A 20A (should be 20Ah, amp hour, but it often get abbreviated to amp) has sufficient charge to deliver a 20A current for 1 hour or 10A for 2 hours, 0.5A for 40 hours, etc.
Therefore charging at 500mA (1/2 A) should theoretically take 40 hours (40A * 0.5h gives the 20Ah) but that is assuming the battery is completely flat.
So your advice was probably somewhere close.
__________________
Team C TC02c - My son breaks it, I fix it.
|