Fridges

[Tony Brooks]

1 minute ago, oats said:

Thanks I said I'm useless at electrics, I was told it was, so what's a diode look like n where would I find it? Cheers

You won't find one apart from some little things that are maybe on the back of the instrument panel.

 

To split the charge from a single alternator to two battery banks you can use one of:

 

A 1, 2, both, off rotary switch.

A passive split charge diode (should have been junked years ago.

A box of electronics known as a zero volt drop split charge diode  (OK but unnecessarily complicated in my view).

A split charge relay (as you have).

A VSR

Fancy expensive alternate controller like the Sterling A to B.

 

You ave a split charge relay but I suspect its not wired for optimum operation. I bet the alternator feeds the engine battery and the relay feeds the domestic bank when ideally it should be the other way round to minimise current through the relay contact. Your contacts MIGHT have burned so another test if you have a hand held voltmeter. Set the meter to 20 volts DC and connect it across the two large nut terminals on the relay FIRST THING IN THE MORNING with discharged batteries. Star and rev engine to at least 1500 RPM. The meter should read all but zero but I suppose up to about 0.3 volt would be acceptable. If much higher we may have found where some fo your charging voltage is going.

 

 

 

 

 

[Guest]

16 minutes ago, Tony Brooks said:

OK so it is a split charge relay 9te black box) and the tap feeds the split charge relay. Nothing much wrong there so we are back to why the low voltage after six hours running.

 

No sign of a revcounter connection on the photo because not enough of the back of the alternator is shown.

 

The little blck box on the end of the alterntor is a radio suppressor.

Checked again yup you correct as usual, the thin wire I've followed through goes to the charge light ' I'm a plonka' wires from alternator : 1 thick goes to starter solenoid, thinner I mentioned goes to relay, white bolted to casing goes into loom so asume an earth. Black thick goes to mounting bracket so earth.

19 minutes ago, Tony Brooks said:

OK so it is a split charge relay 9te black box) and the tap feeds the split charge relay. Nothing much wrong there so we are back to why the low voltage after six hours running.

 

No sign of a revcounter connection on the photo because not enough of the back of the alternator is shown.

 

The little blck box on the end of the alterntor is a radio suppressor.

Checked again yup you correct as usual, the thin wire I've followed through goes to the charge light ' I'm a plonka' 

[Guest]

Could the PWM solar charge controller cause a problem? 

[Tony Brooks]

No idea what that white wire is and I can't see a revcounter feed - if you have a rev counter I have no idea where it gets its signal from unless there is a flywheel or front pulley sensor. (fairly common on some Broads boats). Are you sure the terminal on the white wire does not sit against an insulating moulding or washer. If so its probably the revocunter iwre. The flare in the photo makes identifying bits hard.

[Tony Brooks]

9 minutes ago, oats said:

Could the PWM solar charge controller cause a problem? 

I am still after the reason for the low charging voltage after six hours of running so as far as the 13V is concerned no. The worst it may do is to cause the alternator to cut in and out so the warning lamp glows and the warning buzzer chips quietly to itself and the voltage would be well above 14 volts.

 

If the batteries were well charged then the solar would have pushed the voltage up to over 13.5 with an absolutely dead alternator. If the solar was playing up the alternator would have done the same.

 

So we still need to know if the low voltage was a result of  a sick alternator not charging the batteries enough OR a faulty cell or cells drawing a high current and thereby pulling the voltage down.

 

Have you run for another six hours or so at well over tick over? Are any batteries hotter than the others? Do you have any horrible smells coming from the batteries?

Edited July 2, 2018 by Tony Brooks

[Guest]

7 minutes ago, Tony Brooks said:

No idea what that white wire is and I can't see a revcounter feed - if you have a rev counter I have no idea where it gets its signal from unless there is a flywheel or front pulley sensor. (fairly common on some Broads boats). Are you sure the terminal on the white wire does not sit against an insulating moulding or washer. If so its probably the revocunter iwre. The flare in the photo makes identifying bits hard.

Oh dear you have some patients, yes white wire goes back of rev counter still not sure where the thin one goes, my mind just not with it, got worries, wife due for big op so not concentrating. Cheers hope this pic better.

[ditchcrawler]

2 hours ago, oats said:

Just re checked everything I think, belt is notched tightened it up a bit didn't need much, if any, checked connections all clean & tight. Did find wire from alternator to diode has been spured off for rev counter but someone has connected the thin wire to the alternator & spured off the thicker wire. Could that create the problem, I am going to replace the thick wire then spur off the thin rev counter wire, if all that makes sense, out shopping now will try sending pic when I get back. Cheers

Photo please    You have

 

Edited July 2, 2018 by ditchcrawler

[Guest]

5 minutes ago, Tony Brooks said:

I am still after the reason for the low charging voltage after six hours of running so as far as the 13V is concerned no. The worst it may do is to cause the alternator to cut in and out so the warning lamp glows and the warning buzzer chips quietly to itself and the voltage would be well above 14 volts.

 

If the batteries were well charged then the solar would have pushed the voltage up to over 13.5 with an absolutely dead alternator. If the solar was playing up the alternator would have done the same.

 

So we still need to know if the low voltage was a result of  a sick alternator not charging the batteries enough OR a faulty cell or cells drawing a high current and thereby pulling the voltage down.

 

Have you run for another six hours or so at well over tick over? Are any batteries hotter than the others? Do you have any horrible smells coming from the batteries?

Batteries not hot, no smells, can't move too far now as waiting for hospital, just Started engine for a couple hours. Not a lot of sun on solar at mo showing 0.4 batteries at 12.0, fridge motor still running not turned off all morning.

[Guest]

5 mins after just starting difference between engine panel volt meter & multimeter held on relay wire from alternator 

Solar control shows 13.0 volts 0.4 a

[Tony Brooks]

OK, that white wire is on the W terminal.

One brown and yellow thin wire comes from the warning lamp and the other one goes to the split charge relay to close it when the alternator is ch

charging.

 

In an ideal world we would need charging current readings as well as voltage readings so we could tell if the alternator is faulty or the batteries are still pulling a lot of current.

 

OK from the photos your boat voltmeter is wrong  unless there is volt drop in the system.  13.93 is a far more acceptable charging voltage. maybe your batteries were really flat and are taking a long time to come up. 13.93 does not indicate a diode/phase problem.

 

Keep the charging u and I hope your wife’s hospital visit goes well.

 

[Guest]

Multimeter onto batteries shows 12.9 don't know any of this helps with diagnosis x

[Guest]

Relay wires: 1 red comes up from wiring loom connects onto relay with red wire to domestic batteries, singal red from other relay post goes to starter battery. After two + hrs running relay is hot. Alternator showing 13.9 on multimeter n batteries showing 13.2

 

[ditchcrawler]

2 hours ago, oats said:

Multimeter onto batteries shows 12.9 don't know any of this helps with diagnosis x

What voltage is the start battery with the engine running after its been going for sat half an hour? Measured on the battery terminals with your meter   

[Guest]

15 minutes ago, ditchcrawler said:

What voltage is the start battery with the engine running after its been going for sat half an hour? Measured on the battery terminals with your meter   

Same as domestic

[ditchcrawler]

8 minutes ago, oats said:

Same as domestic

12.9 with the engine running?

[Guest]

Engine running for 5 hrs, 13.4 starter. 13.3 domestic with engine running, going to stop engine now will leave to rest then recheck

[ditchcrawler]

20 minutes ago, oats said:

Engine running for 5 hrs, 13.4 starter. 13.3 domestic with engine running, going to stop engine now will leave to rest then recheck

any chance of a reading from the back of the alternator before you switch off

[WotEver]

24 minutes ago, ditchcrawler said:

any chance of a reading from the back of the alternator before you switch off

I think that’s what we had in post #76. 0.7V drop from alternator to batteries but of course at an unknown current. 

[Guest]

Blow, stopped before i saw your post will have another go tomorrow, Tony suggest something to try in the morning before starting so will try that as well first cheers

[Guest]

18 hours ago, Tony Brooks said:

You won't find one apart from some little things that are maybe on the back of the instrument panel.

 

To split the charge from a single alternator to two battery banks you can use one of:

 

A 1, 2, both, off rotary switch.

A passive split charge diode (should have been junked years ago.

A box of electronics known as a zero volt drop split charge diode  (OK but unnecessarily complicated in my view).

A split charge relay (as you have).

A VSR

Fancy expensive alternate controller like the Sterling A to B.

 

You ave a split charge relay but I suspect its not wired for optimum operation. I bet the alternator feeds the engine battery and the relay feeds the domestic bank when ideally it should be the other way round to minimise current through the relay contact. Your contacts MIGHT have burned so another test if you have a hand held voltmeter. Set the meter to 20 volts DC and connect it across the two large nut terminals on the relay FIRST THING IN THE MORNING with discharged batteries. Star and rev engine to at least 1500 RPM. The meter should read all but zero but I suppose up to about 0.3 volt would be acceptable. If much higher we may have found where some fo your charging voltage is going.

 

 

 

 

 

Hi Tony, checked reading as you suggested 00 flicked to 0.1

[WotEver]

2 minutes ago, oats said:

Hi Tony, checked reading as you suggested 00 flicked to 0.1

Great. Another check, with the engine running at a fast idle and again with discharged batteries (so in the morning), would be to put one multimeter lead on the positive post of the battery and the other on the main (B+) alternator output. Again it should read a very low figure. If it reads half a volt or more then you either have a very poor connection somewhere or severely undersized cabling. Hopefully it’ll only show 0.1V or so. 

[Tony Brooks]

36 minutes ago, oats said:

Hi Tony, checked reading as you suggested 00 flicked to 0.1

Ok. That rules out the relay contacts.

 

Now do WotEver's test but I would say at 1200 to 1500 rpm to make sure the alternator is running at high output and I emphasize when WotEver said battery post he meant the LEAD post, NOT the clamp/terminal. Push the meter probe into the lead.

 

While you are at it repeat between the alternator case and the lead of the negative terminal. One hopes for an even lower reading but if not there is a poor negative connection somewhere.

[WotEver]

1 hour ago, Tony Brooks said:

While you are at it repeat between the alternator case and the lead of the negative terminal. One hopes for an even lower reading but if not there is a poor negative connection somewhere.

Good idea, I’d not have thought of that

 

[Guest]

2 hours ago, WotEver said:

Great. Another check, with the engine running at a fast idle and again with discharged batteries (so in the morning), would be to put one multimeter lead on the positive post of the battery and the other on the main (B+) alternator output. Again it should read a very low figure. If it reads half a volt or more then you either have a very poor connection somewhere or severely undersized cabling. Hopefully it’ll only show 0.1V or so. 

Hi which is the B+ on alternator sorry I'm thick as far as electrics are concerned cheers

[WotEver]

8 minutes ago, oats said:

Hi which is the B+ on alternator sorry I'm thick as far as electrics are concerned cheers

The one with the fat wire on it. It will almost certainly be marked B+ on the alternator case.