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LG Chem 2KWH 48Volt Power Wall for off grid house

I’d recently bought 48 of these same batteries, and have done pretty much exactly what you’ve described. I’ve broken down 32 of them so far, reconfigured them in parallel and have set up each block of 8 (doing 16s) with it’s own (Daly) BMS in an insulated steel box. It’s funny we should arrive at almost the exact same configuration. In any case, here are some pictures of the work in progress:

1B158C73-E2FB-41EC-B9AF-15227E0B5308.jpeg7C83F623-8FC9-4DD5-8FDF-0BB6D4C64751.jpeg24DCDECB-E585-46A0-B71A-C0B1012D6265.jpeg

The boxes end up weighing about ~1000lbs each, so I’m building them directly on our trailer and will take them off at our building site with our Versahandler, which has pallet forks.
 
Hi Jallum,
That looks awesome!
I actually started working on these on Friday last week, I set out three days to finish 14; big mistake. I ended up extending my trip and managed to finish 7 modules (14S 48V) and switched on the power to the house for the first time yesterday in over a year. The Daly BMS software via Bluetooth is really a nice touch.

All the cells tested out great, very well balanced, one issue I had was corrosion on 6 of these units. It looks as though the water had entered and settled in base of the box as only the base was corroded and the first set of cells, so you cant tell until you open the unit. These cells also tested out perfect on voltage.

Thanks to all the great help from DIY solar members!
 

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That work looks great! Nice job. I'm glad to hear that you were able to get it all up and running.

It does take a while to get through processing them! I managed to get it down to about a half an hour each, by doing batches of 16 in passes: disassemble them all, cleaning, module disassembly, testing and restacking, etc. etc. I could get through a whole stack in an eight hour day. That, and a whole lot of practice. ;)

I found the voltages and internal resistance numbers to be shockingly well-aligned across the cells in each module. That stock BMS seemed to know what it was doing. Almost all of my cells all tested out at ~35-39 mohms, but realigned as a parallel pack, combining resistors works in our favor and dropped that to ~5 mohms for the module. Yay!

I had a little issue with some corrosion as well, but on close inspection, it was just the housings that had seen a little water -- leaving some zinc dust. I cleaned the affected metal with soapy water, left it to dry and don't expect any long term problems as a result.

One thing I discovered is that the temperature sensors that are part of the stock wiring harness (one on each side, pink and black) are just normal 10k NTC thermistors... which can be read by just about anything, and since they fit between the cells so nicely, I decided to keep them and put them back in to use at some point in the future. You can see the wires coming from the center of each pair in my pictures, I think. Anyway, if you haven't thrown the harnesses away yet, they might be worth scavenging to you.

Are you in a climate where you'll have to worry about low temperatures and heating them? Mine will live outdoors (used batteries, and all) in coastal Maine.
 
Hi Jallum,
Yes, I am concerned! The offgrid system is CO, so it gets rather cold in the winter. I have the BMS set for trip at -2DegC and I have placed copious amount of insolation around the battery . For next winter I do need to think how to have this system heated, any thoughts?
 
Two solutions which might be adaptable to your situation:


 
Hi Jallum,
Yes, I am concerned! The offgrid system is CO, so it gets rather cold in the winter. I have the BMS set for trip at -2DegC and I have placed copious amount of insolation around the battery . For next winter I do need to think how to have this system heated, any thoughts?

I’m going to do a try a variation on the suggestions from snoobler. I’ve got a pet project going to communicate with the Daly BMS through the serial port, and I was planning to monitor it’s built-in low-temp and high-temp alarms to run a pair of relays for heaters and fans, among other things. I figure if the BMS isn’t running, then I’m probably not going to be have charging / discharging problems in the first place... other problems sure, but not those. ;)
 
For temperature monitoring I'm thinking of using the Sonoff Temperature sensor (Link below) This allows for wifi monitoring from anywhere, operates on 110V and and can take up to 15amps. I have a similar set up in battery box for my remote gate, and as along as there is 2.4 GHz wifi available it seems to monitor quite well.

Just out of curiosity, what size wiring are you using? I'm using 2AWG for the series connections to each battery module, with the plan of parallel x4 14S batteries to heavy duty bus bars (can just be seen in the stacked battery pic) and from the bus bar to the main breaker (300amp) I'm using 4/0.

 
For temperature monitoring I'm thinking of using the Sonoff Temperature sensor (Link below) This allows for wifi monitoring from anywhere, operates on 110V and and can take up to 15amps. I have a similar set up in battery box for my remote gate, and as along as there is 2.4 GHz wifi available it seems to monitor quite well.

oh! these look neat!

Just out of curiosity, what size wiring are you using? I'm using 2AWG for the series connections to each battery module, with the plan of parallel x4 14S batteries to heavy duty bus bars (can just be seen in the stacked battery pic) and from the bus bar to the main breaker (300amp) I'm using 4/0.

i had short bits of some 2/0 marine grade and a pile of lugs left over from another project that i used for the interconnects. each battery will get its own internal 125a breaker and an Anderson SB175 plug to the outside world, flush mounted through a pre-existing cutout in the back of the jobsite box, so that i can plug/unplug each one. i’m planning on running short (~10-15’) lengths of 1/0 from each battery to the box that has houses the inverter, coming into a pair of 500a busbars for pos and neg, and then a 250a breaker between that and the inverter, using 2/0 for the short hops inside the box. the idea is to get a second inverter that’ll get it’s own breaker, etc.

running at 60v, each of the six batteries will only see ~33a when the inverter is running at continuous 12kw. i should be able to disconnect a few of them at a time without exceeding any limits.
 
For temperature monitoring I'm thinking of using the Sonoff Temperature sensor (Link below) This allows for wifi monitoring from anywhere, operates on 110V and and can take up to 15amps. I have a similar set up in battery box for my remote gate, and as along as there is 2.4 GHz wifi available it seems to monitor quite well.

Just out of curiosity, what size wiring are you using? I'm using 2AWG for the series connections to each battery module, with the plan of parallel x4 14S batteries to heavy duty bus bars (can just be seen in the stacked battery pic) and from the bus bar to the main breaker (300amp) I'm using 4/0.

I’ve got a similar setup that needs float, absorption, and equalization settings. What voltage settings did you end up using in your charger and are they working well?
 
I have mine set up with x2 5KW offgrid Growatt inverters in my vacation home. I initially had them set at 55bulk and 52 float but this didn't give me good results, and one time I had to travel 1k miles to reset the system. I tried to automate as much as possible but I thought a low voltage reset would be automatic on the growatt but it isn't. Next trip I'll be installing a ups and a wifi reset.
Any how, recently I set at these to 50amps charging for each inverter, and increased the bulk voltage to 58V and 56V float. I'm getting so much more out these, I'm still in experiential mode but the previous setting didn't get me much more than 15KW. On what should be a 54KW system, I now belive I'm much closer to the 54KW, but I'll have to wait for my next trip test.
 
I have three of the six batteries online at the moment. Because the house loads are more "gentle" than their previous jobs, the batteries are doing much better than expected.

Things I have learned:
  • When I bought them, they were being sold as ~2.2kwh, per unit. I'm seeing about 2.6kwh per due to the more gentle cycling they're receiving. The three packs are totalling ~62kwh (3x 16S) and I was only expecting ~50kwh.
  • Cold weather hasn't been a problem with the NMC chemistry, at all. I regularly charge/discharge them at -10° to 0°F without issue. The large capacity of the batteries means that the batteries never see more than ~0.12C when charging. (I'm using a gas generator, once a week to charge them @ ~8kw because my solar is not up and running yet.) Bringing the other three online will halve the charging amps each battery sees.
  • My Daly BMS's SoC estimation is junk. Each of the three units will report wildly different values, even with regular synchronisation.

Things I would do differently:
  • I wouldn't use one large, central inverter. I'd use one less battery-cell per box and I'd put a Multiplus II in each. This would make each box a potential standalone unit, and I could save money on interconnection cable by being able to run thosenat 240v AC instead of 60v DC. As a bonus, the waste heat from the inverter would warm the batteries in the winter. The primary downside would be that it'd be a bit more expensive to start.
 
Hi Jallum,
I have all 4 modules up and running now, that's 28 units in x4 14s configuration. I wasn't pushing them hard at all at first, but after a low voltage trip and a 1,000 Mile trip to reset them, I increased the voltage setting from 56V to 58V (4.14V per cell) max and float at 56V. Now they perform a lot better, I'm still not sure of the KW from each unit but they were advertised at 2KW each, which would be 54KW I'm definitely getting 30-35KW which is more than enough at the moment.
It's very encouraging to hear about your temperature use. I keep mine heated above 32F, I use around 800Watts on really cold days (single digits). One day when I get time I will put them through their paces and report back.
 
I have three of the six batteries online at the moment. Because the house loads are more "gentle" than their previous jobs, the batteries are doing much better than expected.

Things I have learned:
  • When I bought them, they were being sold as ~2.2kwh, per unit. I'm seeing about 2.6kwh per due to the more gentle cycling they're receiving. The three packs are totalling ~62kwh (3x 16S) and I was only expecting ~50kwh.
  • Cold weather hasn't been a problem with the NMC chemistry, at all. I regularly charge/discharge them at -10° to 0°F without issue. The large capacity of the batteries means that the batteries never see more than ~0.12C when charging. (I'm using a gas generator, once a week to charge them @ ~8kw because my solar is not up and running yet.) Bringing the other three online will halve the charging amps each battery sees.
  • My Daly BMS's SoC estimation is junk. Each of the three units will report wildly different values, even with regular synchronisation.

Things I would do differently:
  • I wouldn't use one large, central inverter. I'd use one less battery-cell per box and I'd put a Multiplus II in each. This would make each box a potential standalone unit, and I could save money on interconnection cable by being able to run thosenat 240v AC instead of 60v DC. As a bonus, the waste heat from the inverter would warm the batteries in the winter. The primary downside would be that it'd be a bit more expensive to start.
Good to hear. I’m also babying my batteries because my tiny solar array will only send about 22 amps into the battery at peak and I’ve limited my charging from grid to a similar 20A.

I took another look at your battery configuration and noticed the smaller control wires through the middle. Are those for the can bus?
 
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Hi Jallum,
I have all 4 modules up and running now, that's 28 units in x4 14s configuration. I wasn't pushing them hard at all at first, but after a low voltage trip and a 1,000 Mile trip to reset them, I increased the voltage setting from 56V to 58V (4.14V per cell) max and float at 56V. Now they perform a lot better, I'm still not sure of the KW from each unit but they were advertised at 2KW each, which would be 54KW I'm definitely getting 30-35KW which is more than enough at the moment.
It's very encouraging to hear about your temperature use. I keep mine heated above 32F, I use around 800Watts on really cold days (single digits). One day when I get time I will put them through their paces and report back.
1k miles for a reset is brutal. How did you get so low that you tripped on low voltage? No alarms or alerts configured?

I run my system from 48v to 56. No issues thus far. My utility has forced us into TOU rates and I’ve selected the one with the highest peak rates so that I can offset them with my battery and small PV system.



Nice rack

:p

Here is my setup as I filled up the front:

1643175896107.jpeg
 
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