Alternator gone?

[Buller]

All lights come on. Started with a booster but lights still on. Drove to garage. Guess it the Alternator? Batteries all showing fully charged. Couldn't check the Alt output though. AA Breakdown didn't have a Multimeter!!

 

[karl2000]

Just out of interest, how did you test the batteries?

 

[Buller]

Hey there, I didn't/couldn't, the recovery bloke didn't have a multimeter! The inspection windows on the batteries looked Green but thats just a guide. I'm going into the garage later to drop my keys off so I'll check then, and the output if it starts.

 

[karl2000]

You'll have a LIDL multimeter in the glovebox next time though!

 

[nick_the_fish]

From my understanding of the dark arts you can't really test modern batteries with just a multimeter because the need to be tested under load. I had an Odessey Battery that was testing 14.2V with the alternator on, 12.something V with alternator off but wouldn't start the truck. Got it onto a proper tester who diagnosed a damaged cell. Just a thought. Somebody with greater knowledge than I please correct me if I'm wrong.

Back to the OP, I once had my dashboard go haywire, turned out to be a lose connection in the fusible link box.

Good luck

 

[Buller]

11.85v each battery. Won't turn over enough to start

 

[karl2000]

Agree with Nick's comments above- you need to test the cranking amps of each battery, not just the voltage with a multimeter.

Having said that, a multimeter test is better than nothing - if that shows 11.5V or less, you know the battery is flat. If it shows 12v+ (usually about 12.6 for a fully charged battery) then test the CCA (cold cranking amps) to check if the battery is ok

At 11.85v your batteries are at about 30% - almost flat.

How did you check the voltage of each battery? Assume your batteries are connected in parallel (and you havent got them split into a starting battery / aux battery for example) you need to disconnect the negative lead from one battery before you check and test each battery separately otherwise youre just getting the combined voltage of the two. Same goes for testing the CCA.

Also if they're connected in parallel, one knackered battery will bring the other one down. (Which is why they should generally both be replaced at the same time). If possible, fully charge each battery separately and retest them both separately.

Does it start ok with a jump? If so whats the voltage at the battery terminals when its running? Obviously looking for 14v+ if alternator is ok.

 

[Buller]

Hi there. Yes, it started with a jump but the breakdown bloke didn't have a meter. I took my meter to check but of course it wouldn't start!!
Hopefully find out tomorrow when the garage look at it Thanks

 

[AdventureWagon]

You can put some load on the battery with headlights and other accessories even without the engine available. If the battery is good at no load but drops to like 10 volts or something with these then you know it's shot.

Not the same current as cranking but something doable in the field with minimal equipment.

 

[Bob]

That's the light show I got when my battery got low after the alternator died.. drove it 70 miles with the alternator partly working, mostly not, the dash lit up about 5 miles out.. headlights were getting dim by the time I got home.

 

[Buller]

Yep, sounds about right. Its the alternator defo confirmed today. Annoying thing is I had one fitted 2019 and 25k miles ago. A Delco Remy one. guess they are crap then!

 

[Bob]

I changed it for genuine Denso from Toyota in 2018... its done 100,000 miles since then and perfect

 

[AdventureWagon]

Could just be rotor brushes, these are easy to replace, at least were on my 90 series' alternator.

 

[Buller]

All fixed. New Alternator. Batteries on trickle to get them back up. Truck rides again!!! £270 all in