This is pissing me off to no end.

I have a bad battery drain on my Cosworth, I can drive the car all day with my SECS monitor showing the battery voltage between 13.3 to 13.8 volts. Leave it over night and try and start it on the morning and its not got enough charge to turn the car over.

When the engine is running, I have tested the voltage of the battery and it gets to around 14 volts at its peak.

I have just rewired the large alternator feed and added a new 10mm earth to the engine (using one of the engine eye lifters for a fixing point) to the battery as previously I was only charging at 12.9 - 13.1 volts on the SECS.

Fuel pumps have been both rewired using 6mm cable and use the correct relays etc.

Now I'm getting stressed out with this. None of my lights are staying on to cause a drain, but yet I am getting a drain.

Any ideas where else I might be having a problem?????

And any ideas on how to potentially reduce or eliminate the problem??

I have been thinking of putting in a battery isolator etc, but that's a last resort as I shouldn't need to do that as the car gets used often.

Any help/advice gladfully received