Battery Drain Woes

[Matt&JoyBongling]

My N Reg Bongo new battery has been losing power and drains completely within 3 weeks (the old battery did the same), with or without a solar trickle charger which should maintain the battery charge when the a vehicle is not in use.

With the engine running, the battery reads 14v+. When off, it shows 12v and 60mA. The only device which appears to draw any power when everything is turned off, is a radio, which, when turned off, has a small flashing red LED.


Having removed fuses in turn, I have found that by taking out the 40 A BTN fuse in the fuse box under the middle of the bonnet, the battery drain drops to 10v and OmA. I thought that this fuse might be for the alternator, but did not get any drop in ampage when I disconnected the live feed to the alternator with the fuse in place.


Can anyone advise
1. What does the 40 A BTN fuse do?
2. Is it related to my loss of battery power?
3. How might I solve my battery drain problem?
4. Why does the voltage drop to 10v when the fuse is removed?


Background

The problem became apparent during the autumn – possibly as the bongo was not used so much. In May 06, I wired in a loom for my tow hitch. We used the bongo throughout the summer but I had to disconnect the trailer brake light from the loom as the bongo brake light fuse kept blowing. Suggestions on solving this problem also appreciated! 18 months ago, I re-wired the ignition switch to allow power to the radio and electric blinds without a key in the ignition. The radio is switched off when not in use.

I also found a shredded belt in the engine bay, close to the alternator - a separate question will be posted.

[mikeonb4c]

I know this isnt a proper solution, but it is at least a cheap and handy way to stop teh problem until you do find the solution. Moonshine (BF) put me onto these and I bought one. Seems inexpensive for what it is. Volvo BATTERY MASTER CUT OFF SWITCH on ebay at

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... mot_widget

Dont know why the vendor says 'Volvo' as I dont think he did a couple of weeks ago (he also has TVR and others on sale). Just check that he is sending one that fits your battery.

Hope this may help in some small way. no doubt the BF Supreme Beings will be able to give you a proper answer.

Mike

[roysheiling]

Good advice, I,ve just bought one of those ebay isolators myself
cheers Roy.

Veni Vidi Bongi

[mikeonb4c]

Its a 'get you by' solution - cant do any harm. Glad its of use - BF member moonshine dserves thanks for this one.

Mike

[johnzbenson]

Hi, you matye wish to read this thread http://www.igmaynard.co.uk/bongo/forum/ ... 3547ab7294

Essentially the thread points to a battery diode breaking down I did at one point have every fuse withdrawn and there was still a current draw. A new alternator has sorted the old rover- I now its not a bongo but who knows? Question about your battery how old is it and how big is it? if you have a 60mA demand on a battery of say 70 AH rating then the battery will discharge beyond normal usable service in about a 4 to 6 weeks if its a good battery- 60 ma does seem a little high although the standard current demand is around 30 ma for a car. there is something in the members area regarding battery checks. I hope this is of help

[Matt&JoyBongling]

Many thanks for the advice. The battery isolator seems to be a sensible added security device until I get an alarm fitted (not sure how it would work if an alarm was drawing power unless the alarm earthed some where apart from the battery).

I had a look at the alternator - and disconnected what I believe to be the live feed. However, the drain did not change or stop. I will try disconnecting all the wires to the alternator in case I disconnected the wrong one.

The battery is new and is as large as I could get. I changed it because I thought that the old (original) battery was failing but now suspect that it was OK. I still have the same problem and regret not having my old battery checked before buying a new one.

I have not found any information about the fuse 40 A BTN for a bongo - the closest I have found is that it is for the alternator in a Ford Fiesta or Escort.

[clogger]

sounds like one of the diodes in the reg/rectifer circuit has conked out and allowing the current to draw back or backflow from the battery
hence it will be ok when running but only noticble when the engine is stopped there is a posh name for it but i can`t remember it

either put a new reg/rectifer unit on the alty or much easier exchange the alternator for a new one

[mikeonb4c]

Keep the old battery, put a leisure tray for £29 off ebay, consider getting 2 x 70Amp cables like I am (with an inline fuse I guess just in case the alternator tries to charge a fully flat battery), and use the isolator to isolate the leisure battery except when engine running and you want to charge it. Any experts care to discuss this one (again!)

[adam]

I think that the 40 amp fuse under the bonnet supplies power to the fuses that are under the steering wheel.

[johnzbenson]

Try disconnecting the alternator totally. just the live feed wont do it. I belive somewhere in the members area there is a fact sheet on testing alternators and I believe you can get an alternator refurbished for around £80 -£100. as for fuses withdraw the lot and see if you still get the current draw- then its almost certain to be the alternator (if the alternator is connected of course.)

[Matt&JoyBongling]

Thanks for the advice . I will look at the supply to the fuse box under the steering wheel and try disconnecting all the leads to the alternator. Feedback to follow. Cheers.