How can I proceed if my battery does not supply all the charge I need and want to compensate by supplying the rest with an AC source connected in parallel with the battery?
You cannot connect battery output with AC source. As mentioned captcha a battery produces DC (direct current) and it cannot be mixed with AC power supply. The best solution for you it will be to connect two same batteries in parallel. It must have the same output voltage. Check this link for more information. Also you can use a battery charger (credits to captcha), but it may require additional circuits to protect the AC/DC converter or battery and may a filter required.
for this first of all please tell us if load is AC or DC.
for DC you need to rectify AC into DC and bring the rectified AC's output DC voltage to DC battery's voltage level and connect them in parallel.
if load is AC, then you need to convert DC into AC and make sure that phase and magnitude of converted AC voltage and AC supply voltage should be same.
share some more info, maybe then i'll be able to help you on this topic.
Current moves from a higher voltage node to a lower voltage node.
Let's assume that you have a 3 volts battery that produces DC (Direct Current) and an AC supply that swings between 0 to 5 volts.
Here is two cases:
When the AC supply produces a voltage lower than 3 volts, The voltage of the DC battery will be higher than the AC supply. so, current will move from the DC battery to the AC supply and the AC supply will be damaged.
After a very short time, The AC supply will produce a volt that is higher than 3 volts because it swings between 0 and 5 volts. so, the AC supply voltage will be higher than the DC battery voltage. As a result, Current will move from AC supply to DC battery and that will consume more power and damage your DC supply.