outboard charging

[chaotic]

when running my 8hp mariner charging via rectifer unit the voltage can increase to 16volts approx. can this damage battery or log/echo intr,mts gps.If so ideas of regulating to 14volts welcome

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[ccscott49]

Was that open circuit or connected to the battery, try connecting it to the battery and see what the voltage is across the terminals. You may find it'll drop to a reasonable level. The current (amps) output of these outboards is not that great, so it might be ok. A diode in circuit will drop the voltage a volt or two, this may help if it is 16 volts, by the way you need 14.4 - 14.7 to fully charge a 12 volt battery.

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[VicS]

Yes you may damage the electronics. Some years ago in my haste to get away I ommitted to connect the battery (I use some decent crocodile clips) to the system and burnt out the voltage stabiliser circuit in my autohelm becuse the output volts from the outboard rose to such a high value. No problem with the battery connected though.
Different pieces of equipment will have different levels of tolerance however, for example my old Seafarer echo sounder will accept from a 9 volt internal battery to a 24 volt external supply.

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[andyball]

Most (check with manufacturer if unsure) electronic kit will cope with up to 16V (often says on the back/in manual)....battery won't really like it, tho' ok for short time....not too good for bulbs of course.

Had same prob. with yam 8hp....I used to switch on interior lamps/vav lights if running at high rev's for any time: this reduced voltage nicely to 14V'ish.

Naturally, a voltage regulator is ideal, but prob. expensive from outboard makers?....small scooter reg/rect would possibly be fine & cheap s/h if you want to go that way.Requires some wiring alterations of course .

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[coco]

I have a Mercury 6 HP 4-stroke and I am using a solar regulator to feed the battery from its built in generator. Although the current is not very high (max. 1.8 amps), I get a very good efficiency through the regulator which is a 4 stage charging PWM unit from Morningstar. I am using the ProStar PS-15 which also has a digital meter to check the voltage. Very nice setup, working very well and able to protect my expensive gel battery. Look at http://www.morningstarcorp.com/. There are other makes doing similar things of course.
I strongly reommend you to use any kind of regulator. You may damage your electronics and/or your battery by feeding your battery directly from the outboard (in the full charged state, the battery might cause the generator voltage to rise well above the accepted ratings).

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[Boathook]

In over 20 years with outboards I have never had a problem with the output from the charger. I must admit though that the 30 hp Honda only shoves out 10 amps into a 210 amp battery bank so in theory it is impossible to over charge. If you are worried about the voltage an interior light turned on does normaly pull the voltage down to a 'safe' level.

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[Joe_Cole]

I had exactly the same problem with my Mariner 8hp, the battery was being overcharged and was boiling. It needed constant topping up. In the end I fitted the Mariner regulator and the problem was solved. My engine is about 4yrs old.

If you give me the details of your engine I can look it up in my workshop manual.

Joe

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