PWM controller with no float
OK, I have a Morningstar Sunsaver 20a PWM controller. It's not the current generation, which is a 3-stage unit. It's basically a 2-stage without the float stage. It delivers full amps till the targ...
Forum Discussion
full_mosey wrote:Hey John, from what I've read about the Optima line, they can take a higher float voltage than other VRLA batteries before vent opening occurs.mena661 wrote:westend wrote:This is the "conclusion" HiTech came to with his experiments (not saying that's where you got this from). I didn't think they gassed at all unless severely overcharged but a float voltage that's too high does cause gassing.
Yes, AGM VRLA batteries are very tolerant but you don't want to float them so high that the valves are constantly opening. If the valves open, you are losing the oxygen and hydrogen that recombines to form the electrolyte.
That gassing may not escape the valves. Plus this points out the importance of a temp-comp charging source for AGMs.
Here is some info re my Optimas under severely hot conditions.
Note that the MS SS-10 lowered the charging Volts to 13.8V when the jumper was set to 14.4V. When I set the jumper to 14.1, the charging volts dropped to 13.5V. That is temp-comp in action. IF there was any gassing, it did not get past the valves. BTW, yesterday I reset the jumper to 14.4V as we are cooling off to the mid 90s in OKC.
HTH;
John
Agreed on the temp compensation, it's a valuable function.
FWIW, one day I was charging some AGM's with my automotive shop charger. I was nearby and heard a small "pop". Looked over at the charger and saw that I had inadvertently set it on the 40 amp setting. It was charging at 19v and I guess that's over the threshold of vent opening.:B
