Cause of high voltage alarm?

[Caddy Shack]

Shortly after starting my engine I'm seeing 15-16 volts on my meter, followed by a high voltage alarm. I'm not connected to shore power. The only recent change is to install a new start battery, which involved two leads (+ and -) so I can't have cocked that up...start battery is charged by engine only, house bank by engine and smart charger on shore power.

Any suggestions appreciated.

Thanks

[SilentOption]

Could be as simple as a failed alternator voltage regulator. I wouldn't run the engine in that condition more than you need to for troubleshooting. You absolutely can cause a battery to blow apart from overcharging. That will be quite a mess to clean up.

[rgleason]

Internal or ext reg?
Check and clean all connections.
If ext reg with voltage sensor wires make sure they are located at or close to the battery.

Read marinehowto.com article on this topic.

[Caddy Shack]

External. A bit more info. When I initially started the engine, I was plugged into shore power (normally I unplug whenever running but I forgot). There was a red error code on the regulator and h voltage alarm.

I shut down engine and unplugged shore power. On restarting, the error code on regulator cleared but I still have the high voltag reading and alarm.

Thanks again.

[Bleemus]

Sounds like a faulty regulator to me.

[smac999]

Are both batteries high or only one? How does the alt charge both? Whete is the voltage sense wire connected too?


The shore power means nothing. Both can be on just fine.

[belizesailor]

+1. Sounds like a failed regulator to me. I had an old Ample Power regulator fail in the same way (high voltage). Great regulators and very dependable, but everything fails eventually. Mine that failed was about 15 years old and was repairable.

Ample Power used to do repairs, but they cut back on that service.

I cant load their web site on my phone. Can anyone else?

[kmacdonald]

Is the voltage sense wire connected to the battery? If it didn't get connected to the battery when the battery was changed it would tell the regulator the alternator output is 0 volts and cause it to output max voltage trying to get the battery to about 14.6 volts or whatever the regulator is set at.

[Sailmonkey]

Well I’ll be dammed. I’ve just had my ample power sarV3 fail at the 10 year mark. Although a different failure.

[Sailmonkey]

Originally Posted by belizesailor

Ample Power used to do repairs, but they cut back on that service.

I cant load their web site on my phone. Can anyone else?

My research has led me to believe that they’re out of business.

[belizesailor]

Yeah, I thought they might be, they had been scaling down for a while. Shame, good product.

[rgleason]

I think this is a wiring problem not a failed regulator.
Without givimg the full set of conditions how can you expect good advice?

[skipmac]

ALWAYS check the easy solutions first. If that's the problem you've saved yourself a lot of time and money. If it isn't the cause you haven't invested much in time/money to check it so small loss.

In this case, since the problem started after a battery change then I would check the wiring, specifically the voltage sense wire to the regulator.

If that isn't it then start suspecting the regulator itself.

[Caddy Shack]

Originally Posted by rgleason

I think this is a wiring problem not a failed regulator.
Without givimg the full set of conditions how can you expect good advice?

Good point - what other info would you like?

[hellosailor]

I'll hope kmac nailed it on the head. If for any reason the alternator/regulator is not getting back the information on the voltage sense wire ("Are you charged yet?") it kicks the alternator voltage up up up. And if you get 15-16 volts on the boat wiring, that can blow out all the electronics and bulbs. So you might want to make sure everything else is disconnected wile you check this out.