AUX battery discharging even when the car is off

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zakenone

Member
Joined
Apr 3, 2022
Messages
6
Location
Denmark
Hi Forum,

I'm new into this community. Last week I purchased a Ion on discount because the AXU battery was getting discharged. The previous owner changed the AUX battery round 2-3 mouth ago and have held it charged trough a charger.

I can start the car and drive, if the AUX battery is charged to a high level. Im getting 14,6V on the AXU when the car is on, so the DC DC seems to work. The car can AC charge.
The wireless "mode" for locking and unlocking the key didn't work yesterday, so I will change the battery inside the key today, and try again.


I did my measurements in series through negative wire, and pulled all fuses and relay from the 3 fuse boxes in front of the car.

So far :
  • the car constant pulls 0,25A from the AUX battery when its off, door closed, ect.
  • When I plug the AC home charger in the pulls around 1,5A more, is it normal?
  • When I turn the key one click up, before going into ready mode. The car will pull around 3,2A into the Electric Motor Switch Circuit, ETACS-ECU (Tail Lamp Relay) fuse. is this normal again?

At this moment i'm slightly lost.
Can it be the DC DC converter thats pulling some current when it's not active?
Any inputs are welcome!

Thanks!
 
Howdy and welcome to the forum,

Sounds like you are on the right track to monitor the current while pulling fuses.

The only thing i can think is to try pulling the fuses and relays in the ETACS under the dash in the footwell. But it may be fed from one of the fusible links that is attached directly at the Positive terminal of the aux battery in the red holder. So maybe remove the 2 plastic clips holding the Positive terminal wire to allow easier manipulation and twisting of the red holder to access those fuses, then remove them one at a time to hopefully find the culprit circuit.

Good luck to you,
 
Zakenone, welcome to the forum. Nice approach with your initial troubleshooting and excellent advice from kiev. When you do find the problem, please be sure to follow up with us and let us know what the cause was. TIA. Good luck!
 
Thanks for the kindly replies!

Today i did some testing and now im even more confused.
The other day, i was testing with the key in off position, which trigger some relays i think. + my OBDLink MX+ inside :roll:

I found out that when I lock the doors and wait around 2 minutes the car will only drain 0,008A. Good!
When I insert the key the car will pull 0,11A
when I turn the key into ACC position the car will pull 0,75A
when I turn the key into ON position the car will pull 3,43A
The battery was dropping 0,1V every 20 second on 3,43A load, can you tell if those numbers are normal?

Today the car could not go into ready(driving) and kept getting P1A15 error every time. I'll try charging the AUX battery with a other charger over night.

Also the fusebox in the footwell seems to be missing 3 relays.
op4l8il.jpg
 
So today I had same issue. p1a15 and the car would not go into ready. I even tried with a other AXU battery.

So on my car scanner tool, I found this. Does it mean that the hybrid board is the issue? 346V on the Capacitor and 358V on the battery
qZU8dWt.png

KQ3aT5z.png

EDIT pictures
 
zakenone said:
...I found out that when I lock the doors and wait around 2 minutes the car will only drain 0,008A. Good!
That's a lot better than your initial 0.25A measurement! I had measured 0.012A on one of my i-MiEVs. The other current measurements look ok but I haven't performed those myself.
zakenone said:
The battery was dropping 0,1V every 20 second on 3,43A load, can you tell if those numbers are normal?
Presumably this is before the car goes into READY. This drop depends on what voltage the battery starts out with, as the drop is large initially and then should stabilize before dropping precipitously as the battery becomes fully discharged. At the rate you show, the battery would drop one volt within 3-1/3 minute and be almost completely discharged within ten minutes, indicating a weak battery.
zakenone said:
Today the car could not go into ready(driving) and kept getting P1A15 error every time. I'll try charging the AUX battery with a other charger over night.
Best to replace that battery and not stress the system - there is a suspicion that a very low 12v battery may be one of the contributors to the early demise of the (very expensive) OBC.
zakenone said:
Also the fusebox in the footwell seems to be missing 3 relays.
Sorry, can't get to mine to have a looksee at the moment. Perhaps someone with an iOn can help?
 
I ordered a new 12V battery today. In theory a 40Ah battery should last over 11 hours on 3.4A load.
But if the new battery doesn't fix it, I have a theory of a faulty hybrid board.
 
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