Battery charger recommendation???

[scook]

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.

[macojoe]

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!

[spareparts]

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

[Destroyer]

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.

[garbubba]

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.

[scook]

Thanks for the responses - I just spent a bunch of $ getting a new kicker motor, so I'm not excited about spending on a new alternator but I need the batteries in good shape - planning to start hitting the ocean and don't need any problems.

Spare - did you find the trouble shooting chart for the regulator? I do have the Merc factory shop manual but haven't had time to dig into it. About what is a reasonable cost for a kit, if I need to go that way and can I buy it from you and get it drop shipped to me on the left coast?

[bradford]

I'm with Garbubba, 12.2 is gonna leave you stranded. Check the voltage at the batteries with the engine running, don't trust your dash gauge. A good charging system is money in the bank in my opinion.