David Baillie

John Weiland wrote:A tangentially-related question on the thread contents.

Most of what is posted above refers to LiFePO4 batteries being charged with solar.  I'm curious about an efficient wall-plug charger that might do as many different amperages, volts, and battery chemistries as possible, *within reason*.  I understand that having something to charge flashlight batteries -and- industrial forklift batteries is likely asking too much.  But I'm finding that, partially due to a learning curve, I have lead-acid batteries ranging from 12V car/tractor to golf cart 6V deep cycle (36V as a series connected pack, but has own charger...and soon upgrading to higher V) to some newer 10Ah to 100 Ah LiFePO4 batteries, each needing charging independently.  I'm thinking rather than having so many different chargers around, there may be some rather reliable unit out there, switchable (manually or automatically) between lead acid and lithium that may range from 6-12V (maybe higher?), and can be adjusted for 2 - 20 A, again possibly manually, but also via algorithm profile automatically for best life of battery.  It's not that I haven't come across some chargers that appear to do this, but if there is a brand or source of plug-in (120VAC) charger that those with years of experience have found to be robust and have useful parameters for diverse charging needs and could post those here, I would be grateful.  Thoughts welcome as well....Thanks!

This interests me a lot.  You might be best to start your own thread on that. My personal belief is you are asking too much from a single charger. The range of amperage alone would require several units let alone chemistries. I don't worry too much about it for large batteries because most of my inverters have a range of charging profiles for all the different chemistries.  Stand alone charges are usually for portable batteries. I have two in the garage for lead acid batteries for 10-100 amp hours 6 or 12 volts and an Iota charger with different plug ins for different types of batteries. The iota is a pricey option but great for charging up a clients battery bank with a small portable generator to bring them back to life.
Cheers,  David

Michael Qulek wrote:I have Schneider's Conext SW4024, which I am VERY happy with.  It makes native split-phase 120/240VAC, and has built-in generator charging.  It's a very robust inverter that has powered a cement mixer, 1.6hp air-compressor, and a 7" circular saw, all at the same time.  If you want to mate it with a generator though, you need to get the optional COMBOX, or have a laptop for communicating with the unit's software, to calibrate the generator horsepower to the inverter.

Didn't think of it but the SW is a great inverter. Won't communicate with lithium though they might add it at some point.

Eric Hanson wrote:I don’t know why I didn’t see this thread long ago and what I am about to say might fall into the day-late-dollar-short category.

Has anyone here, including the OP, considered *Building* a battery?  By this I mean acquiring individual battery cells (LiFePo4 being the most common, but other chemistries are available), adding a BMS and wiring them together inside some housing.

I have been involved in building a battery box based on LiFePo4 battery cells for about a year.  I would have had my project finished long ago, but sourcing a supply of my specific sized and dimension battery took some time.

The relevant point here is that if a custom BMS is installed, then the upper and lower charge limits can be adjusted and therefore still take advantage of solar panels working at low and especially high output.

There is definitely a skill set required to build one of these devices, but jumping in and building it helps develop that skill set.  My current project is based on 105 AH cells housed in an ammo box.  Now that I have the batteries I hope to accelerate my project.

My conclusion statement is that LiFePo4 batteries might still be the appropriate chemistry, but it will require building in an appropriate Battery Monitor.  If you are looking for pointers, I can certainly point you towards some possible solutions.

Eric

Eric, I think the OP's issue ended up being the older style charge controllers he was using. My view is If you cannot control the voltage accurately coming out of the charge controller you will have issues with lithium batteries regardless of the BMS you use.  Re reading it all I think a work around could be a small lead acid bank to act as the wind or hydro buffer and a relay controlled dc to dc charger to look after charging a lithium bank. He could even voltage up that way. He would loose some efficiency of course but avoid a complete rebuild of the system.

Tom Moran wrote:Hi. I’m looking to upgrade a 20+ year old solar system. Currently running a magnum pae 4024 capable of charging batteries from a generator cranking 220 volts. I’d like to set up a separate system but can’t bring myself to buy another magnum unit for 2400.
Anyone have recommendations for a similar, less expensive inverter?

The magnum is most likely being discontinued as they were recently shut down by their parent company. I know as of last week tech support is not answering their calls. though that could be the holidays. I have had one since 2007 and love it but i would not reinstall another one today as it does not do communication with lithium batteries so wont pass an electrical inspection in places that call for 2 way communications between the battery and the inverter. If you were looking for a cheaper all in one the EG4 from lux power has all its certifications, is of similar capabilities and is pretty affordable.
Cheers,

Steven Murpy wrote:Hello, guys. I wanted to say about  LiFe PO4 batteries. As far as I know, this type of battery is now widely used in portable power stations like EcoFlow. I am not a fan of those battery types, but I am just thinking of a practical point. Moreover, LiFe PO4 batteries have more charging cycles it's up to 3500

HI Steven, Welcome to Permies. Lithium has taken over most straight forward solar applications but lead still has a lot of use scenarios. In this case the Original Poster was talking about lithium for his micro hydro. Micro hydro and wind installs on lithium would require a complete rebuild of the charge controllers for those applications. I think the consensus was that it was not worth the effort in this case.
Cheers,  David

bogdan smith wrote:Some say that solar panels are located on the roof of the house (in most cases this is the highest point of the household, therefore it attracts a potential discharge). Connecting this most dangerous (potentially) point to the common grounding - connecting all consumers of the household to objects of increased danger. Others say that one grounding circuit is needed so that there is no potential difference

That is old thinking based on the lower voltage charge controllers. You simply cannot connect the negative side of a high voltage array to ground they will not work. You do run the risk of conducting a lightning strike down to the ground cable with a metal assembly on the roof. The alternative is a lightning strike happens, it does not have a clear path to ground and it finds the best one it can; usually through the positive AND negative solar feed and shorts out everything it comes in contact with. I would suggest you install a whole home surge protector if you install a roof mounted array if lightning is an issue but really all homes should have them.

Roger Dodger wrote:Good day everyone! I am inquiring as to anyone’s input/experience with AIMS 48V inverters. If you have any knowledge please let me know what your thoughts. Thank you

The Aims is a decent off grid inverter but they are rebadged chinese inverters at their core.  As mentioned lots of similar type of units out there. The one pictured would be a transformer based unit and as mentioned the solenoids that do the transfers between grid or generator and charging batteries are the weak points. My Magnum MS is 18 years old and still going strong as a daily user but I rarely see an aims more than 5-7 years old.  I see them more as a portable/ RV/minimalist/starter kind of unit as they simply don't have the certifications or durability I look for in systems I design. If it works for you that is fine. If you are trying to use it in a 120 volt setup in north america you simply have to balance your loads between line one and line 2 so that you put similar strain on each leg. You would have to run it into a 240 volt panel though to seperate out the legs. Really you would get more response if this topic was in the energy section not the homesteading. Something for Admin there.
Cheers,  David

bogdan smith wrote:Thank you, do I understand correctly that I can connect the ground wire from the panels to the general ground for the house, but for some reason they recommend making a separate ground for the panels or not making a ground for such a small station

NO that is not quite correct. The new high voltage solar charge controller built into your unit do not have a "ground" really. They have a negative input and a positive input which go into the pos and neg ports of the unit. On older lower voltage arrays the "negative" feed and the system negative were the same, not on these ones.  The only ground is from the solar array metal components to your house ground wire. Some places refer to this as "Earthing" or " bonding"  if that helps.  The only grounding you do to the inverters and feed from the solar array is connect the grounding terminal of the inverter to your home grounding wire preferably the large main one leading into the house.

bogdan smith wrote:10 solar panels
https://static.longi.com/Hi_MO_6_Explorer_LR_5_54_HTH_415_430_M_V03_DG_cd1618eade.pdf

Assuming you are using the 430 watt panels then you would be limited to strings of 8 panels each, 16 panels total. The math works out this way

39.13Vx1.25 safety margin X 8 panel string = 391.3 volts open circuit voltage which is within the inverter parameters
32.85volt working voltage X 8 = 262 Volts which is well within the middle range of the voltage curve
430watts per panel X 8 panels per string= 3440 watts per string X 2 strings=  6880 watts total . The inverter is rated at 6500 watts total but with heating, shading, efficiency losses you wont hit that.
If it was my system that is what I would install. You could do a single 9 panel string if you were going to install less panels but i would not install two strings of 9 panels each because if the sun hits them just right the cooling fan on the inverter will sound like a screeching cat and probably live a shortened life as you will be pushing the equipment to its absolute limit; never a good thing.

As to grounding the high voltage charge controllers in the inverter requires no grounding of the panels as the PV  circuit is not grounded. That is why its important to install an array disconnect before the inverter in case you need to work on the system. For grounding the array you usually run a ground wire to each rail on the roof down to your house ground wire and you ground the inverter ground terminal to the house ground as well.
Cheers,  David

bogdan smith wrote:

David Baillie wrote:Based on the posted specs of the inverter I would say you go for the strings of 10 Panels. With these lower end all in one inverters they often have a "turn on" voltage for the charge controller higher then the low voltage cut out for the charge controller. So it says it can go down to 90 volts on the solar string but really needs 120-140 volts just to Wake up. If you were to go with 3 strings of 6 you would risk having them not turn on until they are in direct sun with any shading shutting down the string. I would say with your setup a string of 10 would be your best bet. You will have to play with the arrangement in terms of shading but you might end up with the east one producing all day despite the chimney and the west one loosing power in the afternoon due to the roof shading. That is a better option then trying to balance the two strings so they are equally mediocre.  Without doing a full workup of your site that is what i would recommend. You will have to watch out for high voltage in the string. On cold days when the sun first hits the panels the voltage they produce spikes and can exceed the high limit of the charge controller. The newer all in one charge controllers usually just overload and refuse it but some of the older ones burned out and died.  We usually design max string voltage to 1.25x the VOC of the solar panel x # of panels. That value should be bellow your max voltage of the string. Of course time of year, angle to sun, gauge of wire, length of wire from panels to charge controller all play a role.  
I am attaching a modified picture showing how I would do the strings. you will have to figure out the best wire path for each string and I killed three panels to give you 20 total. Based on experience the three closest to the intersecting roofs will have the biggest loss due to shading and snow.  In terms of safety replace the inverter wire when you can with a 0 or 00 gauge wire, I put a fusible link in the positive wire near the positive terminal for safety. Usually the breakers rated CE that can be mounted on a din rail even of chinese manufacture I find work well enough. I do not like the black square screwed on ones with the resetable temp overload as they are usually low voltage marine gear and unreliable. The din rail mounted fuse holders you showed are good. Make sure they are rated for the voltage you will be using. I wish you well as winter rolls in.
Cheers,  David Baillie

. If I understand correctly, it is necessary to arrange 10 panels in 2 rows, which is indicated by fractional numbers in red and yellow?

Yes, the order will depend on you but you connect the panels positive to negative so there is only one positive and one negative per string. Looking it over I would order them differently than I did to minimize the return wire length. String 1 in red string two in yellow/orange. String one will be your main producer string two will fade away as the roof shades it.  Here we install a fancy electronic panel shut down system if its on a roof. If your inverter only has one solar input port you will need to combine the strings somehow. Usually you install a combiner with fuses in a weather proof box somewhere reachable but not easily reachable. I usually install the box at the 2 metre range off the ground. Understand all this is theoretical until you have your specification sheet for the solar panels themselves. The sheet will list working voltage of each panel and open circuit voltage of each. With that you calculate your string length. It might be better to go with a 9 panel string once you factor in 1.25 safety margin.
If it ends up being a 9 panel string here are two  possible alternates. I think the second one makes better use of wire but might have more shading... Its hard to fine tune this stuff as there are some non describable elements to how you wire a string for balance.
Cheers,  David