[RedDevil]

Originally Posted by TimV

Maybe I missed it, but is it not possible to make a batterie that is permanent in parallel with the IMA batterie? To increase its capacitie and hook up a big charger to charge the total pack?

It is possible to do so - I did try, and still can when I remove my lamp shunt and hook up the battery directly.
However, then it will draw a large current when it uses support or EV mode; the IMA system detects that and throws an error.
The voltage fluctuations on the IMA system are quite large, so when matched with a more or less steady voltage pack using LiFePO4 cells large currents will flow.

In practice I can only use a direct connection when I'm on a steady pace on the highway. At lower speeds or when I'm decelerating and pulling away again it will throw an IMA code. When it goes in AutoStop it will throw a code.
I simply do need a current limiter...

Instead of a current limiter I have another idea.
I can use a DC-DC step down converter to feed the 12V system at about 13.8 Volt from one of my 39 Volt boxes so it would relieve the Insights DC-DC converter; as that power does not have to pass through the IMA terminals it enhances the maximal power I can put into my car.

The two remaining boxes each get a DC-DC step up converter to produce 58 Volt, for 116 Volt combined. The current will be limited by the converters capacity to about 10 Ampere (I'm aiming for 600 Watt converters) which should be good.

But before I do so I want to have my meters up and running.
Insight in the voltage and current flowing from my buddy pack to the IMA system is essential.
I've got the stuff and next Tuesday my Insight will go for its annual inspection so I'll remove the harness for the occasion, which makes it easier to work on.