Battery discharging quickly

[whaleys]

Hi guys,

I have a problem with the battery discharging when the car is just sitting in the garage. Over winter the battery died (wasn't on trickle charge) but it was generally good for 2 weeks being sat then I would notice it struggle to start. Then a couple of weeks ago it was dead again. So I charged it fully, put it back in the car and it started perfect. Went out for a drive and it was fine, a couple of days later it was dead. I recharged it (and took a mental note to buy a new one cause it was likely damaged from winter discharges and I'd had it a while) put it back in car and it was fine. Day or two later again, dead. So went and bought a new one, fitted it went out for a drive, two days later, dead.

I'm now thinking its more than just the battery . The only thing I could think that it would be is the alarm, but it's still working fine?

Info that may help with diagnosis...

When its in the garage, I dont alarm it (to help with battery drain).
I recently fitted the new rear LED light clusters and have used the link leads for the exterior rear lights (the problem arose just after I fitted these, although probably just coincidence).
This one is going to sound stupid, but when i was in the garage at the car I have heard what sounds like the neighbour hoovering (that sort of quiet higher pitched sound) but it was coming from the engine bay. When I opened the drivers door it went off, when I closed it again it started.
I tested the voltage at the battery terminals when the car was running and its reading 14v.

Any advice greatly appreciated as usual. It's going into Ali for a service on the 21st of this month.

Cheers guys,
Graeme

[robin]

You could always measure the battery discharge current while parked in the garage.

Loosen (but don't yet remove) the negative battery terminal.

Once it's loose and ready to be removed disarm the alarm/immobiliser (even if you haven't armed the alarm, it will still go mental if you remove the battery without first clearing the immobiliser).

Now remove the negative terminal.

Now set your multimeter to current measuring mode - note that on most multimeters to measure with the 10A setting you need to move the red lead into a different socket on the meter, whereas for the smaller current ranges you leave it in the normal position.

It will help if you have crocodile clips or similar at this point (perhaps improvise with some jump leads). Connect the red terminal to the negative lead and the black terminal to the negative battery terminal.

The meter will display the current flowing. If you wait a minute for ECU and alarm to settle down, you should see the steady state current flow.

I would guess something around the 100mA mark is acceptable; more than this will be a problem (2 weeks at 100mA is 33Ah which is around the capacity of your battery).

Cheers,
Robin

[whaleys]

Cheers Robin,

Will give that a go tonight and report back the results...

Graeme

[whaleys]

Ok, I went out with my multi meter and these were the results...

I improvised with jump leads and followed what you said Robin. Please excuse my uselessness but I dont often use the current part of the multi meter. There was the option to put the lead in the A or mA so chose A. Then set it to 200mA setting and it gave a reading of 3.9 to 4.1 fluctuating. So if we round that off to 4.0 I assume that means the total draw from the battery is 400mA?

If that's the case it would seem that something is broken, but everything seems to be working fine?

Apologies for the rather newbie approach, I'm just not that experienced with electronics.

Cheers,
Graeme

Also, I forgot to add, I checked the battery voltage when I removed it tonight, it was at 3.8V

Last run it had was Sunday past.

[alicrozier]

There was the option to put the lead in the A or mA so chose A. Then set it to 200mA setting and it gave a reading of 3.9 to 4.1 fluctuating. So if we round that off to 4.0 I assume that means the total draw from the battery is 400mA?

Not sure about your multimeter but on mine when you plug the lead into the A socket you have to use the 10A max range. Plugged into the mA socket you can use max ranges of 200mA, 20mA etc. So I'm not sure if you are reading a valid range for the meter or if it's reading 4.1A or 4.1mA?

Plug it into the A socket and reading is in A or,
Plug it into the mA socket and use the 200mA range - reading is in mA.

I'm very far from competent so I'm sure Robin will be along soon to advise.

[whaleys]

I chose the A one because underneath the mA one it said "warning 200mA max" and under the A one was "warning 20A max". Since Robin figured that it should be 100mA (and mine was likely drawing more) I thought I should put it in the other one in case there was more than 200mA draw? It might not work like that, but I didnt want to blow up another multi meter (blown a couple in the past, not tonight)

[alicrozier]

OK, so..
Plug it into the A socket and set to 20A max - you have to read it in A. If it's reasonably less than 0.2A then,
Plug it into the mA socket and use the 200mA range - reading is in mA.

[robin]

Yes, you were reading noise - the A socket requires an A setting, the normal V/mA socket works on only the 200mA range.

However, with the battery voltage at 3.6v you are already wasting your time as the current draw at 3.6v is not going to be representative of the current draw when the battery is properly charged.

So charge battery first, then once it's nicely charged do the current discharge test.

If your battery wasn't brand new I would say it's shagged ... certainly if you keep discharging it to 3.6v you will shag it soon enough (lead-acid batteries hate deep discharges).

I suggest that until you have figured out what's broken you should disconnect the battery at the -ve terminal whenever you're parked up for any length of time.

Cheers,
Robin

[whaleys]

Ok, I'll try again tonight.

The battery that was drained to 3.8v was only a week old. I have two batteries so have been switching between them for testing. If it is likely to be the alarm, is there a fuse I can remove to disconnect it for the time being?

Cheers as always,

Graeme

[whaleys]

Sorry for not replying in a while but I have been on holiday.

It seems that my discharge problem is the alarm/immobiliser. The quiet high pitched noise starts when the immobiliser kicks in and the draw goes up from 0.03A to 0.45A.

So it seems to be coming from the rear of the car (so I am assuming the immobiliser) so its car apart to prove it. I was looking at this site for a replacement alarm should it be knackered. They do a replacement alarm that plugs in to the original stuff...

http://www.abacuscaralarms.co.uk/alarms ... _VX220.htm

That one however doesnt seem to include a replacement immobiliser, but they do they whole thing here...

http://abacuscaralarms.co.uk/store/view ... 20M99/36T2

Anybody have any experience of replacing these alarms?

Cheers,
Graeme

[robin]

Hmm. It'll probably be the immobiliser relay. I would simply disconnect and bypass it (there still remain two other immobilisation mechanisms, so your car won't be totally unprotected).

No idea about the other alarm systems, but beware there are at least 4 alarm systems for the elise, depending on vintage.

Cheers,
Robin

[whaleys]

Hi Robin,

Is the immobiliser relay the black box behind the passenger seat, behind the fascia bit, behind a little panel?

I have a Feb 2002 Sports tourer. The Manual says that its a Meta system and on elises.co.uk it says that the Sports Tourer pre April 2002 has the Meta M99T system. Do you know if that is correct? I certainly have the extras that it describes that comes with the cat1 thatcham upgrade.

Ta,
Graeme

[whaleys]

Hey all,

Figured out what the problem was, it was the alternator, again! The sound when the immoboliser kicked in was a symptom not the cause. Although it was strange that the alternator was making the high pitch tone.

So instead of replacing the regulator pack (I was supposed to mail the first one to you Robin but my better half cleaned up and through it out!) like I did last time I resigned myself to buying a new alternator altogether. It's strange/worrying though that the new regulator only lasted 5 months.

I bought an eliseparts alternator heat shield as well and when I went to fit it i could not for the life of me figure out how it fits on! Does anyone have any instructions/diagrams/pics/advice?

Cheers,
Graeme

[robin]

I bought an elise parts alternator heatshield, which when it arrived was flat rather than the nice alternator shape in the picture. I couldn't figure out how to bend it into the correct shape and eventually battered the living daylights out of it with a hammer and threw it in the bin. Utter sh*t. Perhaps I'm just cack handed and stupid, though.

Cheers,
Robin

[whaleys]

I emailed eliseparts to ask if they have any instructions or diagrams for fitting. I recieved it flat as well but did manage to bend it to look the same as the picture. Not sure if thats correct though . I was a little surprised as eliseparts are usually really good with instructions (from my experiences anyway).

Will see if Geary gets back in touch, and if so, I'll post the instructions somewhere should anyone else buy one, to avoid them spending the majority of their day scratching their head.

Greame