TOPIC: Charging system question

We finally were able to get out on the water for our 1st shake down cruise this past weekend and noticed that the 115 tower was putting out 16.1 volts when we were cruising at 4000 rpm. My question is this too high and if so what corrective measures are in order. A new rectifier was installed when I discovered it wasn't charging.

that is fine it has a rectifyer not a regulater

Thanks Dave. I am more familiar with auto charging systems and 16 + volts would be a concern.

If you want to drop it a bit just run with your nav lights on. Kinda like daytime running lights on your vehicle.

Yeppers, that's what I did but with little difference.

Melanie

It takes some getting used to not worrying about the voltmeter being pegged Melanie. (Like you I thought this can't be right!) I brought up this same question some time ago, and was advised it was normal, and since the "alternator" on most outboards only puts out around 6 (or 8 ?) amps, it won't do any damage. The folks who know were right, as usual, and regular usage year round I haven't blown or burned anything up. LOL The one caution that should be noted here is not to run "gel cell" (Optima type) batteries on unregulated charging systems;
www.fiberglassics.com/fiberglassics-forums/home/main-forum/what-s-the-deal-with-marine-batteries#25410

Or,...

You can watch eBay for a good used Mercury regulator that has the rectifier built into it and is regulated to only allow 13.8 vdc max.
I buy them from some of the eBay vendors that are salvage yards and sell them at a very reasonable $40 to $60 each.
I swap out the OEM rectifier and life is good!!!
The one you want to watch for supersedes to Mercury Marine part number 883072T.
New, the MM regulator lists for about $173 +/- and Sierra Marine (NAPA) sells the equivalent part number 18-7543 at about $129 +/-.
Way too rich for my blood and the used ones don't seem to have a noted failure rate.
Real simple to wire up too.
The Merc one has a black wire that needs to attach to powerhead ground (-). The Sierra one doesn't have an external ground wire and just needs to be mounted directly to powerhead ground (-).
The gray wire is the tach sendor lead.
Each yellow wire simply go to each yellow stator wire.
Both red wires get tied together and then go to the big red Primary terminal of the starter's solenoid so it has 12v(+) all the time.
Thom

nice one Thom
& there are several on Ebay now