Looks like the Enginer conversion kit 4kwh for $4000, 20 miles range, only saves $485/Year, assuming gas price at $4, everyday drives 20 miles, electric price at 1/4 of gas equivalent. It will takes 8+ year to break even. But the battery life is between 6 and 8 years normally, not to mention performance will be lower after couple of years. Do I miss something here? Oh, the added dead weight will lower some mpg too.
That's about right. The only significantly cost effective conversions appear to be by DIYers, be them custom one-offs or using something like a BMS+. The batteries in a 4kWh enginer kit should only run ~$1200, so if someone were to go with that and something like a BMS+, then the kit cost would be amortized within the first five years or so, and battery replacement every ten years would reduce costs by ~$350+/year, or more if someone went with a larger pack. Another problem with the enginer kit is that it uses the NiMH pack as a buffer, so that increases wear on the OEM pack.
