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Compass Marine How To | all galleries >> Welcome To >> Installing A Marine Battery Charger > NO, NO, NO, NO !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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NO, NO, NO, NO !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Okay how do I put this politely with regard to using automotive or non-marine UL chargers on boats? Oh yeah I know..... NO !!!!!!!!!!!!!!!!

Still not getting it? Okay.......

#1 Car chargers when used on boats can be one of the worst offenders & cause of stray current corrosion due to their internal architecture which very often does not isolate AC & DC sides like a UL Marine charger will. So this = NO !!

#2 Most of the car/auto type battery chargers use what is often referred to as an "autoformer" or autotransfomer. These are transformers with just one winding. Cheap, dirty and they can work ON LAND. Because of this single winding they share a common internally. Portions of the same winding act as both the primary and the secondary. This is bad news and not how a "marine" charger is built. With a marine charger all AC source current runs through the AC hot wire of the charger and is fully returned to shore via the white/neutral wire. The "case" is also grounded to the ships DC ground just in case it becomes energized in an internal fault. Again this = a big NO !!!! DO NOT USE AN AUTOMOTIVE CHARGE ON A BOAT......

#3 If the "car charger" has a two prong plug, many do, especially the older ones we all seem to have lying around the house, these can inadvertently become reversed. This is especially true if your boat has old AC outlets.. Follow me here, if the AC feed neutral & hot are reversed the ships DC negative bus can now become 120V AC with a "car charger"... This is what Mr. Konz observed in my statements in the last photo. You don't want to be a swimmer near a boat with a cheap car charger on-board, trust me. You also do not want to be the cause of an Electric Shock Drowning or ESD.. So again this = a BIG NO!!!!!!!

PLEASE, PLEASE, PLEASE use a proper marine UL charger not a cheap Wal*Mart type automotive charger..

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