Battery charger recommendation???
 

The Guest 2610W (10 amp) charger that was on my boat when I got it seems to be dead (red light on constantly and the shop that did some other diagnosis says its bad). I have two Optima batteries in the boat and hear that their life is shortened if you charge them at too high of amperage.

Is 10 amps too much? What charger should I buy?

Thanks - Scott

i like those little 10 dollar ones from harbor freight. got one on my tractor, trencher, scallop boat, & V. will not charge a dead battery, but works well as a trickle charger

Anything over one amp will eventually shorten the life of a battery if left on for too long a time. You can use a shop charger @75 amps or a home unit @ 10-20 amps. It really makes no difference except for the length of time it will take to charge the battery. The damage is done after the battery is fully charged and you continue to try and pump juice into it.

What you want is a battery charger that has a tapering charge that then switches over to a float charger. A tapering charger will decrease the amperage as your battery gets full, and once it's full it will then switch to a float charger that will constantly monitor your battery and pump in a very small amount (typically 500ma) of electricity if your battery looses some of it's charge from sitting.

for what a proper charger would cost, you could buy at least two new battereis. I'd just get another guest and put it on a timer, let it charge for 15 minutes a day, that should keep your batteries more than ready. If you know you're going out hte next day, let it charge for a while longer. if that won't keep the batteries up, you have a drain or a battery issue

or crank the boats engine and let her run for 15-20 minutes every week or two.

Bradford brings up the second issue. The shop says my alternator is only charging @ 12.1 to 12.2 volts. It seems to me that's enough to keep the batteries from draining while I'm running, but not enough to charge them up. It's the Mercruiser 170 (I think that's pretty much exactly the same thing as a 470). It has the alternator that's integral with the crank pulley.

A couple of years ago I had to rebuild the water pump, which is buried deep and needed to pull the crank pulley. The magnets were all loose, it was full of rust and there was some corrosion on the windings. It had eaten probably 1/4 of the way through the wire in a few places. I cleaned out the corrosion and varnished the coils thoroughly. I think the dash gauge was reading 13+ volts when I fired it up, but can't swear to it. Thanks again to Spare for getting me through that project with a little bit of sanity left.

I'll need to go to the manual - I don't even know where the voltage regulator is located. Any diagnostic comments would be appreciated.

Spare - the Guest chargers say they drop off to a float charge after the batteries are charged up - shouldn't I be able to leave that on all the time? Destroyer comments that the 10 amp charge doesn't hurt the battery if it not left on too long.

I cooked a couple of batterys in mine by over charging!! Thought my sears garage charger was great till i learned it does not shut off, charged them babys for 4 days!! when i went out they were boiling! now it has a timer on it!

some of the newer chargers will go into a float charge, they should be OK, I'd still put it on a timer just to make sure. The voltage regulator is located on the port side of the engine, just follow the water hose from the water pump(regulator is water cooled). Pull the two yellow wires from the stator and put an ohm meter on them, if its open, your stator is bad. I'll see if I can dig up the trouble shooting chart for the regulator(been while). If you end up just needing a balancer, I have a brand new one. Odds are you will need a balancer, startor and regulator so you're better off doing the alternator conversion

If you are going to charge your batteries on a regular charger than by all means get a Battery hydrometer. (it looks like a turkey baster with a float inside of it). Open the caps on the batteries and suck out some acid into the tester until the float inside just starts to float. Read the color chart on the float where the fluid is and it will tell you how much your battery is charged. Shut off your charger once the float says the battery is charged and you'll have no problems using any kind of charger. Just remember that battery acid will eat your pants for lunch if you get any of it on them, so be careful and ALWAYS wear safety goggles.

For general info, I use a shop charger that charges my batteries @ 12 amps, and it has a timer built in so I never overcharge them.

If your alternator is only putting out 12.2 it's shot, that number should be over 14. A fully charged battery is about 12.7 volts, the charge has to be above that or no go.