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Ok - so i did a standalone charge cycle from around 30% up to 100% several things happened: 1. on charge start - Battery A had an orange charge state indicator. Q - does anyone know what this means - web search did not find anything relevant? then it changed to blue after a few min. Battery B...

UPDATE - i changed the settings for the Multiplus down from 100A charging to 40A charging - and the batteries like it much much better. I'm going to wait on the active load balancers until I use the system a while. Thanks everyone.

I got the active balancers from china. check! Here are my suggested next steps: 1. reconfigure the multi-plus to charge less aggressively from shore power - maybe 20A? 2. reset the BMV-712 to 100% once the batteries are fully charged. The BMV is the most accurate indicator of SOC for the...

Btw - here is my install - to tell the truth - if i pull these batteries to top balance them again - i’m likely to just order 2 x SOK 206ah and just call it good. It was fun to build these - and I’m pretty sure i did this by the book - but i want something that is not going to let me down when...

Thank you! Interesting - so I also have a Victron BMV - battery monitor - I was thinking that the BMV indication was less accurate than the BMS - but maybe I'm wrong? BTW - full charge cycles are very low - like 5-7 cycles - these batteries are basically brand new.

Good point - to my knowledge - the answer is NO. Max I can see from my screenshots is 3.616. Maybe the 3.97 is from another poster? But coming back to the max capacity for the battery - has anyone seen the BMS (overkill solar) "reset" capacity to a lower number - by itself? thanks, C

I know - that's what's worrying me. As well - now the BMS is showing 100% at 243Ah - instead of the 271Ah it used to show. This was part of my concern about toasting the batteries. Why did the BMS show this "new" and diminished max capacity - when I did not change any BMS settings?

it this what I'm looking for? I'm just concerned this is too small?

Interesting. I was hoping that these battery modules would be pretty much like an SOK or similar - no need to disassemble when storing. I posted the settings at the start of this thread - cell overvoltage trigger setting is 3650mV and cell full voltage is 3400mV. I think these are the right...

So I read some more on this and looked at some videos. My batteries are tucked in to a bench in the van and not easy to get at for top balancing in situ. Here is what I think I need to do (please correct me): 1. remove them from van 2. take them mostly apart (by removing the BMS) 3...

Is this the one? Heltec 4S 5S 6S 5A Capacitor Active Equalizer Balancer Lifepo4 Lithium Lipo/Titanate LTO for Battery Car Audio Group Balancer https://www.amazon.com/dp/B08JCL4G2X/ref=cm_sw_r_cp_api_glt_i_MYN96KZTSF182BH2DJ72

I will try to buy a couple of those heltec 4s. Thank you!

Hi - i wanted to exercise the battery - so i left the inverter on - it slowly discharged the battery over a couple days. I totally agree the charging is too aggressive- i will reduce the charge settings. In storage - i fully disconnected the battery. Thank you!!

I figured out the top balance in situ thing.

Thanks - What are you using for busbars and what active balancer are you using - i went looking and found like 100 different active balancers for 4s lifepo batteries!

This was super helpful - i’ve seen this exact problem! I guess I need to 1) reduce my charge current; 2) get a JK active balancer; 3) re-top balance the pack (with the cells assembled) - i will search for a guide on this. Thanks!

Thank you - the 2 batteries seem to charge differently- which i was ascribing to slightly different cable lengths from the charger? Also - can i top balance these in situ? Or do i need to disassemble the pack/ remove the bms? Thanks!

Hi - So last spring I built 2 x 12V batteries each with 4s 280Ah lifepo cells and 120A overkill solar BMS. I top balanced the cells and hooked everything up and it seemed to work great. Then I installed the pack in my van and discharged to around 50% - since it was going to be a few months...

Thanks!

Hi - Does anyone know if these batteries be mounted with the faceplate facing upward? This would be as if the server rack was lying down. I hope that makes sense. Thanks, C

Ok - battery build is together and running. Still tweaking the samlex settings in bench mode. I will likely switch to Victron multi for final install. Currently cycling the batteries a few times with a 1700+ watt electric space heater/fan. Thanks for all the help here, Clyde

Thank you. That’s super, super helpful. Also very clear. (Not that I won’t have questions.) On BMS - I have the default overkill settings. Only thing I set was the 280Ah capacity. Agree a totally get BMS is last line of defense. One question: is the SOC showing from the BMS app reliable...

Wow both of those were fantastic. Thank you!!!

Ok - for clarity here (since I'm just putting the pieces together). Controlling systems: 1. BMS settings (first line of defense for batteries) 2. Inverter/Charger settings (second line of defense for batteries) Charge settings: (from Will Prowse sticky post) "12V 4S LiFePO4 Battery w/ BMS...

That is super helpful - I will try this. I will charge it back up and then discharge again with the BMV 712 going. See what it says. Thanks, Clyde -

I read somewhere that these batteries should not regularly go below 20% SOC. I have overkill solar 120A BMS. I discharged for the first time after top balance and I saw 0% battery Indication on BMS app. So question is: - Do I need to set this? - Where do I set this? Similarly - looks like...

Here is the option 2 - 2 stage charge profile. Looks like it effectively shuts off at 14.x v - i will confirm with samlex on monday.

That is super cool. Thanks for posting.

Update! I top balanced both banks. Then waited a few weeks for build. Here is the test assembly. Went with 1/2” baltic birch and dominos. (For final - i will glue 3 sides and screw 4th side with small grk’s). Bolt the whole thing down with 1/8 aluminum angle to 80/20 - which is bolted to...

Well now i have 2x280 + 1x 200 - i may just do that. As you say - bms will cut off the smaller bank when it’s done - the others will continue to run. Thx! C

Thank you everyone!!! It worked!!!! I got to 3.61v - (was a little worried about going to 3.65v). The voltage really does move superfast once you get to 3.4v. Wow. working on the second set of batteries now. Just completing the initial charge.

ok - so they seem to be charging now - one measurement at the terminals is showing 3.4V now - which is up from 3.37 just about 2 hours ago. I realize that the trend is going to slow as it approaches 3.6v. I will just keep at it. Thanks! C

no - they seem fine - not warm. Maybe they did not get as charged in series as I thought they did. Nonetheless - they seem to be charging now. I'm going to leave them charging all day and report back.

ok - so maybe I have a problem? I have been trying to top balance for the last couple of days. Pausing when away from the house or asleep - since I wanted to monitor this closely. But I am not seeing these cells budge from 3.374V. I know this could take approx. 17 hours - but I have had...

thanks - any comments on the wiring size from the BMS to the inverter? did you use something like 2/0 the entire way? BTW - if I remove the SB connectors - I can and probably will just go 2/0 the entire way. That way if one battery goes down - the whole thing works with 2/0 end-to-end.