Easy Battery Charging question...

[YamaHog]

I have not had to charge the battery on my new 2020 Yamaha195S as of yet, but I'm about to put it on the charger for the first time. It's the "Super Start" Group 24 battery that came with the boat and is standard Lead-Acid type. I always thought you are supposed to remove the vent caps on this type of battery when charging, but the caps on my battery seem to be on pretty tight. Am I not supposed to remove the caps when charging?

 

[YamaHog]

I think I have answered my own question. The caps are vented on the newer batteries, so I should be good to charge with the caps on. For regular maintenance I should remove the caps and check the water level of each cell, adding distilled water as needed.

I was paranoid about removing the caps since my grandad always took them off when charging his boat batteries. Mg guess is those old batteries didn't have vented caps.

 

[212s]

Yes you're right - marine batteries are semi-sealed so they don't splash acid out of the battery when bouncing over waves. And vents are only necessary when the charge current is very high, such as above C/4, or over-charging. So for a typical G24 battery of about 85A/h, the charge rate of 20 amps or less would not causing venting unless the charger is "dumb" and doesn't reduce current when the battery is full. A "smart" charger will change charge rate as needed. For overnight charging needs, something in the 4-8 amp range should be plenty.

 

[YamaHog]

Yes you're right - marine batteries are semi-sealed so they don't splash acid out of the battery when bouncing over waves. And vents are only necessary when the charge current is very high, such as above C/4, or over-charging. So for a typical G24 battery of about 85A/h, the charge rate of 20 amps or less would not causing venting unless the charger is "dumb" and doesn't reduce current when the battery is full. A "smart" charger will change charge rate as needed. For overnight charging needs, something in the 4-8 amp range should be plenty.

Thanks! I'm working with a 12 amp dual bank charger and got it hooked up about 8 pm last night. Battery was at about 50% capacity, and this morning it's at the full 100% per the readout on the ProMariner smart charger. I've read conflicting information around checking the the electrolyte level. Should I remove the caps monthly and check/add distilled water as needed? or should this really only be done every 6 months or so?

 

[212s]

At that charge rate, you should never have gassing. Plus these ProMariner smart chargers (I have the dual 12amp too) will not overcharge and they reduce output as the battery gets full to prevent gassing. If your battery really has caps for the cells (maybe take a pic and post it?) I'd consider checking it a couple times a year, maybe spring and fall to make sure they're good.

And it sounds like it's just a regular start battery so I'd consider swapping it out down the road with a maintenance-free deep cycle marine battery, or if adding a second battery. My boat came with two batteries, both starters, and in a few years when the house starts to loose capacity, I'll replace it with a deep cycle. I'm only running a small digital JL amp pumping out about 220w to the stock Polk speakers at max volume, so it doesn't run down the house much when floating - most of the time it's running only about 10-20w for music when floating which is plenty loud, over 90dB, so we have to talk loud to hear each other. At these power drain levels, it would take days without charging to kill the house battery.