Batteries charging at 17 volts

[Wakes]

I have tested the batteries directly with a multimeter also with exactly same voltage recorded.

[rusty69]

29 minutes ago, Wakes said:

I have tested the batteries directly with a multimeter also with exactly same voltage recorded.

Post a picture of the cable connections at the back of your alternator (Assume you only have one). Someone will then be able to advise where to put your meter probes to measure the output (Usually between the big cable and alternator casing- but may not be)

Edited December 2, 2018 by rusty69

[MtB]

1 minute ago, Wakes said:

I have tested the batteries directly with a multimeter also with exactly same voltage recorded.

 

Ok can we have a recap then please? Could you post a list of voltages. We need starter battery terminal voltage with the isolator in all three positions (A, B, A+B), and domestic battery terminal voltage with isolator switch in those same three positions 

 

all with the engine running please, and with the solar panels covered up. All readings to be taken with the multi meter not the noddy plug in or the solar controller. 

 

Tganks. 

[ditchcrawler]

My thoughts, the domestics are being charged at 17 volts, the alternator is putting out 14 volts, with the switch in both, both batteries are connected to the solar, with it switched to 1 the alternator is only connected to the starter which is reading 14 whereas the domestic is still connected to solar measuring 17. hat is unless I lost track working through the thread.

[Wakes]

The selector switch is set up as follows:

Position 1 - Leisure batteries

Position 2 - starter battery. 

Both - Leisure and Starter

 

Position 1 always gives out up to 17v

Position 2 is normal giving up to 14v 

Both  gives out up to 17v 

 

with the solar disconnected, same as above.

 

With engine running have tested all 3 batteries with multimeter and only starter is normal at around 14v full revs. The 2 leisure batteries register up to 17v 

 

Edited December 2, 2018 by Wakes

[Alan de Enfield]

1 minute ago, Wakes said:

The selector switch is set up as follows:

Position 1 - Leisure batteries

Position 2 - starter battery. 

Both - Leisure and Starter

 

Position 1 always gives out up to 17v

Position 2 is normal giving up to 14v 

Both  gives out up to 17v 

 

 

Where are you measuring these voltages ?

 

Please answer the questions as per post #23 & post #28

 

There is no help in just saying position 1 gives 17v.

[Wakes]

I just tested all three batteries with multimeter with engine running and in all battery selector positons. This time  everything was high. I then put multimeter on alternator and couldn’t get a reading from any of the terminals however there was a device next to alternator with wires coming from alternator and i measured a red and a yellow wire and it then recorded voltage up to 17 volts, possibly higher if I had gone full throttle. I’m guessing that it is the alternator at fault judging by this. 

[ditchcrawler]

6 minutes ago, Wakes said:

I just tested all three batteries with multimeter with engine running and in all battery selector positons. This time  everything was high. I then put multimeter on alternator and couldn’t get a reading from any of the terminals however there was a device next to alternator with wires coming from alternator and i measured a red and a yellow wire and it then recorded voltage up to 17 volts, possibly higher if I had gone full throttle. I’m guessing that it is the alternator at fault judging by this. 

Did you try cleaning the crap of that terminal with the large brown wire on it. If you haven't got any volts coming out of the alternator it has to be coming from somewhere else, back to solar or shore supply . The yellow wire is going to the starter solenoid. Even if the alternator was not turning there should be battery voltage on the fat brown wire. You don't have a second alternator on the engine do you? 

[Tony Brooks]

That is a 10 or 11AC with external regulator/control box. Probably also has a "flasher unit" style hot wire ignition warning lamp controller but later versions used a special relay to do both jobs.

The control box needs energising via a relay (usually) and if that relay. If the relay contact input is not connected to a point that is connected to the batteries wwhen the switch is in 1,2, both then in one or two switch positions the control box will not see the charging voltage so will give a high reading.

 

This is what I was thinking about earlier when I talked about battery sensed alternators.

 

I will try to find an 10/11AC circuit diagram.

 

In reality its time for a minor rewire and a change to an A127.

[Tony Brooks]

Here you go but there are different systems like the one with the external warning amp control and the one that uses a different relay to do the same job.:

 

 

If you switch away from the engine battery the control will not be able to see the charging current. I suspect the 6RA C1 connection needs feeding from the common terminal on the 1,2,both, off switch.

 

 

Edited December 2, 2018 by Tony Brooks

[Wakes]

I just looked at the alternator again and found another wire at the bottom and this time gave a reading, again sky high 

[Bod]

How are the leisure batteries wired?

Parallel or series?

A photo of them might help. 

 

Bod

[Wakes]

Parallel wired, see photo.

[tizzy]

Have you checked the split charge relay. If you have a battery charge controller monitoring the domestics and the relay is goosed then the alternator will increase voltage in a vain attempt to charge to domestics.

 

Easy to check by putting a jump lead between starter and domestic positives. If it all goes back to normal then that is the problem.

[Tony Brooks]

It probably does not use a split charge relay because of the 1,2,both, off switch but that switch can be wired in at least two ways.

 

1. As a charge distribution switch fed from the alternator.

 

2. As  battery bank election switch

 

In either case one must ensure the 4TR can see the charging voltage whatever position the switch is in apart from off.

 

In the case of 1 above the system should have, but may well not, at least one master switch.

 

In the case of 2 the 1,2,both,off switch also acts as a master switch.

 

The 11AC will probably produce between 30 and 40 amps maximum and the 10AC less. The performance would be greatly improved with a 70 amp A127 and the a Voltage Sensitive Relay would automate the 1,2,both, off switch AND allow the solar to charge both banks whine one (the domestic hopefully) is tolerably well charged. But it would then need a couple of master switches as well.

 

 

Measure the voltage on the 4TR terminal plus or the relay terminal C1 or C2 with the switch in the different positions and the engine revving. All positions should read the charging voltage but I bet in at least on it will just be the battery voltage without any charging voltage on top of it.

 

We are all guessing (some with more idea about how the system works than others) because we do not know in detail how it is wired and I suspect Wakes does not know either. I also suspect that unless the person who did the engine work was a "grey beard" they did not know either so anything may have happened. It might be a faulty track in the 1,2,both, off switch but the tests I outlined above should give a clue - still only guessing.

Edited December 2, 2018 by Tony Brooks

[Wakes]

Thanks for the help Tony, so I suspect it is the alternator that needs replacing. I will put this information to the boat yard where I’m moored.

[Tony Brooks]

8 minutes ago, Wakes said:

Thanks for the help Tony, so I suspect it is the alternator that needs replacing. I will put this information to the boat yard where I’m moored.

I don't think so from the point of view of sorting out the 17 volts but to do that the circuit needs testing. From a practical point of view to optimise the charging I think it does BUT it will need a degree of rewiring to cope with the higher current and the simpler warning lamp circuit. As I said, ideally doing away with that switch, fitting a VSR and master switch but it all depends upon money.

 

If per chance there is a fault in that switch it might ruin a new alternator.

 

The A127 should be a direct replacement as far as the fixings are concerned.

 

Highline have been around long enough to fully understand that system but I am not sure about their staff.

Edited December 2, 2018 by Tony Brooks

[rusty69]

9 minutes ago, Wakes said:

Thanks for the help Tony, so I suspect it is the alternator that needs replacing. I will put this information to the boat yard where I’m moored.

That's not what I understood from Tonys post.

 

Crossed post

 

Edited December 2, 2018 by rusty69

[Tony Brooks]

Better still find the 4TR and the 6RA or 16RA relay and do the tests I last described and tell us the results.

[Boater Sam]

I suspect that the 4TR is energised only with the engine battery hence the high readings when on leisure battery and that the 1-2-3 switch is only switching the charge from the alternator.

If so its a chronically out of date system, time for a new alternator, a rewire and VSR, dump the switch.

Are there separate isolator switches for the batteries?  

[Tony Brooks]

2 hours ago, Boater Sam said:

I suspect that the 4TR is energised only with the engine battery hence the high readings when on leisure battery and that the 1-2-3 switch is only switching the charge from the alternator.

If so its a chronically out of date system, time for a new alternator, a rewire and VSR, dump the switch.

Are there separate isolator switches for the batteries?  

I agree and have said as much but I think the 4TR should see the charging voltage when the switch is in the both position, it seems it does not so the more I think about it the more I suspect a fault in the 1,2,both, off switch that isolates the 4TR when not set to the engine battery. In view of the recent work it might be a cable that has fallen off and been replaced on the wrong point but without some tests who knows, especially as we still don't know if its wired as a charge selection switch or a battery bank selection switch and I doubt Wakes does not either.

 

FWIW When I left the hire fleet in 1976 the AC series of alternators had been superseded by the ACR range and they were superseded by the A127 range in the 90s so AC parts will be harder and harder to find so well worth changing.

[trackman]

My money is on a failed field diode in the alternator. I've seen 16+ volts from an alternator which had failed that way.

The work on the engine may be a coincidence, though I suppose it's possible those doing the work ran the engine without connecting the alternator properly to a battery & damaged it.

If that's it, a good car electrical specialist should fix it and not charge a fortune. I got mine done for the cost of the parts, less than £20.

Edited January 8, 2019 by trackman

[Tony Brooks]

12 minutes ago, trackman said:

My money is on a failed field diode in the alternator. I've seen 16+ volts from an alternator which had failed that way.

The work on the engine may be a coincidence, though I suppose it's possible those doing the work ran the engine without connecting the alternator properly to a battery & damaged it.

If that's it, a good car electrical specialist should fix it and not charge a fortune. I got mine done for the cost of the parts, less than £20.

No field diodes in the 10 or 11 AC alternators. They use an ignition controlled relay for energisation via a remote regulator.

 

Its machine sensed 9 diode alternators that do that.

 

The only thing I can see that would cause it on the AC range is resistance on the relay power circuit so the regulator sees a lower voltage than battery voltage.

Edited January 8, 2019 by Tony Brooks