Why a different battery pack?
First reason,the present packs are not holding up.
We can't change the control software that is not doing a good battery management job.We need a replacement pack that fits where the stock pack is, uses the same power/relay board and fuse, uses prius subpacks, with the battery management software built into the new pack (open source).This pack would interface with the present BCM, and simulate the battery signals, so the stock SOC guage would work normally to show the battery SOC, and the BCM always thinks the pack is perfect.Any error that our battery management system would detect can shout down the IMA by simulating an error to the stock BCM, which will respond by setting an IMA light and disabling the system.
With PIMA, the bigger the pack, the longer you can run in Electric Priority mode, and the longer you can get >100mpg.
What is the ultimate Insight pack for the minimum cost?
Of course a pack of the new A123 LiPo Hybrid batteries would be my first choice. But my finances dictate that unless they donate some to the cause, I will have to go with NIMH. I have almost enough Prius subpacks to make up four 144V strings of 20 prius batteries.
The 4 packs could replace the present battery pack, with three additional parallel booster packs, increasing the total pack AH to 26. The 80% to 20% SOC range would now have 16AH instead of 4AH. I estimate that this setup will extend the Boosted Battery PIMA range (> 100 mpg) to well over 60 miles, even at 65mph and hills.
With proper design,each of the 4 packs could also work individually as a plug in replacement for the stock Insight pack, or as part of a multy pack system.
Will probably need some custom rear springs to maintain proper ride height.
Then we build a BLDC 10hp 144V electric rear drive system and power it from the same battery pack.Allowing an electric only mode with possibly 40 mile range, but with the ability to recharge with gas while driving under full electric.
Lots of possibilities, the only missing ingredient is the money to get the components and a good mixed signal storage oscilloscope, so I can proceed efficiently. Too many projects not enough time or money .