Domestic Battery Warning Light coming on. Belt not slipping.

[Motters79]

Hello everyone!

 

Since I installed my solar panels several months ago (they work great) every time I run my engine my domestic battery light flickers and the alarm sounds very weekly. The belt isnt slipping however and it seems to charge OK. I get 14+ volts. Any ideas what's happening? It seems to be related to there being 2 power sources active at once. Any knowledgeable advice would be appreciated.

 

I have a Beta Marine 43 with a 95 amp domestic alternator and 500w of solar coming through a 40amp Tracer BN charge controller.

 

Thanks

[nicknorman]

9 minutes ago, Motters79 said:

Hello everyone!

 

Since I installed my solar panels several months ago (they work great) every time I run my engine my domestic battery light flickers and the alarm sounds very weekly. The belt isnt slipping however and it seems to charge OK. I get 14+ volts. Any ideas what's happening? It seems to be related to there being 2 power sources active at once. Any knowledgeable advice would be appreciated.

 

I have a Beta Marine 43 with a 95 amp domestic alternator and 500w of solar coming through a 40amp Tracer BN charge controller.

 

Thanks

You haven’t really said when this happens : solar working hard, batteries nearly fully charged, batteries not well charged etc.

 

If it happens when the batteries are fully charged or nearly so, and it’s sunny, I might just be a “feature”. But if it happens when the batteries are not well charged and/or the solar not working, I’d suspect a faulty diode in the alternator. Try covering the panels (or do this in the dark, away from other people) and turn on some things to drain the battery a bit. Then start the engine and see what happens. If all is fine, I wouldn’t worry about it (though I appreciate it is irritating). If it still does it, the alternator is faulty.

[Motters79]

1 minute ago, nicknorman said:

You haven’t really said when this happens : solar working hard, batteries nearly fully charged, batteries not well charged etc.

 

 

Sorry nicknorman. You're right. It doesn't happen always, I'd say it is occurring when I'm cruising mid day and the batteries are already pretty full from solar charging. I will try to confirm this. The alternated is certainly able to charge. Maybe it is just 'a feature ' like you said.

[Tony Brooks]

When it happens turn on a fair electrical load like a water or shower pump. If the symptoms stop it is probably more or less fully charged batteries allowing a high solar voltage to cause the alternator's voltage regulator to oscillate on and off. I don't think that is anything to worry about but if its a faulty diode then it is but at over 14 volts I doubt its a diode.

[Dr Bob]

I dont want to hijack this thread and apologies to Motters if it steers off course, but hopefully it will generate some useful ideas.

We have the same problem on our Beta 43, 90A domestic alternator, 500W of solar...since putting the extra couple of solar panels on in January. Cant see a warning light but the alarm on the panel sounds weakly during part of the charge cycle. Our battery bank is 660Ahr (6*110Ahr) in reasonable nick....ie at least 90% of original capacity from voltage at rest/Ahrs used. Overnight we typically use 100Ahrs. On starting up, the voltage going in from the alternator is circa 13.8/13.9V @ 60A initially. At this voltage we get the weak alarm. The A's drop and the voltage rises. At around 14.05-14.10V the noise stops and does not appear again unless something with a bit of power demand comes on to drop the voltage back to below 13.9v. Typically the charge current will be circa 40-50A at that point. I am making an assumption the charge is in Bulk when below 14.0v and absorption when above it. Once it is in absorption ie 90%+ charged, the noise stops.

We are of course using a Sterling AtoB which complicates things. Performance of the charging hasnt changed in the last 12 months, but we only started noticing the noise after we increased the size of the solar (we have 2 separate controllers each fed by 2 panels in parrallel).

The noise is not affected by the panels as it does not change as you move from full sun into a tree lined section. My 2 solar controllers are usually in float when the alternator/AtoB is charging

From all of this, my conclusion is

- I am charging ok, Voltage rises to 14.5V at end of charge with tail currents down to 1% in times that you would expect with lead acids. No difference in charging with a year ago. Batteries doing well.

- It seems like it is a low voltage alarm....but the BMV is showing good voltages....which agree with my £50 multimeter and the voltages on the solar controller.

- I suspect a bad joint on one of the wires to the ignition panel but I have pulled them all apart and cleaned them and reassembled....with not change.

 

Motters problem may be similar so important to know when the noise appears on his system.

[WotEver]

1 hour ago, Dr Bob said:

The noise is not affected by the panels as it does not change as you move from full sun into a tree lined section. 

In which case I can’t see it having anything to do with the extra solar panel. 

[Dr Bob]

8 minutes ago, WotEver said:

In which case I can’t see it having anything to do with the extra solar panel. 

No I agree....and least not in my case. Any ideas on what might be causing it. What wires activate the alarm and if it was a 'low alternator charge voltage' then what voltage would set it off? Could it just be a duff buzzer?

To the OP....What sort of panel does your beta 43 have? There are different panels. Ours is the 'Murphy deluxe 2C' panel IIRC.

[Buckely]

If the light/buzzer is coming on, you have a voltage across it. Obvious but true. Measure  it, and measure the voltage each side wrt ground. If you have a MPPT solar controller moving to shade doesn't prove much. The controller can step up the voltage as well as reduce it, for maximum power transfer. The current will of course go down if the output power reduced. I suspect that one side of the lamp is being held high by the solar, the other side is going low enough when the alternator cannot main 14.2 v, due to high current, to cause the lamp, buzzer to come on.

 

[nicknorman]

The controller can only step up voltage when it has sufficient input power to provide the output current that the output voltage will cause. Obviously it also depends on what we mean by “shade”. The middle of a tunnel would be a better test!

[Dr Bob]

25 minutes ago, Buckely said:

If the light/buzzer is coming on, you have a voltage across it. Obvious but true. Measure  it, and measure the voltage each side wrt ground. If you have a MPPT solar controller moving to shade doesn't prove much. The controller can step up the voltage as well as reduce it, for maximum power transfer. The current will of course go down if the output power reduced. I suspect that one side of the lamp is being held high by the solar, the other side is going low enough when the alternator cannot main 14.2 v, due to high current, to cause the lamp, buzzer to come on.

 

Now that is an interesting post. If i can see the wires to the buzzer, I will try it....we are off the boat for 2 days so back tomorrow. Where do the wires from the buzzer go? Why would the solar input not be on  the same side as the alternator input?

To Nick,  yes a tunnel would be better but there are more trees than tunnels.

 

edit to add.....OP, please jump back in or else this thread my not be answering your problems.

Edited August 6, 2018 by Dr Bob

[Motters79]

Hey guys, sorry I went quiet. I've tried switching on various appliances when the light/alarm is is happening and it makes no difference. I've also tried covering the panels whilst the problem is occurring which also makes no difference. What i didn't mention in the original post is that it doesn't happen in the evening or mornings when the system voltage is lower, so there is definitely a link between the system voltage pre-engine start and the occurrence of the problem. My understanding of electrics is limited. Does this shed any light on the subject?

[Dr Bob]

29 minutes ago, Motters79 said:

Hey guys, sorry I went quiet. I've tried switching on various appliances when the light/alarm is is happening and it makes no difference. I've also tried covering the panels whilst the problem is occurring which also makes no difference. What i didn't mention in the original post is that it doesn't happen in the evening or mornings when the system voltage is lower, so there is definitely a link between the system voltage pre-engine start and the occurrence of the problem. My understanding of electrics is limited. Does this shed any light on the subject?

Probably more important is turning various appliances on and off when the engine is running but the alarm is not sounding. Does a load make the alarm sound?

Am I understanding you right that when you start your engine first thing in  the morning, you dont get the alarm..but at some time later it starts. Is it sounding as the batteries get to 95% plus charge. Are you able to quote any voltage figures for when it happens as I have done?

[Tony Brooks]

Begins to sound much more like a diode problem.

 

Voltmeter between D+  and B+ with everything still connected and rev engine when the problem is happening.

 

In theory the meter should read zero but will probably read a few mV. If it reads half a volt or more suspect a diode problem. Sir N's test, not mine).

 

 

 

Edited August 7, 2018 by Tony Brooks

[Boater Sam]

The indicator lamp  is between the alternator D+ and the ignition switch. If the 2 voltages are the same then it stays unlit and the buzzer is quiet.

If the voltage on either side goes up or down with regards to the other side, it will glow and the buzzer sound weakly.

So if the alternator voltage is high but the solar drives the ignition voltage even higher, it will glow.

I would think it depends on where the solar is connected to the battery.

[WotEver]

48 minutes ago, Boater Sam said:

The indicator lamp  is between the alternator D+ and the ignition switch. If the 2 voltages are the same then it stays unlit and the buzzer is quiet.

If the voltage on either side goes up or down with regards to the other side, it will glow and the buzzer sound weakly.

So if the alternator voltage is high but the solar drives the ignition voltage even higher, it will glow.

I would think it depends on where the solar is connected to the battery.

I can’t see that. It’s only happening when the batteries are at high SoC, so little current flowing and consequently very little voltage drop anywhere. If the Solar is lifting the voltage at the batteries it would be the same voltage at the ignition switch. I’m with Tony B that it sounds like a diode failure (one or more shorted). That’s the only way that I can think of that D+ and B+ can be a long way apart. 

[PeterF]

As this is the domestic batteries could you be seeing a large voltage difference between the engine and domestic batteries and the warning light is the one cross connection, does the solar push the domestic voltage higher than the alternator foes, which would explain this happening now. On my Barrus shire the domestic warning light provides a cross over but looking at the wiring diagram it has diodes in the domestic alternator D+ wire to prevent a higher voltage on D+ from flowing to the engine battery.

[Tony Brooks]

21 minutes ago, PeterF said:

As this is the domestic batteries could you be seeing a large voltage difference between the engine and domestic batteries and the warning light is the one cross connection, does the solar push the domestic voltage higher than the alternator foes, which would explain this happening now. On my Barrus shire the domestic warning light provides a cross over but looking at the wiring diagram it has diodes in the domestic alternator D+ wire to prevent a higher voltage on D+ from flowing to the engine battery.

Actually the cross connexion via the waning lamp is only there because boat builders etc. can't be bothered to fit a second warning lamps and relay to energise it. Omitting the second warning lamp and relay on a twin alternator boat makes fault finding far more difficult and sometimes you may have diodes gone (low output) and not even know it.

Edited August 7, 2018 by Tony Brooks

[Iain_S]

5 hours ago, Tony Brooks said:

Actually the cross connexion via the waning lamp is only there because boat builders etc. can't be bothered to fit a second warning lamps and relay to energise it. Omitting the second warning lamp and relay on a twin alternator boat makes fault finding far more difficult and sometimes you may have diodes gone (low output) and not even know it.

 Beta do.  (OP states Beta 43)

Power for the leisure alternator lamp comes from a wire on B+ to lamp to relay. A connection to the negative on the warning buzzer goes via a diode from the relay side of the lamp (which can cause weird effects if the diode goes faulty or the diode pack gets wet!)

[Tony Brooks]

7 hours ago, Iain_S said:

 Beta do.  (OP states Beta 43)

Power for the leisure alternator lamp comes from a wire on B+ to lamp to relay. A connection to the negative on the warning buzzer goes via a diode from the relay side of the lamp (which can cause weird effects if the diode goes faulty or the diode pack gets wet!)

So? I know many do but in my view the diode is just a bodge and it is not best practice. But each to their own.

[Dr Bob]

8 hours ago, Iain_S said:

 Beta do.  (OP states Beta 43)

Power for the leisure alternator lamp comes from a wire on B+ to lamp to relay. A connection to the negative on the warning buzzer goes via a diode from the relay side of the lamp (which can cause weird effects if the diode goes faulty or the diode pack gets wet!)

Iain, I am not understanding where the diodes are here. Physically are they located on the small circuit board that the buzzer is mounted on? Is the B+ connected to the negative on the warning buzzer?

[nicknorman]

Yes. The purpose of the diodes (one for each warning circuit) is to provide a logical “OR” function. You couldn’t just connect all the warning circuits directly to the buzzer, otherwise if one light illuminated, they’d all illuminate.

[Iain_S]

2 hours ago, Tony Brooks said:

So? I know many do but in my view the diode is just a bodge and it is not best practice. But each to their own.

The diode is just for the warning buzzer. The D+ supply is from the leisure battery bank, via alternator B+, lamp and relay.

 

1 hour ago, Dr Bob said:

Iain, I am not understanding where the diodes are here. Physically are they located on the small circuit board that the buzzer is mounted on? Is the B+ connected to the negative on the warning buzzer?

On the board, yes. The connection is from the warning light, the other side of which goes to B+. The connection to the buzzer will be at +12V with engine switched off. When the key is turned, the relay closes and that point goes negative , with the 12V across the lamp. Once the engine is running, there is +12V on each side of the lamp, so it goes out and buzzer goes silent. 

[Tony Brooks]

1 hour ago, Iain_S said:

The diode is just for the warning buzzer. The D+ supply is from the leisure battery bank, via alternator B+, lamp and relay.

 

That is what I understood was the case but Ian-s seemed pretty adamant about why the diode is there.

 

Whatever he & presumably Beta say I will stay convinced one warning lamp for two alternators is just corner cutting.

Edited August 8, 2018 by Tony Brooks

[Iain_S]

8 hours ago, Tony Brooks said:

That is what I understood was the case but Ian-s seemed pretty adamant about why the diode is there.

 

Whatever he & presumably Beta say I will stay convinced one warning lamp for two alternators is just corner cutting.

There are two warning lights. The engine alternator one is connected "conventionally" between ignition switch and engine alternator.

I think we're at cross purposes here : I agree with the main clause of your last sentence, as, presumably, do Beta 

[nicknorman]

10 hours ago, Tony Brooks said:

That is what I understood was the case but Ian-s seemed pretty adamant about why the diode is there.

 

Whatever he & presumably Beta say I will stay convinced one warning lamp for two alternators is just corner cutting.

The diodes have nothing fundamentally to do with twin alternators. They merely allow any one of the warnings (temperature, pressure, domestic not charging, engine not charging) to sound the buzzer without affecting the other lights.

 

I suppose it might be different with older Beta 43s (they have been around for a long time, and have evolved) but on ours there is a warning light for each of the two alternators. The engine alternator warning light is of course fed from the ignition switch. The domestic one is fed from the domestic batteries via a relay which is turned on when the ignition is turned on.