Are you saying once I get down to .006 difference, bump up the charging voltage 1/10?
Should my battery go into over voltage protection eevery time in charges up?
- Thread starter slayer666
- Start date
Koyaanisqatsi
Electron addict
Yep, incrementing the voltage as the cells become more balanced encourages more balancing and results in higher pack capacity. Imbalanced cells reduce pack capacity because the lowest cell voltage determines when you can't drain the pack any further without damaging something, even if the rest of the cells have plenty of capacity (seen as voltage) left.
outboard1196
Solar Addict
Stop increasing voltage when the cell diff gets to around .06v
Yes voltage will converge in middle charge range. Increase voltage to 13.60 and let it balance.
Take a look tomorrow and if all is good go up to 13.70
Check and do same each day until balanced.
OK to post an afternoon screenshot each day for guidance.
In all your pics, there is no current flowing so it's very hard to tell what all the cells are doing and how long they have sat in that state, other than Cell 1 (C1) is extremely out of balance and in an extremely high state of overcharge > 3.7V.
Start at the highest SOC that let's you put a constant 5A charge into the pack. When C 1 is at 3.600V, take a screen shot and post so we can see the other C's V's.
I suspect you are too out of balance to try and use default BMS settings as it is harming your C1 each time going over 3.65 possible low current at length of time.
Is it okay to use the battery while I do this? I'm just curious. I don't really need it cuz it's just in my camper. I was just wondering for the learning aspect.
Yes in use is fine. Although when the battery is partially discharged the cell voltages will converge and balancing may stop until the next charging cycle.
Actually in normal use the balancing may only function for 20 to 60 minutes per day. This is fine to maintain the balance. The higher constant voltage is there just to speed up the process.
Actually in normal use the balancing may only function for 20 to 60 minutes per day. This is fine to maintain the balance. The higher constant voltage is there just to speed up the process.
You can prob bump it .2V at a time now.
Can you post the parameters page?
You got it into balance territory pretty fast and its showing balancing at 3.386V and 3.391V.
We want to make sure balancing start V is not set too low.
Looking good. Yes bump it up. 13.70 should hold fine today. If tomorrow still looks good it can go to 14.00
By the weekend it should go 14.20 and that is 100% charged and ready for heavy service. Then reset the balance for only during charge with 15mV delta.
By the weekend it should go 14.20 and that is 100% charged and ready for heavy service. Then reset the balance for only during charge with 15mV delta.
Thanks a lot man. I really appreciate your help!
Your start balance V is low, but sometimes starting it low is exactly what you want when a cell proves to be the high SOC, imbalanced one. In your situation, it definitely helped.
Under normal conditions, 3.410V with a .015V differential is a good setting to catch early drifters as long as the connections are good.
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Are you saying to bump that up from 3.35 to 3.41? If so, do you mean right now or later?
That is dead nuts on perfect.
This really says something for those that insist on only balancing at the very top or the balance will be lost.
Yes the voltage to start balance can be increased to 3.40 3.41 is fine.
outboard1196
Solar Addict
Change it now ,.
Looks good, go to 14.2v tomorrow ( or today if you have time)
Thanks a lot you guys. Between you and that German who lives in Australia who told me to turn the charging balancing off and just have it at static balance, everything seems to be doing really well! I already bumped it up to 14.2 and that made it kick back into balancing mode which it did not do at 14. That would be 3.55 Volts for each cell. Seems pretty good to me. That German guy I was talking about says it's what he sets his at. 3.55 or 14.2 volts on all four cells, I mean. That's what the German guy sets his at..
99% of the time 3.35V vs >3.40V will mean little since you also have to realize a .015V differential before balancing will actually start and you'll never see that unless cells are truly imbalanced.
The 1% exception is this... with variables of:
higher charge rates, possible temp gradient, actual balance lead connection point / continuity, you could see a .015V delta in the 3.375V range that would not correspond to cell imbalance.
The only harm is that the resistor gets warmer, earlier falsely. It's really inconsequential since the rate you charge at vs the rate the balancing resistor acts act is at least a couple orders of magnitude (100x) difference and will self correct once you hit >3.4V anyhow.
Going into the 3.400V area, the current will naturally taper down and give a more accurate reading of true cell V, but also gives less time to balance before potential cell oVp.
time2roll? I see you gave me a thumbs up about my last question. It's 5:00 right now and probably only 3 hours of shitty Sun left. You think I should cycle something small in my camper all night long or what should I do? I can leave the TV on it takes about 60 watts. Or you tell me how many watts you think I should leave on it. I usually turn something on like my max air vent fan which takes about 30 Watts all night long to cycle the battery. Tell me what you think please.
I've testes a bunch of JBDs over the years and their V accuracy is very good. So based on that, I would say your battery is more than good enough to put in use already. their shunt is not quite as good though, so if you have a way to verify current, do for peace of mind.
outboard1196
Solar Addict
Use it as normal, looks like a healthy battery.
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