Jumpstart a car

[VJ]

Hello,

Yesterday, a guy in the garage at work came to me with jump leads, asking if I could help jumpstart his car (his car door wasn't properly locked, the interior light drained the battery). We both never did this before, so took the manuals of both cars.

1. connect + of empty battery to + of full battery
2. connect - of the full battery to the chassis of the car with the empty battery

Ever tried finding a piece of metal that goes to the chassis on these modern cars? It is all plastic and panels, nice covers, but nothing metal. We didn't managed to find anything, until passer-by said to connect the - to to full to the - of the empty battery. We did, and the jumpstart succeeded.

Why do they make this so hard?
(allthough I must say, my car has a metallic pin to which one can connect the - kabel should my battery be empty)


Jörg

[Fat Tone]

I've always done it + to + and - to -. There ought to be a good grounding to the chasis but you can't rely on it. In fact ISTR corrosion under the battery causing one of my dad's early Mondeos to fail.

[Brian Ellis]

How do you do this with a Prius with 200-300 V batteries?

[Fat Tone]

hehe. Did you get it? Do you like it?

[gt40]

you normally connect the - of the leads to the a piece of metal on the dead car to prevent any sparks at the battery igniting any gases produed by the battery.

[Brian Ellis]

No, I'm not getting a Prius (too expensive and not very economical for non-urban use). I ordered a Honda Civic Hybrid last autumn and I've been told delivery may be at the end of April, if I'm lucky!!! It is better than the Prius for highway consumption, but not as good for urban use. It is also better than the Prius for comfort, noise and roadholding. I road tested both on the same day under the same conditions over the same roads - and nearly overturned the Prius on my roadholding test! This was accelerating round a small roundabout until I felt it giving; the tyres were squealing, big understeer at 5 km/h less than the Civic, which was quite well behaved and neutral. The big negative for the Civic was the baggage space, but it is rare that I fill the space, anyway. I made the choice relative that I don't live in a town and 90% of my kilometrage is non-urban: also, the shape of a Prius is rather too much of a statement for my liking.

[Dr Mordrid]

Me....want....TESLA

[Gurm]

The correct way to jump a car is... + to +, and - to ground on frame. There's always bare metal, they do it on purpose. If they're nice, they give you a nice ground post. When the battery in a BMW fails or if you need to jump someone, there are nice + and - posts under the hood (battery is in the trunk) for that express purpose!

[Tjalfe]

you normally connect the - of the leads to the a piece of metal on the dead car to prevent any sparks at the battery igniting any gases produed by the battery.

With modern sealed batteries, is that even an issue?

[gt40]

With modern sealed batteries, is that even an issue?

you would be surprised how many manufacturers supply standard vented batteries as standard equipment or how many folks buy the cheaper ones as replacements

Besides, it's just good practice.

[gt40]

I was present once when a charging battery exploded.
not a pretty sight, and the acid does wonders to a paint job

[Gurm]

BMW specifies vented batteries as standard equipment. But then again, they ARE in the trunk, and the charging/jumping posts are under the hood...

[Greebe]

Hydrogen gas buildup is a non issue if the hoods been open for any real length of time or if there is even a slight breeze.

I have always connected directly to the battery unless it's in the trunk (as Gurm mentioned) or behind the rear seat as in older model Vets

and like has been said repeatedly, always connect + to + and - to -, never ever any other way or major meltdown WILL occur (both batteries and cables WILL fry, damage to car and possible explosion from the massive discharge let alone possible injury to you and anyone else nearby)

[cjolley]

hehe. Did you get it? Do you like it?

We got our Civic Hybrid in November.
It's got about 4,000 miles on it now.
I'm going to write up a full report sometime, but the gist so far is:
39.5mpg city, 42mpg highway (fully loaded @ 75mph)
Almost all of our driving is city.

It had no trouble in the mountains. (>10,000 feet)

BTW it has both the hybrid battery and motor for normal startups, plus a standard battery and starter that take over if the Li battery is discharged.
That starter is going to last a long time, it's never activated.

Lots of engines have a lifting eye somewhere on them.
It makes a great ground.

[Nowhere]

So...you never hear it starting its enigne like a "normal" car? It just starts to drive?