Possible to add Voltage Regulation?

[SeaKaye12]

Hi,<br /><br />Correct me if I'm wrong. On older Mercs (I have a '77 85HP) the stator charges the battery at ever increasing voltages as the RPM picks up.<br /><br />Isn't that pretty hard on today's batteries?<br /><br />And, wouldn't it blow many modern electronic accessories?<br /><br />So, what is involved in adding voltage stabilization?<br /><br />Thanks, Chuck

 

[andy6374]

Re: Possible to add Voltage Regulation?

Chuck-<br />Have you measured the voltage across your battery at WOT? What is it? If it is below 15V your electrical acessories should be fine. As soon as you run more acessories it should drop due to the extra current drain.<br /><br />I put in a new CDI/Rapair Stator (only 9amp) but it was overcharing, so I installed a rect/reg. in one. There product doesn't allow a voltage above 14.3V.

 

[Chris1956]

Re: Possible to add Voltage Regulation?

Seakay, You could add a rudimentary voltage regulation system if you need it. I would first check the voltage at WOT, with a fully charged battery to see what it is. If it is too high, install some Zener Diodes of the correct voltage, and they will dump the excess voltage. Alternatively, you could isolate your electronics behind a DC-DC Converter, if your wattage requirement is not too high. These converters accept a wide range of voltage, and convert it to a particulat voltage.

 

[emckelvy]

Re: Possible to add Voltage Regulation?

You could adapt a later-model Merc's voltage regulator/rectifier assy.<br /><br />This would not allow it to charge at any greater rate than the present current output of your charging system, however it would clamp the peak output voltage to a reasonable level.<br /><br />The Big-Inch I-3's and I-4's (say, early-to-mid-90's or so and later) have this regulator/rectifier assy, and so do the V6's.<br /><br />I found a couple of them in my Sierra catalog, the 18-5741 with longer leads and lugged connections would probably be suitable but you could probably make the 18-5743 unit with shorter wires terminated in bullet connections work, too.<br /><br />Check prices on Sierra stuff at www.boatfix.com as they have decent prices and, in my experiences ordering parts from them online, fast shipping.<br /><br />They list the following Merc part #s also:<br /><br />815279-A2 and 815279-3 or 815279-5. Likely the Merc #s are all superceded to one # by now, if you check www.mercurypartsexpress.com you can find out the latest part #.<br /><br />HTH and G'luck...........ed

 

[SeaKaye12]

Re: Possible to add Voltage Regulation?

Thanks so much guys...that's some great information for me to pursue. I'm making a note of the names and numbers of the products you'r suggesting.<br /><br />Chuck

 

[emckelvy]

Re: Possible to add Voltage Regulation?

P.S. I've seen these go used pretty cheaply on eBay, if you do a search on 'regulator' or 'rectifier' in the outboard section of eBay Motors you may find some.......ed

 

[JasonJ]

Re: Possible to add Voltage Regulation?

I have never had an over charging problem with my rig, and it is a 36 year old unregulated charging system. My idle voltage is in the high 12s, and my WOT voltage is in the low 14s, well within the limits. If you are really concerned, you can run accessories while under way such as running lights and VHF and whatever. I would confirm your idle and WOT voltage before spending the cash, I think you will find you are okay. Good luck...