Broke down - Alternator / Battery

[Simon_K]

Hi all

Car broke down today, completely died whilst driving with no electrics. I’ve been recovered to my local garage but I just wondered if I might have damaged anything expensive.

Full story:

I’ve got a voltmeter installed in the car (to a switched live) , and for a little while i’ve noticed the charge has been getting a little less. Still starts, still runs and no warnings, just finding it around 11v before starting but running was always about 14v.

Got in today, noticed it was just 9v! Still started with no grumbles but the needle didn’t rise. Thought it would once I’m driving so started to go to work.

Kept an eye on it and not long after driving the charge light on the dash lit up. Thought “That’s not good” so turned for home. Managed to nurse it but as I approached some traffic lights the abs / tc / airbag lights came on, then all dash went off and once I’d stopped the car died 2 blocks from home. No life at all.

Called the AA. 

Took one sniff of the alternator and said it was burnt out, metered the battery and it only had 2v!

 He then disconnected the battery live cable, and ran his jump leads to charge the battery in isolation while he disconnected and isolated the alternator (said the charge cable was red hot). 

After 5 minutes he reconnected the battery live, and tried the dash, but no life still. Tried reconnecting his van to the battery now the alternator was isolated but again, no life whatsoever. 

At this point I was towed to my local garage but I noticed as I was towed the red immobiliser light started flashing mid journey, so some life returned. 

 

So...

I’ve got the garage to fit a new alternator and battery. I’m just a bit worried the car dieing like this may have damaged something else, ecu? No life while he was charging the battery from his van - could that be the battery completely open circuit or something? I fully agree with his diagnosis, just concerned about fallout.

In other joyful news they noticed I have leaking injector seals to our so they are sorting those at the same time...

[Micro]

Does the cable from the alternator still get hot under normal operation?

Automotive electronics are generally well engineered now against power supply issues - you'll probably find the majority of systems will withstand voltage spikes of 20-30V+, and manage voltage drop outs/low voltage gracefully - the most you might have to do is disconnect the battery for up to 30 mins to reset some learned values.

If you have no issues now, I wouldn't expect any more in future.

[Simon_K]

Ah, well it’s still at the garage getting sorted. I haven’t had it back yet, just in a bit of a flat spin. 

I’d hope they are robust, but I’ve been reading other horror stories!

[Simon_K]

Sigh of relief. 

All good, only had to reset the one touch windows. Turns out it had a lead acid battery fitted, so I guess that died taking out the alternator. Should have checked it when I bought it I suppose, expensive lesson. Also had 2 stuck injectors when they did the seals.

 £600 lighter for all that, but it’s back in front of my house so I’m happy.