Parasitic Battery Drain

[Prospective Owner]

Hi,
I have an unconverted 2.5 Petrol Bongo and I appear to have a parasitic drain on my battery as it won’t hold its charge overnight. The battery in the morning has a reading of under 12v but after being jump started and ran for a significant time goes up to 12.6v. However, it will not start again the next morning!
Using the Bongo fury’s excellent guide I have narrowed it down to 2 fuses:
Bonnet fuse 16: Cabin, Central Locking (40a) and Interior Fuse 1: Cabin (10a)
Removing both (at separate times) cause the multimeter to drop from 0.02 to 0.01 amps.
It seems more than a coincidence that they are both cabin fuses. Does anybody have any idea where I should start looking first?

Also when I removed the bonnet fuse 13: Ignition (60a) the amperage shot up from 0.02 to 0.10! Is that normal?

As you may have guessed I am not an automotive electrical engineer but am quite capable and know how to use a multimeter. I am hoping that I might be able diagnose and fix the problem before taking it in to the garage.
I have searched to find if somebody else had the same problem but I'm not great at this and couldn't find anything specific to my problem!
Thank you in advance for any help or advice you may give.
Carl

[g8dhe]

A current draw of 0.01 to 0.02 is only 10 to 20 milliamps and is to be expected as you have things like the central locking, ECU and radio backup currents and if you have a remote fob then the receiver current for that as well. I won't normally get too concerned until its at least above 50mA, that sort of drain isn't going to flatten a good battery overnight.
More of likely concern is the state of the battery itself, if its several years old its likely lost a lot of its capacity and hence despite what looks like a good resting voltage (12.6v) as soon there is a significant current draw then the voltage will fall. One quick and easy check, is when the battery appears to be "full" turn the engine off and whilst measuring the battery voltage turn on the headlights full beam, a good battery will only fall 0.2 to 0.5 volts from the resting 12 .6 volts, if it falls further than that then the battery is due for replacement.

[Prospective Owner]

Hi Geoff,
I think you may got it.
I tried what you said and it went from 12.89 to 12.00 with the headlights at full beam.
Looks like it need a new battery.
Thank you for your help.

Any idea why when I removed the bonnet fuse 13: Ignition (60a) the amperage shot up from 0.02 to 0.10! Is that normal or could that be caused by the dodgy battery as well?

[g8dhe]

Too be honest no idea! Its not something I would immediately have expected but can't rule it out as normal however given that the Ignition 60 Amp only feeds the Ignition switch itself, it suggests that there maybe something, additional wiring etc. - does it have an alarm system of any sort fitted, in which case it could be associated with that!

[Prospective Owner]

Yes it has a Cobra alarm. There is a single beep (I can't locate where from) when I replace the fuse so it could be linked with the alarm.

The gentleman I bought it off was totally honest and said in his advert that it had this problem and that he just always used a jump starter as it wasn't used very often. It's not a major problem as I myself will not be using it as my day vehicle I was just hoping that it might be something I could work out myself.

[g8dhe]

In that case its most likely the immobilser section arming itself and preventing the vehicle from starting in that state, as it thinks the ignition system is being tampered with!

[Prospective Owner]

Thanks for the help, I think it will be down to a mechanic to sort it out as I think I may be in over my head!
I've already accidentally disconnected an aftermarket usb extension lead and can't find the socket to put it back in!

[g8dhe]

Probably back of the radio/audio system!

[Prospective Owner]

Thanks Geoff,
From what I've seen you are the go-to guy when it concerns Bongo's.
I've seen how you've helped so many people in the past and wanted to say thank you for helping me as well.

[Bob]

Taking Geoff's advice, and reading that the previous owner had battery problems, it's likely the battery is well overdue for replacement.

Before paying someone to chase shadows I'd replace it, then see how things are.

A few peeps here have had good service from these guys:

https://www.tayna.co.uk/car-batteries/

And welcome to BF?

[Prospective Owner]

Thanks all,
So far I've found Bongo enthusiasts certainly live up to the welcoming and kindness that I've been on the sidelines watching.
This is a dream come true for my wife and I. Now we can finally go off exploring.

And yes, I'll definitely take your advice and change the battery first ASAP as it does look a little tired.
Thanks again

[g8dhe]

On the electronics side yes its been my interest for many years, but on the mechanical side I can only pass on what I have read on here and links to the info. I don't even do my own servicing !

[willow2u]

Possibly something strange going on in the alternator. Some sort of internal short if you jump start it when battery is flat you would normally see around 14 volts Charging

[Prospective Owner]

I'll check that as well, thanks

[Prospective Owner]

Possibly something strange going on in the alternator. Some sort of internal short if you jump start it when battery is flat you would normally see around 14 volts Charging

It's showing 14.34. Does this mean that it's ok to rule out the alternator?