What's the rate I should charge my 6v SLA batteries? I have an old charger for nicd batteries and it has a slow setting, that used to take about 8-10 hours for a 1200mh 7.2 battery, I imagine that's about 150mh/hr. Is that too much, or could I get a faster one without harming them?
Lead acid batteries should charge at 1/10 C for maximum service life. That is 1/10th their capacity per hour. So for a 20ah brick, that would be 2 amps. I normally would use a small 1.5amp car battery charger like this guy: https://www.walmart.com/ip/Schumacher-XM1-5-Maintainer-1-5-Amp/15140193 and charge batteries in pairs. Generally my North Carolina would use two of the 6v bricks, so I would take that matched pair and charge them together in series on the 12v setting.
So that would be anything up to 450ma. And batteries that live together in the boat, if you use multiple, can be charged together just like they are in the boat. That also increases the amount of amps you can put into the set of batteries. Two 4.5AH batteries in parallel could be safely charged at 900mah, etc.
