Finding cause of excessive battery drain...

[Bassfiend]

Does anyone have any idea how to start locating and isolating what is causing my Chim to go flat if it isn't run for 48 hours? I don't think it's the battery itself as that was replaced only 18 months ago but if I don't run it over a weekend then it is unable to start afterwards ... in fact it wouldn't turn over yesterday so I had it on the Accumate for a few hours until about 6pm (started fine after that) and it wouldn't turn over this morning at 11am.

I notice that the Accumate has never been able to get off it's yellow "charging" light and onto its "maintaining" light which I can only assume is down to the continual current drain...

Phil

[peaktorque]

Try removing a few fuses, if you still have a drain then put them back and remove some more. Once the circuit causing the problem has been disconnected it'll make it easier to pin point the problem.

Does you alternator feel warm to touch, even though the engine hasn't run for a few hours? My old Wedge had a power drain due to a dodgy voltage regulator in the alternator.

[WOO5IE]

Hi Bassfriend

Are you sure that the battery is fully charging. Are you Ok with a multimeter i.e checking charging voltage and currect drain. Could be the alternator or even the main 100Amp fuse perhaps.

[John042]

Hi Bassfiend. I experienced similar problems; measured the static drain on the battery which was 0.42 amps. Excessive I thought but replaced the battery anyway. I put the drain down to a greedy imoboliser system? However a previous post about relays did suggest that fitting a after market ignition or fuel pump relay might be the cause. Apparently certain relays don't have a diode fitted preventing a static power drain. Again I've not checked or replaced mine. What bought your post to light was the fact that your 'smart charger'never reach full charge indication. Mine was the same after a week as if the charger couldn't keep up? Solved by putting it on a higher setting. Let us know if you discover the problem please. Cheers John C

[Bassfiend]

peaktorque said:

Try removing a few fuses, if you still have a drain then put them back and remove some more. Once the circuit causing the problem has been disconnected it'll make it easier to pin point the problem.

Hmmm ... good thinking. The only downside is (of course) that I need to keep leaving the car unused...

peaktorque said:

Does you alternator feel warm to touch, even though the engine hasn't run for a few hours? My old Wedge had a power drain due to a dodgy voltage regulator in the alternator.

Not that I'm aware of and I did replace the entire voltage regulator and brushes assembly just before Xmas anyway as I've always had a discharging issue and that didn't change anything ... it's just that it suddenly seems to have got much worse.

Phil

[Bassfiend]

WOO5IE said:

Hi Bassfriend

Are you sure that the battery is fully charging. Are you Ok with a multimeter i.e checking charging voltage and currect drain. Could be the alternator or even the main 100Amp fuse perhaps.

Hiya Woo5ie,

I checked the charging voltage a while ago (before and after changing the voltage regulator and brushes packs on the alternator before Xmas) and was getting >14v ... unfortunately I'm away from home at the moment (and away from my tools) but I may be back home on Friday and can check it again then...

Phil

[Bassfiend]

John042 said:

Hi Bassfiend. I experienced similar problems; measured the static drain on the battery which was 0.42 amps. Excessive I thought but replaced the battery anyway. I put the drain down to a greedy imoboliser system? However a previous post about relays did suggest that fitting a after market ignition or fuel pump relay might be the cause. Apparently certain relays don't have a diode fitted preventing a static power drain. Again I've not checked or replaced mine. What bought your post to light was the fact that your 'smart charger'never reach full charge indication. Mine was the same after a week as if the charger couldn't keep up? Solved by putting it on a higher setting. Let us know if you discover the problem please. Cheers John C

Thanks John,

It's been suggested that the likelihood is that it's the old alarm draining more and more juice as it gets older - I've been told that I can get the whole shebang replaced for £500 with a modern-day version ... unfortunately I'm still waiting for the specialist in question to get back to me to get it done (I've told him on a couple of occasions now that I can drop the car round whenever it suits him) but it seems he's busy or forgetful...

Working on the theory that mine's depleting in about 36 hours then that would indicate a drain of about an amp constantly (I think they're a 38Ah battery) mind you I suppose it was still up to running the fuel pump and would *ALMOST* kick the starter motor into life so wasn't completely dead.

I wonder if the local Halfwits has a battery tester (and knows how to use it)? I might just try throwing in a new battery as this one has been completely discharged a number of times and may be suffering because of that? (And hopefully get the drain fixed at sometime in the near future.)

Anyone know if the alarm is separate to the immobiliser? (Mine has a separate immobiliser fob that has to be swiped around the ignition barrel housing to defeat it.) I'm quite tempted to get the entire alarm removed as it doesn't actually seem to do anything useful other than trigger the central locking but unfortunately I suppose the insurance copany wouldn't be too pleased with that.

Cheers

Phil

[Harrytsg]

Assuming the above confirms you are charging and the battery isn't faulty , I would use a clamp tester to measure the current drain, and, with the interior light and everything else off, pull (then reinstate) one fuse at a time checking to see when the drain stops.
Obviously you need a clamp tester to do this though some multimeters have a DC current setting usually capable of measuring 1amp or so.

[Bassfiend]

Don't clamp meters only measure AC though?

Phil

[Harrytsg]

Not the ones I've used, they have always done both.

[peaktorque]

My 'Fluke' meter does both.

[Harrytsg]

peaktorque said:

My 'Fluke' meter does both.

Snap, Fluke 336 to be precise.

OP, can you get access to one, it may prove just the tool.

[roysum]

Bassfiend said:

Don't clamp meters only measure AC though?

Phil

Hi Phil,

You can get DC clamp on ammeters, we use them for PV installs to measure panel and array current.

I had your problem recently, and it turned out to be the battery. I had my racing battery on the bench ready for a boot conversion and it has been fine ever since. You probably have a cell gone down, try a hydrometer to measure the SG of each cell (if it isn't a sealed one).

good luck, Roy.

PS. Really like the turning power of my Odyssey battery.

[Bassfiend]

If I was at home then I'd have access to tools and test kit but I'm away at my GF's for a fortnight "recuperating" after minor surgery last week so the nearest thing I have to test kit here is a spoon ...

I know it's always drained the battery quickly but I'm suspecting that the battery has also decided to take the opportunity to expire so I think it's going to be a trip down the the local Halfwits for one of their overpriced Bosh 'five year warranty' specials - I fitted one of their 3 year warranty batteries about 18 months ago but don't have the receipt with me of course and may not even be able to find it at home as I've moved house since fitting it. At least I have a trade card in my wallet which should remove a bit of the sting...

Phil

[Bassfiend]

Harrytsg said:

Snap, Fluke 336 to be precise.

OP, can you get access to one, it may prove just the tool.

I'd have to pop to Maplins for one which in itself isn't an issue however looking at the clamp meters they do they all seem to be AC only for current measurement and not DC...

Phil

[Bassfiend]

spend said:

It's a bit of a pain but I'd start by removing the big cables from the alternator to see if that isolates the problem whilst standing.

You don't have to reconnect just check the battery voltage over a period of time, before reassembling...

Good thinking batman!!!

Phil

[peaktorque]

Bassfiend said:

I'd have to pop to Maplins for one which in itself isn't an issue however looking at the clamp meters they do they all seem to be AC only for current measurement and not DC...

Phil

Fluke meters are a bit pricey (I use mine for work so it's a must for me) from memory they are at least £90. Maplins don't sell them, but somewhere like City electrical factors (CEF) or RS components will.

They are very easy to use, with features like auto change-over between DC an AC, so you don't have mess around with the option of 700 different settings.

Edited by peaktorque on Thursday 7th April 10:29

[Bassfiend]

peaktorque said:

Fluke meters are a bit pricey (I use mine for work so it's a must for me) from memory they are at least £90. Maplins don't sell them, but somewhere like City electrical factors (CEF) or RS components will.

They are very easy to use, with features like auto change-over between DC an AC, so you don't have mess around with the option of 700 different settings.

The Fluke 336's mentioned above seem to be running at about £300 each...

Phil

[haircutmike]

My money's on the battery.

Disconnect the earth, fully charge the battery, leave for 48 hours or so, reconnect and start, or not, you will have your answer if it is the battery.

I have one of tose battery isolaters fitted to the Disco winching circuit, these can be usefull if the car is left for long periods.

http://cgi.ebay.co.uk/Car-Battery-Isolator-Cut-Off...

[Bassfiend]

haircutmike said:

My money's on the battery.

Disconnect the earth, fully charge the battery, leave for 48 hours or so, reconnect and start, or not, you will have your answer if it is the battery.

I have one of tose battery isolaters fitted to the Disco winching circuit, these can be usefull if the car is left for long periods.

http://cgi.ebay.co.uk/Car-Battery-Isolator-Cut-Off...

• chuckle* Mine has an isolator switch installed in the inner wing but I haven't yet worked out what (if anything) it actually does isolate ... it certainly still leaves most of the car powered.

TVR's huh? Love 'em!

Phil