Join Date: Aug 2012
Location: Vermilion Alberta Canada
Mentioned: 5 Post(s)
Quoted: 2315 Post(s)
yes, the current is so low especially with the big batteries it is just fine. A 5 watt charger will never overcharge even a motorcycle battery. Also with solar, its not charging all the time. Lead acid is happiest fully charged, but as it approaches 14.4, the ability of the charger decreases since net current is supply minus battery voltage. Intercell/inter battery resistance difference causes the greatest amount of current drain in tractors semis etc. If the batteries are in relatively good shape, a tiny trickle charge of 100mA is all that is required. If there is one battery at say 11.95 volts and the other 3 are at 12 volts, that 0.05 volts diff gets burned up in the cell resistance - but it will never catch up since the low one discharges faster then the rest pulling them all down. All it takes is one cell in one battery of 4 parallel batteries to discharge the whole lot prematurely.
Lead acids love to be charged, and a small solar charger is ideal to compensate for those inherent intercell and interbattery resistance differences that kill batteries - if there is sun occasionally.