Moderated Discussion Areas
ContinuousWave: Small Boat Electrical
|Author||Topic: Battery Storage|
posted 09-10-2005 10:30 PM ET (US)
The boating season is short on Cape Cod so boat batteries are stored for 7 or 8 months of the year. What is the best charger or charging system to keep the batteries healthy? I have both starting and deep cycle batteries.
posted 09-11-2005 01:09 AM ET (US)
You want to keep them on a smart trickle charger. I use the
Schumacher, which is available under several brand names.
Keep them someplace they won't get real cold or real hot.
Top up the water.
posted 09-11-2005 08:39 AM ET (US)
Even better than the trickle chargers are the newer "float" chargers. These charge a battery and then maintain them at charged level by cycleing on and off when necessary without over charging which trickle chargers can do. They are available under several brands, with "Battery Tender" being the most popular. "Battery Tender" also came out with a waterproof model. They are available in motorcycle shops, but ads in motorcycle magazines, like CYCLEWORLD, generally have the best prices.
I have one and cycle it between my boat, motorcycle, and lawn tractor batteries over the winter. All appear fresh in the spring. It also prolongs their life as the plates in the batteries don't sulphate. A "Battery Tender Jr." in the Competition Accessories company ad runs $20, the waterproof model $40. After a check I just discovered their magazine ads prices are lower than their website prices. Phone # is 800/543-4699.
posted 09-11-2005 09:33 AM ET (US)
Speedo, that's what I meant by a SMART trickle charger.
posted 09-12-2005 08:20 PM ET (US)
Thanks guys, I appreciate the advice.
posted 09-12-2005 09:58 PM ET (US)
I found this site to be very informative. I have purchased 4 AGM batteries from them with no problems in quality of the product and service.
posted 09-13-2005 09:08 PM ET (US)
I do not think a constant float charge or trickle charge is mandatory. If a battery is charged to full-capacity before storage and kept in a cool dry location, it probably can survive 3 to 6 months with minimal self-discharge.
I made some measurements of my own batteries over the winter. Over about 5 months the state of charge declined only 10-percent. See:
posted 09-13-2005 10:30 PM ET (US)
Thanks, I hadn’t read your reference section on batteries before tonight. My battery storage practices have been similar to yours. I store them fully charged and charge again in spring. Mine just get stored for longer so I was thinking that one of the battery “minder”, “tender” devices might work. Like you I have three marine batteries. I might rotate a trickle charger between each of the batteries so that each of them gets some charging over the winter.
posted 09-14-2005 04:01 PM ET (US)
Top off the water.
I charge mine overnight, 1 or 2 nights per month.
No problems in 3 seasons.
posted 09-16-2005 09:58 AM ET (US)
If you use Optima AGM batteries you will not have to charge them in the off season. Their internal leakage is very low and they will be ready to go in the Spring if they are stored in a cool dry location.
posted 09-18-2005 11:56 AM ET (US)
Some of us have to leave our boats in places over the Winter where it is VERY cold (Maine) and there is no heat anywhere - I've been doing this for 15 years. A fully charged battery will not freeze and will not necessarily discharge faster because of cold temps. I just top off the change every 6 weeks or so.
Also one of the boating controversy items that always comes up is removing the battery from the boat. Some sources say to do this, but if the battery cables are disconnected (thus minimizing parasitic leakage - also helps to clean the battery), it is my opinion that it doesn't prove anything to pull it out of the boat.
There is also the business of noy putting directly on a concrete floor if you do pull it. Some people think this is an old wives tale.
posted 09-19-2005 08:07 AM ET (US)
If you leave the battery in the boat, it is good advice to disconnect one of the leads. I noticed that with everything off, I still have a current drain of a few mA. Next Spring I have a battery switch on my todo list.
I would still recommend removal of the battery and storage in a cool dry location. If you have to get to the battery to remove the cables, why not pull it out?
posted 09-19-2005 08:31 PM ET (US)
I was a boat owner and in the marine business for 17 years in Alaska. Batteries were never removed from the boats. A full charge was put on and the Pos cable disconnected. A good battery was in good shape after wintering at down to -30, a weak or cheap battery might need a charge in the spring.
We also didn't top the batteries off with water, we used electrolite (battery acid).
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