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New Battery Build -- did I ruin the cells

IDMT

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I purchased 4 304AH Docan power cells -- and started to top balance them -- I should have read the PDF file here first - BUT ... so now I'm here asking for help -- Please be nice -- I know I should have asked firdt

I'm using a Lonwei Power Supply - I have it set at 3.55 v and it has been running since last Monday (8 days) and it's still at 2.56 amps -- it has never been over 3,5 amps

I'm trying to get this battery built, charged and installed before a planned trip on 9 March. i read - i read in the PDF I could do a quick near charge by doing the build and set the BMS to 3.6 v and charge with the Trailer converter -- ( I Upgraded my trtailer to WFCO 8955 Auto detect ) I have a Daly BMS with low temp sensor )

Now my question -- Can I change my plan and finish the build - set the BMS cell voltage to 3.6 v and set the Low temp to 5c --and install in the camper and chargr with the converter ?? the only problem - I'm in Colorao and for the next week or so the evening temp is going to be under 32 defg F -- I would turn the converter on only during the day and shut off in the evening -- would this damage the cells???

Any advice would be geatly appreciated -- abd again please be nice --

Alex Z
 
Throw the pack together complete, charge with an AGM profile from an automotive battery charger. When it stops taking charge (mine took about 14 hours with a 25a charger on 280ah cells) then tear the pack apart and top balance from there (mine took about 7 hours on the same pack, 10a @ 3.65v) and it should be ready to go before you leave.

While you've got your pack loose on the initial charge, that's a good time to stick your temp probe in a glass of ice water and test that low temp protection.
 
Keep in mind the ambient air temp isnt necessarily what the internals of the battery would be... For example if temps were below 32 degrees consistently for a few days the battery migh stay below freezing temp wise for a bit longer even after the temp comes up.. The same works in reverse. I chose to balanace my new pack in the house for this reason
 
Throw the pack together complete, charge with an AGM profile from an automotive battery charger. When it stops taking charge (mine took about 14 hours with a 25a charger on 280ah cells) then tear the pack apart and top balance from there (mine took about 7 hours on the same pack, 10a @ 3.65v) and it should be ready to go before you leave.

While you've got your pack loose on the initial charge, that's a good time to stick your temp probe in a glass of ice water and test that low temp protection.
OK i put the pack together -- I have a Daly brand BMS - put a charger to it and in about 2 hrs -- it shut down -- It now says the pack is 100% charged. I have it on a 304 ah 12v pack. The individual cell volts are 1- 3.324 , 2- 3.344 , 3- 3.350 , 4- 3.432. I gave tried to turn on The balance switch but it will not turn on . I did set the top cell value to 3.6v and the low cel to 2.5 v

And I did check the low temp and it does shut off the charge at 5deg C

What did i do wrong???

1677108711499.jpeg
 
OK i put the pack together -- I have a Daly brand BMS - put a charger to it and in about 2 hrs -- it shut down -- It now says the pack is 100% charged. I have it on a 304 ah 12v pack. The individual cell volts are 1- 3.324 , 2- 3.344 , 3- 3.350 , 4- 3.432. I gave tried to turn on The balance switch but it will not turn on . I did set the top cell value to 3.6v and the low cel to 2.5 v

And I did check the low temp and it does shut off the charge at 5deg C

What did i do wrong???

View attachment 136241
You have done nothing wrong. Your BMS did its job and likely shut down charging when Cell # 4 hit 3.6v. You just need to follow rednectek's original suggestion and put the cells back in parallel and finish the top balance.

Be very carful when you connect them (safety glasses and gloves) as cell #4 has a much high voltage than the others. There could be quite a lot of current flow and perhaps a spark.

Follow the top balance instructions on this forum EXACTLY. For eg. be sure to set the voltage on your power supply BEFORE you hook it up to your battery.
 
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Yup! You're most of the way there. Doing the initial charge as a complete battery the first time just saves you a buttload of time and gets you close.

Now throw the cells in parallel on the DC supply and finish the top balance.

Once your top balance draw drops to 0, turn it off and let it sit a couple hours, then do it again. It helped me get a very 0.02mv difference doing the 2nd pass.
 
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An update -- I want to thank you all for the help -- well it took a little time - but seems I did the final and now ready to install in camper -- just the one problem i have now is the Blutooth module keeps shutting off the app battery charged.jpg
 
Up the sleep time in settings to get BT to stay on. I think it's something like 65355S.
 
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