David Baillie

Rico,
When I sit down with someone the first things I try to get them to articulate is what their goals are. So many people who do solar start with gear and build the picture around it. Usually those are the systems I visit to troubleshoot and rebuild. So what are your goals? With the property: size and intended use? What are the growth plans? how much care do you want to give the system?  Will a central power connection be involved? Would you feed back excess?  Will you be fully off grid? If so can you accept shortfalls in production or will a generator be required? Is it going to be a portable occasional generator or will it be an auto starting unit in case you are away for prolonged periods? Does gasoline work best for your area or propane or diesel? You are starting out in an area blessed with regular predictable sun with a large solar presence already which is nice. So before you ask for gear choices and advice you need to tell a story about what it looks like in your head. Keeping it all close to your chest results in poor advice. I enjoy Permies because by and large we are a very easy group to talk to and not much prone to judge. So tell me a story...
Cheers,  David Baillie

HI Rico,
https://www.amazon.com/GREENOE-12V-100Ah-LiFePO4-Rechargeable/dp/B0DP6WNN96?th=1

Here is a link to the company's amazon page. It lists a charge voltage of 14.6 volts. It seems to be made as a direct drop in for an automative battery. I believe you should be good with a charger that you can adjust to 14.6 volts. I might choose 14.4 volts as a safety measure and experiment with it from there. As to how to use it in conjunction with your other unit... I would probably use the larger battery to feed power into the DC in of your all in one unit and power loads from the all in one. It should deplete the stand alone lithium battery to keep itself charged which will shut itself off when it reaches a low voltage state. Power yur loads from the all in one. Use the adjusted vicron ac to dc charger to top off the stand alone lithium battery at home. That is how I would do it. You would need a separate dc charge controller if you want to feed solar into the stand alone lithium battery.  The sketch you showed above would only work if you were charging the lithium battery remotely before using it on site but would not help you increase your run time when you are working remotely.
Cheers,  David

Rico Loma wrote:David , I wanted to send this again, please refer to specs on my all in one unit. Internal battery is very small.   My only question at present is how best to chargethe battery shown here, it is 100Ah 12v battery,  LFP chemistry.  Would you advise using AC power for a smart charger designed for LFP battery?  If not, 0lease explain.

you would need to pull up the specs on the secondary battery not the all in one unit. It will tell you the charge voltage and you program your victron for that voltage.

Rico Loma wrote:

Wise masters of the craft, I need guidance, as i am not certain about properly charging my three batteries.  From several sources I discern that best practice means keeping the LifePO batteries between 20 and 80 percent. This is touted as best for battery health and longevity. Is thisาฟ a hard and fast mandate?

But what about the days I charge one to 96 percent?   For example, the charge controller  on this one doesn't stop at 80, so I must manually stop the charging from its solar panel.  This specific system is all in one, so battery, inverter and charge controller are integrated into one box.

Should I let the system operate as designed, or follow the 20- 80 rule?  All comments and opinions welcome

You would have to provide a make and model for your batteries. Every BMS is slightly different. Usually "100%" is just a value they assign to indicate full without damage to the battery. Some BMS just monitor others actively block power input/output. So the model matters. If its a unusual unsupported one then it gets harder.

John Weiland wrote:

thomas rubino wrote:Today I finished wiring a string of 12-volt lights.
No more juggling a flashlight and frozen food while traversing the maze on the floor of the barn.
Heck, it is so bright in there now, that I might even clean it up!
We will be able to see everything in the freezers without needing a flashlight.
.......(snip).....

These MPPT charge controls are amazing.
The sun will not rise above the ridge to my east until apx. 9:30... I'm getting power at 7:22!
If only I had understood about these sooner...

Ha!.... My wife likes to say "Keep those lights off....we don't need to see how dirty it is in here!... " :-)   Maybe we should go back to kerosene lamps!.... lol

Yeah, I bow in deference to those stout engineers who came before us and were installing solar before the plug-n-play days of today.  I've had one installer come out to give me a quote ..... an older gent who had been installing back into the 1970s.  After our discussion of power needs and desire for grid-interie vs. stand alone battery/solar, he said, "you know, with the technology the way it is today, you really don't need me at all!...Just have an electrician and the power coop approve everything and I think you could DIY the project."  Which was a bit funny coming from a guy who could lose his sale.  But my take was that he was well off enough being the CEO of the installation company and a local near-retirement installer.  So I admit I'm a bit glad to be diving in now when it is so much easier for the homeowner to do self-installs and I'm loving the educational aspect of it as well.   Great to see your project, Thomas, and agree with your mention of David B. and others on the group who have been super helpful.

You would be amazed at the amount of sites I end up trouble shooting where the home owner bought a pile of equipment and just hired an electrician to install. I agree the design process has gotten much easier as panel costs fall, the all in one inverters remove all the complex wiring and the lithium batteries ad incredible storage capacity. The down side is the gear is changing fast and the learning curve never stops. My biggest headache is some people's belief that if they are off grid they don't have to conform to rules or have things inspected. While that might be true is some areas generally it is not so the gear has to be certified for home use and permitted or else they won't qualify for insurance. Again some people don't need to care about that.

thomas rubino wrote:Official sunrise was at 7:07 this morning.
At 7:22, I was receiving power at my freezer batteries!
These MPPT charge controls are amazing.
The sun will not rise above the ridge to my east until apx. 9:30... I'm getting power at 7:22!
If only I had understood about these sooner...

I now have plans next summer to replace the entire house solar system, upgrading to a LiPo 4 48-volt system.
Currently, the house uses four solar panels: two 150-watt, one 120-watt, and an ancient 58-watt, wired in parallel for 12 volts, providing apx. 25 amps @12Vt in full sun.
The two 150-watt panels will be relocated to my shop building next summer, after the new 48-volt system is up and running.
The 120 panel may be moved down to the Subaru parts room in the field; time for some better lighting than a flashlight!
The 58-watt might get listed on the F.B. marketplace.

Meanwhile, to help go through the coming winter, I have purchased a second Victron MPPT controller.
I intend to separate the four panels on the roof. Leaving the 120 and 58-watt panels in parallel, but taking the two 150-watt panels and wiring them in series to 36 volts open circuit, and running them separately through the new MPPT and directly to my batteries.
The remaining two panels and the hydro will continue to run through the TriStar constant diversion charge controller.
This will boost my charge time for this winter.

Sounds like a good Plan Thomas. When you go Lithium it will be time to invest in matching newer panels and retiring the PWM controller from that install. Lithium does not like the pwm controllers. Looking it up in montana new panels are going as low as $0.19 cents a watt... Wait until you see what lithium can do with a really sunny 1 hour a day exposure and a newer matched array; Full utilization of your panels potential... You could even install a pair of 405 watt panels for less than $200...
Cheers,  David

Eric Rothoff wrote:I am wondering if anyone compared thermal verses electric solar. I read a few articles claiming electric is now better(cheaper.) I heat with hot water, and I can build a thermal solar system compared to buying the panels and building an electric system. Either way I would be installing and assembling the system. What are peoples recent experiences?

Eric, as a longtime solar guy I will just say it depends. Here are some rough numbers for you. Approx 20-23 percent of the light hitting a solar electric panel is transformed to electricity. When you are using manufactured evacuated tube heated water system you will transform 80-90 percent of the light to heat. It seems like an easy comparison right? It gets complicated though. To get that high conversion for solar thermal you need to be the type of person who can trouble shoot plumbing, pumps, thermostats, holding tanks, vapor locked runs, failing mechanical valves, etc so all that efficiency comes at a cost. Then there is the financial. Retail solar panels are going for 30-50 cents per watt whereas the cost of solar thermal arrays have not changed much in the last 2 decades. Then you have the issue with all you get from the solar thermal array is heat which is considered a low end energy versus electricity which is very flexible. Add in the recent gains in heat pump technologies which give you a 3 to one gain in heat generation over simple resistance heaters and you have efficiencies that are virtually identical... One is more high tech, one is more prone to requiring maintenance. I have not fielded any inquiries about solar thermal in 5 years which corresponds with better heat pumps and the drop in solar electric panel prices.
Cheers,  David

thomas rubino wrote:I still need to install inline fuses, but for now, my new system is up and running!
The Victron app loaded easily on my phone( after Liz showed me how)
Unfortunately, the Bluetooth range is limited, so I will have to enter the barn to monitor battery condition.
It is really cool to see live input from the solar panels.
You can bet that I will be out in the barn at dusk this evening to see when I lose charging and again at daybreak tomorrow to see how early the charging starts!

Thomas, I still remember when I transferred over the same 12 volt panels from my trace 60 amp PWM charge controller to an Outback 60amp MPPT 18 years ago; it was a transformation. You will see, its not so much the gains you get on good days its how it can still pull watts from the panels on the crummy days, earlier in the day and later into the evening. That unit is still doing work to this day on the garage system.
Cheers,
David

thomas rubino wrote:Hi all;
I  bought four 150-watt 12V panels to run my 12V chest freezers.   https://permies.com/t/216684/newest-volt-deep-freezer
For the last 5 years, they have been leaning against the wall in my shop.
Today they are in the sun for the first time!
I didn't have time to finish the wiring to the new MPPT charge control today, but I've got 77 open circuit volts at the wires!

I wired the panels in series, increasing the voltage output to a working level of 48 volts, but the amperage output remains at 8.2 amps.
My new Victron MPPT charge control will use that 48 volts to charge my 12-volt battery bank.

I use two six-volt deep-cycle batteries to run my two 12-volt chest freezers.
I have been charging them with a trickle charger that is plugged into our house's power system.
I finally decided it was time to step up my game and give them their own power system.

Tomorrow I will finish the hookup and disconnect the trickle charger for good.

Looks great Thomas! glad you went with the Victron

Ben Mosley wrote:I saw this video and got inspiration from it. Unfortunately, I am to old and broken to persue it. I believe that this could be a viable option for those in this community. I think this should be spread, especially in areas where homesteaders are building communities. This could be scaled up, if the community can come together and work together. Maybe I'm just an old fool.

I remember being fascinated by the Jean Pain story and the idea of the large biomass pile. The video actually lays out pretty well the problems you run into. Some of the issues i found that kept me from going for it:
Size: it does not scale down well so was more suitable for a community or large greenhouse complex or something similar.
Equipment: it requires a chipper shredder to get the mass at the right size so it breaks down at the right pace to allows oxygen into the pile to allow break down and heat release..
Climate: Jean Pain's work was in southern france so his need for winter heat was minimal, the pile would probably not freeze in my climate but the rate of decomposition would slow to a crawl in winter
Labour: It is extremely labour intensive for the quality of energy you get from it. I figured a day of labour making firewood would be the equivalent of 5 or 6 days of work on the pile.
Technology change: Very cheap solar panels provide far more electricity than the pile could provide, technological developments like an RMH can produce massive more amounts of heat from the small wood feedstock with much less labour input using far less machinery.
Possible environmental problems: in the 1980's I read reports of leeching into the soil of concentrates which would affect groundwater similar to what a manure pile produces.  My own concern was you are creating basically a self contained bog which releases vast amount of CO2 and Methane far in excess of what smaller distributed piles would release. You are tapping the surplus heat but at what cost? All that said I always wanted to build one to experiment.
Its a great idea especially  an end product of large amount of compost.  My take was I was better burning the larger wood that would have been chipped for heat, composting the green mass from the tops of the trees, using solar to replace the methane he was burning in a generator for lights. Same idea; energy independance, different tech, less labour. Different answers for different regions.
Cheers,
David