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wellerd
wellerd

Posted: Mon Jul 13, 2015 2:38pm

Post Subject: Warning Light

I have a Beta 38 with a 2AB instrument panel, recently on first starting from cold all is well on the panel (with revs at about 1400) but then after anything from 10 to 30 seconds the tacho starts to act erratically finally reading zero and the starter battery indicator lights up and the buzzer sounds if I then increase the revs up to about 2000 after anything from a few seconds up to a minute the tacho comes back to life and the warning lamp goes out and buzzer stops sounding, after this initial trouble for the rest of the day everything is fine with no further occurrences. I have checked the wiring loom couplings as I know these can cause problems spraying the connectors with WD40 but this has not helped. I also know that whilst this event is happening the starter battery is not charging as I have a separate gauge to monitor this with a direct connection to the battery ( so the warning is correct). All wires to the Alternator are connected, three small wires plus the main and no wires have come of the instrument panel, the engine is 6 years old and a new battery was fitted two years ago. Please can your experts help

Tony-B
Tony-B

Posted: Mon Jul 13, 2015 3:10pm

Post Subject: Warning Light

I would first check the alternator belt for tension and condition. A loose belt can slip when under a high load (like first thing in the morning) and then grip as sections get hot. Once the initial high charge is over a slack belt can drive the alternator perfectly well. The tacho certainly confirms a lack of charge. It it is not the drive belt then I fear it may be worn brushes in the alternator making and breaking contact, however worn brushes in 6 years seems rather quick so it could be some other alternator fault like a faulty doides or in this case "dry" solder joints. I am not sure from your post if this is a twin or single alternator engine. If its a twin then I think we can be certain its the engine alternator playing up. If its a single alternator AND if the charge wiring is correct then no charge to the engine battery with a faulty alternator is as would be expected.

wellerd
wellerd

Posted: Tue Jul 14, 2015 2:42pm

Post Subject: Warning Light

Thank you Tony for your swift response. I should have mentioned that it is a two alternator set up. I have checked the fan belt tension and that is fine, so it looks like investing in a new alternator, what is in your opinion on new or having my old unit refurbished and do you know any firms that can do either. My boat is kept in Pryford marina on the river Wey is there anyone local . Thanks again Francis NB Nauti-Lass

Tony-B
Tony-B

Posted: Tue Jul 14, 2015 2:56pm

Post Subject: Warning Light

Pity you did not post this a week or so ago because I could have popped into Pryford and tested it for you. I know of no-one local to you but I would have thought the marina engineers should know, or the local garages. I would always take it for testing and overhaul because most places will tell you if its cheaper to buy a replacement and then they are less likely to charge you the "marine" mark up. Before you go down that route do you have solar charging connected to the engine battery or some form of alternator combiner in use? If so next time it does it try putting some kind of load on the engine battery (glow plugs possibly) if that "cures" the problem then it is likely to be the solar or other alternator's charging voltage causing the engine alternator to shut down.

wellerd
wellerd

Posted: Tue Jul 14, 2015 3:48pm

Post Subject: Warning Light

Hi Tony I do have a solar panel but it is connected to the domestic bank only, through a solar controller and the panel was fitted at the same time as the boat was built so I would have thought I would have had trouble before, but I will try loading the battery as you suggest. I also have a split charger that charges the thruster battery through a Sterling splitter, which is on the same circuit as the starter battery perhaps I could try to operate the thruster whilst the non charging is happening and see if that helps to power up the alternator. It does seem prudent to have the Alternator tested and as you say to keep the marine part quiet to avoid the "Marine Surcharge". Thanks again for the suggestions Francis

Tony-B
Tony-B

Posted: Tue Jul 14, 2015 4:04pm

Post Subject: Warning Light

As long as the solar is not connected to the engine battery and the other alternator is in now way connected to the one that is playing up you can forget about loading the engine alternator. It should not have any effect, it only has an effect it the load pulls the battery voltage down a bit so the engine alternator's regulator can start working again. If there is no other charge source involved then there is nothing to make the engine regulator shut the alternator down. By all means try it though. However all this assumes the rev counter feed is taken from the engine alternator, if by some chance its on the domestic one then turning a domestic load on when the problem occurs is worth a try.

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