Charge light staying on leisure battery not charging

[Boatymcboaterson]

So we have solved this problem around three times. Originally battery left to go flat when work being done- okay, not revving enough - okay, electrical switch not turned fully enough - okay. Yet again the charging light remains on and our leisure battery is nearing flat!

 

The wires, alternator, regulator, split diode everything have been tested and are fine. We have a Lister SR2 and are about to pull out our hair. Any suggestions?

[Tracy D'arth]

When you have explored all the possibilities, the impossible is the cause.

 

If the battery + is connected to the + terminal on the alternator and the - is also connected by wire or by virtue of being attached to the engine.

then connecting the D+ terminal briefly to the + terminal, the alternator will charge. Check with your multimeter that the battery voltage rises.

 

If that works, its either the wiring, or the warning lamp or the engine is not running fast enough.

 

Warning lamp needs to be at least a 3 watt bulb, not an LED, not a midget bulb.

[Tony Brooks]

1 hour ago, Boatymcboaterson said:

So we have solved this problem around three times. Originally battery left to go flat when work being done- okay, not revving enough - okay, electrical switch not turned fully enough - okay. Yet again the charging light remains on and our leisure battery is nearing flat!

 

The wires, alternator, regulator, split diode everything have been tested and are fine. We have a Lister SR2 and are about to pull out our hair. Any suggestions?

 

Is this a report from a previous topic or a new posting?

 

The warning lamp - is this an LED or a lamp with a non-replacable grain of wheat bulb? If so t wont energise the alternator. Do what Tracy said, B+ to D+ for a moment or two.

 

How was the diode checked and what were the readings?

 

Is it a passive diode or a zero volt drop electronic thing?

 

How was the alternator tested and what were the readings - RPM, Volts, Amps, at a range of speeds and loads?

 

Rough idea location in case a member who knows about such things is willing to come and give a second opinion.

Edited July 30, 2020 by Tony Brooks

[ditchcrawler]

If there is a split charge relay then why is it the leisure indicator, surly both banks are charged from one alternator or is there more involved

[Tony Brooks]

4 minutes ago, ditchcrawler said:

If there is a split charge relay then why is it the leisure indicator, surly both banks are charged from one alternator or is there more involved

He says split charge diode and if one diode goes open circuit then one battery will not charge.

I have a feeling this is a rehash of a previous topic where questions asked were not answered.

 

 

[Boatymcboaterson]

1 minute ago, ditchcrawler said:

If there is a split charge relay then why is it the leisure indicator, surly both banks are charged from one alternator or is there more involved

Both starter and leisure are charged from the same alternator. Both batteries will charge at a mains so they are okay. When the alternator is on the batteries don't go to 13v though (both 12v).

 

Think I've managed to follow B+ D+ suggestion nothing has changed ?

 

We've had the alternator & regulator off and checked at an engineer's and everything aparently okay.

[Tony Brooks]

3 minutes ago, Boatymcboaterson said:

Both starter and leisure are charged from the same alternator. Both batteries will charge at a mains so they are okay. When the alternator is on the batteries don't go to 13v though (both 12v).

 

Think I've managed to follow B+ D+ suggestion nothing has changed ?

 

We've had the alternator & regulator off and checked at an engineer's and everything aparently okay.

So Tracy's test suggest the alternator is faulty and as you don't seem to know how it was tested or any readings the assertion that it is "apparently OK" must be questioned.

 

Any chance of a photo of the bulb in the warning lamp although that test bypassed any warning lamp issues if you did it correctly.

 

The warning lamp not going out tends to rule a split charge diode fault out but to be surer we still need to know what type of diode it is and the test method & results.

[ditchcrawler]

Can you measure the voltage at the B+ terminal on the back of the alternator without the engine running. Then start the engine and at a reasonable speed again measure the voltage on the B+ terminal, follow this with the link between B+ and  ind terminal and measure the voltage yet again.

[Tony Brooks]

Further thoughts. Your words "alternator, regulator" suggests these might be separate items because most people just call modern alternators an alternator and don't mention the regulator. With a modern alternator I doubt anyone apart from an electronics engineer with some very specialised equipment can test the regulator on its own. So this poses more questions about exactly what make and model of alternator you have and what the regulator is. Sometimes when an external alternator regulator is fitted the built in one is disabled. The suggestion that you might have an external regulator means that you may not have a normal 9 diode alternator so we need to know exactly what you do have.

 

Surely you can take some photos of the alternator, regulator, split charge diode and warning lamp BULB and post them here. Then we have a better chance of helping.

[Sir Nibble]

1 hour ago, Tony Brooks said:

Further thoughts. Your words "alternator, regulator" suggests these might be separate items because most people just call modern alternators an alternator and don't mention the regulator. With a modern alternator I doubt anyone apart from an electronics engineer with some very specialised equipment can test the regulator on its own. So this poses more questions about exactly what make and model of alternator you have and what the regulator is. Sometimes when an external alternator regulator is fitted the built in one is disabled. The suggestion that you might have an external regulator means that you may not have a normal 9 diode alternator so we need to know exactly what you do have.

 

Surely you can take some photos of the alternator, regulator, split charge diode and warning lamp BULB and post them here. Then we have a better chance of helping.

Yes this. I am a professional, I've been rebuilding and testing alternators for 45 years and I'm not the only pro on here. Take a picture so we know what we are dealing with and a few simple tests will identify the fault.

[Tony Brooks]

This problem has been worrying me all night (too hot to sleep) and I realised that the reluctance of the OP to answer questions etc. has kind of obscured the obvious.

 

The OP says split charge diode and be it passive or electronic the diode will isolate the B+ terminal (still assuming  a 9 diode alternator) from B+ so B+ is electrically dead until the alternator starts to charge. This means Tracy's test (B+ to D+) needs modifying as below.

 

Connect a length of cable to engine battery positive taking great care not to allow the free end to touch any metal.

 

Start engine and set to about 1000 to 1200 RPM - something well above fast idle.

 

Touch the end of the cable conductor to the D+ (warning lamp terminal) and watch the warning lamp.

 

If it goes out and starts to charge then its probably a warning lamp bulb or wiring problem. If not it is probably the alternator.

 

If the bulb dims and imidiately brightens up I would suspect the split charge diode is open circuit or there is an open circuit on the main charging cables some where. Reason - the field diodes are trying to supply the engine  electrical circuits and charge the engine battery by back feeding up through the warning lamp.

[Boatymcboaterson]

3 hours ago, Tony Brooks said:

This problem has been worrying me all night (too hot to sleep) and I realised that the reluctance of the OP to answer questions etc. has kind of obscured the obvious.

 

The OP says split charge diode and be it passive or electronic the diode will isolate the B+ terminal (still assuming  a 9 diode alternator) from B+ so B+ is electrically dead until the alternator starts to charge. This means Tracy's test (B+ to D+) needs modifying as below.

 

Connect a length of cable to engine battery positive taking great care not to allow the free end to touch any metal.

 

Start engine and set to about 1000 to 1200 RPM - something well above fast idle.

 

Touch the end of the cable conductor to the D+ (warning lamp terminal) and watch the warning lamp.

 

If it goes out and starts to charge then its probably a warning lamp bulb or wiring problem. If not it is probably the alternator.

 

If the bulb dims and imidiately brightens up I would suspect the split charge diode is open circuit or there is an open circuit on the main charging cables some where. Reason - the field diodes are trying to supply the engine  electrical circuits and charge the engine battery by back feeding up through the warning lamp.

Not reluctant just have no power & iffy signal near the narrowboat.

 

Think a reply has gotten lost? It is a Lucas blocking diode and the website won't let me upload photos from my phone which is really frustrating! Alternator reads 14 when on.

 

It is indeed an old fashioned set up with a separate regulator, the alternator is a Lucas 11 AC it doesn't have a prebuilt regulator. It has been taken off the engine and fully checked by a qualified specialist as mentioned, so this is why I say apparently. My friend is coming to check on it on Sunday (auto electrician) so will update then if the mystery is solved.

 

 

[ditchcrawler]

3 hours ago, Tony Brooks said:

This problem has been worrying me all night (too hot to sleep) and I realised that the reluctance of the OP to answer questions etc. has kind of obscured the obvious.

 

The OP says split charge diode and be it passive or electronic the diode will isolate the B+ terminal (still assuming  a 9 diode alternator) from B+ so B+ is electrically dead until the alternator starts to charge. This means Tracy's test (B+ to D+) needs modifying as below.

 

 

That is why I asked him to check the voltage before starting the engine

[Tony Brooks]

OK, so a very old fashioned passive blocking diode that will cause up to about 0.7V voltage drop across the diodes so your 14V at the alternator suddenly becomes 13.3 V at the battery.

 

I think the 4TR control regulator can be wired to sense battery voltage but it may also be wired to sense from other parts if the system.

 

Originally the warning light on the AC series of alternators were turned on and off by a 3AW warning lamp control. These were unreliable so later in the AC series life a different relay was used that I think was designated 16RA with resistors underneath it. @Sir Nibble probably has the details.

 

If you still have the 3 AW warning lamp control that looks like an old fashioned cylindrical car flasher unit from the 60s then that may well be the problem.

 

Now - the AC series is obsolescent if not obsolete but the A127 is an easy to fit direct replacement that does away with all the separate control components, has a much higher output and will only need the warning lamp rewiring. My advice is to change to an A127 and while you are at it get rid of that diode and ft a Voltage Sensitive Relay to split the charge so you do not suffer voltdrop. The SR2 has bad enough charging without adding to it. If you need to know how to do the  wiring of the relay etc. please ask. Changing to a relay will involve a bit of work with heavier cables.

 

Why, oh why could you not have told us what you just have at the start of this or your other identical topic.

[Sir Nibble]

35 minutes ago, Boatymcboaterson said:

Not reluctant just have no power & iffy signal near the narrowboat.

 

Think a reply has gotten lost? It is a Lucas blocking diode and the website won't let me upload photos from my phone which is really frustrating! Alternator reads 14 when on.

 

It is indeed an old fashioned set up with a separate regulator, the alternator is a Lucas 11 AC it doesn't have a prebuilt regulator. It has been taken off the engine and fully checked by a qualified specialist as mentioned, so this is why I say apparently. My friend is coming to check on it on Sunday (auto electrician) so will update then if the mystery is solved.

 

 

Oh my god! An antique! The warning light will tell us nothing because as Tony says it's got a separate control. His advice above is sound and I suggest you follow it. An A127 should be cheap enough on eBay and good news is that there should be a market for the old alternator and regulator with the classic car fraternity. You will need to replace the diode with a relay though, though it sounds like it's possibly kaput anyway.

[Tony Brooks]

3 minutes ago, Sir Nibble said:

Oh my god! An antique! The warning light will tell us nothing because as Tony says it's got a separate control. His advice above is sound and I suggest you follow it. An A127 should be cheap enough on eBay and good news is that there should be a market for the old alternator and regulator with the classic car fraternity. You will need to replace the diode with a relay though, though it sounds like it's possibly kaput anyway.

 

I think the "need" in red is more about optimising the useful charge rather than the A127 not working with it. Passive diodes are horrible things for charging circuits so the sooner out the better.

[Tracy D'arth]

7 minutes ago, Sir Nibble said:

Oh my god! An antique! The warning light will tell us nothing because as Tony says it's got a separate control. His advice above is sound and I suggest you follow it. An A127 should be cheap enough on eBay and good news is that there should be a market for the old alternator and regulator with the classic car fraternity. You will need to replace the diode with a relay though, though it sounds like it's possibly kaput anyway.

I can't remember when I last saw an AC11 with 4TR etc, they are museum pieces. You will be getting pathetically little charge and with an SR2 I'm surprised you have managed to use the boat.

A nice 90 Amp Leece Neville Prestolite alternator and a bit of wiring removal plus a split charge or voltage sensing relay will transform the charging.

 

The antiques will certainly be very attractive to the classic car lads, may even pay for the new bits.

TD'

[Boatymcboaterson]

10 minutes ago, Tony Brooks said:

OK, so a very old fashioned passive blocking diode that will cause up to about 0.7V voltage drop across the diodes so your 14V at the alternator suddenly becomes 13.3 V at the battery.

 

I think the 4TR control regulator can be wired to sense battery voltage but it may also be wired to sense from other parts if the system.

 

Originally the warning light on the AC series of alternators were turned on and off by a 3AW warning lamp control. These were unreliable so later in the AC series life a different relay was used that I think was designated 16RA with resistors underneath it. @Sir Nibble probably has the details.

 

If you still have the 3 AW warning lamp control that looks like an old fashioned cylindrical car flasher unit from the 60s then that may well be the problem.

 

Now - the AC series is obsolescent if not obsolete but the A127 is an easy to fit direct replacement that does away with all the separate control components, has a much higher output and will only need the warning lamp rewiring. My advice is to change to an A127 and while you are at it get rid of that diode and ft a Voltage Sensitive Relay to split the charge so you do not suffer voltdrop. The SR2 has bad enough charging without adding to it. If you need to know how to do the  wiring of the relay etc. please ask. Changing to a relay will involve a bit of work with heavier cables.

Why, oh why could you not have told us what you just have at the start of this or your other identical topic.

3 minutes ago, Sir Nibble said:

Oh my god! An antique! The warning light will tell us nothing because as Tony says it's got a separate control. His advice above is sound and I suggest you follow it. An A127 should be cheap enough on eBay and good news is that there should be a market for the old alternator and regulator with the classic car fraternity. You will need to replace the diode with a relay though, though it sounds like it's possibly kaput anyway.

 

New to boating so sorry if there is another topic I couldn't find it? Can you drop me a link @Tony Brooks ? I will have my friend check out the light situation against what you've said. It was charging 2 days ago, previously the isolators just weren't switching on properly, the switch was literally just blocked. But it's been like this something simple then kaput 30mins later. The previous owners have had the wiring a bit of a rat's nest if I'm honest too.

 

Glad to hear someone will want our old alternator at least! @Sir Nibble    

[Sir Nibble]

I was confronted with an old rover with one of these gone tits up and needing to catch a cross channel ferry a few weeks ago. Took about half an hour to get an A127 on there and working. Unplug warning light control, bridge the wires from terminals L and N, at the alternator use the N wire for D+ and B+ is self evident.

[Tony Brooks]

50 minutes ago, Boatymcboaterson said:

New to boating so sorry if there is another topic I couldn't find it? Can you drop me a link @Tony Brooks ? I will have my friend check out the light situation against what you've said. It was charging 2 days ago, previously the isolators just weren't switching on properly, the switch was literally just blocked. But it's been like this something simple then kaput 30mins later. The previous owners have had the wiring a bit of a rat's nest if I'm honest too.

 

Glad to hear someone will want our old alternator at least! @Sir Nibble    

 

First of all please accept my apologies, there was a topic started by Bigga a few days ago that was so similar to yours I got confused. I don't think that one has been sorted or if it has he has not reported back.

 

Also don't apologise for being new to boating, we all were once new boaters but unlike cars each boat must be considered a one off so before much in the way of a diagnosis can be made  those of us who know need to find out exactly what we are trying to help with. This is why I kept on about 9 diode alternators, yours is a six diode alternator. Without that being clarified it was impossible to give much sensible help.   As soon as you said 11AC the most likely problem is a faulty warning lamp control.

 

Further information for you.

 

You say you have "no power". If that refers to discharged batteries than 13V may well mean the alternator is charging but running at maximum output. The higher the charging current from a given alternator the lower the charging voltage so with well discharged batteries and a spilt charge diode 13 volts could well be a perfectly acceptable charging voltage. If the alternator is working then after about an hour of charging at 1200 rpm+ you should find the voltage starts to creep up as the charging current falls. Eventually the regulator will start to work and yours was set for between 13.8 and 14.2 volts.

Edited July 31, 2020 by Tony Brooks

[PhilR]

Attached is a photo of a wiring diagram from the SR2 handbook and a photo of the controller. I thought someone might find it useful?

[Sir Nibble]

I look back on these old systems with a simultaneous chuckle and a wince of pain but remember the ever so advanced Japanese for many years used a pretty well identical system but with vibrating contact regulators.

[Tony Brooks]

3 minutes ago, Sir Nibble said:

I look back on these old systems with a simultaneous chuckle and a wince of pain but remember the ever so advanced Japanese for many years used a pretty well identical system but with vibrating contact regulators.

Didn't the French do something similar? Actually the ACs were a good machine in their day once the warning lamp control was dispensed with. Better in my view than the ACRs with the end face slip rings.

[bizzard]

1 hour ago, Boatymcboaterson said:

New to boating so sorry if there is another topic I couldn't find it? Can you drop me a link @Tony Brooks ? I will have my friend check out the light situation against what you've said. It was charging 2 days ago, previously the isolators just weren't switching on properly, the switch was literally just blocked. But it's been like this something simple then kaput 30mins later. The previous owners have had the wiring a bit of a rat's nest if I'm honest too.

 

Glad to hear someone will want our old alternator at least! @Sir Nibble    

Do you have the large diameter 10''or 12''  pulley on your camshaft that belt drives the alternator?

Edited July 31, 2020 by bizzard

[PhilR]

38 minutes ago, Tony Brooks said:

Didn't the French do something similar? Actually the ACs were a good machine in their day once the warning lamp control was dispensed with. Better in my view than the ACRs with the end face slip rings.

I find that interesting Tony. Thanks. My installation doesn't have a warning lamp/warning lamp control. But it does have an isolation switch and engine hour counter. My old controller (see photo in post #21) seems to do a good job of maintaining bulk charge at 14.4 volts.  I am sure most people on here with modern boats have bigger electrical needs but it works fine for me.