Charging and sediment light on but Alternator ok

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AndyIOW
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Charging and sediment light on but Alternator ok

Post by AndyIOW » Mon Jul 09, 2018 12:26 pm

The charging and sediment light came on after a long drive. I have previously had this and know it usually means the alternator has gone. I have a nearly new alternator on my other Bongo which is off the road at the moment (you can never have too many Bongo's). I put the alternator from that on to my main Bongo knowing it was good but the lights are still on. So i put the used alternator from my main Bongo on the spare bongo and that was fine. I have tested both at the battery and they are both charging between 13.8 and 14.7v. So both the original and new alternator are good. The lights are not glowing bright which is strange. To rule out the sediment light I disconnected it and both lights glowed brighter. When i make the connection manually both lights stay on but dull as before. The alternator is definitely ok and charging the battery but these lights are on. Anybody have a clue what is going on?
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Re: Charging and sediment light on but Alternator ok

Post by Ian » Mon Jul 09, 2018 1:02 pm

Have you got a leisure battery fitted?
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g8dhe
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Re: Charging and sediment light on but Alternator ok

Post by g8dhe » Mon Jul 09, 2018 1:09 pm

I suspect you have a Split Charge Relay triggered by the Alternator charging signal - bad choice. The signal from the alternator is designed to operate a standard filament lamp, not an inductive relay that generate high voltage spikes on release and causes a continuous current draw hence lighting the Charge lamp at a glow level.

You would be better driving the relay from the IG2 circuit from the ignition switch, using an existing fused circuit like the one below;
Image
This can handle spikes, also it gives you some control over the SCR, in that it only operates when the Ignition switch is in the "On" and not in the Acc or Start positions, this allows you to link the batteries by turning to On but not starting the engine in the event that the SB is flattened in error.
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AndyIOW
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Re: Charging and sediment light on but Alternator ok

Post by AndyIOW » Mon Jul 09, 2018 1:13 pm

Sorted, it looks like there was a dodgy connection somewhere. Used electrical cleaner spray on the plug to the alternator, pushed it on and off a couple of times and the lights go out now.

As there was a good charge going to the battery i gathered it must be something to do with the charge light circuit.

Sometimes you just need to try stuff.

Cheers for the above useful to know, but no i don't have a split charger. I like my Bongos unfettered, Getting harder to fine unconverted ones now.

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Re: Charging and sediment light on but Alternator ok

Post by g8dhe » Mon Jul 09, 2018 1:47 pm

It won't have been a dodgy connection as such, more likely a bridge thru dirt to chassis as the lamp requires an earth connection to make it light up, so the connector might well have been covered in oil/muck perhaps.
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AndyIOW
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Re: Charging and sediment light on but Alternator ok

Post by AndyIOW » Mon Jul 09, 2018 7:59 pm

Cheers for that, yeah probably that instead. I was trying to work out how the light worked, that last bit is handy to know. Been driving it around and all seems fine.
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