Got the alarm apart and found this...

[Green Goblin]

Probably the most pristine innards you could imagine!

I continued this from my other thread about changing the light cluster and didn't want to hijack the sticky thread on the subject, so started this one.

Did the light (no issues there) and decided to have at the alarm.

2 reasons really: First, for a period of about 2 weeks, was getting the dreaded constant beeping, as though the batts were low or dead. And second (and what with so many woes on assorted forums about acid leakage), was nervous about the condition of the batteries.

Got the alarm out (again, no probs there) and against my better judgement resorted to a Stanley knife to score along the edges of the alarm, as my hacksaw blade was bent, spindled and mutilated! Well, the knife method worked amazingly well because it cut almost right through, making the remaining prying apart with a screwdriver very, very easy.

Anyway, what I found was what rolled off the production line! No battery leakage whatsoever, no dry solder joints, shiny clean pcb and both batteries (Varta 3.6v Ni-MH in bright green heatshrink x 2) reading 4.06 and 4.07 volts respectively (I desoldered one side of each battery to get accurate readings).

So, I'm relieved but confused. What caused the temporary period of bleeping from the alarm (it did stop doing it, which made me think it'd gotten to the corroded stage)?

Could the batteries have just needed charging? Maybe internal sensor fault or door switch fault? And when *do* the batteries get charged??

How can I check what it was? I can tell you that when I got in the car after it was beeping, the interior light was fading up and down, up and down etc., like it was trying to tell me something.

Any ideas?

EDIT: Oh, and after all that, failed the damn MOT with sticking rear calipers!! Anyone know a good caliper refurbers in Norfolk (or elsewhere with fast turnaround?). Cheers chaps

[Adrian E]

Possible the main battery is getting weak?

[HPsauce]

Dunno, as I think I noted in another thread my alarm with new batteries still varies hugely in volume (and very occasionally does the beeps warning) so I think there is some sort of problem with the charging.

Oddly, I had mine out of the car for several days, while fruitlessly experimenting with a newer-type (too new as it transpired) replacement. When I put it back at first it was silent but within a few hours had presumably recharged and was appropriately "chirpy". Since then it's faded and varies between medium and quiet.

[Green Goblin]

Hmmm...

Decided to give the batts a quick measure as the alarm is still on my living room table while the brakes are being attended to at the garage.

Both are now showing 3.70 and 3.71 volts respectively, after just a couple of days sitting. So I'm thinking that (as often happens with car batteries) the voltage reading by itself is simply not good enough to determine the condition of them. I'm betting that they are probably on the way out in terms of their ability to hold a charge. And, actually, the high reading (4.1v) may even be an indicator that they're defective.

Whatever their condition, I'm gonna change 'em. Be rude not to while the alarm is out of the car and I suppose I'm one of the lucky ones in that I'm doing this before they've leaked!

Any recommendations to source Varta Ni-MH 3.6v 140mAh with the 2 pins either side of each battery? Most of the ones I've seen have the 2+1 pin configuration, which wouldn't be the end of the world but they'd need to be modded slightly and mounted end-on (i.e. tall not low) so as to fit.

[Green Goblin]

Batts are now very low, so didn't last long. Now ordering some newuns. Car passed its MOT btw.

[moltuae]

Congrats on passing the MOT Need to get mine booked in this week ...


I ordered these batteries to repair my alarm a few months ago:
1 x http://www.ebay.co.uk/itm/099-1x-7-2...-/190953054780

2 x http://www.ebay.co.uk/itm/Battery-pa...-/400837494079

I never used them in the end because, as I discovered when I opened it up, the PCB was too badly corroded to repair.

If you (or anyone else) can make use of them, I'll bring them along to the meet. Brand new and free to whoever wants them.

[Architex_mA8tey]

I wouldnt mind them Mark if poss - mine starts to make strange noises on odd occasions normally when the car is stood for a while so I could do with taking a look at mine

[moltuae]

You can have them with pleasure Neil

I'll put them in my box of 'things to remember take to the meet'.
(now just watch me forget the bleedin' box!)


They're not the same size as the original batteries of course, since they're no longer available, but with a bit of fettling, it should be possible to get them to fit.

From memory, I think the original batteries consist of 2 x 3.6v batteries in series, giving a total of 7.2v.

My plan was to either use 2 of the 3.6v batteries (in the 2nd link above), or the single 7.2v pack (in the first link). From memory, I think the original batteries had a lower capacity, something like 140mAh each, so either option should be at least as good as the original batteries.

[Architex_mA8tey]

Thanks that's great - they can be collected at the bar where your drink will await!