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AnthonyB
AnthonyB

Posted: Mon Nov 09, 2015 3:40pm

Post Subject: high charge voltage

I recently noticed that the charging voltage showed approx16 volts, does this mean my (beta) regulator is failing? My engine is 2009 Beta JD3 tug with single 70A ISKRA alternator feeding starter + 4 x 110A domestic batteries via a Victron Cyrix. This arrangement has worked fine for 6 years, I recently fitted solar panels via mppt controller but don't think this should have caused this. Any help very welcome.

Tony-B
Tony-B

Posted: Mon Nov 09, 2015 6:43pm

Post Subject: high charge voltage

First I need to know if your alternator is machine sensing or battery sensing. Machine sensed alternators measure the voltage they are controlling inside the alternator while battery sensed ones have an extra wire and measure the voltage at the batteries. In the latter case when anything cases voltdrop on the main charging circuit the alternator will increase its regulated voltage to compensate. This can lead to high voltages at the alternator. I think Beta normally fit machine sensed alternators so if there is a high voltage (check with a hand held voltmeter across the batteries) the problem is most likely to be with the alternator itself. HOWEVER with no information about how you use the boat and size of solar panels I can not rule out the solar brining the batteries to a much higher state of charge that what was normal so the alternator output (amps) is very little. In that scenario it could be the solar in put overriding the alternator and trying to do an equalisation charge. To be sure cover the solar panels and measure the voltage. If it is still high I would suspect a field/auxiliary diode or solder joint has failed so take the alternator off and get it tested. It would be as well to clean and check all the battery and charging circuit terminals to make sure they are still tight. The Cyrix is a split charge relay and with a machine sensed alternator it should not be the cause.

AnthonyB
AnthonyB

Posted: Wed Nov 18, 2015 10:35am

Post Subject: high charge voltage

The alternator is machine sensing (B-, B+, W connections) it charges via beta 200-02580 controller. Solar panels are 2 x 150W Biard semi flexible wired in series charging via Solar 40A mppt controller. I have tried with solar disconnected and charge voltage still high (16.01v at alternator, 15.91v at batteries. At present boat used relatively little so not much load on batteries (bilge pump & Alde boiler). Could the alternator have been damaged by turning off engine switch before engine has fully stopped?

Tony-B
Tony-B

Posted: Wed Nov 18, 2015 11:18am

Post Subject: high charge voltage

As you have ruled out the solar then it must be related to the alternator. Although you say the alternator is machine sensed I think the external controller probably has the ability to convert it to battery sensed when the charging voltage has risen high enough, depending upon exactly how it is wired. Unfortunate I can not find much on-line information about the controller or a wiring diagram. I suspect the controller has another connection on the alternator, probably a flying lead coming out of the alternator case. If it does try disconnecting this lead or if not disconnect the multi-plug on the controller. Then start and rev the engine. If the voltage stays around 14.4ish then the controller is faulty (not unknown, I think Beta may have discontinued the option|). If it stays high then its inside the alternator so it needs to come off for testing by a specialist. In this case it could be a faulty internal regulator, ,a blown field diode, or a poor solder joint. You can not damage the alternator by turning the "ignition" switch off, engine running or not, only by disconnecting the battery from a running and charging alternator. All this assumes the Beta external regulator works as I think it does. If you have the instructions and wiring diagrams you could scan them and email them to me to double check. Tony@tb-training.co.uk

Tony-B
Tony-B

Posted: Wed Nov 18, 2015 6:39pm

Post Subject: high charge voltage

One other possibility I should have mentioned. The Beta Controller should have its own sense wire. Normally I would expect it to connect to the battery positive but it could connect to any positive connection. If the other wiring between alternator and where ever that sense wire is connected develops resistance you will bet a high charging voltage so check all the battery connections and wiring connections on the charging circuit for tightness, cleanliness and having a good tight crimp. Pay particular attention to any multi-plugs you may have in the main engine wiring harness.

Tony-B
Tony-B

Posted: Wed Nov 18, 2015 6:39pm

Post Subject: high charge voltage

One other possibility I should have mentioned. The Beta Controller should have its own sense wire. Normally I would expect it to connect to the battery positive but it could connect to any positive connection. If the other wiring between alternator and where ever that sense wire is connected develops resistance you will bet a high charging voltage so check all the battery connections and wiring connections on the charging circuit for tightness, cleanliness and having a good tight crimp. Pay particular attention to any multi-plugs you may have in the main engine wiring harness.

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