Jump starting another car....

Absolutely not. The 12V battery in a 4th Gen Prius is a very low spec battery that is suitable for booting up the computers until the HV battery can kick in. It was never intended to power starter motors. The power the 12V battery plus the HV-12V inverter can provide to the car in total is limited via a fuse rated at 100 Amps, so that gives you a clue as to its maximum safe current.

Cranking a traditional car takes several hundred Amps (let's say 500).

 

Tips: Buy a decent portable Lithium Ion jump starter. They're not very big and do work. You can also use it to start up the computers on your Prius if/when your 12V Battery dies in a couple of years.

 

For a slightly different opinion:

IF there is any life left in the low battery at all, there should be no problem jumping from a Prius with a couple of conditions:
IF your model has the battery where it is easily and safely accessible........and his is too.
Be very careful making the connections WITH BOTH VEHICLES OFF.
Leave them connected for a good 5 minutes then start the "dead" one and disconnect the cables.

At no time during this process should you start the "donor" vehicle while it is connected to the other one.

Is there a chance of something bad happening ? Yes. But it really is pretty slim, unless maybe you are prone to making bonehead mistakes.

I would definitely not do the jump if the donor vehicle has a battery more than 5 years old.......no matter what kind of car it is.

 

don't do it!

 

I'm kinda with Sam on this: if you're careful, it'll be fine. But yeah, maybe there should be a jump pack under the Christmas tree for you.

 

And yet we have many threads where folks jump started badly and are out hundreds of dollars (it used to be thousands)

A jump starter is somewhere between $40 and $125 USD, depending on how fancy you want it.
They almost all provide polarity protection so you don't damage the DC to DC converter if you attach them wrong.
If you are only interested in starting the Prius you can get them USB powered, so they charge when Ready and provide USB power even when not Ready.
If you need to start a larger engine, they would need to be charged on A/C.

Big one: start any gas car, pickup or SUV, most diesels www.amazon.com/gp/product/B01MY9FZM4
Smaller one, you can charge from USB www.amazon.com/dp/B073PSMR29

 

My opinion?
Even if "Technically" it's possible.
I wouldn't do it.

When I owned my Prius I was happy I had a portable battery jump start station. This allowed me to offer jump starts without using my Prius. IMO, there's just too much electronics and computer controlled aspects to the machine that I would want to ever put any of it at risk by jump starting another vehicle . You can look it up. plan to do everything carefully and right, and still end up accidentally damaging the system. Not worth the risk.

I still hold this philosophy and approach with my tiny, tiny battery, with my Honda Fit. Sorry to anyone asking, but I'm NOT using it to jump start someone else's vehicle.

It's just not like it was in the 70's, when with any vehicle you were pretty much just jumping battery to battery, without a connected system of computer controlled devices, integrated and involved in the operation of the entire vehicle.

IMO, not worth the risk.

I hate to be a jerk, and NOT helpful.
But I'd say to your brother?
Either invest into a new battery. Invest into a portable jump start system Or call AAA.

I wouldn't use my Prius as a electrical current donor.

 

I seriously doubt that AAA makes calls in Finland.

 

Hey you never know...

I have a Clore JNC660, had to run over to our daughter's one day last week, she'd left a light on (in the Pilot) overnight. She dropped a hint about getting her some sort of jump starter for Christmas, and I noticed these Noco GB40, very compact.

Any opinion on the Noco? I notice the cables are pretty much as short as possible: you'd practically need to put it atop the battery to reach both posts, and fugedabout connecting black to ground, just go to both posts. Also, it comes with a charger cord (for charging it) that is USB connector at the other end: I'm a little puzzled as to what that would connect to, maybe cell phone AC charger brick??

 

I have not used that model (too pricey for something I hope I never use) but it does appear to charge via USB, look in lower left "USB in"


So you could charge in car via USB or cigarette lighter, (included) or in the house with a A/C charger. (not included)

 

Yeah the "A/C charger (not included)" is the stumbling block for me. Seems a little counterintuitive: that the only supplied method of charging the device is via a car battery adapter, and that's a car maybe in need of a jump start.

I looked up Noco GB40 A/C adapter, and was finding a few US results, amazon and Ebay, most that would not ship to Canada. My consumer resistance fur starts bristling when something so basic becomes so involved.

I've got some little A/C to USB charger adapters, for our cell phones, but they're 5 volt output, I think not compatible.

It just seems if you want to sell a product, make it relatively complete, usable out-of-the-box.

Guess I'm guilty of thread-hijack again...

 

They are compatible. It charges at 5 volts, but jumps at 12 volts.

Amazon in Canada has it.

www.amazon.ca/NOCO-GB40-UltraSafe-Lithium-Starter/dp/B015TKUPIC

Not quite the same as shipping from US to Canada, but close.

 

USB is always 5V, that is part of its definition. Only amp / mA needs and capacities should vary according to the USB version. Anything smart should interplay, though mismatches may lead to extremely long charging times.

 

According to the internet, Finland is a country of 5.5 Million plus people.
My guess is they have some Finlandic version of Triple A.

 

Yeah, we have Autoliitto |
I pay 100€/year and if needed for example, these guys come and install new 12v battery to my car where ever i am and i only pay battery. There is also hotel, rental car, tow truck etc for free if car breaks down on the road. Must have service i would say. This is also valid if i am passenger on a friends car.

 

@Jeppefinn friend of mine bought brand new Auris hybrid last year. Sales guy told separatly that do not give jump start to anyone, ever and told a story of someone who did and ended up paying over 8000€ for repairs to his own car.

Edit: it was over 8k€ not 6k€, wonderful Finnish prices....