as usual I did a useless search and found nothing on the subject! :?
anyway....I was just thinking in the future (after 2010) if my IMA battery craps out what my options will be and could I actually gain mpg by losing the excess weight of the battery pack but apparently its not doable.
I thought I had read somewhere that someone is driving around with no IMA (for some reason).
I was driving along the other day with a fully charged battery, powering up hills and gliding along the level parts, thinking about how nice it would be the entire IMA system was out of there, not holding the car back with "background charging," etc...
IMO the only "penalty" of the IMA system is its weight. And its MPG hit due to weight is almost negligible.
Reads like you'd be interested in MIMA. Follow the links to further investigate and discuss it if you so desire. IIRC there is also a low cost IMA Charge defeat option for the 02 and eariler models. "Delay" forced charging for more opportune traffic or terrain. Just watch SoC or you'll also loose Auto Stop and Assist if you wait too long. There is some confusion about it not working on 03 and later. Use the forum search feature (IIRC the thread is in _this_ forum).
Removing the IMA system may be posible. It is extremely unlikely that you will gain mileage if you opt for a standard alternator as the drag produced by the drive belt and alternator is substantial. You could theoretically run an aftermarket switching power supply off the IMA motor/generator to charge the 12 volt battery, but you might as well just keep using the one that is built in as part of the IMA system. Controlling the charging and discharging of the IMA system as John suggested above will gain you mileage without having to remove the IMA system.