Jump starting Prime diff from other Prius?

I haven't had to jump start my Prime yet but the 12v is the same that was in my gen4 2016 regular Prius. My manual doesn't mention any special procedures on jump starting or required special equipment or battery packs.

It doesn't mention how big a draw it takes to get everything started but it may be higher than a small battery like a motorcycle's could provide. I wonder if anyone here has attached a meter when jumping to see what amps it demanded for a jump.

 

that prius owner is conflating the two batteries.
common to all prius:
it's the same jump start proceedure as any car, be extra careful not to cross pollinate the + and -.

uncommon even on regular prius:
if the prime hybrid battery were to become too low (that would only happen if something went wrong with the car) and i have not ever seen it reported here, it would need a special charger to bring it up enough to start the engine.

 

Yes, and that job also needs to be done by someone who knows how to do it and live.

But it's very seldom necessary, because as the first post said, the car is protective of the traction battery.

To jump start any Prius is pretty much like jump starting any other car, using a 12 volt battery. Instead of needing hundreds of cranking amps, though, it's been measured at more like 40 to 60 for a second or so.

 

Yup!

Probably. But, if the 12V is low enough, the small jumper battery might get overwhelmed by the current drawn by the dead battery. But if a little battery is all you have, there's no harm in trying.

As @bisco said, he was confusing the traction battery and the 12V aux. battery. Applying super high voltage to the 12V would be exciting to say the least.

Not likely. To start the car, the 12V needs enough power to boot the computers and close the relays that connect the car to the traction battery. Which is pretty much what it has to do to start the traction battery charging process.

 

Crack the Owners Manual?

 

The "portable gizmo" would be a "high amp" portable jump box, not a high voltage unit.

If the OEM 295 cca battery is seriously discharged a motorcycle battery won't jump it. In some cases a Dodge Ram battery may not immediately jump it. The problem is the discharged battery can drag down the jump batteries voltage. If you let it sit jumped for five minutes (typical Toyota instructions) the discharged battery might accept 100 -150 amps of fast charge. Equalizing the paralleled battery to an acceptable 11-13.5 vdc which can initialize the Prius' controls.

Some worse case scenarios like a shorted Prius battery could damage the Dodge Ram. Which is why the Toyota dealer recommends a standalone jump box that includes safety circuits for shorts and reversed polarities.

Does a jump work 98% of the time? Yes because the discharged battery may be 10.5v rather than 7vdc. Would a motorcycle battery work some of the time? Yes, especially if Toyota's instructions to wait were followed. Could a 5 amp hour alarm battery work? Sometimes especially if the bad battery is removed from the circuit.

So the bottom line is smart mechanics use a good jump pack for safety that is really important 2% of the time. They have no desire to blow a customer's fusible links and possible computers with an ill advised old school jump.

 

And not just professionals. My lithium jump pack was only a little over $100. Percentage-wise, a lot more than cables, but given the level of protection -- dirt cheap.

 

correct, they are totally separate. and yes, the wall plug, engine and inertia all charge the hybrid battery.
but it can get so low that the wall plug won't activate the onboard charger, and the engine won't start, so tjat and inertia are eliminated.
so your left with a specialized charging unit (toyota) and special connections direct to the hybrid battery.
completely different scenario than 'jump starting' the car because the 12v died.

 

Yup. Once I jumped the old Gen 2 Prius with two 9V transistor batteries I bought in a drugstore and connected them in series with a couple of pieces of wire and alligator clips I had in my computer repair bag ( this was in fall of 2006 and computers actually used soldering and wires).

The Prime I jumped with an Autowit supercapacitor jumpstart. But anything that can supply 12V is good. Just make sure all other drains are turned off like lights.

Yeah the key here is 12V Accessory Battery and Traction Battery. All techs and most people assume you are talking about the Traction Battery when you tell them I need to jump my car. I still get blank stares when talking about the Accessory Battery so I always add the 12V.

 

If you ever think you might face this situation, and you don't have a bigger battery to jump with, there is a possibility with a Prius that never used to be a possibility with older cars many of us learned on.

The deeply-discharged Prius battery doesn't need to be in the circuit at the time of the jump start. If you disconnect it, it will not load down your jump battery. Gen 1 and 2 have a push-on connection where it can easily be disconnected, back at the battery; Gen 3 has such a connection inside the front fuse box. I don't know about Gen 4 / Prime personally, but I would not be surprised if there is a similar connection.

So there's the option of disconnecting the car's battery, jumping with another source, then plugging the car's battery back in once the READY light is on.

You would never want to do that with a conventional car because the 12 volt battery had an essential role in stabilizing the output of the charging system, which could produce out-of-range voltages without it. But the DC/DC converter in the Prius is more like a modern computer power supply, and produces a stable output either way. (Old-time member hobbit published more details. You could get a trouble code about the battery voltage or state sensor, but the goal in a situation like this is to get the car turned on. If the battery was that dead to begin with, there are going to be codes and calibrations to reset anyway.)

Not a procedure I would choose to use if a better was available, but sometimes one isn't.

 

unfortunately, it doesn't work that way, but it's really nothing to worry about

 

So far, that has never happened to a Prime that I ever heard of. If the traction battery was dead, you'd need to have it towed to Toyota and make sure you bring lots of money if it's out of warranty.

If it was a simple matter of the EV range being depleted, that's a normal occurrence. Just drive it; it's now a hybrid. Regardless of the traction battery SOC, if the 12V is too low to wake up the car, the 12V needs a jump, a charge, or a replacement. Then you can plug in and charge the traction battery if you want to or you can get in the car and drive it like any other car.

 

Too, a jump pack is like a heart defibrillator: if you’re using it regularly, something is remiss…

 

+1.

It makes so much more sense to invest in a jump pack these days than risk the electronics of a donor car, hybrid or otherwise.

I picked a small one up at sale on Costco recently for like $60 (I think it is 8K or 10K mAh?) and is about the size of a VHS tape and comes with short jumper cables and a nice carry case, and tucks nicely under the passenger seat. It doubles as an emergency flashlight and has USB A and C charge ports (which is handy for all of the kids’ many electronics, since the Gen 3 is light on USB charge ports…). Charging electronics on long trips will likely be it’s main use case for us.

In 16 years of driving Prii, I have never had to boost a Prius (nor do I anticipate needing to), but having this tool available is good for emergencies, or perhaps being a Good Samaritan for someone else one day without risking my car.

 

That's the most entertaining use anyway. Maybe more people are aware of them now, but at least when I first got mine, the reactions of the family in the big ol' decrepit van when I walked over with something the size of two decks of cards, and then it started their van, was priceless.

 

Why is that? They all seem to be like that; throw in another 18" on each cable would be nice.

I drive around with one of these beasts, admittedly a dinosaur: