1st Generation Aux. battery

[gastoohigh4me]

I bought a used 2002 Prius not because I drive a lot of miles (under 12k/year) but because of the principal of the thing - giant oil companies gouging poor me, and because I believe EVERY car should get at least 40mpg. It has 88,500 miles on it. I drive 17 miles one way to work which should keep the battery charged. In November the car sat for a long weekend- 3 days- and my wife jumped in to go and it wouldn't start. I placed a trickle charger on the Aux battery and the car was fine until we repeated the 3 day parking over Thanksgiving. Again, dead. The car still had the original factory battery which looked as though it belongs in a motorcycle. <_< The dealer said the original battery was no longer available for the 1st generation Prius because " it didn't quite meet expectations" :!: , they had a conversion bracket for this car to fit a larger battery. The dealer replaced the battery bracket and cable ends to a more conventional battery that can be gotten at any auto parts store if needed. ( while pulling up to the Toyota dealer's service desk the "check engine" light came on, how often does that happen? It was a service bulletin issue with a dirty throttle body. The car now runs smoother and has more power after they cleaned this.)

The dealer tells me now that the new larger battery should be fine for "at least 10 days" when parked. So I ask this;

What is the longest you have parked your Prius and been able to start it?