Electrical problems Mark 1

[atomsoon]

Can anyone help?
I have a 120 Mk 1 with std Rover immobiliser. I've had a couple of occasions where the dashboard display flickers, the guages and warning lights stop working and the car looses power. Yesterday this happened and the car coasted to a halt and refused to start again. All I was getting was a clicking noise from the car, the battery did not appear to have enough power to turn the engine over yet the lights ,hazzards, horn etc were all working. I ended up on a tow truck. I know electrics are tricky and the fault often manifests itself in different ways.
I have checked the battery connections, connections to the starter button on dash and all cables etc.Today I have had the battery on a conditioner overnight and tried the car and it started first time???????
Any suggestions
Rich

[AtomFun]

Hi Rich

Batteries don't last forever, they lose capacity with time and whilst you might have been able to switch the lights on and sound the horn, it's nothing like the current drawn by a starter motor.

I'd guess the clicking you can hear is the solenoid switch but there's just nothing there to turn the starter motor.

You may have revitalised the battery with the conditioner but I'd be inclined to get a discharge tester on the battery and the liklihood is you'll need a new one.

[Driver]

I've seen several posts where people have complained about the battery going down and having to charge it to get it to start. I used to have a old Toyota truck that I let the battery go down several times and it never failed to push start, the smallest hill would get it going. It would start in reverse or in 2nd, didn't matter. My Honda Civic Si was similar. Couldn't you do the same to the Ariel assuming the charging system is in good shape? At least be able to limp it home if the battery dies while your out somewhere. Maybe this has already been covered in the old PH board.

[benyeats]

I sometimes have a problem on my Mk1 where the battery won't start the engine, this has happened twice during my ownership without rhyme or reason, for instance it started first time after my recent two week hols but on another occasion would not start after only sitting for 12 hours.

However I don't think this is quite the same as your problem, loosing power whilst going along sounds more like an alternator problem,  once you are going the alternator is the main source of juice rather than the battery.

Also note that as the battery in the Atom is a race cell it is designed to start the car and little else, leaving the lights on for only 5 mins without the engine on will be enough to flatten it.

Ben

[atomsoon]

Thanks for the replies.
1. Battery is the original 4 years old now so could it need changing?
2. How can I tell if the alternator is charging?
3. Anything else to check, test.
Rich

[AtomFun]

[quote="atomsoon"]
Thanks for the replies.
1. Battery is the original 4 years old now so could it need changing?
2. How can I tell if the alternator is charging?
3. Anything else to check, test.
Rich
[/quote]

I'm not sure what the life of a battery is but it's easilly tested for capacity - most garages just stick a high discharge thingy across the terminals to check it's capacity - pretty crude but works. However, the Atom's battery obviously won't have the same capacity as a standard car battery.

If you have a volt meter. measure the DC voltage across the terminals when the engine is running, should indicate more than 12volts to charge.

I also used to remove the positive terminal and measure to see if there was anything taking current when all is switched off. On old alternators the diodes used to pack up, not sure about modern ones though.

It's all basic stuff that most garages should be able to check in a few minutes.

Even if the alternator is working properly, I think you need a battery to keep the engine running - I could be wrong on this score.

[benyeats]

[quote="AtomFun"]
Even if the alternator is working properly, I think you need a battery to keep the engine running - I could be wrong on this score.
[/quote]

Don't think you do, when I had an MR2 the battery connector came off a couple of times which I only notices as the voltmeter on the dash started fluctuating wildly.  Would not suggest this is a plan as it will wear out the alternator very quickly.  The battery of course has to be connected to start the car in the first place !

Another thought is that the immobiliser on my Merc gets confused when the battery runs down (not to flat) and needs a total battery disconnect reset to get back to normal

Ben

[Andrew Hobson]

This is a don't try this at home thing, but I have started a car on a battery from another car, then taken it out [this is the bit you should not do because it risks shorting the + to earth and causing a fire] and putting the battery back in the car it came from.  The discharged battery can then, equally carefully be put back in the first car, and provided you do not stall charged up.  Jump leads are much easier and much, much safer.  While the battery is disconnected the car continues to run on the alternator.

A stop in motion like Atom soon's is unlikely to be battery related.  More likely is a loose wire, particularly a loose earth somewhere.

Andrew

[Driver]

Do Not jump start a car using jumper cables on a modern fuel injected, PCM/ECU computer controlled vehicle! Each time you do, you risk the chance of frying the computer or other electronics in the vehicle. Welcome to the digital age. Older cars the worse case was messing up a stereo or amp. Now with body contorl modules, electronic dashes, and other assorted microprocessors they are a lot more sensitive.

It is better instead to use a battery booster box. Their cheap, their easy enough to have in your garage and a lot easier to use than finding the cables AND finding another car to hook up to. In a pinch some can also be used as a trickle charger for your car. My booster pack has a cigarette lighter and assuming the cigarette lighter in your car is not switched through the key a simple cord between the two will keep the booster and the car at the same level.

Of course if your car is constantly having problems with sitting so long the battery drains, then get a permanently affixed quick connect plug and a trickle charger so it's easy to plug in. Kost of the Battery Tender products come with a small quick connect for ease of hookup.

[Bruce Fielding]

I always disconnect the battery if I'm leaving the car for more than a week as I have found that the immobiliser etc. will drain the battery in about a week otherwise.

Either disconnect at the battery or get a cut-off switch.

I don't have the luxury of a conditioner as my garage doesn't have power to it.

And at 4 years I would be pretty certain that the battery has lived its life and deserves a well earned rest! A new one is c.£80.

I have regularly jump started both my Atoms without a hitch - doesn't mean everyone will have it this easy ("I had a granny smoked a gazillion cigarettes a day and she lived until she was a thousand"), but just my personal experience.

As a matter of interest, I was told NEVER to use a booster box as that would fry stuff. Just goes to show there's all sorts of advice out there...

[Andrew Hobson]

I cannot see wy it is any different drawing current from the battery in the car or a battery remote frrom the car.
I still have not fixed up my solar trickle carger and therefore have to disconnect or Jump.  Brunters started my atom by jumping wHen I first saw it as it ad been standing about a month.

My garage is at the bottom of a hill and the battery is regularly too low to fire her up.

[Driver]

I didn't say it WOULD fry the ECU, but it could damage them. I also have not been absolutely faithful as in a pinch a few times I've used cables as well. Of course on one of my cars I did have to replace a PCM when it would no longer use 1st gear. $600 (cheap for a replacement) computer and all of a sudden I have first back. I can't relate it to any one thing but the microprocessors are susceptible to voltage spikes. When using jumper cables, you get a surge when you make the connection to the running car as its' alternator is in full charge mode just milliseconds after you hook the cables up. Usually the cables will physically spark when doing the initial connection. Do you think that is good for electronics? There is a risk, albeit a small one, that you can damage your car or the donor car's electronics. With a booster pack there is no spike as it's just a fully charged battery supplementing your existing one. Most even have circuitry to protect the battery. I just mentioned it because some people may not have been exposed to this nuance. It's just a different way to see how to ressurect a drained battery.

[AtomFun]

I've 'jumped' more cars than I'd care to remember and thankfully never had problems! Nothing more annoying than a flat battery when it's cold, wet and you've got a suit on and in a hurry!!

[atomsoon]

Diagnosis is a broken stud on the alternator which the wiring attached to.The stud had been "burnt thru" This was shorting causing the instrument display to flicker intermitantly.The battery was ok but the alternator was not charging up so effectively on a run the battery was using all its charge to keep car running.  This means either a repair (hopefully) or a brand new alternator. (boo)
Thanks for all the suggestions,
Rich