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Charge voltage from Yamaha outboards

Posted: Thu Dec 05, 2013 3:24 pm
by Lady of the Lake
OK so I installed two new Yamahas in Lady of the Lake and everything is good with one exception. One motor is putting out around 15V to the battery and the other only half that, around 7.5V. Each motor is connected to a dedicated starting battery. Any ideas what might be wrong with the motor only putting out half the proper voltage? Anything I can easily check?

Thanks,
Sam

Re: Charge voltage from Yamaha outboards

Posted: Fri Dec 06, 2013 6:40 am
by amytom
Are these the new style engines or just new to you?

If the old style I would check the voltage coming directly off the coil, if that's good then the regulator is where I'd lean. (Let me know if you need a coil or regulator)

If new engines let the dealer worry about them.

Re: Charge voltage from Yamaha outboards

Posted: Fri Dec 06, 2013 1:58 pm
by Lady of the Lake
OK, major embarrassment here...always check the battery before assuming the motor has an issue :-)

Battery experienced a premature death, new battery is working fine, engine is charging at proper voltage, my bad.

Sam

Re: Charge voltage from Yamaha outboards

Posted: Fri Dec 06, 2013 8:57 pm
by thinwater
... Perhaps because of the charging arangment.

You will be MUCH happier with a single bank. Outboards don't need separate starting batteries.

Re: Charge voltage from Yamaha outboards

Posted: Fri Dec 06, 2013 11:19 pm
by Lady of the Lake
I can see your point. Have always had them separated in case I had a battery issue and needed to start the engines but I guess that is what pull start is for :-)

Sam

Re: Charge voltage from Yamaha outboards

Posted: Sat Dec 07, 2013 11:14 pm
by thinwater
It's more than that. Depending on how they are wired, you are most likely not charging or using them evenly. Throw a stitch wrong and you ruin a battery.

This may not be the time, but when you are ready for replacement I would think seriously about a little re-wiring and installing all matching batteries in one bank.

The truth is, if you want the batteries to last you will never draw them much below half, and it takes very little to start one engine. There are also warnings that the batteries are getting low, even if you ignore the gauges; the autopilot will stop and the inverter will stop. Even if they are completely dead and you have to pull start an engine, you only have to pull start one; the other will provide enough power within 10 minutes to start the other.

(When I bough my boat the PO pitted me with ruined batteries for 100 mile trip home.)