Battery Top Up

Forever Mates

Member
Aug 3, 2014
56
Owen Sound Ont. Canada
Boat Info
1996-Sea Ray 270 Sundancer 7.4l Single Garmin echoMap 50s
Engines
Single 7.4l Mercruiser Bravo 111 Drive
Is it normal to have to add/top up battery electrolyte once or twice during the season. I leave my 20 amp charger on all the time when hooked up to shore power. 2 Batteries. 1Starter/ 1 House deep cycle.
 
Totally normal. I check the battery water 3 times a year. In the spring prior to launch, around July 4th and again in Sept. Do no add water in Oct when a freeze may occur soon. The water has to have time to be mixed with the acid or it may freeze and ruin the battery. BTW I also leave my charger on 24/7 when connected to shore power.
 
Yeah. That's typical. Now some chargers are better than others. Newer smart chargers avoid overcharging the batteries, and taper the charge as the battery reaches capacity. This can have a positive effect on the rate of electrolyte loss.

That said, regardless of the charger, you should check your batteries periodically.
 
How frequently you need to top off the electroyte in a lead acid battery is to a large degree dependent upon the ambient temperature where your boat is located.

When I used lead acid batteries, I had to add distilled water to the batteries about every 3-4 weeks (NW Florida, OEM converter) and even with proper maintenance, the lead acid batteries only lasted 18 months. It was a big enough hassle that I installed a distilled water tank to keep from hauling jugs of water to the boat every time I went boating. I changed to AGM batteries and my batteries now last 4-5 years and I removed the distilled water tank from the boat.
 
We have (4) 6-Volt Crown CR-235 Golf Cart batteries for our house bank. I installed them in July of 2009 & they are still going strong. I top them up with distilled water twice through the boating season & have never added electrolyte. I also have a 15-watt solar panel laying up on my dash that is plugged into a 12-Volt outlet that is constantly tickling the batteries.
 

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