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Electrical issues non start and low voltage message

Firepit

CCCUK Member
I'm experiencing some electrical issues. I've had the ignition switch changed few months back after getting "charging circuit fault" messages on starting. (its contacts where quite burnt) I put a new red top battery on in April this year and I've had most of the earthing points cleaned up.

So after all that everything was fine for a couple of months until yesterday when I came to start the car. (It's been on a good quality tender but not started for about 4 weeks). It tried to turn over very slowly and then died, after that just the clicking noise. I tested the battery and it was around 11v, (odd as it has been on a tender) so I took it off and put back on the original yellow top which I still had. that one did barely start the car and after which it ran fine, the alternator was working and charging because the dash voltage went up to 13ish volts. I've got that yellow top battery on charge now also disconnected from the car and so I'm expecting it to be ok for testing again later.

My question though is related to a difference in the actual battery voltage and what the dash shows with the ignition on. Should there be a variance?

I'm guessing my next quest should be to find out if I have battery drain of some kind. New multimeter on order.
 

oelarse

Regular user
The voltage shown in the gauge in the dash is measured after the ignition switch . Since the ignition switch is recently replaced it should not be any voltagedrop due to burnt contacts and the voltage measured over the battery should be
equal to the voltage indicated in the dash gauge . But I think the accuracy of the gauge is lower then a multimeter ( I only trust the values on my multimeter :)) .

The drain current should drop from 8-10 amp. down to 25-30mA after approx 15 min ( mine is approx. 29mA)
If you connect the meter in serial on the NEGATIVE side of the battery on 10 a range it could be done like this

If you observe an excessive current then you can measure voltage ( mV range on the multimeter ) over each fuse in the engineroom and in the fusebox in passenger footwell to locate the fusecircuit containing the bad component
If you look through this video it will show how to
Here is a link to charts showing voltagedrops for the different fuse sizes and fusetypes
 

Firepit

CCCUK Member
Thanks for the advice and the links. I've watched the video through and I'll print the charts out. Some of the directions say to pull the fuses one by one which is what I was going to try. I do like the idea of quickly reading each fuse via this method though. Unfortunately I've got to go to Santa Clara next week so I won't have time to do this for a week or so.

Thanks again very much appreciated.

Paul.
 

Firepit

CCCUK Member
Nope, not had a chance. Although I did pop the original yellow top back on and left it on the tender for a couple of weeks while I was away. When I started the car last weekend it did start but laboured a bit before firing up. The temp in the garage was only a couple of degrees though. I'm not really sure what to do next. I may just leave as is until the warmer weather and then have a look.
 

oelarse

Regular user
I agree with you to wait for warmer weather :)
If you have not measured and verified the drain current yet I will suggest you connect the amp meter in the serial to the negative battery side and observe the value after aprrox. 15 minutes .
If it is way above 30 milliamps , you should look into each fusecircuits like I mentioned above at post #2 .
If you need any schematics , please put a note for it here in the forum and I can upload it
 
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