12v 80ah battery in parallel with 12v 33ah

[SetMil]

New user here…. 65yo lady. I have no one to turn to so please help…
I built a48V battery for my off grid inverter using 4 × 12V (80ah) batteries. They are around 6 months old. Still running honky dory

I need to extend the running time. However money is a serious problem. All I can afford is 4 × 12V 33ah batteries. They get great reviews.

Question: Would it be feasible to create 4 batteries (80- and 33ah) in parallel, and then in turn use these to create a 48V battery that should give 112ah?

 

[fechter]

Yes, that should work fine assuming they are all lead-acid chemistry.

 

[amberwolf]

Yes, if they are all the same kind of lead-acid batteries (all FLA (wet, with fill caps) or SLA (no fill caps, gel type)).

If they are not the same kind of batteries (like if you have lithium and lead), you typically can't wire them directly in parallel, because their full and empty voltages are usually different.

Each pair of 80 + 33 Ah batteries gets their + wired to +, and - wired to -, to put them in parallel.

After wiring all four sets of those, separately, then you connect the + of the set #1 to the - of set #2.

+ of set #2 to - of set #3.

+ of set #3 to - of set #4

Then the - of set #1 is your main pack negative, and + of set #4 is your main pack positive.

 

[SetMil]

Yes, if they are all the same kind of lead-acid batteries (all FLA (wet, with fill caps) or SLA (no fill caps, gel type)).

If they are not the same kind of batteries (like if you have lithium and lead), you typically can't wire them directly in parallel, because their full and empty voltages are usually different.

Each pair of 80 + 33 Ah batteries gets their + wired to +, and - wired to -, to put them in parallel.

After wiring all four sets of those, separately, then you connect the + of the set #1 to the - of set #2.

+ of set #2 to - of set #3.

+ of set #3 to - of set #4

Then the - of set #1 is your main pack negative, and + of set #4 is your main pack positive.

Thank you so much! I am relieved