Flattened auxiliary battery - any consequences?

[littlescrote]

No consequences except reset of guessometer.

That is not entirely true. It will delete the ECU logs too. Please correct me if my understanding it wrong.

It might, but what use are those logs if they're full of crap related to a bat flattery?

[nrayanov]

No consequences except reset of guessometer.

That is not entirely true. It will delete the ECU logs too. Please correct me if my understanding it wrong.

It might, but what use are those logs if they're full of crap related to a bat flattery?

I'm just pointing out it's not entirely true. If you plan to go with the car to a dealer to investigate an issue and you wipe the logs, it will be a pointless trip to the dealer.

[wormwood]

Thanks for advice both, will wait until after Xmas. Haven't found a supplier with correct AGM battery yet, so will limp along until I get one. Sounds like no point in connecting parallel 12V battery whilst replacing, so that hopefully warning will be removed. I didn't intend taking to Mitsubishi, so perhaps no worries as to stored codes. Not sure about radio - in past have had to put parallel 12V on system when changing battery on previous cars.
john

[wormwood]

Update
Charged 12V aux battery and took a couple of short trips including running petrol engine. EV sys service warning disappeared during first trip and hasn't reappeared so doesn't appear to need battery disconnection to remove. 12V battery now looks to be holding charge so might not need replacing. Maybe these things just go down when not used but kept outside in really cold weather. Thanks for help,

[outlander660]

I had the problem of multiple alarm messages, managed to get going eventually probably due to things warming up. Went to the dealer and they tested the 12v battery and said it was only holding 70% charge. They said that they could recondition the battery so I left the car with them. It took them 2 days to sort out using two different methods. No more problems touchwood.

[Stephendnz]

Interesting to see how long this post has endured, clearly an evergreen problem, So I thought I'd add my experience.

The first I knew of a flat battery was when my neighbour - nearer to my charging spot - called to say my windscreen wipers were doing some strange little Tango. When I went to investigate, they were moving VERY slowly over windows. But they were not turned on - and I couldn't turn them off or stop them. Maybe that's actually a preprogrammed visual sign of a flat battery, I kept pushing held down the on/off switch and they eventually stopped their dance.

It was the day after I'd got the car and I think I left some things on while playing with it.

Fortunately, the car was unlocked but still couldn't raise the tailgate - had to do the boot release thing, with a screwdriver slide over the little white lug under the removable cover on the inside of the tailgate - centre near floor level.

Removed the floor section in the boot, 5 screws, the battery showed only about 6 volts. Later discovered you can get the same reading from the + post in the fuse box, under the bonnet.

AA came the next day, put the little Jump Booster on the + terminal in the fuse box, and - to the body. and started all good. Took it for a drive, all fine. Haven't had any problems since - will be getting a small Jump starter to keep in the wagon now. I did already have a larger one - with a compressor - but to be honest, I was scared to try jumping starting it - too many electrics for my liking. Would do it next time though.

I now know that the auxiliary battery gets charged when plugged into the main charger, but apparently won't charge it if it was flat when put on charge.

[LowOnCash]

Hello All - System Errors and Faults are kept in an EPROM permanent memory chips, they can only be cleared though the OBD port. There's no much to lose regarding the 12 volt battery other than user settings.

Regards - Mike