Battery Losing Charge.

[skittletop]

Spider '87. I've had the car only 3 weeks, twice now the battery has lost sufficient charge to inhibit the starter motor from turning. Yanking the battery and giving it a full charge fixes the problem, the battery is fairly new (less than a year old, from the PO's receipts)

Bad earth, alternator? I'm a complete nOOb when It comes to car electrics. So my question is this, where do I start? I've searched the BB for obvious posts (although I'm pretty sure there is relevant advice in this invaluable tome somewhere, I just couldn't easily find it)

Could anyone graciously post links to relevant threads to get me started? I've used a multimeter and soldering iron before, so I'm willing to get my hands dirty.

Many thanks in advance.

[Tifosi]

Start simple:

Make sure the curtesy lights go off with the timer after about 15 seconds or so once the doors are closed.

The lense cover is actually a rocker switch with one postion being off all the time, the central position being on after door opening with timed cut~off once the doors are closed, the final position is on all the time regardless. (presuming they're wired correctly of course) They are kinda easy to bump with a knee when entering and exiting.

Make sure all sundry items are turned off as not everything gets shut off with the key like other makes.

Clean the battery posts, cable terminals, negative cable where it anchors to the body and the alternator junction block located on the left inner fender of the engine bay.

[Alfacliff]

Many (including me) have been embarrased by the glove compartment light, if it stays on, it can run the battery down.
cliff

[skittletop]

Hey Guys,

Thanks for the tips. I ensured my knee light is now in the off position. Checking the glove compartment, there is no bulb in the socket, I'll replace and see if it remains on when closed.

One thing that I did notice, on the drivers side door frame there are two rubber switches that get depressed when the door is closed, one of the rubber bungs on the door is missing, so the second upper switch is not being pressed when the door is closed.

I'm pretty sure the lower switch is the door alarm (as that works), anyone know what the second switch is, and could this be the source of my problems?

I'll check the alternator/battery connectors at the weekend.

Thanks again for the replies.

[Tifosi]

One switch is for the 'hey your door is open and the key is in the ignition' chime/buzzer/warning the other is for the curtesy lights.

Check the passenger door too as there's one switch over there for curtesy lights.

Glovebox should have a switch in the upper right corner that gets depressed when the lid is closed.

[MrT]

We had the problem with the courtesy light in the passenger (right) side footwell having been kicked to the "on" position. They toggle locally and give no indication visible in daylight without sticking your head into the footwell or feeling around under the upholstery for a hot spot (not advisable in all circumstances).

Michael

[Tifosi]

The uber quickest way to get around that is to pop the lamp assembly out, then put it back in the other way over.

At least thay way if it was consistantly being kicked to the 'always on' position, it'll now get kicked to the 'always off' position.

Beyond that, wires can be fiddled on the back of the lamp to prevent the 'always on' position from functioning. (which will almost immediately give rise to a situation where you need it on, but can't do it because you fiddled the wires LOL)

'Course there's always the option of backslapping your passenger every time they exit to remind them to (1) don't kick the damn light and (2) double check the damn light before they walk away after closing the door, even if it means standing there for 15-20 seconds to allow the timer to cycle off.

This method is the least labor inducing on your part and over time creates another person who can eventually take over the driving as they too will know enough to backslap any passenger they may have.

[skittletop]

Okay, I'm starting to think my battery is hosed.

I checked the knee lights, as far as I can tell, they are not wired on the delay timer, so they do not respond when doors are opened, additionally my boot(sorry trunk) light does not appear to be working.

Had the problem a couple of times now where I go to start the car after a couple of days of no use, engine does not turn over. Usual warning lights come on and beepers etc. But starter will not turn, get a clicking from the rear (fuel pumps?)

So, I whip out the battery and hook up the charger, give it a full 2amp trickle charge install back in the vehicle and Hey Presto! Good again for a week of driving.

I was using the voltmeter in the dash to determine when a charge would be needed (without the engine started) , at about 11.5 I'd whip it out the battery and give it a charge which would keep it fresh (side note, is 12 normal? As this is how high it goes with my fully charged battery? Once the engine is started it jumps to approx about 13 volts.

Only trouble is the last time I tried this, the battery refused to take a charge, I switched my charger to the 2 amp circuit, it kept switching between fully charged (light on) and drawing 2 amps, but I left it overnight anyway.

Reinstalling the battery, I manged to get enough charge to start the car (just!) starter motor was turning very slowly and I had to give it gas (which I don't normally have to do.) After a short spin and return home, car would not start on second attempt, starter would not turn.

I think I mentioned my battery is quite new, less than one year old according to PO (and under warranty if I can dig out the receipt.)

I've read up on battery recommendations here on the BB and the Optima Red Top batteries seem to come recommended, also their videos are very interesting and informative (but not really relevant to my troubles.)

So, a few question here:
1.) What is normal voltage reading on the gauge (I'm thinking 13.8?) for a fully charged battery if the car is not running?
2.) Since AFAIK my battery never went completely flat, it was always reading around the 10-12 volts when ignition was turned on, so is it really dead.
3.) Is it worth investing in an Optima Red Top? Or will my faulty electrical system end up killing this pricey battery as well.

Again, TIA. I'm looking forward to the day I might be able to answer someone else's questions

[ghnl]

Generally speaking, Alfa gauges are not known for their absolute accuracy. They can sort of give you an indication of things but I wouldn't trust any specific reading. A $10-$20 VOM (Volt Ohm Meter) will allow you to get more reliable readings - plus you can connect it directly to the battery or at any connections that need testing. And - the biggest plus - you can use it to do Voltage Drop Testing.

A fully charged battery with no loads applied (everything off) should show about 12.6V. Merely switching 'on' the ignition applies a small load and voltage readings will likely drop a little. And what is needed to energize the starter motor is amps - lots of amps. You can have 12+V with inadequate amperage and the starter will not function. And even new batteries can fail.

Optima is a premium brand with an hyper premium price. I use a standard battery with no problems. Check - clean & tighten - all electrical connections between the alternator & the battery - battery cables, negative cable's attachment to the trunk floor, ground strap between the bell housing & transmission tunnel, junction box on left inner fender & (with the battery disconnected) the positive cable's attachment to the starter motor. It would be easy to 'lose' 1/2 volt at each connection. That could add up to, umm, a lot.

[skittletop]

ghnl,

Thanks for your reply, I ended up purchasing a new (standard) battery which seems to have cured the problem, at least in the short term, yay! Although I still think my car has some electrical niggles.

I'll be putting the car away for the winter so will have plenty of time to do some voltage drop testing, excellent article by the way.

Thanks,
Brad.

[ghnl]

TO check for any unknown electrical draw try this: With everything shut off remove the negative battery cable. Then, in a dark garage or moonless night flick the cable end against the battery's negative post. If there is a tiny spark there is likely a significant electrical draw. A modern radio &/or electric clock will draw a few milliamps - usually insufficient to show a spark. An unseen light left on (say inside the glovebox) will draw enough to show a small spark. If you have a Volt/Ohm meter that also has the ability to measure amps that will allow you to measure how much (if any) electrical draw is present when you are expecting none.

If you are going to park & store the car it is a good idea to use a smart trickle charger. Even with the battery disconnected it will slightly deteriorate over time.