battery drain current - when all is Off

I would expect less than a third of this.

BTW, I don't think your MIL should allow her garage to get away with something. If she has a gripe she should at the very least mention it. Complaints don't have to be delivered with venom. Just a mention and then let it develop would be the preferred approach.

Rob Graham

Rob Graham

What year/model of Golf?

Yes I thought it was a bit high too - but apart from boot lights stuck on I don't really know what could be taking that power.

Yes I suppose you are right. We live many hours drive away from her and she's getting on a bit now, doesn't know anything about cars and can't really cope with it. I just wanted to be as sure as possible that a new (quality) battery might fix the problem. The 150mA is giving me 2nd thoughts though. Will go and measure the current on a humble Micra I have access to...

that drain is the equal of a very small bulb left on (1.5w) Generally the drain should be less than about 30 ma. Badly fitted radios are a common cause of a drain. You can try pulling each fuse in turn to isolate the circuit, if no joy then try disconnecting the alternator, they sometimes pull current, and just once I came across a starter that did too, that took some finding!

Well you'll get nearly a fortnight out of a new battery. Pull the fuses one at a time till you find which one's draining it, if it's still leaking try unplugging the alternator.

Well funny you should say that because the same garage as in my OP had (only 2 weeks ago) fitted a brand new alternator! We visited MIL at the weekend which is when I was able to take a look at things. The alternator certainly is bright a new looking and belt tension and leads all seem in order. However, returning to the battery thing, it may well be then that this current drain was the trouble all the time. If so, a kind of expensive solution they chose.

I just checked a perfectly-formed Micra (:-)) - current used is only

4mA. Well, compared to that the 150mA is a pretty beefy drain. Ta again for the things to check - will do so when I can.

btw the car is VW Golf CL

1598 CC 1996

I have replaced the batteries in both my cars recently and before doing so I measured the quiescent current drain as follows:

02 Focus TDCI : .03-.04 A ( 30-40mA) 97 306 D .06 A

The Pug. refused to start after 3 or 4 days so I had no choice !The Focus struggled to start in this cold weather, so since it was on its original battery I had it tested by a shop. They used a digital tester which measured the CA at 100A below rated .

I think batteries last longer than their rated AH rating at this sort of drain rate but 150mA does seem high. If you can't find any problems, then I would have the battery tested at a shop and possibly replaced. Did you get a gaurentee from the garage ?

I was googling to find out about these digital 'internal resistance' testers last night, any one know how they work ?

At a rough guess: From teaching physics you calculate internal resistance by calculating the current through a fixed resistance then extrapolating that to work out the voltage drop across the IR. I'm guessing that it digitally simulates that process.

Except they do it at different frequencys & currents etc. & then play with a bit of fuzzy logic to guess at the size of battery & state of charge.

In message , Duncan Wood writes