever)
Epever 4210 controller ~125$
four 6V golf-cart batteries ~450$
2000W 24V sine-wave Samlex inverter 650$.
call that 1500$ with some copper wire, fuses, and racking that you built yourself.  Use 10 gauge wire from the panels to the controller.  Use 6 gauge wire from the controller to the batteries.  Use 0gauge wire from the batteries to the inverter.

Michael Qulek wrote:I'll agree that skipping 12V completely is a good idea.  My very first solar system was 12V and I was very happy to get rid of it.  Too little capacity for what I wanted in run.  Today I am VERY happy with my 24V and 48V systems.  My 48V home system can run my 240VAC well-pump.

Look at Epever, Midnight, MorningStar, Outback, Samlex, Schneider, and Victron for quality components.

thanks i will look those up.

Michael Qulek wrote:
Here's what you can put together not too expensively.....
four 250W residential panels, ~160 to 200$  (wire them 2S2P if using the Epever)
Epever 4210 controller ~125$
four 6V golf-cart batteries ~450$
2000W 24V sine-wave Samlex inverter 650$.
call that 1500$ with some copper wire, fuses, and racking that you built yourself.  Use 10 gauge wire from the panels to the controller.  Use 6 gauge wire from the controller to the batteries.  Use 0gauge wire from the batteries to the inverter.

i guess this stuff must be starting to sink in and stew from all my reading in circles, because i actually know what you mean here with 2S2P -- i think - thats a way of wiring the panels - 2 in series and 2 in parallel - yes? that seems to be pretty common to combine that. and if i am getting this right -- that will be the base for the 24V ?

so yeah this is almost the basic gist of what i am thinking, except with 2x 100AH - or 200AH LiFePO4, instead of golf batteries (any advantage to using 6V or golf batteries specifically? or is it price? or is it wire them together for 24V?) also now i like the idea of getting bigger watt panels, although they are huge. so maybe it takes up as much space.
but yeah now i am thinking i want about 800 watts of panels to start.

and yeah that epever charge controller looked ok -- but now do i need a  40A ? or bigger? if i eventually wanted to do 1200 watts of panels could that keep up?

the one i started off with in this post is the 40A, and actually thats the one thats still in my shopping cart so i think thats the one.
there is a 100A of that same type -- and i wonder if i should go for that for later expansion --
https://www.amazon.com/gp/product/B07JVQY8QB/
it is more than i want to spend. actually the $140 is more than i want to spend but if this will really amp up the system, pun intended, then that seems doable right now.

and yeah i do get tempted to go with the cheapest method and previous used only cheap PMW. but i want to buy these expensive LiFePO4 batteries, so thats why i think i need a good quality controller.before i just fished lead acids out of junk cars for super cheap so it was like not a huge investment, plus lead acid seems pretty straight forward, where i would think the lithium batteries need a better charge controller.

and thanks i will look into that inverter.

one more question which is still totally foggy in my mind.
if i am to be getting a portable power station, which is what i want to do as redundancy and for the occasional big draw item and vacuum, or whatever else -- i want to be able to connect and disconnect that unit to recharge.
do i plug it into the charge controller (like some of them have an extra spot for direct). or to the last battery? that seems like it would be slow to charge it , but maybe slow isnt bad, as in slow and steady and not taking too much from the other system.
or should i just run a second line straight from the panels?

I'd definitely get LiFePO4 batteries instead of lead acid. They can take greater than 3,000 complete charge/discharge cycles, so they should last at least 10 years. Gotta be careful not to let them get too cold, however. (Or at least check the specs on that.)

Oh, another thing about LiFePO4 batteries... They should be a safe drop-in replacement for lead-acid.

https://www.grepow.com/blog/how-can-lifepo4-batteries-be-used-to-replace-lead-acid.html

Andy Ze wrote:Oh, another thing about LiFePO4 batteries... They should be a safe drop-in replacement for lead-acid.

https://www.grepow.com/blog/how-can-lifepo4-batteries-be-used-to-replace-lead-acid.html

thanks for the info.  i assumed it could be replaced with lithium to begin with, but then i did get to thinking it might not be that easy. actually i am still unsure. my looking into it said maybe i need to replace the converter/ have a lithium based options or maybe...will have to change things if i want to use lithium.

i am going to have to examine the system better and figure it out eventually. but this is integrated into the trailer systems -- theres direct 12V appliances and such, and its set up to be recharged by the alternator of a towing car with the pigtail, or be recharged with the shore line plug in, then theres a dedicated fuse box and little basic system. the heat and hot water, which so far i havent used the propane appliances, have a small electric need for just starting. that comes from an on board battery, as is - lead acid.
theres a lot of changing it into AC and then DC, so yeah going to have to figure it out.
i do know theres a 12v receptacle in the wall. this i think is straight from the battery, again 12V. theres a fridge that works on 12v, AC, or on propane, which i may or may not use, but it is extremely low watt for a fridge, still a big draw.
everything in there is set up with redundant systems, so i can cook or heat with electric or propane, where obviously being off grid i will want to use the propane systems more. but i would like to be able to use both as the need arises, because i will filling up a lot of little propane bottles otherwise, just to use these systems lightly. and there will be times when its good to be able to use either as i can.

Andy Ze wrote:I'd definitely get LiFePO4 batteries instead of lead acid. They can take greater than 3,000 complete charge/discharge cycles, so they should last at least 10 years. Gotta be careful not to let them get too cold, however. (Or at least check the specs on that.)

and totally this is an issue, it gets really cold.
for the now though i think its actually good for a cooler climate through spring and nice weather, in that lithium doesnt like to be too hot either. it doesnt get very hot either.

i may eventually bring the batteries and system inside, but my plan to try out is to use geothermal -- to dig a large hole between the panels ground mounted array and the catalina. then i will put in some kind of box, maybe just repurpose a cooler or some such, a plastic tub. but yeah i am going to fill it with some kind of scrappy insulation/ maybe even something simple like bubble wrap/ something not sure what...and also may get the kind of heaters that people use for trailer water system. it does take a draw obviously, but they work on direct current, and are just small simple heated sheets, that i can place around the batteries.
then submerge the whole thing about 3-4 feet down in the hole in a little somewhat insulated heated nest. the heated sheets only use a small amount of power and only turn on when its below 40 F, to get it up to 50F and shuts off. it s my hope that wont need much -- and that the more stable underground temps of the earth as a huge thermal mass and heat sink, will keep it closer to 50F anyway.
the effect of being charged and discharged also generates a small amount of heat. that alone may help through the more mild cold days of late fall and winter. its a little experimental though. i do think i can keep that box around 40-50F which is not exactly warm but thats ok for temps. i have considered getting nice heated batteries, but i think my plan may be better.

that and i may not spend next winter there, shut the system off entirely and bring it all inside, which all seems likely. i spend the last part of winter in california with my old friend, after going through a bit of a very harsh winter glamping out. but i would like for it to be somewhat set up for in general until i can get things better and maybe set up a bit better the following winter.

so even though i am thinking i will go with THIS one, this simple but higher capacity and really solid looking PWM is appealing too  -- https://windandsolar.com/70-amp-pwm-solar-charge-controller/
actually it being simple in this case is why it appeals, one of the reasons anyway.

i am even tempted to get both -- as the internal battery for the trailer -- 3rd subsystem, maybe theres a better way to wire it, not to turn DC into AC back into DC. none of that is clear to me, i think i may have to figure that out on my feet, after working on upgrading the battery inside and seeing if i can replace it with lithium and once i figure out whats what with the internal system wiring.
apparently some people do use the pigtail -- 7 pin connector to trickle charge the internal battery. i think i may need a converter in there. i want to use a lithium LiFePO4 battery, maybe 100AH or even 200AH.

i looked into midnite solar and i did like this product -- https://www.amazon.com/gp/product/B0975K74W3
as a possibility, as that seems like one of the better ones of the all in one dealios. one thing about these is apparently they have some draw even when idle, but then again so does any inverter, but these can be a bit more.
i've seen a few others but they seem to be mostly where small charge wont show up, you need a huge array to even get them to work? so i have looked at some of the smaller things, and cant always tell if its like that. they seem pretty ideal for someone who has both grid power and battery/solar set up.
but i do like the looks of the smaller cheaper all in ones, the few i have looked at and that one seems most appealing of those. i think thats just about the right size for what i am working with.

also i think i may cheap out with the inverter. not the cheapest but get something like this -- https://www.amazon.com/gp/product/B07GDH711G
i've seen the 3000 watt version inverter elsewhere for cheaper, and that may be the one i try out to start with anyway. or something along those lines. mid grade i guess, not that cheap not the top quality.

I'm using Renogy products in a 12V, 2x200Wp, 2x100AH LiPeO4 with MPPT and inverter system for my tool shed. I use the system to pump water, charge tools, power devices, everything working very well so far.
I prefer to invest more than have headaches with cheap systems, so Renogy was a good choice, I think. Not the cheapest, but good quality.
My advice would be to better define your needs, down to the math: how much power you need, how long the batteries should last, peak hours, panels location, etc, etc... before checking any product on the market. Also, consider what kind of expansion you intend to do in the future, if you intend to have separate systems for different areas, or will integrate everything...
With a basic sketch and all your needs defined, you can make better choices.
Good luck!

yes, surely i need to get some more information. i'm starting to get a little clearer here, although now i am wondering if i dont have this a bit spun up.
theres also the just do it, and figure out as you go method, of course this method involves trial and error with emphasis on error, sometimes, its sort of the only way.

as i said i am well used to living quite minimally, the tiny system is already way more than i previously have done. i lived for years on a system much much smaller than what i am talking about.
so from that i do have  vague idea of what i am getting into here, and its a lot more than i have managed to make do with previously.
so i know most people have huge needs and wants to tons of power, but this actually feels like this will be sufficient for my - "for now" type system.

and yeah totally, future needs. i am trying to make sure that everything i get can be upgraded later and work with that. the plan would be complicated but its something like put this together as good as i can for now, take it apart and move it in a bit (actually shut it down and put it back together when i leave again), then get more stuff, better set up elsewhere. so the plan is always to eventually move it, upgrade it and expand it a bit.

i know everyone says do this energy audit,get real solid on the numbers- but i am not that concerned with that. i'm confident this will actually be more than i truly need, some extra luxury even in this tiny set up.
i will adjust to what i can get for the now, and work out the real deal later. these components will hopefully all be useful in the eventual third and more permanent insulation, and in the second set up i can by then hopefully know enough of how it works with boots on the ground.

well apparently that midnite solar all in one....is actually a slightly modified -- SRNE manufacturing -- https://www.amazon.com/Inverter24V-Inverter-Hybrid-Inversor-HF2430U60/dp/B0CMPJKQR3
also rebranded under several names like the -- EASUN -- one.

and seems like people put their nose up at these a bit, as lower end stuff, but i still like it and that its small. not in spite of it being small but because it is small.
although i have some concerns about the whole having to program it and set it up, like it could just be difficult to program or if it started being glitchy.
ah idk. its about the same as a charge controller and budget inverter in price. but i will think on it and let all this info stew.

if anyone has recommendations for anything else though i am still looking around.
for a small size budget all in one unit, or a moderately priced charge controller, or even your favorite brand of lithium battery, and again - budget LiFePO4, or for that matter a different type of battery.
i think i have a pretty good handle on what i am doing to start. maybe i will come back and post up some pics once i set it up in a month or 3.

For an all in one unit, something like this might make your life much simpler.

https://www.amazon.com/dp/B0CJNPZRC7

Andy Ze wrote:For an all in one unit, something like this might make your life much simpler.

https://www.amazon.com/dp/B0CJNPZRC7

Yes! this is where i started ( although not that brand, but i did check out that brand). just get this and 2-4 panels.
and its still a thought in my mind sometimes to just do that as the for now system, hold off and buy the rest of the stuff in my eventual build....or over the next months more slowly.

and actually i am probably going to get -- https://www.amazon.com/gp/product/B0CKWTHM8K/
however even though this is nice for middle of the road, not too big not too small system, i do not think that alone will be enough for my needs.

this is what i have been seeing as a second system, but maybe i have this backwards. maybe this, and integrating it with the onboard battery, upgrading the system in place in the RV already by switching it to lithium/ maybe even two batteries -- maybe that should be the first system. then i dont need an inverter, just use the on board stuff. to be true there is sense in that.

but when i think of doing only one of these systems...well for whatever reason the way its come to me is to do both -- the panels, and a "regular" set up - batteries, charge controller inverter etc....and also the other system - on board RV stuff, upgrade that so no matter where i tow off too, the heat and hot water systems will be able to be used without any solar or shore line power, at least for a short time or with basic foldy panels or some such. so one of those -- along with upgrading and using the on board system.
basically i want to set one of those portable power stations up with the onboard system for the RV -- and i want to start slowly  building an eventual system that will stay on the land.
and even if it seems over the top to do both, thats what i want to do for several reasons. use that for laptop/ printer/ screens and the occasional high draw use....use the other system for recharging the onboard system, power the RV stuff . and be able to shut them off and on, charge the portable power station and then have it be a standalone. turn off the inverter at night, be able to switch back and forth to let each system recharge, if one fails, and to overlap them for trying to use like two high draw things at once.

Excellent discussion so far.  There are many points that I agree with.

I do have a couple of thoughts about lead acid batteries vs LiFePO4 batteries though.  LiFePo4 batteries are not *quite* a drop-in solution.  Probably you could use them for light loads and be fine, but heavier loads can damage them.  It comes down to something called a "C" rating.  A LiFePO4 battery has a "C" rating of 1.  That means that a, say, 10 amp hour battery can at most discharge 10 amps without suffering damage (and a 20 amp hour, 20 amps, and so on).  A lead-acid battery has something like a 6-8 or even higher "C" rating, meaning that a 10 ah batter could safely deliver 60-80 amps.  As long as your current needs (amps) fall within the "C" rating, you should be fine on the power output side.

But another area worth noting is that LiFePO4 batteries have an exceptionally flat discharge curve, so flat that voltage cannot be used to safely determine state-of-charge.  In order to know how charged or discharged your LiFePO4 battery is, you need a device that reads and calculates how many amps have been pumped into and then drawn out of the battery.  This makes the wiring a little bit more complicated, but it is certainly doable.  You also need a dedicated Lithium battery charger as a regular Lead Acid charger may damage the battery.

I am tinkering with a very small, portable system based on a 12 volt, 80 amp-hour prismatic cell battery.  Basically, I am building the battery from basic components and mounting in a plastic ammo can.  I have recently become fairly well-versed in the subject so I thought I would pass along some of the meaningful details.  I could summarize by the following:

LiFePO4 Batteries Good                                                                                         Lead Acid Batteries Good
*Many charge-discharge cycles                                                                             *Solid, robust technology
*Light weight (ish)                                                                                                   *Simple Charge setup
*Flat voltage discharge curve                                                                                 *Very high "C" rating
*No Peukert Effect (diminishing power w/discharge)                                         *Cheap
*Good energy density
*Very safe chemistry
*

LiFePO4 Batteries Bad                                                                                            Lead Acid Batteries Bad
*More expensive (at setup)                                                                                   *Heavy!!!
*Needs specialized Battery Monitor                                                                     *Reduced Capacity w/age
*Low "C" Rating                                                                                                      *More limited charge-discharge cycles
                                                                                                                                 *Strong Peukert Effect


In the end I think that the LiFePO4 batteries are worth the investment, but just be aware that they are not exactly drop-in replacements.  I am personally sold on the LiFePO4 and I think that you will like it as well.

Eric

I should contextualize my previous post.  If the idea is to add a battery simply to buffer out changes in power output from solar panels (such as if a cloud passes overhead) or simply to store a little bit of energy to run thinks later AND to do this on the cheap and simple, then Lead-Acid shines.  If the goal is to *store* up a *lot* of energy for later use, LiFePO4 might be the way to go.  Either can be a winner, but I realized as I posted my last post that cost and simplicity were paramount.  Sorry, I get this way when I delve into a topic!

Eric

Eric Hanson wrote:Probably you could use them for light loads and be fine, but heavier loads can damage them.  It comes down to something called a "C" rating.  A LiFePO4 battery has a "C" rating of 1.  That means that a, say, 10 amp hour battery can at most discharge 10 amps without suffering damage (and a 20 amp hour, 20 amps, and so on).  A lead-acid battery has something like a 6-8 or even higher "C" rating, meaning that a 10 ah batter could safely deliver 60-80 amps.  

ok that math does not seem to be mathing =)
but maybe i understand. do you mean as a pass through charge?
like if a lead acid battery could transmit that much power if theres power on the other side?

Eric Hanson wrote:
You also need a dedicated Lithium battery charger as a regular Lead Acid charger may damage the battery.

this is the main reason i may not put lithium batts in the RV. it is set up to work on lead acid and the charger system through the pigtail, and through the shore line power, are all set up to work with lead acid.
and i want to do a 24v system, and everything on board is 12v. apparently i can get a rather inexpensive converter type dealio, or a DC to DC converter or some such...to adapt the system to lithium. but as far as i know the current system is already functional as is, just needs a new freshy lead acid. idk. i am going to examine all this in depth.

it may be easiest to just replace the battery inside the RV with lead acid, and then build up another lithium battery system elsewhere.

Eric Hanson wrote:I should contextualize my previous post.  If the idea is to add a battery simply to buffer out changes in power output from solar panels (such as if a cloud passes overhead) or simply to store a little bit of energy to run thinks later AND to do this on the cheap and simple, then Lead-Acid shines.  If the goal is to *store* up a *lot* of energy for later use, LiFePO4 might be the way to go.  Either can be a winner, but I realized as I posted my last post that cost and simplicity were paramount.  Sorry, I get this way when I delve into a topic!

Eric

its all good, it is a HUGE subject. its felt like literal homework to be doing all the reading and opening up like way too many tabs, absorbing all this info on solar.

cost and simplicity are the main values, yes. in my initial build anyway. i want to get enough to set up an initial small system though, that could be later build up to be a bigger system.
now i am still tempted to try these "all in one" type units, even by the standard of cheap and simple they fit that.
one of the smaller 3000 w - 24v ones- i am finding the lower end of these to be 300-600$ -- less than the cost of the decent charge controller and mid grade inverter. plus its just...idk that simplicity of the just wire this main thing and its even kinda cute =)
ok cute is definitely not the value here...but the whole all in one deal... it feels like a nice clean and simple way.
i could set it up inside the RV, leaving the other regular lead acid battery alone, and just go off that, or well idk.
i could instead wire it inside a shed and just go with the portable power unit in the RV.

Leila,

So about the "C" rating;

The "C" rating is a multiple of the battery's rating in Amp-Hours (AH).  So if a 10 AH LiFePO4 batter with a "C" rating of 1 were used properly, then the maximum output it could safely discharge would be 10 amps,

LiFePO4 Battery examples ("C" rating=1)
10 (AH) x 1 ("C" Rating)=10 amps max output
20 (AH) x 1 ("C" Rating)=20 amps max output


Lead Acid Battery Examples ("C" rating=6)
10 (AH) x 6 ("C" Rating)=60 amps max output
20 (AH) x 6 ("C" Rating)=120 amps max output


Lead Acid can safely discharge much faster than LiFePO4 batteries, though per volume (and certainly per mass) they have less energy stored.

Regarding your RV situation, while a LiFePO4 battery might physically fit where a lead acid battery previously sat, it would need to be wired with a proper battery meter.  This is not terribly hard and the battery meters are pretty reasonably priced ($20-$30).  Getting to 24 volts might be more challenging depending on your exact circumstances.  It is true that you could get a buck converter to easily boost the voltage (but drop the amps) to 24 volts.  This could be accomplished with a simple wiring addition.

Does any of this help?

Eric

yes thats helpful, i did not know that. actually i still dont completely grok the whole C rating thing you are talking about.but i will take your word on it.

and for whatever reason i had that backwards in my mind. like especially if i were to spurge on 2x 200AH lithium. i was under the mistaken impression this would be a lot more than say two lead acid batteries.
i do not have a lot of high draw appliances or anything. the only three high draw things i may be running are -- a mini shop vac, very rarely do i use it, an electric kettle, which ok i may just switch to boiling water in regular kettle on propane, but for times when propane may be out or nearly out...and the fridge. which i may not even run, and is - relative to most fridges - a low volt fridge meant to run on 12v or shore power or even propane. i suppose on further thing would be i do have a nice tiny heater that can work on 600 - 1200 watts...but that doesnt have to be used, as theres a propane heating system- and o yeah its finally nice weather. !

i would though be going through massive amount of little propane bottles i am always having to fill up -- if i tried to stay in RV in winter. i am leaving next winter to next winter though, as more than likely if i dont have a better set up by then, most likely i will come back to cali for next winter.

but all to say i dont need high watts usually, only for these occasional things, or if i have no propane. i want stable medium watts that last even when its not sunny, for laptop and internet and music and movies, all low watt stuff but i would like those constant, or any time i need them. this to me seems like lithium is the way to go for that.

200 ah lithium batteries will store a *LOT* of energy!  This also means that a single 200 ah battery could discharge 200 amps at a time.  Assuming that it is a 12v battery, then that single battery could discharge 2400 watts, but only for one hour (200ah X 12 volts = 2400 watt hours).  I guess you could run the little electric heater with that battery but you would drain the battery quickly.  My personal thought is that batteries are not a great way to produce heat.

But for running other things, a single 200 ah batter could be really great.  You would have to add up the total wattage of all the things you would use.  That vacuum would be a pretty big draw but you would not use that all the time.  When using that, I recommend turning off the electric kettle & similar items.  The more items that you can switch to propane the (much) longer you can make that battery last.

Eric

Eric Hanson wrote:200 ah lithium batteries will store a *LOT* of energy!  This also means that a single 200 ah battery could discharge 200 amps at a time.  Assuming that it is a 12v battery, then that single battery could discharge 2400 watts, but only for one hour (200ah X 12 volts = 2400 watt hours).  I guess you could run the little electric heater with that battery but you would drain the battery quickly.  My personal thought is that batteries are not a great way to produce heat.

But for running other things, a single 200 ah batter could be really great.  You would have to add up the total wattage of all the things you would use.  That vacuum would be a pretty big draw but you would not use that all the time.  When using that, I recommend turning off the electric kettle & similar items.  The more items that you can switch to propane the (much) longer you can make that battery last.

Eric

yes this is why i have been thinking to have two systems. i am familiar with the whole -can only run one high watt thing at a time. if i do run the fridge, which would be ideal, and i would like to- that would be the one big draw thing. if i have two separate systems - i have a second place to run the occasional high watt thing on a totally separate system. actually thats why the portable station. if i have that i can have that as a standalone for the occasionall high draw things and a back up for basics like my laptop, phone and printer.

that and so i could completely shut off one system. like at night. i could shut the main system off ( and not open that fridge door, it is sealed really well as its meant to be travelling so very tightly sealed) if i shut off the main system...i could still use the portable power station. let the other system recharge some before i turn it on. and vice versa. take the standalone and shut it down to recharge faster, and i have that first main system for small loads and the fridge..

Leila,

Actually, I think that you are making a very good case for the dual system.  Those little backup boxes are pretty capable.  I would get one myself but I prefer to build mine--I just like doing that type of stuff.

The little portable systems are absolutely fantastic for all the little low-power items like cell phone and printers.  It may or may not run a fridge, that depends on the power draw from your fridge and the individual portable system that you get.

Eric

Eric Hanson wrote:Leila,

Actually, I think that you are making a very good case for the dual system.  Those little backup boxes are pretty capable.  I would get one myself but I prefer to build mine--I just like doing that type of stuff.

The little portable systems are absolutely fantastic for all the little low-power items like cell phone and printers.  It may or may not run a fridge, that depends on the power draw from your fridge and the individual portable system that you get.

Eric

yes i think it is the way, it is what i want to do even though it ups the price a lot and ups the complexity. i think it is worth it to do that way.

i think no matter what - all these pieces will also be useful in later applications as well. theres a lot of flexibility in it, later i can set it up differently, so i should go for this - two seperate systems. one that integrates with the the on board stuff and has an additional portable power unit that could even be useful for travels, or take to town and charge up to boost the other system or at least take off the load for a while to let the other system recharge. and especially for the shut off main set up at night and just use that for small loads, night time movies before bed, keeping my phone charged.

btw - this is a repeat link here -- but this -- https://www.amazon.com/gp/product/B0CKWTHM8K is the one i am going with i think. it is bigger watts and more storage, for ones in this medium large size and price -- and it will take an input of 700 watts in panels. most of them will only take 400-500 watts in panels. of course there are other ways to charge it...you could have it on a system with middle sections -- like through the battery.

i would like to just charge this directly from the panels, and 700 is about what i will get...which ok isnt always 700 watts, in fact is probably a bit less than that even in ideals.

but i am still fuzzy on that if i should directly connect to the panels, as a second straight line. or maybe i plug it into the battery at the end, which i would think would slow it down a LOT, but maybe slowly trickle charging may actually be a better way for long term health of the unit, for not taking a huge chunk of the system too fast. or potentially i wire it to connect after a charge controller, or from one of those all in one units (basically a fancy charge controller) if i go that way.

my understanding is it doesnt need a charge controller, as it has that all built in.