Optima Blue Top venting Gas

[Kahi]

I recently purchased a pair of Optima 'Blue Top' marine batteries for my 30' footer. I was having excellent results with the new batteries until this morning when I was checking the engine compartment, and noticed the forward battery (battery#2) was venting gas from the top, extremely hot and hissing. The other battery (battery#1) was not hot to the touch. The batteries are connected inline.

I checked the volt meter on my gauges and both batteries had healthy charges and showed no problems.

I had the boat docked at the time, and connected to shore power and had the battery charger on and both batteries switched on, which I kept on overnight. Its a Guest Charge Pro...which I think is about 4 years old....only used a few times a year when at a dock with shore power to top off the batteries and keep them healthy. I turned the charger off and the shore power and returned a few hours later and the battery had started to cool off. hard to tell in Miami in the summer.

Other than the charger, I kept the a/c (Humidity control setting) running overnight to dry out the cabin.

Any ideas as to what might have caused this?

When running a Battery Charger, do I need to keep the battery switches off?

Thanks in advance..

Kahi
Miami, FL

[Avenger]

Those Optimas are AGM type batteries right? I'm about 90% certain that you need a "smart" charger that can be set specifically for AGMs to slow charge them or they'll cook.

Do you have a manual for your charger? If it's AGM compatible it should tell you how to set it for the right type of battery. If it's not you'll need a different charger.

Hope this helps.

[Kahi]

Those Optimas are AGM type batteries right? I'm about 90% certain that you need a "smart" charger that can be set specifically for AGMs to slow charge them or they'll cook.

Do you have a manual for your charger? If it's AGM compatible it should tell you how to set it for the right type of battery. If it's not you'll need a different charger.

Hope this helps.

Does help indeed. You are right. Confirmed with manufacturer. Thanks

[Avenger]

You are very welcome, and thank you for the follow-up.