Storing a Prius vs. Selling It

If you were talking 3 weeks, I would vote store it. Nine months is time to sell it.

 

There are too many variables for me to offer an opinion. When you return, there are likely to be even more options available. Heck, even a used NHW20, 2004-2009, will look pretty good with more usable space and power. But there will be other options including possibly a 2010 with the 1.8L engine and even more space and power. You'll have lots of options.

We never drain the traction battery, in fact we might even put a forced charge on it (holding the foot brake and flooring the accelerator until the battery reads fully charged.) Then we'd disconnect the 12V battery ground wire. If you have small rodents in the area, some bait traps make sense to keep them from 'finding a new home with tastee wire.'

When you come back, just connect the ground wire and the car should start right up. The clock and radio settings will be off. After it warms up, air up the tires, change the lubricants, filters, and check all fluids.

Then drive to a dealership and see what they might have in trade. <GRINS> Somebody with a car has more options . . . the ability to 'think about it.'

Bob Wilson

 

If one has a low amperage charger for the 12 volt, it might be good to also charge up the 12 volt fully before disconnecting it and embarking on the trip.

 

I agree that there is some possibility that the traction battery will fail to operate after 9 months of disuse. I would be inclined to sell the car now while it remains operational, then buy a replacement vehicle upon your return.

You can always rent a car while you are looking for a purchase.

 

Is there anyone you can leave the car with who will drive it occasionally? I've been in similar situations, and have left my car(s) with friends and family and had them drive them occasionally. Similarly I have had friends leave their car with me when they were away for months... almost always it's better to have them used regularly than to sit unattended. Of course you have to be prepared to deal with accidental damage and unexpected maintenance/repairs, but that can be worked out among reasonable people.

A couple of thoughts if you do lay the car up - fill up and add some fuel conditioner to you gas tank, and rather than changing fluids after your return change them before departure so the car isn't sitting with old oil, antifreeze, etc. Here in the frozen north I change the oil in my lawn mower, pressure washer, and boat in the fall as part of the layup process.

There's no easy answer. But changing cars has its own sets of costs, risks and challenges, so it may come down to whether you would otherwise be completely happy keeping your car if you weren't planning to be away. If you are contemplating a change anyway then this could be the impetus for that change.

 

They are two separate battery systems:

• traction battery isolated by three relay contacts - the two high-voltage terminals are relay isolated from the car when it is off. There is a third relay contact in the middle that is also open. After the 'forced charge,' the traction battery will be very happy to sit there . . . for years.
• 12V battery powers the control computers that operate the relays - during the 'forced charge', the car will be putting ~13.8V on the 12V battery, giving it a peak charge. Provided the battery is not failed, disconnecting the ground will pretty much preserve the charge for a long but not infinite time. After disconnecting the ground, measure the 12V battery voltage:
  • 11.95-12.85V - all cells in the 12V battery are OK but if closer to 11.95V or lower, the battery should probably be replaced. If it is below 11V after disconnect, it needs to be replaced.
  • discharged battery vs freezing - when a 12V battery is discharged, the electrolyte changes from sulfuric acid that has a very low freezing point and water that freezes at 32F (or close depending upon how bad it is.) I once had a marginal battery freeze and break the case (one heck of a mess!)
  • If the isolated battery voltage (i.e., the ground disconnected) is under 11.95V, I would consider it a freeze risk. But if I had to choose before the trip, I would not just disconnect but take it out and leave it in a pan in the trunk. When you come back, if it freezes, no problem, no mess, replace it. If it still has 12.85-11.95V, put it back in (make sure the B+ goes to the red-plastic connector and then the ground to the B-.) Give the car a start and have a happy.

The rule of thumb is pick two:

• Good
• Fast
• Cheap

Having a car to drive around while shopping (and/or using Ebay,) gives you a lot of options to achieve "Good" and "Cheap." <grins>

Bob Wilson

 

A while ago I went on a 4 week business trip. I had a relative come in the house and check it out and drive the car a little. Why not have a friend or relative drive your car to work once a week.

My son went to Italy for 3 months. I drove his Xterra once a week

 

Toyota published these TSBs for the Gen 2 Prius: Prius Storage Time Limitation | PriusChat. I wonder if there's a Gen 1 equivalent.

You can look at those for some guidelines. The car doesn't need to be moved to charge the HV battery or 12 volt. Putting it in READY mode should be good enough.

One problem w/having the car sit w/o movement for so long is the possibility of flat spots on the tires. I'd over-inflate to help prevent that or have the car driven around periodically.

 

It is entirely optional but disconnecting the ground is not an option:

• ~0.035 amp parasitic load - the keyless entry system and control computers use the 12V battery for power even with the car is turned off. But once the ground wire is disconnected, the 12V battery has reasonable shelf-life measured in years.

Personally, I would get the new battery when I return because I'm going to be driving that car. The old battery, assuming it holds at least 11.95 V when disconnected, lets the replacement come from 'fresh stock' for maximum service life. ONLY if the disconnected voltage is under 11.95V and anything close to 10V . . . well it becomes iffy.

My thinking is take the car by an AutoZone or other car parts store and ask them if they can do a 12V battery test. Let them tell you how much capacity remains. <grins> (Warning, I would recommend getting 'the old' guy to test the battery. . . when I retire, it might be me!)

Bob Wilson

 

Worth a try. Alternatively, this is what is behind the felt cover:

The ground wire goes from the 'green', anti-corrosion washer to the center bolt in that dark-gray, battery shield. The felt cover of the area has little, cheesy, plastic pins that hold it on. Just use a flat screw driver to 'worry' them out. If I remember correctly, that center bolt is 10mm but some of our collaborators may have better photos and recent work in that area.

Never forget, negative terminal nearest the bumper and positive terminal by the tire. Always, check and double-check the polarity as the one thing that kills a Prius is reversing the battery. . . . that rates right up there with always cut with a knife away from you; don't fiddle with hot grease, and; do not spill hot soup and beverages on yourself or gulp it down.

Anyone have better photos of a stock, battery configuration?

Bob Wilson

 

Also gasoline is good for 6 months. You may have to drain it or put some additive in the tank to preserve it.

 

Patrick Wong on Prius Chat is a Master Mechanic and resident expert in storage. You can private message him. This Is his advice to a Gen 2 long term storage. Good to read the thread also


How to store a Prius? | PriusChat

 

They don't need to drive it, just let it run for 30 minutes once a month to charge the traction battery. Maybe a trusted Neighbor can help.