Help finding a replacement battery - do amps add up?

Question

I'm trying to replace a NiCD battery that has 24 sub-C batteries in it. I can directly connect any battery of similar voltage to the unit to power it, so I'm really just looking for a 28V DC battery that I can charge. Each sub-C battery has about 3000mA on it. Now, I know the voltage accumulates to give me approximately 28.8 volts when connected in sequence. Since I'm just looking for a comparable DC power source (again, just leads from the battery to the device), I don't know if I should be adding the amps of each battery to try to find a 28V DC battery at 72000mA. That sounds way excessive and not like something I'd be able to find. Which brings me to my next question: if amperage does get added up, would it be possible for me to just get a charger that would plug directly into the leads on the battery and charge it that way when necessary?

Thanks.

Answer 1

Each cell would be marked with its capacity, not a current, so it's probably 3000mAh. If your appliance discharges it in 3 hours, you are probably drawing 1A from it. If the cells are connected in series, yes the voltages add, but the same ampere of current flows through all of them. With those assumptions, a power supply providing 28V at 1A could substitute for the battery. Don't try to power your appliance from a charger without also having the battery connected, since the charger probably provides unfiltered, unregulated rectified AC, at a higher voltage.