What Is Draining My Battery?

[JRL 14 1 Cars]

My 205 has really let me down for the 1st time in 4 or 5 years I have owned it. I took my girlfriend to the isle of white for her birthday and I was looking foward to driving around the island. last week I replaced the alternator after having the battery light come on faintly when heater and lights are on etc and prior to fitting this I was charging the battery every few days as it was going flat. thought it was fixed wentaway and it drained overnight. so I bought a new battery as mine was old and hoping this was the problem and it still drained. whats going on?

[Rich_p 23]

Have you got an alarm on there?

 

I had one on an old car that would drain the battery if the car was sat unused for a days

[JRL 14 1 Cars]

Nope mate I have just an imobiliser. I have removed the stereo as well. it must be something to do with re-locating the battery to the boot but it was fine until recently.

[Anthony 1,003]

A multimeter is your friend for diagnosing issues like this.

 

Firstly check that the battery is actually being charged when the engine is running, and then check to see which circuits are draining current when the ignition is off - should only be a few mA and anything significantly higher than that needs investigation.

 

Moving the battery to the boot by itself shouldn't cause a problem with the battery draining.

 

(PS. the dim battery light when the interior fan is on full speed doesn't usually indicate an alternator fault, but a wiring/earthing one and is very common on 205's, usually with no ill-effect)

[JRL 14 1 Cars]

thanks, i have been over with the multimetre but all appeared ok I will have to check again. since fitting the alternator the battery light no longer glows even with everything on. The battery is ok for about 4/5 days before it wont start the car.

[Anthony 1,003]

What sort of current draw are you seeing with the ignition / electrics off?

[Simes 248 2 Cars]

Check the door switches for the interior light - bad contacts mean the light can stay on but incredibly dim.

I only noticed mine were draining current after installing the alarm.

Clean them up or replace with ones from a 306.

[GLPoomobile 958]

Simes - whilst I'm not disagreeing with what you may have experienced, on the surface it doesn't make sense Bad contacts on the door switches would make it more difficult to get the interior light live, so less likely to be drawing a current. And they shouldn't stick on with the door closed unless the switch is physically broken, becuase the door will push the switch to open, so no current flows.

 

One thing I've experienced, and I don't know if this perhaps relates to what you are saying, is the interior light being very temperamental due to loose contacts in the light unit itself. I've had this on every 205. The light will be a bugger to get on, and you have to tap it to get a connection, then it'll go off again as soon as there is any movement or vibration. Now, if like me you can never remember which position the light needs to be in for off/on/door activated, it would be very easy to leave it in the permanent on position, but assume it is off because of the temperamental connection. You then walk away and leave the car, and that temperamental connection might come and go while the car is unattended, which then obviously draws current.

[gtmotorsport 0]

Another thing to check which I once had was the boot light staying on. You usually shut the boot and because of the shelf don't notice it is still on and hence drawing current and draining your battery. It was only late one night when I shut the boot up and noticed it was glowing through that I noticed it.

 

Only other thing for it is to go through and pull every fuse until you issolate the circuit that is drawing current when idle and then investigate from that point.

[JRL 14 1 Cars]

the reading was giving 13.5 or so with the engine running. I try to think what have I done to the car recently since this has been happening. the rear i stripped ages ago so no boot light but that has happened before to me on a 106. I leave the courtesy light in off position since this has been happening. One thing I have done is i removed the glovebox door as it was catching on the roll cage I did disconnect the glovebox light not sure if the drainage is related to this switch.

[Anthony 1,003]

13.5v is a little on the low side (assuming no significant electrical load), particularly if it's a new alternator. Should really be seeing 14.0-14.4v

 

However, that's not testing current drain that would flatten a charged battery when left for a few days. To do that, with the ignition/electrics off, disconnect one of the battery terminals, and with the multimeter in current measuring mode (set to mA), use that to complete the circuit between the battery and the disconnected terminal. That will show you the current draw - something around 25mA will be about right without an alarm, and if it's much higher than that, there's your problem.

 

You can then disconnect each fuse in turn to see which circuit is drawing excessive current when it shouldn't be, and from there, identify the culprit. As has been said, alarms and stereos are both common, as are interior lights staying on - if you've ruled out all of those, then you're going to have to track it down.

 

DO NOT DO THIS WITH THE ENGINE RUNNING OR WITH SIGNIFICANT ELECTRICAL LOAD otherwise you're likely to fry either the alternator or the multimeter, the later often only beign rated upto 5-10A at most.

[JRL 14 1 Cars]

thank you for this I will let you know how it goes, im guessing the imobiliser is the culprit

[JRL 14 1 Cars]

More investigation with the multimetre. Fully charged new battery up overnight started the engine up and battery showed 14 or more but when I put the lights on it started going down slowly. So this shows it hasnt been using much charge to start her up but electricals have slowly drained it hence the reason why I can use it for days with no problems then just doesnt have enough juice for the engine management. So why would the alternator not be charging the battery? dodgy wiring? hopefuly this rules out parasitic drainage.

[JRL 14 1 Cars]

Im afraid I have to drag this thread back up as the problem still persists.

 

Had to get recovery Last night from oxf to london and it was bloomin freezing. The car started but stalled after low idle and wouldnt start again. Tried hooking up my brothers car battery but still nothing. The AA guy came out put a jump pack on and said the battery is fine as its cranking over fast but just not firing, the ignition coil wasnt firing and injectors were not pumping. The crankshaft sensor was brand new 3 years ago but he cleaned it anyway. His thoughts were the crankshaft sensor needs replacing as he has seen this a lot.

It has recently had new alternator, new battery, and on friday found and fixed the alternator eyelet conector was barely attached the battery volts now show 14.5 when running.

im guessing either

1. crank sensor

2. ecu

3. ignition coil

please help im desperate its my daily driver.

James

[Anthony 1,003]

Or the ECU relay - if that's not working, then the ECU doesn't get power and thus no spark or injection. If the relays are floating around loose in the engine bay then they seem to be particularly prone to failure given they're exposed to the elements and vibration.

 

Easy enough to test - either check with a multimeter, or just hand-wire a link joining the two thick wires together.

[JRL 14 1 Cars]

Il try that I dont want to replace everything to rule out issues as this is costing a fortune. Thanks Anthony

[JRL 14 1 Cars]

Just took a look. found the relay I gave the electrodes a clean It was dark and couldnt see which electrodes go back on where... but must be on right it started 1st turn of the key and seems to be alright now. Im just hoping its not an intermittent issue and not just luck it started.

[large 33]

What engine are you running, Mi?

 

If you can try and get someone with a running car to come over (you). So you can swap parts as it could be a number of things.

What you have said + ignition amp or starter motor.

 

Have just seen your reply above, I would take it for a run get it nice and warm go home and try and start it again when hot. If it starts, happy days.

[JRL 14 1 Cars]

thanks Large, got it nice and warm and it did restart. I dont think it will be the end of it though fingers crossed.

[JRL 14 1 Cars]

So far so good I havent updated this as I didnt want to speak to soon but finally after all the hardwork I think its ok,

 

new Valeo alternater, new battery, new charge cable and eyelet to alternator, Valeo igniton coil, new spark plugs and cleaned the ecu relay its been holding its charge even with 5 days without use. With parts that could be 20 years or more sometimes you just have to get your wallet out.

thanks for your help.

[TT205 42]

Just for the record, I fitted a new alternator on my 309 a few years ago and continued to have similar problems to you - the new alternator was faulty, fitted 2nd alternator and all well

[JRL 14 1 Cars]

Blimey that was unlucky and must have been a headache when you replace something with new you dont expect it to be at fault and you start scratching your head at what else it could be. I got an original valeo alternator and its all charging well now.