Battery drain

[Rachel]

Hi,

My 480 suffers from a pretty bad battery drain - it can drain a battery in about a day. I have to disconnect the earth every time I park up for any length of time. Does anyone know the best place to start? I assume it could be a a dodgy earth but I really have no idea where to begin! Any help would be great, thank you.

[brinkie]

Start with looking at the interior light in the glove box, sometimes the light doesn't switch off due to a faulty switch. Then check the interior lights if you have closed the doors and locked the car. Look at the dashboard, is the "door open" warning light still on?
Disconnect the radio. Especially the cheaper ones are prone to current leakage.

The real test is by using a digital multimeter in large current range (not in the milliamp range, unless you are willing to change the internal fuse of the multimeter very often ) between the ground of the car and the negative pole of the battery.
Leave the hood open, lock the car. Stick a screwdriver in the hole of the hood lock (i.e. make sure the microswitch is closed - you can hear a faint click) to fool the CEM that the hood is down and locked. The current should soon drop to less than 0.1 A (1 Watt) which is needed for the clock and the CEM alarm. Even with 0.1 A current drain a fully charged 60 Ah battery will last about a month before it's drained.

(Remember to open the doors with the key again before you take out the screwdriver, otherwise you might trigger the alarm )

[Rachel]

Hello - and thank you for your reply.

I have done all the first things already. All is ok.

I will try the next suggestion - what do I do next if the reading is high - which I suspect it will be.

Thanks.

[arthuy]

If it is a quick drain though check the big drain items, heated seats, rear screen, mirrors. also worth pulling relays, they can stick in the energised position or occasionally people swap them and fit the incorrect type, try not to mix them up.

Dont rule out getting the battery tested by halfords or similar, so long as it is free, you arent obliged to buy a replacement. If the battery is on the way out a nominal drain could drop the voltage enough to cause problems.Alernators can cause a drain to, which is why the battery testers are good, if your not getting a fully charge that will be picked up. if you can reach the plug try taking that off instead of the battery see if it makes a difference.

[brinkie]

Couldn't agree more with what arthuy is saying

What do you measure with a digital voltmeter across the battery terminals? With engine running and without? Do you see a very fast drop in voltage?
Together with the winter temperatures, it could indeed well be that your battery is on its way to battery heaven.

I had my car's battery and alternator tested at the local Volvo dealer for free. Not that they usually do everything for free, but they haven't had a 480 ever in their workshop (apparently this specific Volvo dealer hasn't been around for long?) and they were very pleased to see one.

[brinkie]

.

[Rachel]

Mine is not on the road at the moment. It's in hibernation but has had the drain for some time with 2 different batteries so I'm sure it's not the battery. You say check heated seats etc - but how? Everything is turned off when I leave the car. Also what do you mean by the plug?
I will get the alternator checked. It seems to be charging ok though and battery is at a good level after a run.

[Ade]

Put the multimeter in series with the battery negative as suggested (measuring current), maybe with some extended leads so you can read the meter from inside the car and pull fuses one by one until you find one that makes a big difference to your drain. If you do find that removing one particular fuse kills the excessive drain then that's your offending circuit and you can start further investigation. If none of the fuses make a difference then maybe try the same technique of putting the multimeter in series but instead of the earth, the different main power distribution wires near the battery (separate them first obviously or there is nothing to be gained by this ) and you are bound to find a drain on one at least if there is a drain there to be found, then it will be a matter of seeing what that particular line distributes power to and going from there. If you've already done the one by one fuse thing to no avail then you can discount any circuits fed by the particular line that are fused under the dash so this will narrow it down still further. Just take a logical and systematic approach and you will be able to narrow it down and down until you find your problem. If removing all the fuses (one at a time I would suggest!) makes no difference then maybe the alternator suggestion is worth following up, that's easy enough, again with multimeter in series with the battery circuit, just disconnect the charge lead and see if it makes a difference.

Relays are worth doing as well as mentioned, again I would suggest one by one, paying attention to your meter.

Hope this helps, pulling fuses one by one helped me locate a seemingly undiagnosable drain on a VW Corrado a little while ago, turned out to be the window motor in the drivers door would you believe! No prizes for guessing which fuse stopped the drain......

[Ade]

Oh yeah, probably goes without saying but DO NOT operate electrical stuff in the car with your meter taking the current unless you have a decent current capacity on the meter and you are sure that the circuit you intend to operate will not exceed it, otherwise......

[Ade]

One last thing I've just thought of as well, I have once experienced a starter solenoid draining current and of course this is not fused on the 480 (well, not on mine at least!). I know this because mine (although not the 'draining' one, that was a different car) shorted out in some weird and wonderful way and cooked all the wiring near the ignition barrel

Had to separate all the 'merged' wires, bodge with sellotape and effectively hotwire the car but with the key in to release the steering lock so I could get it back to the workshop and fix properly!

[Rachel]

Wow, thank you so much for all your help, I don't think I'm confident or knowledgable to tackle all that though! I can do easy bits. I guess a garage would charge a lot due to it's time consuming nature. I'll do the bits I can - hopefully it will be an easy fix!

[arthuy]

You will probably have got the gist of what I meant thanks to the other posters.

Quickest way to check if it is the heated seats or whatever is to pull the fuse, have a look at the fuse chart/manual see what operates off which fuse, you can do the same with the relays.

The alternator plug, look at where the wire go in there should be a platic plug, sometimes they have a wire retaining clip this come off so if the alternator has a fault you have isolated it.

Getting the multi meter out and going through all the fuses is obviously the best way to go but if you pull the fuses from the high drain items mentioned and see how you get on.

If you dont have a multi meter they can be picked up very cheap on ebay and the likes, basic but will do the job. I also have a battery tester which cost about £2, you plug into the cigar socket or clip on battery, it has LEDs which indicate voltage so engine off around 12v, engine running 14v ish. maybe not ideal for this fault but handy.

You may find if you pull a load of relays out and put them back it the fault may disappear.

Electrical gremlins are the bain of classic car owners lives but hopefully you get it.

Colin

[Ade]

Don't pay a garage, it will be the biggest waste of money ever!

Get yourself a meter, as arthuy says, they're cheap enough, and start with fuse pulling, one by one. Report your findings and we'll steer you from there based on what you come back with.

You'll probably find guides on YouTube, the technique is universal, not 480 specific. If you're still not confident, I'll take some demonstration pics on my blue one before I rip the engine out tomorrow and post them up. Alternatively, depending whereabouts you are, you can always swing by my workshop and I'll do it for nothing. It's near market harborough and I'm there some evenings and most Saturdays. I don't mind helping a fellow 480'er in need!

[brinkie]

Get a cheap multimeter, for instance
http://www.halfords.com/workshop-tools/ ... multimeter
http://www.diy.com/departments/0-600v-p ... 251_BQ.prd
etcetera. Will set you back around a tenner and it's a very handy tool anyway.
These cheap ones might not be the most accurate, but it will do fine if you're not working in a high tech lab, they both have a 10 Amp range which allows you to read currents from approx. 10 mA safely. A 60 Ah battery can supply 80 mA for a month so this setup will be accurate enough to detect current leaks.

Remember to measure between the negative terminal of the battery and the earth lead only! (can't miss it, it's the braided metal lead)
If you measure from the positive terminal and mistakenly make an earth connection with the other multimeter lead while the multimeter is set to current range, your multimeter will go up in smoke and flames or even explode.

[Rachel]

hello,

Thanks again for the replies. I have a multi meter, I have used it quite a bit although not 100% confident in choosing the correct setting! I'd like to have a go myself once my 480 is back home (it's having a holiday in a family members garage while we have had building works done to the house)

Ade, your offer is so very kind. thank you so much! I'm based near Aylesbury so not a million miles away about 1hr 30mins. I'll see how I go with the easy bits and if I get stuck or need extra help maybe I can contact you and we can arrange something? I nice trip out in the 480 would be lovely anyway Thank you - I'd be happy to pay for your time

So, when the 480 comes home, first thing I need to do is get my MOT as that has expired and then I'll get to work with all this great advise.

Thanks guys

[Ade]

It's not just choosing the correct setting on the meter, although this is vital of course, but if you normally use it to measure voltage, resistance, continuity etc then most meters will need the red lead swapping over to the other socket to measure current. I'd take a pic of mine to show you but I'm at home and it's in the workshop so no can do right now unfortunately, I could do this tomorrow though, most 'average' multimeters are a very similar layout (and mine is nothing fancy, think it cost me about £15 from a motor factor some ten or more years ago but it's always done the job!) What would be really handy is if you still had the instructions... You might find something online though, as I said, most average multimeters are a very similar layout and operation I'm sure you'll find something of use with, oh I don't know.... something like "basic multimeter operation" as a search term in google.

My offer to take a look at it for you if you're not too far away, which it seems you aren't (I know Aylesbury, I have family there, not been there for many years mind you) still stands when the car is driving again and there's no need for payment (although I am partial to a drop of Captain Morgan rum ), I'm just happy to help if I can to keep a 480 going, they're a very special and rare car and I enjoy working on them, plus it's always nice to meet a fellow owner, which, due to the aforementioned rarity of these cars, is not something you get to do very often!

Good luck figuring out your multimeter and remember, logical systematic approach. Locating a current drain in these type of circuits is not a technically difficult thing to do if you know how to use your meter, it will just take some time and applied logic. I'm not professing myself as an expert electrician, I'm not, mechanics and manufacturing engineering are my specialities and not too many years ago I found electrics scary too but I have learned, mostly through necessity if I'm honest, old cars will do that to you, it goes and finally


and so through this process you learn and every time you fix another problem, you learn a little more. Get your logical head on, look at some wiring diagrams, figure out the meter and have a go! It's a perfect job for the novice electrician to start getting their head around vehicle electrics.

[jifflemon]

Just a couple of things to add....

Places to start: Is there anything "non-factory" installed - Headunits, alarms systems? They're usually a good starting point.

Secondly, are you sure you're battery is good? You say it'll drain in a day - That's a pretty serious drain given that the standard Volvo battery is a 67 Ah thing.

[Rachel]

That's a good point. It does have an aftermarket alarm - seen better days - sounds like a very likely candidate! Thanks jefflemon

[Ade]

That's definitely your starting point, should have mentioned aftermarket stuff, well pointed out jifflemon.

Here's how you want your multimeter.....

[Ade]

Great, you can't see it

Let me give you the image URL instead...........

[img][IMG]http://i1043.photobucket.com/albums/b43 ... jl3vew.jpg[/img][/img]