OK, I accept that the Gen III Prius will develop a dead 12 V battery after being parked for 3 weeks. So if I go on a long trip and leave the Prius in an airport parking lot I should have a portable JUMP START box. Question is: 1. What's the best jumper box to buy? 2. How big (how many amps) should it be? 3. Can it be too big and damage the Prius battery? I saw that Sears has a DieHard 750 amp (peak amp) model for $59. Some like the Black & Decker unit. What should I buy? It would also be nice if it would work on my RAV too. Thanks -
Get a small one. The 12v battery does not start the car. You only need enough power to close the contactor to the traction battery that is used to start the car.
Get one that clamps to the battery terminals*, not the cigarette lighter, as in a Prius the lighter is not active until after it starts. * there is a 'jumpstart' terminal under the hood, even though the battery is in the back.
The smallest ones will work but if you want one to use on larger vehicles and use the power outlet and a light this would work good
CAUTION: When choosing the correct size buzz box.. Note that when you first push the START button, and before the traction battery relay begin their dance, there is a very large pull from the 12V battery as all the electronic packages power on and boot up. There are literally a dozen such packages. Until these boot and the traction battery relays to their dance, the 12V battery must hold on. Now, as to how much current is pulled, that is unclear. I've read posts here that say as small as 25A and as high as 40A is pulled off the 12V battery during this time.
Why "accept" this? The Smart key system shuts itself off after 5 days (see owners manual page 49). There are numerous posts in this forum disproving this dead battery "myth", with people leaving their Gen III parked for several weeks with no issues. Also, the owners manual page 30 states: However, if the vehicle is left parked for a long time the hybrid battery will slowly discharge. For this reason, be sure to drive the vehicle at least once every several months for at least 30 minutes or 10miles (16 km). I think you'd be just fine parked for several weeks.
I think the specs you were looking at with the Sears will work well. JRitt's link adds the 120AC option. I did similar--probably a bit bulkier and expensive than needed...has more outlets. Holds its charge well. http://www.amazon.com/gp/product/B000TKHMWK/ref=ox_ya_oh_product Nice power pack for a picnic/tailgate. Haven't had to jump the Prius yet. I think Xantrex makes this for Duracell.
Rainy Day Magazine: RainyDayGarage - JNC Air FirstLook How about this unit. With compressor for those wanting to do their tires as well.
