Starting issue (battery or electrical)

[Lukeis]

This morning I drove my car to get a wheel alignment, it had been sitting for 12 hours without use.

started as normal, drove 10km to the mechanic, picked up an hour later and they told me the battery died while it was in the shop and wouldn’t start

got in the car, battery light was on the dash. drove two shops down to a battery shop and they tested the main and the alternator and he said both were good. battery came up as 89% health, alternator was charging at 13.86V

At the shop we turned car off after about 5-10 minutes so we could test the battery, while off the battery light stayed on the dash.

Turned the car back on and it restarted just fine, light disappeared.

drove 5 minutes to an auto elec (a fuse had blown between the main and dual battery) was with him and hour, started again ok then used a few more times around town all ok. Then got home and sat still for an hour, won’t start - main battery showing (11.2v) - dual battery is showing 12.2 - keep in mind it was coming off being completely flat due to the blown fuse between the two.

any ideas what is happening?

seems like either the main battery is dead - but passed the test at the battery shop and worked several times since then. Is that possible?

or something is draining the car while it’s locked - all my extra accessories ie CB, USB plugs and fridge are all turned off and are wired to the dual battery in any case so can’t see how. And that battery has more charge indicating the VSR isn’t stealing power from the main.

Or the alternator but it was showing as working when car was running (car is flat now so can’t check again)

Anything else? so confusing

[matti4556]

So the auto 'leccy told you why the fuse between starting and aux battery had gone open circuit?
What rating is that fuse?

My money is on the Aux battery being "dud".
Keen to find out how it goes.
Matti

[Tombie]

Light staying on is often a symptom of failed Diodes in the alternator.

Lift the bonnet, can you smell an electrical smell?
If you don’t sort it you could be up for an alternator and a battery.

[Bulletman]

Do you have a code reader ? , any alternator faults showing up..

Can only suggest disconnect or isolate the aux battery and put the main battery on charge. Once its charged back up see hows things go for a day without the aux connected.

I would have thought if it was a dud Aux battery the dual battery system would isolate it but strange things happen with batteries in these cars.

I had a similar issue where mine would start and the battery light would stay on for up to 2minutes then would go out. I have a in cab battery meter and the low voltage alarm would sound if I turned the ignition on. but the car would start . I plugged in hawkeye and had a alternator fault saying something like field wiring to ground. I checked my battery terminal connections and 1 was slightly loose , tightened it up and never had the issue again and never had the fault again.

Bulletman

[josh.huber]

This morning I drove my car to get a wheel alignment, it had been sitting for 12 hours without use.

started as normal, drove 10km to the mechanic, picked up an hour later and they told me the battery died while it was in the shop and wouldn’t start

got in the car, battery light was on the dash. drove two shops down to a battery shop and they tested the main and the alternator and he said both were good. battery came up as 89% health, alternator was charging at 13.86V

At the shop we turned car off after about 5-10 minutes so we could test the battery, while off the battery light stayed on the dash.

Turned the car back on and it restarted just fine, light disappeared.

drove 5 minutes to an auto elec (a fuse had blown between the main and dual battery) was with him and hour, started again ok then used a few more times around town all ok. Then got home and sat still for an hour, won’t start - main battery showing (11.2v) - dual battery is showing 12.2 - keep in mind it was coming off being completely flat due to the blown fuse between the two.

any ideas what is happening?

seems like either the main battery is dead - but passed the test at the battery shop and worked several times since then. Is that possible?

or something is draining the car while it’s locked - all my extra accessories ie CB, USB plugs and fridge are all turned off and are wired to the dual battery in any case so can’t see how. And that battery has more charge indicating the VSR isn’t stealing power from the main.

Or the alternator but it was showing as working when car was running (car is flat now so can’t check again)

Anything else? so confusing

If they didn't isolate the battery's when doing the initial test, then the reading is normal. Both battery's combined are 90% of 1 good battery.
The lower reading on the main suggests the main is dead and blew the fuse when cranking the engine. I'd pull the negative off the aux battery and get them to test then both separately.
Or if you have a multimeter. Isolate them yourself and see what's happening.
If it's charging I doubt its diodes. Especially if it's pouring in 13.86 v which presumably was at idle

[Tombie]

If they didn't isolate the battery's when doing the initial test, then the reading is normal. Both battery's combined are 90% of 1 good battery.
The lower reading on the main suggests the main is dead and blew the fuse when cranking the engine. I'd pull the negative off the aux battery and get them to test then both separately.
Or if you have a multimeter. Isolate them yourself and see what's happening.
If it's charging I doubt its diodes. Especially if it's pouring in 13.86 v which presumably was at idle

Bleed back through the charging light when off isn’t the result of a dud battery.

[Lukeis]

The dual battery was isolated when they tested it as the fuse was still blown at the time (the fuse between main battery and the VSR)

since I have roadside assistance I called them tonight and they came and tested the main battery again and it is showing a cell has gone and suggested a new battery.

Just to be certain before I buy one I’ll follow the tip above to completely detach the second battery, jump it again, run the car for 40 mins and see if the main gets and holds a charge. It came back to life this morning before the sparkie visit, but then this afternoon (after being re- fused to the VSR) for a few hours didn’t work so I want to rule this being related before I drop money on a battery

on a side note, the auto elec put his blow torch down on my bullbar while working and has melted my headlight - like I needed that extra drama.

[josh.huber]

The dual battery was isolated when they tested it as the fuse was still blown at the time (the fuse between main battery and the VSR)

since I have roadside assistance I called them tonight and they came and tested the main battery again and it is showing a cell has gone and suggested a new battery.

Just to be certain before I buy one I’ll follow the tip above to completely detach the second battery, jump it again, run the car for 40 mins and see if the main gets and holds a charge. It came back to life this morning before the sparkie visit, but then this afternoon (after being re- fused to the VSR) for a few hours didn’t work so I want to rule this being related before I drop money on a battery

on a side note, the auto elec put his blow torch down on my bullbar while working and has melted my headlight - like I needed that extra drama.

That's the auto elecs problem not yours. Give him the part number!
Remove the battery and bench charge it. It'll need two days to fully recover if it does recover. If not replace it. I know it's not the news you want. But the longer you wait the closer you get to a dead aux battery aswell. I would have it bench charged aswell.

[josh.huber]

Bleed back through the charging light when off isn’t the result of a dud battery.

I'll have to pull a wire diagram but I'm 99% sure the light isn't in the circuit. So it can't bleed back thru it. It's all ECM controlled on Luke's. Plus the dash is led, take ten years to kill a battery through that light. 1/4w at best.

A dud battery is seen by the ECM and is shown to the driver with a light.

My guess is the light went off the alternator got it high enough to pair with the aux.

[Lukeis]

The confusing part is that the fuse was still blown when the car was turned off at the battery shop and started again (allowing me to drive 1km to the auto elec). meaning it couldn’t have been leveraging the aux battery

so car died at mechanics
presumably jump started
left running max 20 mins (during hand over and time to drive to the battery shop
Noticed fuse blown - tested alternator
car turned off - momentarily
started again ok

drove to auto elec - fixed fuse
One more drive - stop for two hours - starts ok
one more drive - stop for two hours at home - doesn’t start - fuse still ok


so how would it start if the battery was dead from the get go?