Did you change the bal start V diff to a lower setting than default .03V?
Did any cell go over 3.650V?
What’s charger set to pack V?
Why are you >56V pack lvl?
New batts - big cell deviation
- Thread starter Muskoka
- Start date
Did any cell go over 3.650V?
What’s charger set to pack V?
Why are you >56V pack lvl?
Muskoka
New Member
The available parameters in the bms's in these batteries seem to change on their own, very strange? Anyways, the available range now for Bal Start Vol Diff(V) is 0.005~0.02v, I have it set to 0.01v.
No cells went over 3.65v, no cell OVP. I don't recall seeing any cell get to 3.6v the whole charge cycle, with bulk/absorb set to 56.0v, 3.58'ish was the highest. For the bulk of the charge cycle they were at 2C charge rate, fluctuating between 18-25a most of the time. There was a bit of light cloud coming and going. Both batts are in service.
At this point I have bulk/absorb set to 56.0v. Both batts crept slightly above that, settling somewhere between 56.05v to 56.1v during absorb. No cells hit 3.6v. System went to float fine, within maybe 1.5 hrs cell deviation for both batts was around 0.005 to 0.011v, they jump around.
I'm going to bump the pack voltage up some, maybe 56.2v today and see what happens. The Midnite Classic offers 0.1v increments for absorb voltage, unfortunatly the rebranded SRNE controller only has 0.4v increments for absorb, can't fine tune like the Midnite.
Here's a screenshot of the current Bal Start Vol Diff(V). A few days ago the range for this parameter was 0.025~0.04v. No idea why it's changing on it's own.
No cells went over 3.65v, no cell OVP. I don't recall seeing any cell get to 3.6v the whole charge cycle, with bulk/absorb set to 56.0v, 3.58'ish was the highest. For the bulk of the charge cycle they were at 2C charge rate, fluctuating between 18-25a most of the time. There was a bit of light cloud coming and going. Both batts are in service.
At this point I have bulk/absorb set to 56.0v. Both batts crept slightly above that, settling somewhere between 56.05v to 56.1v during absorb. No cells hit 3.6v. System went to float fine, within maybe 1.5 hrs cell deviation for both batts was around 0.005 to 0.011v, they jump around.
I'm going to bump the pack voltage up some, maybe 56.2v today and see what happens. The Midnite Classic offers 0.1v increments for absorb voltage, unfortunatly the rebranded SRNE controller only has 0.4v increments for absorb, can't fine tune like the Midnite.
Here's a screenshot of the current Bal Start Vol Diff(V). A few days ago the range for this parameter was 0.025~0.04v. No idea why it's changing on it's own.
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Muskoka
New Member
Here's where the batts were right before the transition to float today. Absorb was set to 56.2v, the batts measured very close to 56.2v on my various meters, the bms's display a bit higher voltage. They would have tripped OVP a week ago at this voltage I think, they didn't today. This is the highest the cell voltages got, the max deviation as well. The system went to float seconds after this and all values started to decrease. Still on the fence about returning them, I do have the return labels.
MisterSandals
Participation Medalist
Wait wut? 2C of 200Ah of batteries is 400A charging!
Muskoka
New Member
My bank is 480ah total. I have another (4) 12v x 280 as well. And, it should say .2c, my bad.
MisterSandals
Participation Medalist
Can you share how much you paid for these? It would be great to know the brand too but you're not sharing much with the collective.
Muskoka
New Member
I don't want to name them until I've either decided to keep them, or return them. I just don't feel like saying anything until the decision has been made.
Cost was $1966.18 Cdn shipped to my door, (2) 48v 100ah 200a BMS, BT obviously, Low-temp protection, yet to be tested. Claim to have overcurrent protection. That was a sale price. Most 48v 100ah 200a BMS with BT and Low Temp are $1000 and up on Amazon Canada.
Cost was $1966.18 Cdn shipped to my door, (2) 48v 100ah 200a BMS, BT obviously, Low-temp protection, yet to be tested. Claim to have overcurrent protection. That was a sale price. Most 48v 100ah 200a BMS with BT and Low Temp are $1000 and up on Amazon Canada.
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Solar Guppy
Red Cobra Guppy
There is nothing wrong with those voltages, once your over 3.4 the energy storage left is measured in 1/10ths of a percentage. Even as shown, I bet it would pull more than rated Ah capacity. There will always be a low and high cell but its almost unmeasurable in the Ah if at termination everything is as you images show.
I lost track of this thread. Yep you pack is fine.
Personally, if it was my pack, I'd guage the pack V to charge to by limiting max cell V to 3.55V. That might = pack charge to 55.8-56.0V.
It is getting better each day and I'm guessing you are about 200-400mAh off = a few more hours of balance and you shoud be within 20mV diff.
I'd say both packs are keepers!
Personally, if it was my pack, I'd guage the pack V to charge to by limiting max cell V to 3.55V. That might = pack charge to 55.8-56.0V.
It is getting better each day and I'm guessing you are about 200-400mAh off = a few more hours of balance and you shoud be within 20mV diff.
I'd say both packs are keepers!
Muskoka
New Member
Both batteries were returned. Looking at server rack batteries, I can at least get inside the case if needed.
I have a good bank of batteries here that take a proper charge, without having to baby them. If the next purchase is the same as these last ones, and the first ones I purchsed 3 years ago, they'll go back as well. The end user does not have to accept something poorly manufactured, mismatched cells. Three days this week I tried to get those batteries to at least 56.4v, wasn't happening without a runner (multiple) getting close, or tripping cell OVP. I'm not accepting that in a new battery. My other bank takes 56.4v or higher if I choose, and has no problem completing a full charge cycle, no cell OVP. They've taken a good charge since day one.
I have a good bank of batteries here that take a proper charge, without having to baby them. If the next purchase is the same as these last ones, and the first ones I purchsed 3 years ago, they'll go back as well. The end user does not have to accept something poorly manufactured, mismatched cells. Three days this week I tried to get those batteries to at least 56.4v, wasn't happening without a runner (multiple) getting close, or tripping cell OVP. I'm not accepting that in a new battery. My other bank takes 56.4v or higher if I choose, and has no problem completing a full charge cycle, no cell OVP. They've taken a good charge since day one.
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Muskoka
New Member
New server rack batteries arrived a few days ago, Friday actually, within 24hrs of ordering, that was impressive. They both were able to take a much higher voltage first charge, not triggering cell OVP until almost 57.4v, bms shut down charging, and the charger shut off like it should. That's over a full volt higher than those other batteries, that could only get to 56.2/3v before cell OVP. Theses cells are much better matched. Every cell was 3.5v plus when the bms shut down for the runner, where those other batteries had stragglers still at 3.3ish volts, probably 1/3rd of the cells. The cell deviation was just over 100mv for both these new batts, unlike the other batteries that were over 300mv deviation first charge.
Much happier about the future longevity, performance of these batteries. Were they more expensive, yes, money well spent in my mind though. I should have just bought these in the first place to expand my bank capacity. I'd been contemplating buying these for quite a while, but decided to buy cheap(er) instead, as usual, and that's what I got, cheap. Happy I made the switch.
Much happier about the future longevity, performance of these batteries. Were they more expensive, yes, money well spent in my mind though. I should have just bought these in the first place to expand my bank capacity. I'd been contemplating buying these for quite a while, but decided to buy cheap(er) instead, as usual, and that's what I got, cheap. Happy I made the switch.
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MisterSandals
Participation Medalist
Are you willing to share the battery brand/models now?
Muskoka
New Member
HumsiENK, 48v 100ah. They were very nice to deal with, prompt. Just wanted some information, data. They received the batteries back a few days ago, refund has been issued.
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