I take it driving isnt impacted?
For the gen 2 and gen 1 insight the car becomes rather gutless and the ac quits working. Good thing the ac cuts out as it wouldnt have enough power to spin the compressor and drive down the road.
Assuming its a bad cell in your battery pack, Id say charger. Maybe join the insight site and see if someone lives near you who could let you borrow theres?
If you are going to always own a hybrid, then get the charger and consider it a special tool for servicing hybrids.