Jumping ground location

I have used the bolt just behind the engine fuse compartment. There is no large amount of current needed like in a normal starter car; it's just control power. While this pic is Gen 2, a Gen 3 Prius is basically the same with a bolt behind the fuse box.

 

How long are the cables on the GB40? As rjparker suggests, there are usable, exposed grounding locations within 12" of the fuse box.

Or use this, apparently designed for NOCO GB40:

NOCO GBC007 Eyelet Accessory Cable with X-Connect Adapter To Allow Charging With NOCO Genius Battery Chargers


Product Details
Size: X-Connect Adapter
Brand: NOCO
MPN: GBC007
UPC: 046221160178

 

In addition to all of the above, note that the positive jump point in the fuse box has a metal plate on only one side.

Some clamps on battery jump packs and cables have a conductor on only one side of the clamp jaws. If that is the case for your jump pack, then you have to turn the clamp in the appropriate orientation to ensure a proper connection.

Posted via the PriusChat mobile app.

 

I have an upper strut sway bar connected to that bolt you mentioned.

Are there any other ground points close to the fuse box where the positive connection is located?

I want a portable modern battery jump starter that I can store in my glove box.

However, with the short cables that the clamps are connected too, II cannot reach the Toyota recommended ground, left of the engine, way on the other side of the engine bay.

 

I usually just glom the negative clamp on to one of the bolts holding the inverter cover onto the inverter case, right beside the fuse box there. The DC/DC converter inside the inverter case is the source of the car's 12 V power system, so it'd be hard to find any better ground point.

I put one side of the clamp on top of the bolt and the other where the bolt comes through underneath, so the clamp's pretty much over the cover-to-inverter-case seam.

 

Think I have an idea what you are saying but anyway you can provide a picture and indicate exactly?
Last thing I need is going to the wrong ground . Thanks.

 

I don't have a picture handy (or a gen 2 to go out and take a picture of). But I wouldn't stress too much over it. There pretty much isn't a "wrong ground". The car is negative ground so pretty much everything metal and unpainted and solid in the whole car will qualify. Just avoid going for small bolts that hold painted cosmetic pieces.

 

I get a 12v reading at most any bare metal near the positive point, I wonder why it won’t jump

 

The stud/nut combo on the EGR valve is my goto for ground. Learned about that one before the car was even our: it had languished on the dealership lot for aboutr 15 months, and the 12 volt was dead as a doornail. They tried to mask it too...

 

If possible, Can you provide a pic and show me exactly?

 

Hah, was just on it:


(the pos meter lead is connecting to the CTEK quick-connect cable I've wired in)

 

Idk how short the cables are, but my noco maintainer has no trouble reaching

 

Well, if Mendel's going to supply the photo, my ground clamp usually ends up, like, here.

 

Here is where I put it but the inverter bracket is an alternative. I certainly would not put it in the ecm bracket.



The thing to keep in mind is the dead 12v battery may draw a lot of current when you parallel it with a jump pack. Toyota recommends a 5 minute wait while the jump is energized. Otherwise the jump may fail.

 

Those instructions assume jumping from another vehicle, with its engine running producing power for 5 minutes to charge the Prius battery. If using a small jump pack like mine (30-some watt hours) that fits in the glove box, the dead battery in back can sometimes suck all the juice out of the jump pack in the time it takes from when you connect the clamp to when you try to press the power button.

The last time I jumped my gen 3, I just unplugged the fat white wire you see right in the photo above (to the battery), before connecting the jump pack. That way my little jump pack did not have to jump the dead 12V battery, but only the car. Once the car was in READY, I plugged the white wire back in and let the car charge its own battery thankyouverymuch.

On many other cars, disconnecting the battery isn't a good idea, because conventional alternators/regulators need the battery as part of the circuit. The Prius DC/DC converter regulates itself more like a computer's power supply and doesn't misbehave just supplying the load of the car.

Of course, this technique defeats any reverse-polarity safety check built into your jump pack (the battery isn't connected, so the pack has no way to tell what the right polarity is). You just have to be extra careful where the red and black clamps are, and then push the "I know what I'm doing" override button on the jump pack.