Battery doesn't seem to be charging

[hackenbush]

Attempts at better pics

 

 

[MtB]

On 23/03/2017 at 11:00, hackenbush said:

Attempts at better pics

 

 

 

Much better, thanks.

I don't think that silver cylinder is a resistor. Looks more like a capacitor to me. Resistors always have coloured bands on them to identify them. Is there any (tiny) writing printed on the cylinder anywhere?

 Its still not easy to tell where each end of it is connected though due to the insulating tape. Both ends appear to be connected into the same wire, in which case I don't think it can be doing anything (other than possibly causing the wire to be making no DC connection to the lamp).

[hackenbush]

the only wire the loose end could possibly connect with is back to the wire it comes out of.

i have tried this while engine was running and there was no change

[MtB]

Hmmm a brief google of what's written on it, suggests it is a high power resistor for vertical mounting...

[MtB]

So should actually be connected across the bulb terminals. Given the low standard of the wiring I'm now wondering if it actually just fell off at one end and this is the root of your failure. re both ends of it actually connected to something?

[hackenbush]

Here is a list of the wires and where they connect. I hope it makes sense

[hackenbush]

1 minute ago, Mike the Boilerman said:

So should actually be connected across the bulb terminals. Given the low standard of the wiring I'm now wondering if it actually just fell off at one end and this is the root of your failure. re both ends of it actually connected to something?

I've been suspecting this. Am attempting to connect it now

[MtB]

On 23/03/2017 at 11:30, hackenbush said:

I've been suspecting this. Am attempting to connect it now

 

AAh so one of the tiny thin wires coming out of the silver thing is actually flapping about in fresh air and not connected to anything?

(Hard to tell from the photos.)

If 'yes', then this is almost BOUND to be the problem. Connect the loose flappy end onto the other warning lamp terminal and I bet it will all work again as before.

Edited March 23, 2017 by Mike the Boilerman

[hackenbush]

5 minutes ago, Mike the Boilerman said:

 

AAh so one of the tiny thin wires coming out of the silver thing is actually flapping about in fresh air and not connected to anything?

(Hard to tell from the photos.)

If 'yes', then this is almost BOUND to be the problem. Connect the loose flappy end onto the other warning lamp terminal and I bet it will all work again as before.

The only place it would seem to be able to connect is back into the wire to alternator but that doesn't make sense to me

[MtB]

On 23/03/2017 at 11:40, hackenbush said:

The only place it would seem to be able to connect is back into the wire to alternator but that doesn't make sense to me

 

I agree. From your drawing, the spare end should connect into the "wire to ign". 

Try poking it back into the end of the crimp terminal, alongside the red insulated wire. That's probably where it was in the first place, but the crimp didn't grab it when the crimping was done.

[MtB]

OR.... pull the 'wire to ign' crimp terminal off the warning light, poke the spare end up into the crimp, then push the whole lot back onto the warning lamp terminal.

[hackenbush]

17 hours 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. 

Pic of wire to alternator. 2 wires come out of left side, 1 to light and the other to relay. I've stripped back insulation. Do you see anything glaringly wrong?

[MtB]

On 23/03/2017 at 11:54, hackenbush said:

Pic of wire to alternator. 2 wires come out of left side, 1 to light and the other to relay. I've stripped back insulation. Do you see anything glaringly wrong?

 

Looks a reasonably good electrical connection, despite the crappy workmanship and liberal use of bodgy insulating tape. Whether the circuit is correct though is open to conjecture.

It probably is though, given it all worked correctly before the breakdown. I'd just put the tape back on and concentrate on reconnecting that resistor properly.

[hackenbush]

10 minutes ago, Mike the Boilerman said:

OR.... pull the 'wire to ign' crimp terminal off the warning light, poke the spare end up into the crimp, then push the whole lot back onto the warning lamp terminal.

Only change is lamp dims a little

[MtB]

Hmmmm that's annoying. Not the fault after all then. 

Disconnect it then and put it back to as it was before, I suggest.

[hackenbush]

4 hours ago, Tony Brooks said:

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.

 

Agreed, I was given bad advice concerning warning light and starter battery.

it would seem you are right about resistor running in parallel however I am stumped as to how it should connect.

thin relay wires and alt wire (thin) disconnected and ignition on. Engine runs but light remains on.

Not quite sure what you mean by thin blades on relay. I assume literally the two thinnest out of four possible blades - one connects to batt (neg) other to alt (neg). Resistance measured at 23.3 ohms

 

[WotEver]

Here's a guess...

Lamp has a wire going to a resistor (?) which then goes to a soggy bit of insulation tape. Has that insulated end fallen off the other side of the lamp?

55 minutes ago, hackenbush said:

 

What you've labelled "loose end" - has it fallen off the other side of the warning light?

[hackenbush]

4 minutes ago, WotEver said:

 The loose Here's a guess...

Lamp has a wire going to a resistor (?) which then goes to a soggy bit of insulation tape. Has that insulated end fallen off the other side of the lamp?

What you've labelled "loose end" - has it fallen off the other side of the warning light?

I really don't know. Until yesterday it was tucked behind and I can't make out where the loose end was exactly 

[hackenbush]

8 minutes ago, WotEver said:

Here's a guess...

Lamp has a wire going to a resistor (?) which then goes to a soggy bit of insulation tape. Has that insulated end fallen off the other side of the lamp?

What you've labelled "loose end" - has it fallen off the other side of the warning light?

Before I start attempting to replace alternator this seems like it could hold the key

[nicknorman]

So just for clarity this is what the resistor is about:

The alternator needs a modest current through the warning light terminal to get it charging. This is supplied from the starter battery via the warning light. The current flowing to the alternator also of course illuminates the warning light. Once the alternator is charging, the voltage at the alternator terminal rises to be the same as the battery voltage and so current no longer flows through the light - it goes out!.

Now add the split charge relay that is connected between the warning light to alternator wire, and -ve. When the ignition is switched on, this relay "steals" some of the current flowing through the warning light to the alternator. So this can mean it is hard to get the alternator to start charging - lots of revs required. So the solution is either to fit a bigger wattage bulb (= more current) or to fit a resistor in parallel with the bulb (= more current). So the resistor should definitely be connected across the bulb. This will have the effect of dimming the bulb slightly, but that is not an issue.

If everything is working correctly, when you put on the ignition and before starting the engine, the voltage on the alternator to warning light wire should be a couple of volts or so relative to -ve. Not zero, and not 12v. If that is not the case, there is something wrong with the wiring.

[WotEver]

12 minutes ago, hackenbush said:

Before I start attempting to replace alternator this seems like it could hold the key

We already know you don't need to replace the alternator. It works fine when energised by the piece of wire, just not with the lamp. 

So... connect that soggy end to the other side of the lamp and see what happens. It can't possibly damage anything to try. 

[MtB]

On 23/03/2017 at 12:59, WotEver said:

We already know you don't need to replace the alternator. It works fine when energised by the piece of wire, just not with the lamp. 

So... connect that soggy end to the other side of the lamp and see what happens. It can't possibly damage anything to try. 

This has been tried earlier.

 

On 23/03/2017 at 12:01, hackenbush said:

Only change is lamp dims a little

 

[WotEver]

2 minutes ago, Mike the Boilerman said:

This has been tried earlier.

But did OP start the engine and rev it?

[MtB]

On 23/03/2017 at 13:08, WotEver said:

But did OP start the engine and rev it?

 

He must have done, or he wouldn't have known the fix didn't work.

[nicknorman]

Most likely there is just a bad connection or broken wire between the warning light and the alternator. The warning light is illuminating because it is seeing the resistance to -ve of the split charge relay coil.

Connect everything up, ignition off, then use a multimeter on ohms / resistance range to check that the alternator warning light terminal is connected to the warning light. You should find that the resistance is less than 1 ohm. I'm pretty sure you'll find it isn't

Edited March 23, 2017 by nicknorman