I've had two marine deep cycle batteries that had the positive posts turn black and it looks as if some acid is on the top of the battery, it has that wet look. I put some baking soda on one and sure enough it fizzed. Any idea on what causes this? These batteries are only a year old? These are used on my hand held minn kota 50 lb thrust electric motor. I charge them with a schumacher charger. They are EVER Start 29dc maxx batteries. Thanks for any info.
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Could be how you charge them. I use a minn Kota charger.
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Acid on the battery top acts like a wire and drains the battery pronto. It also reacts with the lead posts under that current flow. I'm not a chemist but the black look could be from the resulting lead sulfide (or sulfate, or sulfite, or sulf-something.)
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Give them a good cleaning and cover them with an antioxidant. You can get some at the Home Depot called Noalox that has worked well for us at work.
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Clean them with a solution of water and baking soda, not just the soda. Clean the whole top and sides of the battery. Use a wire brush on the posts. Then, spray the posts and connections with some kind of anti-corrosion spray. I use Corrosion X on mine, first on the bare posts, then another shot once the wires are connected. Only have to clean them off about twice a season, and they stay hooked up all year! I use the same batteries as you, with an on-board charger on two, and a Shumacher portable for the third. Be sure to check the electrolite (water) level once or twice a year too. Mine get low, and that can "kill" a cell.
Keep 'em clean, keep 'em full and keep 'em charged all the time for max. life. I get about 100 or so re-charges out of mine, or about two years on the starting battery. That's with about 120 days a year of use and daily loads on all of them.
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A question comes to mind as to why.
Are there time that you run your motor at full speed trying to get somewhere fast?
If so check the terminals after such a run and see if they are getting hot.
Heat will speed up how fast things will corrode.
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appreciate the info guys. I think my issue after all of the research is that if you drain the batteries and let them sit for awhile without recharging them, then you have an issue with "seepage." I will make sure from now on to throw them on the charger after getting home instead of letting them sit for awhile and charging the day before I go somewhere... and I will now throw them on periodically through the winter. Right now they are cleaned and charging, the levels all looked good.
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Good.
Allow me to second the recommendation for Corrosion X. It was designed expressly to protect electrical components in a marine environment. And it really does that.
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I've used plain Vaseline on the posts for years and have never had corrosion issues.
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so it's better than wd40? Does the home depot carry it or wally world?
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CorrosionX leaves WD-40 in the dust. Or can. I don't know what makes it different, but it sure is.
It also is THE best lube for a .22 semi-auto, btw. Lightly spray the inside of a sparkling-clean action, allow to dry completely, and powder fouling just falls out as a gray dust. As they say in the TV commercials...AMAZING!
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Quote:if you drain the batteries and let them sit for awhile without recharging them,
My understanding of lead acid batteries is that it is a no-no to leave them in a deeply discharged state for several reasons. It shortens the life as the ions will precipitate out of solution, and the condition is only partially reversible. It shortens their useful life. Hence trickle charging over winter to prevent natural rundown from ultimately kiling the battery completely.
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BatteryMINDer makes some great products that will keep your deep cycle batteries in great condition throughout the winter and even during the summer months. I've installed them on customers boats and rv's and have had great luck.
Here's a link to their website:
http://www.batteryminders.com
Bring on the ice!
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