Battery Brands that pre-balance and match cells?

[mberding]

Are there any battery brands (besides Battleborn) that match capacity and pre-balance the cells before they ship out the batteries? I'm looking for a quality battery and Li-Time and SOK appear to not do this.

At this point, I'm looking for a simple 12v, 100ah battery, with low-temp protection.

 

[sunshine_eggo]

Not for < BB prices. The issue is with even if it was done at the factory, it must be discharged to about 30% SoC for shipping due to hazmat regs. Over the course of 30+ days, even a perfectly top balanced battery may lose its top balance while in transit, on a shelf or en route to the customer. I've seen top balances get lost simply by sitting for a week or two.

Essentially, a manufacturer is likely to invest a lot of time and cost into top balancing a battery only to have it lost by the time it gets to the customer. Why bother?

A little blurb from the SOK support guru:

Recommended new rack battery charging?

I've got a 2-unit Aolithium rack battery set coming soon, and I'm reading up on charging. Right now, I have a Victron 150/35, and was planning on using solar to charge. I noticed that most people seem to have a dedicated charger for getting their batteries initially charged up. Is solar still a...

diysolarforum.com

 

[JeromeS13]

I do not see an issue. Use the battery as intended (maybe you'll be missing out a few AH to begin with). Over time, it'll balance out.

 

[RCinFLA]

Balance of a new battery is dependent on how long of time between when battery was manufactured and when you receive it. This may be months or more sitting on shelf after being shipped across the Pacific ocean in a hot freight container.

The time between will be subjected to cell self-discharge which may have slightly different rates of cell leakage current, cumulating to unbalancing cells.

Best to assume a new battery will not be fully balanced and give a full charge of sufficient absorb voltage time for BMS to balance cells.

 

[sunshine_eggo]

This is why he's asking:

Li-Time over-voltage cutoff at 13.9 volts

I purchased two Li-Time 100ah "Trolling Motor" batteries. I noticed when charging them with a regular AC to DC shore power charger that they'd be putting in power at around 30 amps until they got to 13.9 volts. Then the amperage would instantly drop to zero and the voltage would read 14.4 (the...

diysolarforum.com

 

[sunshine_eggo]

@mberding

You might want to read through this:

3 year Battle Born Capacity issue

Looks like i have a problem with my Battle Born batteries. After 3 years having 2 (BB10012) in parallel in my RV, i started to expand my solar on the roof and do a capacity test on my 2 Battle Born batteries. I was pretty shocked to find one was down to 52.4 amps (653wh) and the other one at 87...

diysolarforum.com

Battleborn isn't immune from imbalance issues - this poster lost almost 50% of their capacity in one battery because their charger never took the battery up to the balancing voltage.

Recovered to >90% after holding to 14.2V+ for about a week.

 

[Alkaline]

Active balancer can help, SFK has some with it but not in the 100AH range.
I know people with the SOK + active balancer and are very pleased. They are just leaving it plugged on, check cruiser forums

 

[mberding]

Best to assume a new battery will not be fully balanced and give a full charge of sufficient absorb voltage time for BMS to balance cells.

I just figured these things were done ahead of time.

In your opinion: How long should it take to balance the cells (via BMS) in a 100ah 12v pack? (And I'm working blind here because the the LiTime BMS doesn't have bluetooth, so I can't see what's going on.)

 

[RCinFLA]

I just figured these things were done ahead of time.

In your opinion: How long should it take to balance the cells (via BMS) in a 100ah 12v pack? (And I'm working blind here because the the LiTime BMS doesn't have bluetooth, so I can't see what's going on.)

That depends on how out of balance the battery is.

Balancing dump current is likely around 50 mA in 100AH self contained battery BMS.

You will have overvoltage cell shutdowns of BMS when attempting a full charge at less than 1% misbalancing.

1% of 100AH is 1 AH to balance with 50 mA of balancing dump current. 1AH / 0.050A balancing dump takes 20 hours at absorb level charge to correct.