Club 80-90 Forums

When I start the mean machine the batt light stays on untill I rev it - when the light goes of I can hear a click coming from where the leisure battery is. I have tested the charge of the battery before starting -reads 'bout 12.4 v- then when I start it it gradually goes down to around 7 v - that is untill I rev the engine, the light goes out, clicky thing clicks (I m guessing its a relay) after that the battery reads 12.8 ish

A couple of times over the last couple of weeks I have tried to start the beast (1.6td) and the battery has been flat and I have had to jump start it - am I right to tink that som'tin' is draining da battery. The battery is new as is the alternator (which is kicking out a good charge)

Answers on a postcard please....

86 Joker 1.6td

Disconnect the switching circuit on your split charge relay and try it.

Thanks SplendiferousII - have been away this weekend - will try it tomorrow. Is the switching circuit the one that runs to the 12v alt cable (I think number 30)?

If this does work does it mean the relay is knackered?

I'd say your altinator and relay are working fine. Its common for the altinator not to kick in instantly after starting, you need to get the revs up before it'll cut in but it'll stay running there after, unless you nearly stall it maybe. If you have a revcounter (diesel) that won't work eather untill the charge light goes out (when its not making current there is no signal for the tacho to sence).

Split charge relay will be conected to the altinator curcuit so won't conect the leasure battery +ve to the main battery +ve (terminal 30) untill the altinator is charging - thats why it clicks. If you simply remove the relay the main batt should work perfectly as a normal single batt and the leasure batt will be isolated to go flat on its own if its being drained -

Dropping to 7v doesn't sound good though, which battery is that? The main battery should be around 12.5v before starting, might drop slightly during starting but should slowly recover again once cranking stops - if it drops alot and stays there its probubly on its way out/faulty. Would take alot of drain to get it down to 7v - try putting an ammeter between the battery and cable when the ignition is off, current should be mA. Once the altinator cicks in the batt voltage should rise to around 13.5v fairly quickly (more you rev it the quicker it climbs, after a 5 minuite drive it should have recharged what was used to start the engine and voltage should be a steady high 13's; a flat leasue battery will mean this takes much longer as it has more charging to do.

Another thing definately worth checking is your main battery leads and earths between engine/gearbox/battery and body. Corrosion there can make things act funny/seem broke when they are not.

Thanks now have a few things to try

The battery seem to recover its charge once the ignition is turned of so I m guessing that there is something connected to the ignition which is drawing a current - I think its the glow plugs as when the dash light goes out the drop in voltage stops - though doesnt rise untill alty kicks in.

The battery is onlt 1 month old - we got it off an AA man when we lost power en-route. Its a proper diesel one - (cost proper $$ aswell) - its got 70Ahr on the top. I think I might try swapping the leiure and main round (the leisure batt is a normal one). Will try the earths aswell.

Which cable should I put the Ampmeter on?

Thanks for the help - the van is in danger of been down-graded from quirky to unreliable.

It doesn't matter which cable you fit the ammeter to as eather will measure the current direct through the battery terminal - personly I'd go for the earth as if your hand wobbles around and touches some other metal thing it'll make alot less sparks .

Remember most ammeters can't cope with high DC current though so don't try running the starter or heaterplugs through it as it'll probubly break. An ameter big enought to cope with that probubly won't go low enough to show small drains well enough. Also remember that the heaterplugs usally run on for a bit AFTER the orange light has gone out (if you wait and listen carefully you'll hear them click off 10-20sec after the light goes out). Probubly not much point in testing the current drain when the ignition is on as some things will draw a bit of current then anyway which the altinator will handle as its genrally on at those times. VW designed the electric system to automaticly turn off high drain stuff when you try and start the engine - thats what the relay on the top line of the fusebox does (the one with the 2 massive pins), probubly not the problem though (that'll be off if your heater fan stops with the ignition).

Thanks

I swaped the batteries and that seems to have sorted it - the batt only looses a bit of voltage while the plugs heat up and shoots back to 12.6 when they are hot to trot. Will give it a few days before I start counting them chickens but fingers crossed. I ll check for any possible drainage anyway

I m glad its the battery as AA charged us £80 pounds for it whilst broken down on the m6 - I ve never got over the shock and pain - I can get a refund now - just wish i d swapped them sooner.

Looks like its whitby this weekend