Regarding the jump start terminal

That little flat piece is, I think, what you're actually supposed
to grab with the jumper clip, rather than the threaded post.
There's only metal on one side of that bit, however.
.
_H*

 

I like the idea to have a dedicate jumper terminal for (+) under the hood (when 12V battery is at the back but not recommended to jump from there).

Problem is, Toyota didn't design the Fuse box cover to be opened easily/friendly. Instead of using an easy flip-open or top-screw design like in other cars, the fuse cover in Prius uses 4 clips! for tightening. Opening the fuse cover requires some tricky manuever and not intuitive. It may add extra to the frustration when you want to get the car jumped in a stranded condition.

It will be beneficial by seeing stuff underneath (or even learn how to open and hold-up the hood - its support rod is from the hood in Prius). Try open the fuse cover, learn where the clips are to unlock it and where the (+) jump terminal is.

 

Any more definitive confirmation of this and/or reports on success using this flat bit as the + connection for a jump? I thought about using this piece for the + connection in a jump earlier today, but the fact that there was only metal on one side made me a bit suspicious.

However, one thing pointing to the flat bit as being the true jumping point is that even tiny jumper cable clamps are impossible to fit into the compartment in the fusebox with the stud and nut. I used a 12V charger to recharge the dead battery today, but to get it on the + terminal, I pulled the nut off the stud in the fusebox and pulled the copper fitting on the end of the battery wire up as far as it would go (only a couple of inches). This gave me just barely enough room to fit the small clamp of the charger directly onto the copper fitting.

If one is supposed to hook the jumper cable to the flat metal bit even though the clamp would only touch metal on one side, it would be nice to know.

Also, if you carry jumper cables in the compartment under your trunk, the hatch-not-opening-when-the-battery's-dead thing is a real PITA.

 

Agreed - it's easy to open when you know how. You only need to release the catch on the bottom/front edge.

 

It's a good idea to practice opening it in the daylight at home, rather than doing it for the first time with a dead battery on a dark rainy night in some god forsaken parking lot (a bit overly dramatic, don't you think?).

Tom

 

I made my own "Prius jumper cable". On the Prius end I used solid copper Mueller #24 clips. The "doner end" uses much larger solid copper clips. The #24 clips fit perfectly in the fuse box and on the bolt on the firewall above the fuse box (-ve).
BTW, Prius draws about a 1/2 sec. 40-50 Amp pulse when you step on the brake, and another when you press "Start". When it goes into ready you get current back from the charger, so you can then remove the jumper cable (carefully!).
It doesn't take much to get the car into "Ready", and once there, the "boost cable" is superfluous.
If your 12V battery was dead (probably, otherwise you wouldn't be "boosting" the car, right?), you need to leave the car in "Ready" for at least an hour to properly charge the 12V battery. The engine will probably not run much during this time (unless it's very hot or very cold out), but do ensure the A/C is on and set to a comfortable temp. No point stressing the hybrid battery!

 

I haven't had the need to try jumping mine yet, but I don't see why you couldn't use this bit. As long as the metal piece is in contact with the positive post, there is no real difference if you jump from the bit or the post (other than convenience). That only one side is metal shouldn't matter. I admit that I haven't looked yet (I always forget to check this out), but I'm guessing the top side of the bit is insulated to prevent from accidentally making contact with metal on the fuse box?

 

Most small chargers (1-2amp) come with a plug-in adapter with ring terminals. Just attach ring terminals and feed wires out from under fuse cover and there is no need to remove cover to jump or charge. The Prius does not need high amperage to jump just a good 12-13 volts.

 

I thought you absolutely had to use a Toyota charger?

 

True for the traction (high voltage) battery. The 12 volt battery is a small lead/acid battery. It is similar to batteries found in 'normal' cars except that it is small, has a vent tube, smaller terminals and the electrolite is somewhat contained by a glass mat to minimize potential spillage incase of damage.

 

I found another problem with the jump bit only having metal on one side of the connection.

That is my jumper cable has the wire connection only on one side of the clamp. So if I attach the clamp with the wire on the plastic side of the bit no + 12 vdc will be going to the battery. This could cause me to think my jumper battery was dead or something else my be a problem.

 

How often do you have to jump your car?

 

I assume you are asking me. I have never had to jump my Prius but I am a person who likes to know my car and if I ever had to jump it I would know how and where.

And as you can see from some of the post some people dont even know where the correct place to jump the prius.

 

Chuck41,

Go look at your jumper cable clamps again. Isn't there a metal hinge that connects the half of the clamp without the cable to the other half with the cable? The current will be conducted from one half of the clamp to the other through this hinge. Also, isn't there a metal spring (for clamp'g pressure---either by itself between the 2 halves or around the hinge) making contact between the 2 halves? The current will also flow through the spring as well as through the hinge, so your arguement about having the clamp turned the wrong way & not being able to jump your car at the under-the-hood fuse box lug is wrong in my opinion. Sorry to have to contradict you here on this point. If your jumper cables had plastic springs & a wooden hinge, I could concede to your point of view.

Ken (in Bolton,Ct)

 

Hi Ken

No I am sticking to my story about my jump start pack ( Vector mod # VEC013) connectors have this flaw that the hot wire does not connect in any way to both sides of the clamp.

So that I can say 100% sure I used a OHM meter to check if there was a connection between the two halves of the clamp and the spring and found no connection between any of the clamp haves or the spring.

I know that the springs use to be connected to both sides on some old jumper cables that I have had in the past.

However on this model jump pack it looks like they wanted to save on the copper used. There may be other models that have this flaw and that was the reason for my post.

Chuck

 

I thought I would provide some pic's of the cable clamps.

chuck

This one has no connection to the wire

This one has a connection to the wire

 

Hi Chuck,

Good point, and owners should be aware that inexpensive jump cables may have this problem. Looking at your photos, I suppose that the red-colored parts are plastic - not metal?

 

Yes Patrick they are plastic