Car jump started OK - but now deader than a dead thing?
Discussion
My daughters 2018 Aygo, sits idle whilst she's at University. The battery went flat about a month ago. Jump started it drove it. All good. (At this point, I should have disconnected the battery but....)
Last week I went to check it again. Flat battery. Jump started it off my Mondeo (but this time I had to get the revs up to 3000 rpm for it to start) let it run for about 15 minutes. Switched it off.
One week later, decided to start it and give it a longer run to hopefully save going through this again...
The door wasn't locked (I had locked it previously). When I put the key in the ignition, the dash didn't come on. I checked the battery voltage - less than 3v. I connected up the jump leads to the running Mondeo, got in the Aygo, dashboard still in darkness. Turned the ignition key. Nothing.
Looked up. smoke pouring off the jump leads... this suggests they were connected up incorrectly. I'm absolutely positive they weren't but don't discount anything.
Car is still as dead as a dodo. I had another go at a jump start but the dash still didn't light up.
My immediate thought was fuses. But now I'm thinking more along the lines of new battery.
Thoughts please.
Last week I went to check it again. Flat battery. Jump started it off my Mondeo (but this time I had to get the revs up to 3000 rpm for it to start) let it run for about 15 minutes. Switched it off.
One week later, decided to start it and give it a longer run to hopefully save going through this again...
The door wasn't locked (I had locked it previously). When I put the key in the ignition, the dash didn't come on. I checked the battery voltage - less than 3v. I connected up the jump leads to the running Mondeo, got in the Aygo, dashboard still in darkness. Turned the ignition key. Nothing.
Looked up. smoke pouring off the jump leads... this suggests they were connected up incorrectly. I'm absolutely positive they weren't but don't discount anything.
Car is still as dead as a dodo. I had another go at a jump start but the dash still didn't light up.
My immediate thought was fuses. But now I'm thinking more along the lines of new battery.
Thoughts please.
Sounds to me like a dead battery . Letting it get that discharged and it sounds like it never had a proper charge between each of your jump starts could well have killed it. Even if it is not totally dead it is unlikely to be in full health even after a proper charge.
An Aygo battery can’t be too expensive, I would put a new one in and go from there.
An Aygo battery can’t be too expensive, I would put a new one in and go from there.
As above good advice battery was done for the first time you jumped it, now it is deader than a dead thing & flatter than a flat thing!
However from what happened later in your story, that may not now be the only issue.
Fit a new battery & see what happens, if it all works get it fully charged & disconnect it if it is to remain standing.
However from what happened later in your story, that may not now be the only issue.
Fit a new battery & see what happens, if it all works get it fully charged & disconnect it if it is to remain standing.
Ear you are
https://www.tayna.co.uk/car-batteries/enduroline/0...
Next time, make sure it has a proper run, or a full charge up.
https://www.tayna.co.uk/car-batteries/enduroline/0...
Next time, make sure it has a proper run, or a full charge up.
Lead acid car batteries are designed to provide a huge current for a few seconds and then be recharged promptly. They do not like deep discharges. The battery may have been ruined the first time it went flat - if not, it would at least have been damaged. I'm not sure you even recharged it after that first time. Second time would do even more damage.
You need to either isolate the battery when it is laid up, or connect it to a battery maintainer. If the owner isn't mechanically minded, it would be worth investing a few quid in an intelligent isolator.
You need to either isolate the battery when it is laid up, or connect it to a battery maintainer. If the owner isn't mechanically minded, it would be worth investing a few quid in an intelligent isolator.
One of the failure modes for a lead acid battery is distortion of the plates leading to an internal short circuit across a cell. If your battery is down to just a few volts and had an internal circuit across a few cells, you would effectively have been shorting out your car's fully charged battery. No wonder the leads got a bit hot.
GreenV8S said:
One of the failure modes for a lead acid battery is distortion of the plates leading to an internal short circuit across a cell. If your battery is down to just a few volts and had an internal circuit across a few cells, you would effectively have been shorting out your car's fully charged battery. No wonder the leads got a bit hot.
This makes me feel a bit better. As I was positive (insert your own pun here) I hadn't connected the leads up the wrong way.GreenV8S said:
If the owner isn't mechanically minded...
Guilty as charged for this episode. I have also been baby sitting my fathers 2007 Focus Estate (26,000 miles on the clock!) for 6 months. I have religiously disconnected the battery on that every time it has been moved. Complete blind spot for the Aygo.
Unless you've omitted something - such as fully recharging the battery with a battery charger after each jump start - the battery was deeply discharged & apart from jump starts & a short bit of running which at best would put a tiny surface charge into it it's still deeply discharged.
Disregard the redtop/bluetop blurb;
https://www.optimabatteries.com/experience/blog/fa...
Most cheap thin jump leads are utter rubbish & I'd be entirely unsurprised if they overheat & start to smoke.
You could try charging it but I'd suggest a new battery.
Disregard the redtop/bluetop blurb;
https://www.optimabatteries.com/experience/blog/fa...
Most cheap thin jump leads are utter rubbish & I'd be entirely unsurprised if they overheat & start to smoke.
You could try charging it but I'd suggest a new battery.
Edited by paintman on Sunday 22 November 20:24
quyeno said:
Try a CTek charger on the battery, there's a chance it could bring the battery back to life assuming there isn't something defective inside the battery.
At 3V for the battery, you've got four cells at zero volts. Even getting one of them to come back up would be a lucky break and you'd expect the battery to have substantially reduced capacity afterwards. Taking the battery down to 3V is pretty much a death sentence for it, let alone doing it several times and leaving it discharged.I think it's safe to say this battery needs replacing.
New battery fitted. The world is now a happier place.
I have disconnected the battery and the car awaits my daughters return from University.
All I need to do now, is to find the 12mm socket that fell into the bowels of the car when I was tightening up the battery clamp. There's always one thing.
On older cars you can simply stick your arm in from underneath and fish around. This car has got undertrays and other bits of plastic that need to be removed first.
I have disconnected the battery and the car awaits my daughters return from University.
All I need to do now, is to find the 12mm socket that fell into the bowels of the car when I was tightening up the battery clamp. There's always one thing.
On older cars you can simply stick your arm in from underneath and fish around. This car has got undertrays and other bits of plastic that need to be removed first.
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