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Discussion Starter #1
Forgive me if this topic was raised previously. I couldn't find it by searching.

I'll be leaving in September for a four-month trip without my '02 Prius (ElMo). I'm wondering if anybody can point me toward any special procedures that I should follow for this sort of extended storage. I have the option of loaning him to a family member, but . . . .

It will be covered and safe. I'm in San Diego, so I can easily plug a low-powered solar charger in through the 'cigarette lighter' or disconnect the starting battery, or . . . .

The usual stuff would be: fresh oil, a fuel additive to stabilize, potentially a similar oil additive, fully inflate the tires (or put the car up on blocks/jack stands). Any ideas (or, better yet, sources for the 'right' info) would be greatly appreciated.

Thanks much,

Neil
 

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The main problem with storing a Prius is that the standby drain of the computers and other accessories will discharge the smaller-than-normal auxiliary battery after 2-3 weeks. You can reduce the standby drain by turning off your headlight switch (instead of using the auto-off function) and disabling any aftermarket equipment, such as security systems.

The battery will drain faster if it had ever been drained before, because each draining reduces a lead-acid battery's ability to hold a charge. Since you don't know what might have happened while it sat on a dealer's lot, it's hard to predict how many weeks you might have, but I haven't heard of anyone having a problem with only 2 weeks.

So, you have several choices:
1. Disconnect the auxiliary battery. This is easiest to do where the negative cable bolts to the trunk floor. Pull up the corner of the carpet, unbolt the plastic handle-like thing, and the negative cable bolt will be accessible. When you return and re-connect the cable, you will have to re-program your radio stations and clock, and your trip odometers will be reset to zero, but your real odometer and average mpg readout will be retained.
2. Have a friend come over every two weeks, start the car, and leave it in "Ready" for 30 minutes. The auxiliary battery has a 28 Ahr capacity, and the DC/DC converter will allow around 50-60 A to flow to it, so if it was completely dead, it will be completely charged in about 30 minutes. (The engine won't run the whole time, but the battery will be charging the whole time anyway.)
3. Install a solar charger. However, you can't just plug it into the cigarette lighter hole, because this is disconnected when the car is off. So, you will have to either buy and install Coastal's mod kit or wire the solar charger into the auxiliary power bus somewhere less convenient. Note, also that the standby drain is significant, so the solar panel will have to be large enough; otherwise, connect several in parallel.

Regardless of your precautions, if the auxiliary battery is flat when you return, you can jump it easily with any power source that is approximately 12V, because it only needs enough juice to boot up the battery ECU, which can then throw the main system relay and access the main battery, which does not self-discharge appreciably over time. It has been theorized that even a 9V battery would work for this, and I've heard that voltages above 15V might damage some accessories, but anything in-between should work. I have a Campbell Hausfeld portable 12V battery and tire inflator for just such an emergency. I even made a little cigarette lighter plug that runs to alligator clips to quickly connect it to the auxiliary battery.

Otherwise, normal car storage procedures apply. The oil and gas in the Prius are no different than other cars, and so they will degrade over time. So, your other precautions sound prudent.

Douglas (2002 Silver, Wisconsin)
 

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Douglas,

Can you elaborate on the Campbell Hausfeld unit you have ? Any pictures on how to charge the aux battery using this unit ?

Thanks,

Michael
 

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Discussion Starter #4
johnson487682 said:
So, you have several choices:
1. Disconnect the auxiliary battery. This is easiest to do where the negative cable bolts to the trunk floor. Pull up the corner of the carpet, unbolt the plastic handle-like thing, and the negative cable bolt will be accessible. When you return and re-connect the cable, you will have to re-program your radio stations and clock, and your trip odometers will be reset to zero, but your real odometer and average mpg readout will be retained.
Douglas,

Sounds to me like disconnecting the aux battery is the "set it and forget it" way to go. Many thanks for your advice!

Neil
 
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