Hi there, Had my Copen a couple of months now and noticed the battery was horrific when it came to holding charge, but once started up the car ran fine. Now I've recently replaced the battery after the car came to a coughing and spluttering halt on the A41, and she fired back up no problem at all and drove back home. No battery light on dash, but I have noticed that it doesn't charge at all, and I only get 12 volts across the battery, and the same directly at the alternator. I'm presuming this means my alternator is dead, as I cant seem to see or find an in line fuse which can cause issues on some alternators in other cars, not allowing them to charge to their full capacity. Thanks, Dan.
Alternator, when running, should be pushing out 13 to 15v. Needs to be greater than 12v to charge the battery. You can check the ciggie lighter with a multimeter when the car is running for the voltage, or an OBD-II scanner will tell you the voltage as well. 12.7v is the full charge of a lead acid battery. If it's exactly 12v, your battery is charged to ~50%
Does the battery lamp come on when you put the ignition on? If not it cannot work. Check the wiring before buying a new alternator. Thin wire should be +12v when you put the ignition on. Fat wire should be low resistance to battery + ( switch multimeter to ohms). If the wiring is good and the lamp doesn't come on it is going to need alternator changing.
Too many years ago to mention, I upgraded my Triumph Herald convertible from a dynamo charging system to using an alternator. One of the things that was important was the the charging light bulb had to be sound because of the way the alternator works. Things may well be different nowadays, but if you haven't seen the bulb light up, it might be worth checking that first. The most you can lose is a half hour of time and the cost of a new bulb.
Thanks for the replies, some good points made. I'll have to get a multimeter on the wiring as the battery light does come on with the first turn of the key to ACC power, and turns off when the car is running, which is what led me to believe that it was charging in the first place, however the voltage return of 12 over the alternator and the battery suggests it is not charging, or there is a wiring issue. I knew the voltage should be higher as both my 350Z and my 4C show 13.5 volts when running, hence the concern for the health of the alternator. I'll crack out the multimeter later to check the continuity of the wiring and see whats what.
For what it's worth, I checked and my alternator pumps out 14.3v according to the cigarette lighter port
Well i've checked as much as I could possibly think of and have come to the conclusion the alternator is dead - as such I've another on order, used but with warranty so no worries. Thanks!
Eurocarparts had one at a reasonable price last month with one of their offers. A how to do it video or pictures would help the rest of us at some point if you get chance to photograph it.
B11 of the Chassis manual covers the Alternator removal. Looks like you "go in" from the wheel well :-|
Haven't actually touched it yet since I've been moving house recently, however from what I saw when I was digging around changing the oil on the car, the alternator could either be removed by pulling off the drivers wheel and arch lining and going in that way, or from underneath the car. So long as I remember to, I'll video the process and stick it on YouTube for viewing. May well also re-dip the car as the current coating is a bit of a mess!
I had the alternator changed on my 1.3 Copen two weeks ago. It took the garage 2 hours as it's not quite as easy as on the turbo in that the access via the wheel well isn't sufficient to remove/replace the Denso unit so they had to remove the drive shaft as well. Luckily, with small hands and a few scrapes, they were able to adjust the belt tensioner without having to dismantle anything else. It ended up costing me £145 for the new alternator (Opie oils ebay site) and the same again for fitting. The annoying thing is it didn't fix what I thought was a standing drain on the battery. Just found out today that it's the battery that's fried. £72 all in so fingers crossed. The standing drain is 50mA so should be good to leave for a couple of weeks if necessary.
I should have added the following which may help others avoid a similarly expensive misdiagnosis. The original autoelectrician noticed that the alternator was pushing out the volts (14+) but not many amps (c2.5 A over the demand). They then tried full load, which meant every heated function and light switched on and declared a deficit of 10A. I suspect that they didn’t take into account the relatively low (70 A) output of the alternator and the small battery capacity. The new guy found that one cell had overheated and caused the battery casing to bulge and the other 5 were deficient with a different fault. It may well be down to me leaving the car standing for 6 weeks while I sauntered off around Oz and the Pacific last May resulting in all the volts running away ! I’ll definitely disconnect it if I have similar thoughts of an extended holiday in the future.
A lead acid battery will self-discharge about 5% every month. Double that as a safety factor. For what it's worth, I pull the battery from my Copen and leave it on a smart charger full time if I don't drive her for over 2 weeks.
