This seems strange because if you disconnect the main battery and leave the under the back seat battery connected the truck 12VDC power stays on? So I would think they are directly connected together in parallel.

Or does ford have a relay / contactor setup to sense the main has been disconnected and switches over? That could be easily done but seems unnecessary.

I would have to look at the drawings or just do some testing on the truck.

What is this second battery for? Just for software updates?

When I killed all DC power to the truck. I pulled the small battery in the back first and then the main to do a complete reboot as you suggested to get my updates going and man I have been some updates about 3 or 4 now.

Thanks

 

I don't remember the technical reason, but there is a circumstance where charging the main 12v won't charge the smaller one.

 

Yea I want to do some testing with this.

I did find this video on the Aux battery.




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The AUX battery is for powering modules in the truck during certain driving situations between the ICE start up and EV driving. Charging one will charge both.

The stock aux battery is a small capacity and once it starts to go "bad" it can cause all kinds of funky issues. Change it for a 14Ah and it'll help. ETX15.

 

I know a few that replace it with this and yes battery will cause issues in powerboost which is 99% of peoples problems that makes them run to a 5.0. LOL

ECO-WORTHY 12V 30Ah LiFePO4 Lithium Battery,

https://www.amazon.com/dp/B09N9BBS68/





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Would there be a problem if this auxiliary battery is a LiFePO and the regular chassis is an AGM?

 

I haven't had any in 6 months since I replaced mine.

 

Yea the LIFEPO4 has an BMS in it all good. Thanks for reaching out with the good news.

I still have the original aux battery and no issues. But I charge the main quite often and it's parked in the garage so easy to do so.

 

I reported in early August that I had received the BlueCruise 1.0 to BlueCruise 1.4 update. Turns out that was just a preparatory update and I actually received the BC 1.4 update this weekend.

 

@tsigwing - what happens to Li battery it if is -20C? Will it still work?
Couple of years ago I was considering switching the main battery to Li, just to get bigger capacity, etc. - but then I learned that they do not do so well when it is cold.
Granted, the aux battery is in the cabin, so as soon as you start the engine and try to heat it up, in theory the aux battery should warm up soon, AND stay warm after you shut off the engine, a bit longer, so maybe it is not a big deal... not sure what is Ecow-orthy is rated for (temperature wise)