JUMPSTARTING A 2011 LEFT OVER THE WINTER

I have a 2011 and a 2017. I have jumped each of these vehicles, using the other vehicle. When the 2011 has had a dead battery I have jumped it with the 2017, and when the 2017 has had a dead battery I have jumped it with the 2011.

Yes, I have high quality cables.

 

Average cables are ok.

Two issues with a car to car jump

1. A split second reversed polarity will fry your fuses and maybe more. Typically causes a tow and $500 worth of repairs over several days.

2. IF your 12v battery is old it could be ruined from a long discharge this time. A bad 12v battery can sink enough current that even a huge truck battery may not raise your battery high enough to Ready a Prius.

So a lithium jump box with polarity checks solves #1

unless #2 has happened when a new battery is needed.

 

Correct polarity is positive to positive and negative to negative.

A bad battery sometimes frustrates people when the voltage does not rise enough. All most people think is it is not working. Realize a discharged battery HAS to increase to about 10.5v to Ready the car. The current in amps the car needs is low but secondary to adequate voltage.

 

Let’s make it simple. Use a lithium jump pack to avoid reversed polarity. If that does not work consider calling aaa or better yet go home with your ride and bring back a new battery the next day.

If you do a car to car jump be very careful. If it does not work, go home and bring a new battery the next day.

 

Late night long flight, then expect aaa to be there within minutes? Good luck.

If you dont have a lithium battery charger portable unit, now is the time invest in one.

 

To answer your question, yes, a regular car can jump your Prius.

 

The 12v battery runs the computers and keeps the memory when the car is off.
It also provides the power to start up the computers to run the checks to tell the main
computer all is well and safe so it will start the hybrid system. Then the hybrid battery
takes over, and also charges the 12v battery up.

Since the 12v battery does not turn the engine over so it can start, the hybrid does, it
doesn't need a lot of cold cranking amps.

Since you have to do this for a few "years?", it's likely it's weak and needs replacing.
Just make sure you put it on a 4amp or less charger over night, or at least 6-8 hours to
ensure it is fully charged before using. Dealerships and auto stores do not keep them
charged.

And as others have said, invest in a good quality jump pack. It will save you a lot of time
and hastle and you might even be able to get someone elses car going!

 

Is this a regular occurrence? If so, one option: if you can come up with some method to disconnect the battery prior to leaving, it will experience much less drain during its wait time. There are cut-off switches that can be installed, and some can be operated with a remote control, which is handy. When you return activate the switch to reconnect the battery and be on your way.

A less invasive, cheaper alternative is to disconnect and isolate the negative cable. You will need to get to the battery on your return, to reconnect it, and that can be tricky with the Prius hatch release requiring power. One practical method:

Stow a compact jump pack in the cabin. On your return, open driver’s door with the physical key (embedded in your fob), pull the hood release latch and raise hood, remove under-hood fuse box lid and connect the jump pack. Then go around back and activate the hatch release. Then disconnect jump pack, reinstall fuse box lid and close hood.

Now, with the hatch open, reconnect 12 volt neg cable. A 10 mm box wrench is all you need for this; snug the clamp firmly but not over-tight, and test wiggle it to ensure it’s secure.

And you’re on your way. The car may be a little weird: start up the first few times it’ll rev up for a few seconds (testing something), radio presets and a few other parameters will likely be lost. But your 12 volt battery should still be in decent shape, having been spared months of low but constant demand.

A simpler, but more arduous variation on the above, that doesn’t require jump pack to release hatch:

After unlocking the car (with physical key), open rear door, flip down rear seat backs, crawl (yes, thanks Toyota…) into hatch area, where there’s a mechanical emergency release for the hatch (more info in owners manual).

 

Yes, it is possible to jump-start a Prius from a regular car.

There are reasons why it might not work, but if you do your part correctly it should be fine.

 

Yes, flimsy cables have thin wire. Thin wire will NOT conduct much amperage. thick heavy wire [like a welding cable] will conduct lots of amps.

Yes.

 

Likely from page 73:



The reality of dealing with this, say due to dead or disconnected 12 volt battery:

1. Open driver's door, with the physical key.
2. Open rear side door, remove cargo cover (if present), and flip down rear seat backs.
3. Crawl into hatch area, rotate-to-release the two hatch floor latches, and tilt up the rearmost section of the hatch floor (it hinges).
4. On the back wall of the underfloor tray, just below the hatch lock, there's a small, rectangular cover. Pry it off.
5. Reach in with a finger, feel around: there's a stubby metal tab in there which pushes upwards, releasing the hatch!

 

Jumper cable thickness matters when you are jumping something that needs lots of amps to start. Just making a Prius READY in isolation takes about 30 amps over about a second and a half. An oscilloscope will show a few spikes up to 60 or 70 or near 100 just instantaneously; even those numbers are small compared to currents jumping a conventional car. There aren't any jumper cables thin enough for those numbers to be a problem.

Where the trouble comes is that usually when you're jumping your car, you aren't just starting a Prius in isolation; you're also using amps from the jump source to charge the very empty battery in the back of said Prius. A very empty 12 V battery can be sucking down the majority of the available power, leaving not much to achieve the objective of starting the car. If the battery is not merely empty but damaged, it can suck down even more.

There are at least a couple ways around that problem:

1. Brute force: Get a jump from someone with a big vehicle and fat cables, that can maybe supply all the amps that go sloshing into your dead battery and still have enough left to start your car.
2. Deviousness: unhook the 12 V battery in your Prius before trying the jump. Now the jump source only needs to supply the amps it really takes to make a Prius READY. Easy peasy. Once your Prius is READY, reconnect its battery and let your Prius itself supply the amps to charge the battery up.

Caution: never try (2) on a car with a conventional alternator and regulator; those need the battery connected all the time to steady the alternator output or Bad Things happen. The DC/DC converter in a Prius doesn't work that way at all and doesn't have that problem.

If all you are using is a small jump pack, this can make the difference between success and failure. Even a small jump pack is plenty to start the car, but the small ones can be drained completely by trying to charge your dead battery, often so fast that the jump pack showing full bars before you hooked it up is showing zero by the time you can press the start button.

The devious approach worked on my gen 1. I've never (knocks wood) needed to try it on my gen 3, but I expect it to work. Gen 2 I'm not as sure about; gen 1 and gen 2 both have a remote voltage sense line to the battery itself (it's the skinny plug next to the fat one), but gen 2 is more strict about setting trouble codes if that reading doesn't make sense (as it probably won't, if you are jumping with the battery unhooked). If the codes prevent going READY (I've never tried this on a gen 2), that'll defeat the purpose.

The remote sensing at the battery is gone in gen 3, which is why I don't expect any problem. The battery can be easily disconnected at the fat white cable in the underhood fuse box.