Battery Charger Rapidly Turns on and off

[LUV'N LIFE]

If you have the Sentry FR Series charger they will turn completely off at the end of a charge cycle. They also have a two position switch, auto & manual. It is possible to bring back a marginaly sulfated battery by running this type of charger in manual and continualy monitering water level, temperature, and specific gravity.

 

[Nonchalant1]

if you have one of the original ferro chargers, how can an equalizing charge be done...or can it? It's time for a new port bank, I think. I have to parallel it to get the port engine to spin up and the batteries are 4-5 years old on that side. But I'd like to try an equalizing charge if it can be done.

Many of the old ferroresonant chargers had a "sense" terminal which is supposed to have separate wires running to + and = on the battery bank. It uses this sense circuit to determine voltage to turn on and off. You can disconnect this "sense" terminal wires and the charger will run forever. Just turn it on and start monitoring. Some systems have a jumper instead of long sense wires. In thisd case the "sense" terminal is connected to the + and - on the charger, and therefore through that to the battery bank. If yours is set up with a jumper, just disconnect the jumper wires to the sense terminal.

Another way is to use a manual 12V charger to do each battery individually or one bad battery individually. Yes, before you experts start saying you can't charge an 8V battery with a 12V charger, listen up. The head of battery engineering at Rolls Surette explained this to me and I have done it very successfully. This engineer is a boating person and he equalizes his bank every year. Get a manual 12V charger with a switch for 10 amp vs. 2 amp. Put it in the 2 amp mode and hook it up to your big 8V battery and turn it on. The charger will charge at about 10 amps to start (because it's an 8V battery) and then drop down to close to 3 amps as the battery is charged. It'll take a full day or more to fully equalize a big 8V battery this way. I did all 4 of my Rolls 8HHG25PMs this way and I watched the specific gravity in every cell come up from a varying 1170 to 1225, to an even 1265 in every cell.

Be careful! Eye protection with acid. Wear bad clothes. Water them with distilled water and watch the water level and temps as they charge. I had to add very little water to my Rolls as they equalized even though they bubbled hydrogen all the time. Be careful around charging batteries to not have an open spark or flame (boom) and disconnect your CO monitor on the boat because it mistakes hydrogen for CO.

Doug Shuman