Charging system 70 HP Evinrude question

[Fiddlefire]

I had a discussion with a friend of mine who said his dad owned this same motor and when I told him that I have a charger to charge my cranking battery he stated that this motor has a charging system in it and it will not be necessary. The motor in question is a 1976 70EL76. Can any one shed some light on this? I don't think that it does.

 

[Chinewalker]

Yes, your motor came with a charging system built in. It consists of a stator under the flywheel, charged by magnets within the rim of the flywheel, which creates AC current. There is then a small rectifier mounted on the engine that converts that AC current to DC. It's only a few amps, but is enough to keep the battery charged up with normal use. If you have lots of battery load, .ie stereo, lighting, fish finders, GPS, etc. then it may not keep up. If your battery doesn't maintain charge, then you may have a blown rectifier (not uncommon).

 

[oldboat1]

^^Agree. If the battery is old or has been stored for a while, it may need to be charged (may lead it load tested if fully charged, but won't crank the engine -- starter won't spin the flywheel quickly.) Or may have other motor or wiring issues.

 

[Fiddlefire]

Thanks very much, I wasn't sure. I did see a rectifier in one of the schematics so that makes sense. My last boat years ago I kept two batteries on board. One for cranking and one for accessories. Right now all I have on this boat because it's only a 15 footer is running lights, bilge pump and a depth finder. I might throw a portable solar panel in for the accessory stuff. Thanks for the info!

 

[F_R]

As far as the battery is concerned, on your motor the battery is only used for starting. Other than that, it will run just fine with no battery at all. However, running with the battery disconnected will instantly destroy the rectifier. You can't re-connect it fast enough to prevent it from happening.

What I'm saying is that a charged battery will last for lots of starts.