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HillbillyRock
08-23-2007, 12:58 PM
I just replaced my cranking battery with a brand new unit from Interstate. It seems that when I bring the boat home and start charging the batteries that my cranking battery is taking way too long to recharge. The battery is more than enough for it's designation. My question is the engine is supposed to recharge it partially while running right? Is it possible my charging unit on my 2.4 is bad? And what would need to be replaced or looked at to determine this? Thanks in advance guys, I am not new to building race engines, just new to the 2 stroke variety.

eli
08-23-2007, 03:41 PM
see what volts you have coming of the rectifier when its running, should be 12+ at 3000 rpm.

HillbillyRock
08-23-2007, 03:46 PM
See here is where it gets funny, where is the rectifier located on my motor, I am mechanically inclined, so a good description will have me on the right path.

captcarb
08-23-2007, 05:01 PM
You can measure it at the battery. Measure the battery voltage with no load and motor off. The charging voltage must exceed that to successfully charge the battery. If you have the high performance 16 amp (or less) flywheel and system, the motor will probably have to rev above 3k to develop enough voltage to charge.

jim

theoldwizard
09-30-2007, 04:34 PM
see what volts you have coming of the rectifier when its running, should be 12+ at 3000 rpm.
Actually it should be at least 14 but not more than 15 volts at that rpm.

CharlieB53
10-02-2007, 06:54 PM
Outboard charging systems cannot be compared to automotive charging systems other than they both are capable of recharging a good battery.

Forget the 13.8 - 14.2 charging voltage of the auto style

Use a digital VOM chack battery voltage - engine off

Check battery voltage again at a fast idle, 1800 - any reasonably comfortably safe speed if using a flushing adaptor, watch the battery voltage slooooowly climb, chaging system is working.

These realitively small amp systems either work or they don't.
Most are NOT regulated, even tho the part is 'named' a regulator/rectifier, IF it regulates it has a simple zener diode inside burning off power as HEAT, be sure to use potting paste anytime the rectifier is moved/removed/remounted to ensure heat transfer/disapation or it iWILL BE a matter of time before you are buying a new one.

If a chranking battery doesn't seem to be charging then check each cell with a hydrometer, charge correctly and recheck, then LOAD test with a REAL load tester, DO NO USE one of those 'electronic' testors such as autozone and walmart use, they cannot load a flashlight battery much less put any REAL load on a 12 V cranking battery.