Battery selection?

[amuller]

Some of the guidance on batteries has strongly worded advice against using sealed or AGM batteries. I suppose this could be related to the use of unregulated charging systems on many motors, and the possibility of boiling away electrolyte.

For instance, CDI in their Troubleshooting Guide says:

"The recommended type of battery for outboards is a single (NOT more than one) 850+ CCA dual purpose or cranking/starting non-maintenance-free battery."

This may be good advice but "non-maintenance-free" batteries (with caps) aren’t always readily available except maybe from a battery distributor. I think they are pretty much obsolete as a common item.

What do folks here think?

Alan

[dockbuster1]

The AGMs are the battery of choice on some of Mercury Marines new engines and a requirement on some like the Verado I would guess if the rectifier was not regulated it could be an issue but generally the ignition usage on battery ignition and accessories makes it rare problem on Mercurys and not dicussed in training as an instructor for Mercury Marine from 2006 to2012. In the seventies when mantainence free batts were introduced it was considered an issue when people had nothing but lites to drain the the battery But I never heard any problems and the sealed battery became the standard

[Tubs]

Pick you poison.
http://www.yachtingmonthly.com/archive/how-batteries-can-explode-and-how-to-avoid-it-3930

A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.

[amuller]

Hmmm a digital voltmeter to plug into a lighter socked costs very little. https://www.amazon.com/TOOGOO-Cigarette … +voltmeter (Readable in sunlight? I don’t know.)

And maybe some sort of switched dump load drawing 5 A or so? (What?)

[outbdnut2]

quote Tubs:

Pick you poison.
http://www.yachtingmonthly.com/archive/how-batteries-can-explode-and-how-to-avoid-it-3930

Good info in that video, and, as they conclude, battery compartments should be vented, but beware that venting alone will not prevent all battery explosions. I’ve had two explode back in the 1990s. One under the hood of a 1968 Pontiac The car had been run about 20 min before and when the key was turned to start it again, it exploded. The other was in a 1951 Buick, in my garage, with a 4 Amp charger put on in the evening and it exploded sometime during the night and the hood was up. The only common factor between these occurances is that both batteries were 8 to 10 years old but were still starting and running these cars. Neither were AGM batteries – both had vented caps. Maybe when a battery gets really old, a connection inside corrodes thin and eventually breaks with a spark? or maybe there was just enough hydrogen coming out the vents and a slightly corroded terminal made a small spark? I will never know, but I now clean all battery connections on boats and cars once or twice a year, and am thinking about replacing batteries when and if they get to a certain age. I should probably replace my pontoon boat battery – it came new in 2003 in a new Ford truck, was moved to the pontoon in 2007.
Dave

[amuller]

Batteries are known to explode due to internal arcing…. It’s not common, but it happens.

[Tubs]

When batteries are charging they generate hydrogen gas.
If the battery is full there is little room for the gas to collect.
The lower the water/acid level the more room there is for the
hydrogen to collect and the bigger the BOOM!. Any gas coming
from the battery through the cap vent holes or if the caps are
off that finds an ignition source will cause it to explode. Before
putting a battery on a charger its important to first check the
water level. Nobody does.
I blew one up on my 55 Ford when I was a kid.
It was many years later when I learned why.

A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.

[garry-in-michigan]

LOVE that Ford – – – 😀

[Author]

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