BMS Parallel DOUBLE flow❓

[DELEOCO]

If I have if I have a LiFePo4 300 amp hour battery with a 100 amp hour BMS and connect three in parallel, what is the Watt hour and current flow in that system?
?
Capacity
•900 Ah (11,520Wh)
Current Charge/Discharge
•BMS 300Ah (3840Ah)
Is my assessment correct?? Does the BMS add current flow in parallel hook up

If that is correct;
What size of DC to AC inverter can I use effectively with the above parameters?

Can I run an inverter
2000W w/4000W peak?
or
3000W w/6000W peak?

Thank you for your help!

 

[MisterSandals]

It took a few times to decipher your system. Lets straighten a couple things out first:
LiFePO4
100 amp BMS (not amp hour: BMS 300Ah (3840Ah))
Watt hour is watts over time, not momentary watts as you appear to be using this term.

Are your 3x batteries 12V? (13.2V actual nominal)

The BMSs if wired properly in parallel would be additive and allow 300A current combined. The tricky bit is what happens if one of the BMSs cuts out or fails. The remaining 2 would have increased demands and possibly result in a cascading failure.

300A (3x 100A BMSs) x 13.2V = 3960W
If you get to this level, if all batteries/BMSs contributing equally, they will start to hit over current protection.
How much peak they can handle will depend somewhat on the BMSs OCP delay and how robust the BMS components are.

I'd think 3000W continuous draw would be about the max.

 

[Steve_S]

Batteries in SERIES increase Voltage.
Batteries in Parallel increase Stored Energy. (Amp Hours stored)

With 3, 100AH Batteries in Parallel, you get 300AH of storage.
With 3, 300AH Batteries in Parallel you will have 900AH of stored energy.

A BMS is the Battery Pack manager, it protects the battery pack from Over/Under charge, imbalances. A BMS also limits max output & input amps going to the battery. It does not control how much voltage/amperage hist a specific cell within a battery pack.

A 12V/100AH Battery has 1200Wh or 1.2Kwh
A 24V/100AH Battery has 2400Wh or 2.4kWh

When batteries are properly installed in Parallel, they will divide & share all Loads & Charging. This reduces cell stress within all the batteries and increases your functional capacity.

In general terms, it is recommended to not exceed 250A Load from a battery system.
A 12V system @ 250A support up to 3000W, while a 24V system can handle up to 6000W and a 48V up to 12,000W. Excluding surge handling.
Stackable Inverters can overcome this and are typically used to provide 240VAC/Split-Phase.

CHARGING: (Vehicle)
A Vehicle Alternator IS NOT HOW TO CHARGE LITHIUM BASED BATTERIES !
This is discussed at great length in several threads. A standard Alternator will destroy Litium Based batteries, they are simply NOT designed for that. Most people will use a new alternator (very $) that can properly regulate OR more often, they use an external charger (DO to DC) that is designed for LFP Batteries

Charging General:
Batteries in Parallel divide incoming charge amperage. Virtually all systems will Discharge at a maximum of 1C-Rate and have a Maximum of 0.5C Charge rate. For a 100AH Battery with a 100A BMS, that means it can discharge at 100A Max and take 50A Max for charging.