No! The wires are really thin and only made for a 6kW maximum load (theoretically max 10kW). Don't do that!
No, if you have a chemistry that is not LMO then the voltage will probably be higher under load on the extender pack compared to the original battery. This will make current want to go almost fully from the extender battery, and you will pull probably 10-30kW of power from the extender pack.3.3 kW is enaugh for my battery extender, I'm thinking of putting a removable 10 kWh 48 V lifepo4 battery in my trunk for occasionally long trips, with this bidirectional dc/dc inverter:https://www.farnell.com/datasheets/3093822.pdf
The explosion in an event of shortcircuit would be 10 times smaller .
Since it is a removable battery extender, it must have some sort of converter so that voltage maching is not an issue, and when I don't need an extra range, I can use the 48 battery for my house battery and have a full trunk space (95 % of the time)
An extender would be built with 2 boxes of 16 lifepo4 105 Ah so that one person can handle the thing.
I newer empty my main battery in less than 3 hours of driving, so 3.3 kW dc/dc is enaugh for 10 kWh battery extender, if I put 20 kWh in my trunk I would use another dc/dc and have 6.6 kW and it would still be in spec for the thin cables from heater connector.
or is there another obsticle, a'm not aware of?