Parallel more than 8 batteries together?

[2500hd]

Hi,
Can I parallel more than 8 of the big battery badger batteries?
I am running a full outback solar setup.

48V BADGER 2 - NMC - 48Ah - 2.1kWh - BigBattery.com

This is one of our best priced 48V golf cart batteries! Capable of a 2C Discharge rate - this battery is the most cost-effective solution offered in our 48V Class.

bigbattery.com

They said their engineers told them not to do it. I currently have 6 of the batteries and I would like to add more capacity with the same type of battery.

Is there a technical reason not to do it? All the batteries had BMS's installed in each battery.
Thanks for the assistance.

 

[gotbeans]

There's no actual limit on paralleling batteries, batteries can't even tell if they are paralleled with other batteries either unless they have some computing circuitry to tell.
1 battery is enough to blow up all the electronics internally & in the inverters, thus fuses & breakers exist.
... not sure what their actual excuse would be? curious to know why they say not to

more batteries in parallel the less C rating for discharge / charge so it's even better imo

 

[sunshine_eggo]

The issue with paralleling batteries is balancing the current shared between them. It's possible that imbalanced current draw/charge could exceed the BMS of one or more batteries. In a package like that where you're locked into an Anderson connector, it would seem to be less flexible.

If you can attach each battery to a common bus bar with equal length cables, you can likely minimize issues.

Link #6 in my signature.

 

[Q-Dog]

Hi,
Can I parallel more than 8 of the big battery badger batteries?
I am running a full outback solar setup.

48V BADGER 2 - NMC - 48Ah - 2.1kWh - BigBattery.com

This is one of our best priced 48V golf cart batteries! Capable of a 2C Discharge rate - this battery is the most cost-effective solution offered in our 48V Class.

bigbattery.com

They said their engineers told them not to do it. I currently have 6 of the batteries and I would like to add more capacity with the same type of battery.

Is there a technical reason not to do it? All the batteries had BMS's installed in each battery.
Thanks for the assistance.

Ask them why?

 

[Solar Guppy]

Just an FYI, this are NMC 12S lithium ion ( the type you should not use for storage ) , typically they would be 14S to be typical voltage window for 48V battery.

There are some on FleaBay for ~220 each , still being Sold at BigBattery and the other names they use for 3X more

 

[2500hd]

Ask them why?

They said their engineers said not to. I asked for some clarification and they didn't respond

 

[2500hd]

Just an FYI, this are NMC 12S lithium ion ( the type you should not use for storage ) , typically they would be 14S to be typical voltage window for 48V battery.

There are some on FleaBay for ~220 each , still being Sold at BigBattery and the other names they use for 3X more

I didn't know that should not be used for storage. They are for an off grid cabin.
The batteries have been working fine for 4 years so far.
Thanks

 

[2500hd]

The issue with paralleling batteries is balancing the current shared between them. It's possible that imbalanced current draw/charge could exceed the BMS of one or more batteries. In a package like that where you're locked into an Anderson connector, it would seem to be less flexible.

If you can attach each battery to a common bus bar with equal length cables, you can likely minimize issues.

Link #6 in my signature.

Currently the 6 batteries have the same length cables going to a copper bus bar.
Thanks

 

[Q-Dog]

They said their engineers said not to. I asked for some clarification and they didn't respond

I wouldn't buy from them if they can't answer my questions. Either there is a reason or there isn't.

 

[sunshine_eggo]

Currently the 6 batteries have the same length cables going to a copper bus bar.
Thanks

Adding two more should produce no additional imbalance.

Again, the concern by manufacturers is they don't want to deal with warrantying bad batteries due to poor installations. It's rare you'll see any battery manufacturer recommend more than 3-4 parallel batteries/strings. It's not important that the flunkies at tech support know, it's important that YOU know why. The Victron document explains it very well, and I'm certain that you have a complete understanding of the issue if you've read that section.

 

[2500hd]

I wouldn't buy from them if they can't answer my questions. Either there is a reason or there isn't.

I agree, but I have 6 and just want to increase the capacity.

 

[2500hd]

Adding two more should produce no additional imbalance.

Again, the concern by manufacturers is they don't want to deal with warrantying bad batteries due to poor installations. It's rare you'll see any battery manufacturer recommend more than 3-4 parallel batteries/strings. It's not important that the flunkies at tech support know, it's important that YOU know why. The Victron document explains it very well, and I'm certain that you have a complete understanding of the issue if you've read that section.

Thanks, I will read the document you posted.
Regards

 

[sunshine_eggo]

Thanks, I will read the document you posted.
Regards

section 3.3

 

[Q-Dog]

I agree, but I have 6 and just want to increase the capacity.

Then do it. Just understand that if one fails and you tell them you have more than they recommend, they could deny your claim because they said you can't. It doesn't really mattery why.

 

[50ShadesOfDirt]

It is interesting that you are choosing a battery designed for golf cart applications, and implementing it as a solar battery-bank.

These batteries (seem to) have a BMS in them, and the manufacturer (of the battery box w/ BMS) knows what they built, and also knows the limitations of various patterns of hooking the batteries up. They should state in their documentation exactly how many can be tied together, and in what wiring patterns.

They aren't telling you "NO" for no reason, they are saying they've talked to engineering, and there is a limit to the wiring pattern you are after (increasing whatever you've got with two more batteries). It could also be that they just haven't tested out your particular combination (8p), and don't want to do the testing to confirm it would work (even if it might work).

Either way, you'll be taking a bit of a risk ... you can choose to go for it, or start over with another battery-bank design.

From a bit of research, it seems that more batteries in parallel just means more difficulty in keeping everything clean and managed; one iffy or bad cable conn, or one battery going bad, and grief happens elsewhere in the battery-bank. But, with more research, you might be able to find an example battery-bank parallel wiring pattern that might work for you, even if your battery vendor doesn't agree with it, and won't warranty their use in that pattern.

 

[sunshine_eggo]

They aren't telling you "NO" for no reason, they are saying they've talked to engineering, and there is a limit to the wiring pattern you are after (increasing whatever you've got with two more batteries). It could also be that they just haven't tested out your particular combination (8p), and don't want to do the testing to confirm it would work (even if it might work).

I have to disagree with some fundamentals here...

BigBattery has demonstrated blatant incompetence as a builder, nor should anyone trust anything they say without secondary verification. One need to look no further than most of their battery datasheets to learn that they don't know what they're doing.

An educated consumer is the best barrier to potential catastrophe.