Newmar RM15 battery charger - SailNet Community
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post #1 of 4 Old 01-12-2008 Thread Starter
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Newmar RM15 battery charger

I have this charger on my '89 Catalina 30. When plugged in, it hums nicely, but always seems to be dumping at least an amp or more into the two batteries I have, and Im worried that I may be frying them. I cant find much in the way of info on the internet on this model - does anyone know if this is a tapering or smart charger? Will I boil the bats if I leave it plugged in all the time (which I do)?

Dave in NC on Sugar Too
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post #2 of 4 Old 01-12-2008
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Rep Power: 16 is a ferro-resonant charge and is not a "smart" charger. Since the meter is analogue I would not trust it and would try to take an amp reading with a digital meter. On a fully charged battery...your voltage seen from the charger should be 13.3 or so and amps should be around .5.
The higher the float amps you are putting into the battery the more often you need to check the water...but if you are doing that, I see no reason to switch chargers as long as you can check levels every couple of weeks and have no active "bubbling" going on.

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post #3 of 4 Old 01-12-2008
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Not familiar with that particular charger, but I can tell you that if you charge full time, "smart" charger or not, you will have to periodically top up your batteries.

Some chargers do seem to "hum" quite a bit.


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post #4 of 4 Old 01-12-2008
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That sounds like an older ferro-resonant charger. It could be frying your batteries. You need to either check the water levels in your batteries regularly, or get a new "smart" charger that has three or four charging stages. They can stay plugged in and not fry your batteries.

You can read more about your charger here.


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