Gone for a week, Recommend disconnecting battery?

[Bobkath]

I connected a battery tender as I was gone for 17 days and it still went into battery saver mode. no issues starting when I returned. Tender showed fully charged battery.

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[HeyBales]

A few months ago I was on vacation and left the the Mav home and it went into sleep battery mode after 5 days. Upon returning, it started up with no issues. Last month I again left the Mav for 17 days, but I had connected a battery tender before leaving. After 5 days it also went into sleep mode. I thought the 12 volt battery was the one that went into sleep mode. Apparently not.

It is the truck that turns off the TCU when it goes into deep sleep mode, that's it.
And that preserves the 12V battery since truck has no idea how much longer it's sitting - so hopefully you can start it, which requires the 12V battery.
So yes it's the 12V system.

But the system only seems to track the Ah charged by truck with key on, and discharged with key off, to decide what some values are.
And your charging wasn't registered, or the relearn overnight can't happen while being charged - so it thought low battery level for the discharge it saw.

Where did your battery tender hook up?
If at battery, to the negative post directly, or other side of BMS?

If to post, that would see the discharge occurring even though it's not from the battery but the tender.

 

[WildGrok]

My 2 cents
Disconnect battery and will have peace of mind

 

[Bobkath]

Thanks for the info. Tender connected at the engine neg and pos posts.

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