What Is the Correct Output for My Battery Charger?

Question:

I have watched several of Jeff's excellent videos on YouTube and your own website, and I'm hoping that he can clarify a comment that he made a couple of times. When he said that a battery charger's output current should produce at least 10% of the battery size, does that mean at least 10% of the battery's total capacity, or at least 10% of the amount that needs to be replaced in the battery? For example, if a battery bank consists of four 220 Amp 6V golf cart batteries in series/parallel (total of 440 Amps at 12V), should the charger be able to produce at least 44 Amps, or should it be able to produce at least 22 Amps since recharging from a 50% DOD would only require replacing 220 Amps (440 Amps x 50% x 10%)?

Answer:

When sizing a battery charger to a battery bank, you always use full rated battery capacity. For instance, a 440 amp-hour battery bank would require a minimum of a 44 amp battery charger. Hope this helps.