Dead battery

I find it odd that batteries can just go "dead" without warning. But I guess the recent cold weather has just killed it off.

The voltage is so low, my charger refuses to charge it.. Was under 4V. It's been on it since before I got in in 2013 so it's done ok.

Off to Halfords with my Trade card tomorrow.

Any recommendations for crank power and Amp hour ratings? Was thinking ~60 Amp hour. Currently 55 on it.

You may find your local motor shop will do you a better deal than Halfords: at least some coupe batteries don't get the trade card discount.

The Coupe lives once more...

I did check out some other sellers, but the Trade Card came up trumps again. Yuasa HSB013 62Ah 5year warranty battery for £84. Was £117, but sale price of £105 then trade card did the rest with 20% extra.

Chuffed

Possible disaster.

When I installed the batt, I checked the voltage with a multi-meter, and it showed 14volts, so the alternator was putting at least 2 volts into the battery. All good I thought.

Drove to work today, and the dashboard volt gauge showed 12.5V and when driving it dropped to about 8 volts
I did have the heated window on first, but switched it off before this happened.

Then it came back up to 12 volts.

I'm wondering if there is a fault with the charging system ?? I've concerned that I won't be able to get home from work at this rate.

Any ideas?

Failing alternator by the sound of it Toby, but I wouldn't believe the dash volt meter so test the voltage on the alternator itself and then the battery and compare the reading.

Thanks Joe.

The alternator was definitely adding power, but perhaps it is intermittent, or the reg/rectifier is not working properly. Or a bad earth?

Yes, the dash volt meter has never shown much more than 12.5volts, even though the battery was at 14v. So I assume it is not accurate. Even so, I was rather concerned when it dropped. I've got a mate at work with a multi meter hopefully, so will check it again before I leave.

Did you get the battery light?

Was it on when you put the ignition on but before starting the engine?

If not, it's possible (likely) that either it has failed, or the alternator thin wire is broken or detached - the light is in series with that wire and without it the alternator won't alternate.

Note that if the bulb is dead, it is of higher rating (don't recall the value) than the other dash bulbs. You need the right one.

Hey Mr B. No battery light, just the drop in the voltage needle on the dash. I may just be paranoid, but with Fiat Coupes, just because you're not paranoid, doesn't mean there isn't a problem !!

The multi meter is showing 14.11v with no load, then about 13.8v with all the lights etc on, which I think is ok. I've youtubed a few more checks I can do, like losses from alternator and checking for resistance at various points. I just want to be sure I don't ruin a new battery.

I'm also told that testing in cold weather is not ideal.

Cheers

That's where it should be, Toby.

You're doing better than me; my alternator is definitely dead and stranded Anita in a car park this week. And guess what? No such animal...

Something like these Neil:

https://www.ebay.de/itm/LICHTMASCHINE-GENERATOR-90A-SPANNUNG-12V-LANCIA-DEDRA-FIAT-COUPE-TEMPRA-NEU/362154358562?fits=Make%3AFiat%7CModel%3ACoupe&hash=item545214f722:g:kbYAAOSw1WJZFczX#vi-ilComp

https://www.ebay.de/itm/Fiat-Coupe-2-0-16V-93-96-Lichtmaschine-90Ampere-14Volt/321859614075?fits=Make%3AFiat%7CModel%3ACoupe&hash=item4af053f57b:g:S9QAAOSw4SlV8BAH

Both possibilities, thanks, Neil. I'm in Germany at the end of the month for a couple of weeks so they might be a possibility. Meanwhile, I have a couple of calls in with rebuilders.

Sorted: turns out that Sahib's < www.sahib.com > come up trumps again. Not one but two on the shelf (and my old one, with an intermittent break on the rotor coils causing sparks that killed the regulator) will be rebuilt.

Good news then Neil.

MMMM. My investigations have shown that when under heavy load (rear window heater, lights, fog lights, fan) the current is dropping to around 12 volts, so either the alternator or regulator (or both) is struggling.

On an average day, with just lights on etc, I should be ok, as I'm getting 13.5 - 14.2 volts, but I think I'd better get it checked out.

Garage confirmed alternator was struggling, so replaced it. Not bad for nearly 100k miles and 17years.

Might also cure a squeal on cold start.