12volt Lipo4 Batts in Parallel - Discussion with Redodo - Correct?

[Davetv1423]

Check this out.
I found a used 230ah Lipo4 battery being sold directly from Redodo and they're telling me to not wire it with any other 12-volt batteries.
My understanding is the BMS will do its job regardless (not that we want to build a bank "relying solely on said BMS" but it still should be fine..?

I questioned why Redodo had "We do not recommend connecting this 12v lipo4 batt with any other 12v batts".... as seen here: https://www.redodopower.com/product...MIwpe-i-bTgwMVWY_RBB0sUg_6EAEYASACEgJtWPD_BwE

Their response was pretty vague and disappointing to say the least.
They have different cells, internal structures, internal resistances, etc. We do not recommend connecting batteries of different capacities together.

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Sophia

Redodo Customer Service Department
Shenzhen Maicheng Technology Innovation Co., Ltd
Website: https://www.redodopower.com/



From: dave proxy1sales.com

Date: 2024-01-12 21:57

To: Hello@redodopower.com

Subject: RE: RE: Greeting from Redodo

That is ONLY if you attempt to CHARGE THEM BOTH over 100 AMPS at a time -
With a 30 AMP Charger (as I have) – this will never happen.

ALSO goes the same for DISCHARGING = so you are INCORRECT.

IE/EG:
If they are in parallel and both feed a 1500 watt inverter to run a fridge and freezer combo being charged by a max of a 30amp charger (Split between two batteries) = this will be fine.

Hi, Dave

To help you understand better, let me take the example of a 12V 200Ah battery and a 12V 230Ah battery.

The 12V 200Ah battery has a BMS of 100A and can support a maximum continuous charging and discharging current of 100A. The 12V 230Ah battery has a BMS of 150A and can support a maximum continuous charging and discharging current of 150A. If you connect the two batteries together and use them together, the 12V 200Ah battery will shut down when the current in the battery system reaches 120A and the 12V 230Ah battery will not shut down. This will affect the operation of the entire battery system.


Regards
Sophia

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Sophia

Redodo Customer Service Department
Hi, Dave

Thanks for message. I am Sophia from Redodo's customer service team.



We do not recommend connecting different models of batteries together. This is because they have different BMS, internal resistance, structure, etc. Connecting them together will increase the risk of battery system operation.

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Sophia

Redodo Customer Service Department

 

[DIYrich]

Same battery in series. In parallel, people are mixing lifepo4 all the time.

 

[Davetv1423]

Same battery in series. In parallel, people are mixing lifepo4 all the time.

yep but FYI- "
We do not recommend connecting batteries of different capacities for use together. I am sorry to say that we do not offer a warranty for battery damage caused by connecting batteries of different capacities together."

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Sophia

 

[Quattrohead]

Just because they don't recommend it does not mean you should not do it, but they are correct as far as they are concerned, they only want to warranty batteries when used exactly as advertised.
Their reasoning is a bit pessimistic but completely understandable from a manufacturer's point of view.

 

[Partimewages]

Just a quick look on their website shows all their batteries seem to be listed as 4s4p. So I don't know what the problem could be unless this is a different old stock.
BTW I would never put 12 volt lifepo4 batteries in series. There are just too many issues trying to keep them balanced.
There are no real problems putting different AH packs in parallel.