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Battery doesn't seem to be charging


hackenbush

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Things to check...

  • The wire from the lamp to the alternator - any chafing?
  • The wire from the lamp to the split charge relay - any chafing?
  • Disconnect the split charge wire at the relay end - does the light now extinguish when it should?

Good luck. 

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2 minutes ago, WotEver said:

The light extinguishing demonstrates that the alternator is charging.  It should always be out with the engine running fast enough to charge the batteries. 

The split charge wiring (unless faulty, which is quite possible) is (or should be) irrelevant to the issue of the alternator starting up. 

But the voltometer reading seemed to be showing that the alternator was now charging the battery - before engine on  or off the reading didn't change on the battery, after fastening the connection on the butt crimped wire going from alternator to warning light the reading jumped from 12.10 to 12.70. However, the light remained on however much I revved the engine

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Just now, hackenbush said:

But the voltometer reading seemed to be showing that the alternator was now charging the battery - before engine on  or off the reading didn't change on the battery, after fastening the connection on the butt crimped wire going from alternator to warning light the reading jumped from 12.10 to 12.70. However, the light remained on however much I revved the engine

But you've already shown that the charging voltage is 14V+ when the alternator is working correctly.

What's the voltage of the starter battery? I'll take a guess at 12.7V. 

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5 minutes ago, WotEver said:

But you've already shown that the charging voltage is 14V+ when the alternator is working correctly.

What's the voltage of the starter battery? I'll take a guess at 12.7V. 

An extra complication:

When I disconnected the warning light wire from alternator and ran engine reading on leisure battery was 14v.

After fixing the loose connection in that wire, I reconnected the warning light wire to alternator and ran engine. The reading was 12.70.

Before fixing loose connection when the warning light wire was connected to alternator reading remained 12.10 regardless of engine running or not

I haven't tested starter battery. Am not on boat right now either

Edited by hackenbush
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Just now, hackenbush said:

An extra complication:

When I disconnected the warning light wire from alternator and ran engine reading on leisure battery was 14v.

After fixing the loose connection in that wire, I reconnected the warning light wire to alternator and ran engine. The reading was 12.70.

I haven't tested starter battery. Am not on boat right now either

That's not an extra complication, it's what you've already told us. 

I think the 12.7V is simply the split charge relay switching on and paralleling the batteries. When the alternator is charging it's putting out 14V+. 

And that's not happening. (Except for when you do Tony's 'cheat' with the piece of wire). 

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3 minutes ago, WotEver said:

That's not an extra complication, it's what you've already told us. 

I think the 12.7V is simply the split charge relay switching on and paralleling the batteries. When the alternator is charging it's putting out 14V+. 

And that's not happening. (Except for when you do Tony's 'cheat' with the piece of wire). 

Ah, OK. 

 

15 minutes ago, WotEver said:

Things to check...

  • The wire from the lamp to the alternator - any chafing?
  • The wire from the lamp to the split charge relay - any chafing?
  • Disconnect the split charge wire at the relay end - does the light now extinguish when it should?

Good luck. 

I checked the wires and the only anomaly I could find was at the butt crimp on the alternator-to-light wire. Not convinced now that I actually repaired it and think the whole wire should be replaced anyway.

Will do the other test in the morning

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34 minutes ago, WotEver said:

I believe that was Nick's point. If it was oil pressure for instance then it would have gone out once the engine started. However, as the OP noted that the light stayed on and that was his first indication that anything was wrong I think we can be reasonably confident that it's the ignition light. 

Ahh, about 120 miles away from me then. 

And no way I am going into London.

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One more  question.

If we assume the split charge device is a relay then t will ave two thick cables on it (nut & stud connections I hope) and two thin ones on 6mm blades. One of the 6mm blades will have a wire connected to negative. Its the other one I am interested in. Where does this one come from/go to?

On the face of what you have told us if there are no one in and two out joints down the warning lamp cable and no extra wires on the alternator warning lamp connection or the alternator side of the warning lamp a split charge relay should not work UNLESS either its a voltage sensitive relay or it is connected to a rising oil pressure switch.

I am trying to work out exactly what charge splitter you have - photo tomorrow?

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1 hour ago, hackenbush said:

Ignition setup. Very basic!

cant work out what the errant wire with what looks like an ancient fuse sticking out is doing? It was tucked at the back I've pulled it out so it can be seen

 

image.thumb.jpg.8fd4cf646bc11f0d746dd456d1e8ff76.jpg

I may be grasping at straws but it looks to me like there is a 5w resistor between one side of the light and the panel. The resistor (if its needed) should be connected across the lamp. If it is on the alternator side of the lamp this will cause the lamp to stay on..........

 

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13 minutes ago, Tony Brooks said:

One more  question.

If we assume the split charge device is a relay then t will ave two thick cables on it (nut & stud connections I hope) and two thin ones on 6mm blades. One of the 6mm blades will have a wire connected to negative. Its the other one I am interested in. Where does this one come from/go to?

On the face of what you have told us if there are no one in and two out joints down the warning lamp cable and no extra wires on the alternator warning lamp connection or the alternator side of the warning lamp a split charge relay should not work UNLESS either its a voltage sensitive relay or it is connected to a rising oil pressure switch.

I am trying to work out exactly what charge splitter you have - photo tomorrow?

My guess is that his split charge relay feed is taken from the ign terminal of the alternator. Once the alt is generating it extinguishes the light and energises the relay. That would account for the two wires coming from the back of the light, one for the alt, one for the relay. 

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1 hour ago, hackenbush said:

I thought the light being off or on was directly related to whether the starter battery had got enough charge before the leisure battery began charging. Could you confirm this?

The warning light should behave exactly like the ignition light on your car. It comes on when you turn on the ignition and should go out when you start the engine. If it doesn't go out immediately on starting then it should do so if you blip the throttle. 

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11 minutes ago, WotEver said:

My guess is that his split charge relay feed is taken from the ign terminal of the alternator. Once the alt is generating it extinguishes the light and energises the relay. That would account for the two wires coming from the back of the light, one for the alt, one for the relay. 

But the photo does not support this, it only shows one thin red wire. If it was taken from there we would see two cables on one terminal.

The second wire in the ignition switch has an unidentified silver component in it, a taped up end and seems to just be hanging loose. This has not been confirmed yet.

This is why I am wondering what this "alternator switch" is. Could someone have fed the relay from a dedicated switch?

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30 minutes ago, Tony Brooks said:

But the photo does not support this, it only shows one thin red wire. If it was taken from there we would see two cables on one terminal.

The second wire in the ignition switch has an unidentified silver component in it, a taped up end and seems to just be hanging loose. This has not been confirmed yet.

This is why I am wondering what this "alternator switch" is. Could someone have fed the relay from a dedicated switch?

It looks to me like there are two wires from one terminal of the ign light. One of them has what looks like a 5W wirewound resistor in series and then a mess of insulation tape, but I have no idea what happens after that. 

As you say, it really needs someone who knows what they're looking at to give it a quick once-over. 

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I thought it may help to record the diagnostic thoughts so far.

1. The test with the voltmeter and the short length of wire suggests the alternator is probably OK.

2. The test with the ignition on and the thin cable disconnected from the alternator suggests there is a short circuit to negative (earth) somewhere between the warning lamp and alternator BUT:

there is an unidentified charge splitter involved that may or may not be connected to the wire from warning lamp to alternator. If its a normal split charge relay connected in the usual way a shorted relay coil could give these symptoms.

3. An "alternator switch" has been mentioned that has yet to be identified or explained.

4. There is an unidentified component hanging down from the ignition switch that may be resistor. What the end that looks as if it is wrapped in insulation is doing has not been clarified.

The Warning Lamp

Assuming this is the charge warning lamp:

1. The talk about it indicating when the engine battery is fully charged is confusing and almost certainly just plain wrong. This suggests whoever told the OP this does not have the knowledge to advise.

2. This style of warning lamp sometimes has a non-replacable grain of wheat bulb inside. These often do not pass sufficient current to energise an alternator - especially if it is also supplying a split charge relay.

3. One way to solve the above is to put a resistor in parallel across the bulb. There may be one half in place.

4. Trying to energise an alternator via a grain of wheat bulb will always be unreliable so may be the cause of the symptoms.

5. A split charge relay coil on its own MIGHT be a sufficient load to allow a grain of wheat warning lamp to illuminate but at a lower brightness to normal

Potential results of there actually being a short circuit.

If we reconnect the warning lamp and energise the alternator with the piece of wire the field diodes would try to supply the short and may burn out so it is vital that we ensure there are no shorts before manually energising the alternator.

 Next steps.

Identify the charge splitting device, a photo will help. It may be a split charge diode, a split charge relay or a voltage sensitive relay. Whichever it is will affect the diagnosis.

As Wotever says inspect the split charge relay thin wires and the warning lamp wire for chaffing or being trapped & report.

Identify exactly what the silver thing hanging off the warning lamp is and report.

If it is a split charge relay see what happens to the warning lamp with the thin relay wires disconnected & insulated, the ignition on and the thin wire on the alternator disconnected.

If the bulb stays off then:

reconnect the thin wire to the alternator, start & rev the engine and manually excite with the ignition on using the small length of wire. The bulb should go out.

ensure the silver thing is a resistor an reconnect it across the warning lamp OR fit a proper warning lamp with a decent bulb in it. I would like at least 1.5 watts but Biz who knows these things well has suggested  6 watt  warning lamp.

measure the resistance across the two small blades on the split charge relay and report back. If its 50 ohms + its probably fine so reconnect. If its less teh coil may have burned out.

If the bulb stays on then:

You either still have a short between warning lamp and alternator OR the field diodes in the alternator are open circuit. If so fit other alternator.

Hope this helps.

 

  • Greenie 2
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Reading thru this thread has given me horrifying flashbacks to my alternator probs two years ago which i referred to in a previous post

Though i had to work thru similar issues , i wasn t stuck in Haggerston & so this situation is now even more urgent . Broken down in Haggerston ..... my god it doesn t bear thinking about . What a toilet ! 

Hackenbush , you're doing admirably so things will be fixed soon and all will be well ...... but you 'll still be in Haggerston ..... 

Good luck with the fault tracing & fixing  

Edited by chubby
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Firstly, greenie to Tony for his excellent post summarising the situation and how to progress from here.

I feel however, for clarity, the OP next needs to concentrate on identifying the three unidentified components. The split charge device, the silver thing, and the "alternator switch".

Tony may disagree but my feeling is these three things need positively identifying (best by good quality photos) before any of the further tests at the end of Tony's post are carried out.

 

On 23/03/2017 at 08:03, chubby said:

Though i had to work thru similar issues , i wasn t stuck in Haggerston & so this situation is now even more urgent . Broken down in Haggerston ..... my god it doesn t bear thinking about . What a toilet ! 

 

Secondly, the boat isn't actually broken down (yet!) as the engine still runs. If Haggerston is such a risky dump the OP could take a fully charged battery and pair of jump leads to the boat, or a genny, and continue with the cruise to a safer area. 

Or failing that, just cruise to a safer area anyway. Most diesel engines don't need electricity run, only a few with electric stop solenoids. And even then only those that require power to hold the solenoid ON. 

 

(Speelling edit.)

Edited by Mike the Boilerman
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It might be a good plan and simple to by-pass the split charge relay or whatever it is by removing the wire on it that comes from the warning light and extend it to reach the alternators W terminal to see if all's well without it. If all's well then renew the split charge relay with new wiring. And as Tony Brooks says if its a grain of wheat bulb ''12v model railway term that'' increase the wattage to at least 2.2w which would mean a different bulb holder.  To excite my alternator without revving the nuts off it I did fit a 6w bulb and holder which did the trick, light went out instantly but I then tried a 2.2w which also did the trick whereas the grain of wheat bulb struggled. I have a 70a Hitachi Ford alternator which I did once swap with an ACR whilst I cleaned and serviced the Hitachi but both struggled to ''Put that bloomin light out Napoleon, the Jerry's can see it for miles'' with the grain of wheat bulb.  Here is a photo of the rear of an ACR alternator which I have in stock, depicting the terminals, which I had at the ready in case the old ACR was going to be used.

001.JPG

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Hopefully a better pic of warning light, ign and "resister". The resister was not in this position, I bent it outwards to make it more visible. The only place the wire sticking out the end could have been connected would have to be the same wire it's coming out of (in a loop).

2 wires coming out of warning light - 1 straight to ign, other (with "resistor") going to "switch"

image.thumb.jpg.72325727bf16117599c26158f959c261.jpg

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That looks like the starter battery isolator to me. The split charge relay is the blue box in the wiring to the right of the first picture. But it looks pretty weedy! Does it have two thickish wires, one going to the domestic and one going to the engine battery isolator?

Edited by nicknorman
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