Jump Starting

Page 543 of the manual shows the location of the jumping terminals under the hood. You have to open the fuse box cover on the right side (as you're looking into the engine compartment, then open the cover on the jump terminals. See a grab from the manual below:

 

if it's anything like the Gen II.. which i assume it is. the 12v lead under the hood, the battery in the rear, or a 12v cigarette lighter. people used to think the 12v cigarette lighters were shut off.. they are.. from the 12v battery.. not the car's computer systems. so it jumps the computers directly and the computers switch everything else on.

 

Glad to see that for the Gen III, they improved the instructions for jump starting by showing exactly how to open the fuse box cover!

(The Gen II instructions didn't show that release tab in the front that you press to open the cover. It took me a full 2 hours to figure out how to open the cover correctly. I'm sure there are a lot of Gen II owners who still don't know how to do this.)

 

Yeah, people like me (until now). It had never occurred to me, nor had I seen it posted, that I could plug my jump-start-box into the 12v socket to jump start my car; it makes good sense to me.

THANKS

 

er.. there's 1 issue with the 12v socket/cigarette lighter idea. ( i should have mentioned this ) since it's directly coupled to the computers.. the second you plug it in, your radio and such will turn on. soooo... don't leave it plugged in or you'll drain your jump pack.

 

Jay_man2's grab of page 543 of the Owner's Manual shows a tiny "exclusive jump starting terminal cover" located in the back of the fuse box (in my Gen II, this tiny terminal cover is red colored ... I'm guessing it's red in your 2010 as well). You lift that little [red colored] terminal cover to expose the POSITIVE (RED) jump starting terminal, which should be a flat metal vertical square:

[imglink]http://priuschat.com/forums/attachments/gen-iii-2010-prius-technical-discussion/17425d1249874466-jump-starting-ownersmanualresult-48.jpg[/imglink]

Then you're supposed to connect the NEGATIVE (BLACK) jumper cable clamp to unpainted metal somewhere under the hood. If you go to the next page of the Owner's Manual (page 544 in my PDF of the Owner's Manual), you'll see that Toyota suggests using a certain screw/bolt located on the passenger side of the engine compartment. Page 544 also illustrates the full jumper cable circuit between both cars.

Finally, page 545 gives the rest of the instructions for jump starting your Prius.

Good luck.

P.S. RTFM!!! (Just kidding.) I have a PDF of the 2010 Owner's Manual. It's much easier to use than the hard copy because you can do word and phrase searches and quickly find what you're looking for. If you'd like a copy, I can email it to you if your email will accept a 35mb attachment. Or PM me with a mailing address and I can send you a PDF of the 2010 Owner's Manual on a CD.

 

I registered on the Toyota Owner's homepage and do searches on the manual there. It returns pdf results, and I use Acrobat to extract the page, save it as a .jpg, and use it here.

80% of the questions on this board wouldn't be here if 60% of us would RTFM.

 

What about jumping another vehicle FROM a Prius? I'm the good Samaritan type, and usually the only guy with cables. Is jumping from the Prius okay?
I assume I'd use the front terminals instead of the battery, and I remeber reading somewhere that getting to polarity wrong would be "bad". Any other issues?

 

I understand that using the Prius to jump start another car is not recommended and can damage the Prius.

I recommend getting a portable jump starter for both jumping the Prius and jumping another car. I keep one in my Prius at all times, and try to recharge it fully once a month. It's really the easiest and best thing to use because it can be awkward, difficult or dangerous trying to jump start any car with another car (e.g., on a highway with little or no shoulder, and without extra long jumper cables).

 

I highly recommend one of those portable jump start boxes to boost another car. Do NOT use a Prius to jumpstart a conventional vehicle, not worth the risk. If something is seriously wrong with the other car, at worst you've fried a $100 jump start box, compared to several thousand dollars worth of inverter/converter parts

Jump start polarity MUST be properly observed in the Prius. We've had horror stories of what happens when the polarity is wrong while boosting a dead Prius

 

Re: Jump Starting -- Add a fuse/breaker to jump cable?

I understand this could put too much strain on the DC-DC converter (aka the inverter), which is generating the 12V from the high-voltage circuit/battery.

Do anyone know if using a modified jump cable with an added fuse/breaker would prevent such issues? What is the rated 12V max output of the DC-DC converter (Amps)? If the other car (starter) was to drain more amps than what the converter can safely provide, the breaker would cut the circuit instead of taking the damage… One could then simply reset the breaker and wait for the other car battery to charge before doing another attempt.

 

Re: Jump Starting -- Battery pack in the 12V outlet to jump start the Prius?

Very interesting… Have you tried this on a 3rd gen Prius? From other threads, I also thought this would not work as the sockets themselves were shut off. Does anyone have some technical confirmation that this would not cause any electrical issues? (to the Prius or to the other car/battery pack used)

Also, anyone knows the required current to boot the car? In another thread (post #14 from David Beale) I found that the 2nd gen Prius needed “a 1/2 second 45A pulse from the 12V battery when you press the brake pedal and one more when you press start. Then it charges with a float voltage of 13.8 V.†Is this still true for the 3rd gen?

Also, what size of 12V battery pack would be needed? I assume it would need to be a lot smaller than what is usually used to jump start other cars as it only needs to boot the computer (if ventilation, radio, etc. are off) rather than run a starter (and also allow the brake electric pump do to its usually cycle). Still, as the car 12V battery is dead, would that drain a big part of the available voltage from the battery pack and then provide insufficient voltage/current to bring the car on?

I really like the idea of keeping an improvised battery pack (something like 8 D batteries chained??) in the trunk in case it is needed. Cheap. And functional?

I’ve quickly searched other threads but didn’t find answers on this…

 

I've "jumped" a car from the Prius. I used the Prius (in Ready) to charge the dead car's battery, then disconnected the cables and started the dead car. I had to hook directly to the Prius 12V.

Yes, there is risk, and this method won't work for cars with a completely dead 12V.

 

Re: Jump Starting -- Battery pack in the 12V outlet to jump start the Prius?

On the Gen II Prius, the 12V power sockets are disconnected when the car is powered down. You can't use them for a jump unless the wiring has been modified. I assume this is still the case with the Gen III, but I don't know for sure.

Tom

 

Just had to do this. Now I have no display on the right side of the dashboard. Any ideas?

 

I think there is a giant 12 volt fuse from the converter designed only to power the Prius' various 12 volt items. Not designed to jump start other cars. If you should blow the fuse jump starting another car, it will be very difficult to replace. Probably have to go to the dealer.

 

DO NOT try to use the cig lighter or accy plug to jump the Prius. They are fused at about 15A. Jumping takes a larger current pulse, which -could- pop that fuse. Don't be lazy, use the provided jump terminal under the hood.

DO NOT try to jump another car with the Prius.
First there is a fuse between the jump terminal and the battery (it's actually at the battery). It is too small to jump most "normal" cars. You -may- get away with it once or twice, but eventually you will pop that fuse. It's not generally available from parts stores, just from Toyota dealers.
Second, the Prius 12V battery is not designed to be a "starter battery". Drawing more than about 100A from it WILL shorten its' life!

The inverter will protect itself, so that's less of an issue. But you -could- pop it with an impulse from boosting another car.

So just don't do it! It's not worth the risk!

If you MUST provide jumps to other cars, buy a portable boost device.
Oh, and remember, no good deed goes unpunished.