Can I connect two batteries of different capacities to the UPS?

Question

Electronics

Can I connect two 12V batteries of different capacities to the UPS?
Namely 9Ah and 7Ah? Both are 12V.

Answer 1

Connect - how? Serial or parallel?
In parallel it is possible, in series - it is very undesirable.
UPS - what? 2 batteries or 1? "Surname" UPS in the studio!

Answer 2

in parallel - it is possible, but carefully, the charge and discharge currents should not be limiting.
BUT in UPSs that are especially not expensive, the discharge currents are just close to the limit even if the sum of the capacities does not exceed the fact that the discharge currents could be skewed, as a result, the electrolyte boiled, and the cooling of the inverter is usually not designed for long-term operation caused by the increased battery capacity in excess of what was put at the factory,
In short, installing a hodgepodge of batteries in a cheap UPS, there is not a small chance to burn the UPS

Answer 3

There will be overflows between batteries, overheating, the release of hydrogen sulfide and other joys.
It's better not to do that.

Answer 4

You can connect, but you don't have to.