Battery? Alternator? Other?

[Kimjon]

Here's my story:

I noticed my car wasn't starting after a 30 minute drive. I'd have to wait until the motor cooled before it would crank.

I brought a Bluetooth battery monitor and it shows this:

Basically the ctek charger brings it to 12.8v give or take. Over a month, when not on the ctek it slowly drops to say 12.6v.

When I drove it today, it showed initially 15v of charging going on for about 10 minutes. Then it just drops from there on to about 9v as I got home after half hour drive.

It wouldn't turn over when I stopped it and tried to started it.

So battery seems to not be receiving a charge after 10 minutes?

Battery problem?

Alternator problem?

Other?

 

Its back on the ctek and looks like its taking a charge okay. So my intuition says Alternator? But im an electrical retard.

 

[mjrstar]

Sounds like a wire building up resistance when hot? This wire could be the starter terminal if it's hidden under a set of extractors? 

This wire could also be inside the alternator, or more likely a voltage regulator, which is most likely also inside the alternator. 

Check alternator plug terminals for corrosion / swap alternator. 

Check battery terminals, engine / body earth.

 

But first of all check wherever the positive from the battery heads off to. 

[ajg193]

Fusible link wire near battery + terminal can get enough broken strands to exhibit this behaviour.

[Bling]

Have another battery you can try in it? I always go for battery first as it's always the first thing to fail for me. I have one on the bench currently that has dropped at least one cell. 

[kws]

My vote is also on a dropped cell. It's doing almost exactly what my battery did was it had a dropped cell.

[chris r]

Another +1 for fucked battery 

[Lord Gruntfuttock]

Whoa. Bluetooth battery monitor...? I'm in..

 

[Kimjon]

42 minutes ago, Lord Gruntfuttock said:

Whoa. Bluetooth battery monitor...? I'm in..

 

Seriously cool bit of tech. Only $30 off ebay. My main use is for each vehicle I have, with an alarm set at 80% remaining charge. So I sets off an alert for me to hook it upto a charger.

[Kimjon]

Back to the problem. I'm thinking I take it for another run, wait until the charging stops on the Bluetooth app, pull over, test alternator at direct source?

This should tell me if irs actually the alternator, or if its the battery?

[chris r]

Just now, Kimjon said:

Back to the problem. I'm thinking I take it for another run, wait until the charging stops on the Bluetooth app, pull over, test alternator at direct source?

This should tell me if irs actually the alternator, or if its the battery?

Yup great plan. Check it with some electrical load on it too (headlights etc) 

[governorsam]

Regulator is poos.

[Kimjon]

10 hours ago, governorsam said:

Regulator is poos.

Is the regular a part thatbi can replace? Or do I need a new alternator?

 

Fyi, its a sbc 283 motor in impala.

[mjrstar]

10 hours ago, Kimjon said:

Back to the problem. I'm thinking I take it for another run, wait until the charging stops on the Bluetooth app, pull over, test alternator at direct source?

This should tell me if irs actually the alternator, or if its the battery?

In theory you should still get charge (if the charging system is working) with the engine running if you disconnected the battery and threw it into the bushes. 

[Kimjon]

2 hours ago, mjrstar said:

In theory you should still get charge (if the charging system is working) with the engine running if you disconnected the battery and threw it into the bushes. 

Ah, so the lack charge coming in definitely points towards alternator then eh.

I found a refurbished one on rock auto for $33+$45 postage. I'll have a think about it, may look at upcoming swap meet too?

[Kimjon]

I imagine these are fairly generic?

[piazzanoob]

first of all get the battery load tested when its charged. i find the carbon pile style ones the best. if no good replace it.

check the charge rate at the battery with the motor running with and without electrical loads lights radio etc. should be 13.5volts or over. if hits 17 volts regulator could be no good or if too low. 

also check all your battery cables and starter and earth cables. may have a rusty earth connection. its common issues on old stuff 

also check what amp alternator it is and if internal or external regulator. may be too small if running better ignition and aftermarket radio.

also if alternator is no good i wouldn't buy another second hand unit as who knows what its like. and some of the units from v8 part shops are hit and miss just cheap china stuff. unless paying more for proper branded stuff

and chevy style stuff is common too. i would recommend trying pan pacific for a new better quality unit.    

[Kimjon]

So I'm pretty sure its a battery issue now. I couldn't start it today 

Even though it was charged to 100% a week ago, and I have a battery cut off switch that disconnects the battery when not in use.

Battery shows this now. But prior to trying to start it was something like 95%. So yeah, think battery is fucked.

[kws]

You still not chucked another battery in it to test? That would've cleared this up ages ago.

[Dell'orto]

Under 10v at the battery would suggest it's shagged. Follow piazzanoobs advice too, but most likely just wang a new battery in it.

[Bling]

Crikey.

I mean it could be multiple things, but battery swap is 5 minutes job even if you're a Spanners Watson on the tools.