with IMA light 12V battery will not charge below 1500 RPM
 

Peter here again. I'm still working on fixing my IMA battery, turning 2 packs into one. In the mean time the car is running fine with a bad IMA battery, just not charging the 12V battery when the RPM is below 1500 RPM. Got stuck once in stop and go traffic for 30 minutes and the car died.
Is there any way to mitigate? An changes I can do to get the IMA to charge the 12V battery all the time? Than I could forget about the IMA battery, the car still gets 35 MPG.
Any ideas?
Peter

Re: with IMA light 12V battery will not charge below 1500 RPM
 

Yes. You can mitigate as follows:

1) Rev the engine and hold at 2000rpm during extended sits.
2) Put it on a charger every night to make sure it's topped off.
3) .

No. There are no fixes besides installing a working IMA battery... or a bad one that isn't as bad as the one you have. It won't charge because your IMA battery is so far out of whack, it's isolated the pack completely, and the DC-DC converter doesn't have the battery there to act as a buffer at high and low rpm.

At idle, the IMA motor/generator output is too low to charge the 12V. You will also see this at higher rpms as well where the output is too high for the DC-DC converter to work properly. This is around 3500-4000rpm.

Re: with IMA light 12V battery will not charge below 1500 RPM
 

thanks, that's what I thought. I build myself a IMA battery charger, that gets the battery up to voltage, but there is still the difference between the cells, that prevents the iMA to work properly.

I saw the high cut out too.

On the other hand it would not be to complicated to rectify the IMA motor output directly use it to supplement the 12V battery with a 60-150V DC to 12V DC/DC converter.

Peter