Jumping another vehicle

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JPWhite

Well-known member
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Jul 31, 2011
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Location
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The User Manual states that a LEAF cannot be used to jump another vehicle, the 12 volt battery doesn't have the power to turn an engine over, just run the accessories in the LEAF.

Is there a replacement for the 12-volt battery, some Optima battery or similar advanced 12-volt battery that will fit and yet provide enough power to jump another vehicle?

It was inconvenient this weekend when the battery on my wife's Altima died and I couldn't jump it to get to an auto parts store. I had to wait 3 hours for a charge to provide enough power to start the Altima.
 
It's probably better to buy one of those home battery chargers that have "jump start" capability.

But, of course, you could put in a bigger battery, but I'd want to protect the LEAF electronics. Perhaps disconnecting that bigger battery prior to jump starting folks.
 
This is to prevent high cranking amps but oe could certainly charge another battery with a LEAF, charging is not like cranking a second car. The LEAF has a 100A DC/DC. There is a better battery replacement from Optima I believe, same one for Prius replacement.
 
I've used the LEAF to jump start the other vehicle.
Of course, that one's a Prius :D Here are the jumper cables I built:
jumpr_prius.jpg

I had to put my foot into the picture in order to give an idea of the scale.
The poor Prius doesn't get driven as much as it used to :D
 
TonyWilliams said:
It's probably better to buy one of those home battery chargers that have "jump start" capability.

But, of course, you could put in a bigger battery, but I'd want to protect the LEAF electronics. Perhaps disconnecting that bigger battery prior to jump starting folks.

One can jump a LEAF from another vehicle and the procedure is in the manual. So there isn't anything wrong with hooking up to another vehicle using jump leads. It made me think that if I was asked to jump someone else in trouble, it would be bad to have to say you couldn't help. Especially if my wife is on the road next time :)
 
I jumped a conventional ICE from the Leaf just the other day without any problems. Just be sure that the Leaf is off so that the inverter does not try to augment the load... It is also a good idea, and this applies to any jump situation, to allow about ten minutes or so after hooking up the jumped vehicle before trying to start it. This allows the battery in the dead vehicle to build up a small surface charge that greatly aids in starting.
 
TomT said:
I jumped a conventional ICE from the Leaf just the other day without any problems. Just be sure that the Leaf is off so that the inverter does not try to augment the load... It is also a good idea, and this applies to any jump situation, to allow about ten minutes or so after hooking up the jumped vehicle before trying to start it. This allows the battery in the dead vehicle to build up a small surface charge that greatly aids in starting.


I believe if the car is off the dc/dc is off so there goes 100A to your 12V battery. The inverter draw is almost nothing when on unless one plans to jump a car under throttle.
 
I was referring to the DC/DC inverter that charges the 12 volt battery. Since a jumped starting load can easily exceed 100 amps, it is likely a good idea not to have the car on so that the inverter does not try to counter that heavy load. It just seems a safer thing to do from the standpoint of protecting the Leaf. FYI, the car I was jumping was dead simply because the lights had been left on, there was nothing intrinsically wrong with the vehicle...

EVDRIVER said:
I believe if the car is off the dc/dc is off so there goes 100A to your 12V battery. The inverter draw is almost nothing when on unless one plans to jump a car under throttle.
 
Hello,
Then there are all the reasons for not jump starting a dead car from any car with modern electronics. Why is the car dead? Lights left on or is there an alternator problem that will take down your system as soon as the other car starts. I had to repair a Cadillac that this happened to. The poor guy jump started another car, his quit and the other car drove off after the jump. He lost his ECM, BCM, Radio & Dash displays. So unless you can verify the failure, my advice is DON'T.
My other advice: If you feel the need to be prepared, use one of the portable jumper batteries. Don't use unfiltered chargers on cars with the battery connected to the car. In some cases the car must be left powered on by an aux battery while the main battery is serviced.

Just FYI.

On Edit: DC to DC over current condition is very possible if the leaf is on when the other car starts. Low battery condition or starter problem can be seen as a dead short or near dead short pulling ~800 amps and dropping the voltage very low.
 
bowthom said:
Then their are all the reasons for not jump starting a dead car from any car with modern electronics. Why is the car dead? Lights left on or is their an alternator problem that will take down your system as soon as the other car starts.

It happens, also many MANY lead acid batteries explode when you make a connection to them, sometimes spewing acid all over.. ask any technician at a battery replacement center and will give you many examples. There are some cases of Priuses needing expensive repairs after a jump, but I think those were incorrect polarity hookup, a fraction of a second to do damage.

TomT 's advice is good, you can also use a dedicated jumping cord that uses the cigarette plug sockets such as this.. mostly they are used to partially recharge the dead battery:

http://www.vat19.com/dvds/easy-quick-jumper-jump-start-cables.cfm" onclick="window.open(this.href);return false;

easy-quick-jumper.jpg
 
I just skimmed this thread quickly, but I didn't see what I consider to be the most obvious point. All jump starting procedures I am familiar with say that the engine of the booster vehicle must be running when cranking the dead vehicle. This is obviously because ordinary 12v batteries don't have enough power to charge a dead battery and crank the engine at the same time; the power needs to be augmented by an alternator. Duh! The LEAF has no alternator (and having the DC/DC active is not recommended).

Ray
 
planet4ever said:
This is obviously because ordinary 12v batteries don't have enough power to charge a dead battery and crank the engine at the same time; the power needs to be augmented by an alternator. Duh! The LEAF has no alternator (and having the DC/DC active is not recommended). Ray
I'm a little confused because when you jump someone you are not charging their battery per se ... when they get their vehicle started the alternator on their vehicle charges their battery. As I mentioned other EVs can jump start other cars.
 
scottf200 said:
I'm a little confused because when you jump someone you are not charging their battery per se ... when they get their vehicle started the alternator on their vehicle charges their battery. As I mentioned other EVs can jump start other cars.

Perhaps those other EVs are using a stronger 12v battery, the Leaf does not have a starter and only needs a deep cycle type lead acid battery, not a high starting amps type.
 
Herm said:
scottf200 said:
I'm a little confused because when you jump someone you are not charging their battery per se ... when they get their vehicle started the alternator on their vehicle charges their battery. As I mentioned other EVs can jump start other cars.
Perhaps those other EVs are using a stronger 12v battery, the Leaf does not have a starter and only needs a deep cycle type lead acid battery, not a high starting amps type.
Good point. The Volt, for example, does not have a have a traditional starter motor (per SAE article **) but uses the 45 kW 'generator motor' to start the ICE/GasGen. It does have a 600:CCA 60:AH 12v battey (picture) but this certainly does not run the 54kW motor to start the ICE/GG.

** Chevrolet Volt Special Edition - SAE Vehicle Electrification - Title: A new role for the ICE section
 
Hello
Well those other EV's, are they powered by 12V lead acid batteries. Then by all means a simple jump from any one of it's hi capacity 12V batteries will jump start another car. BUT, we're talking about a leaf here right?
 
While Nissan doesn't condone it, you should have no issues jumping another car with the LEAF. Be absolutely sure to get the polarity correct, and connect the ground on the LEAF to the DC-DC converter, NOT THE BATTERY (-) TERMINAL!

Procedure: Connect the red/black jumpers directly to the Pos/Neg terminals of the dead car's battery first, then connect the red directly to the LEAF's Pos battery terminal, and then finally, connect the black jumper lead to the case of the DC-DC. The DC-DC is the large aluminum box behind the "engine looking" inverter. You can easily see the black negative terminal on top of it, which is a good place to grab. Once jumping is complete, disconnect in reverse order. Be very careful not to short the jumpers together when removing them from the LEAF.

The LEAF's DC-DC converter is about as powerful as an alternator on any normal car, and should charge a dead ICE battery enough to start it in a few minutes. No need to "rev" the LEAF! =)

-Phil
 
Ingineer said:
While Nissan doesn't condone it, you should have no issues jumping another car with the LEAF. Be absolutely sure to get the polarity correct, and connect the ground on the LEAF to the DC-DC converter, NOT THE BATTERY (-) TERMINAL!

Procedure: Connect the red/black jumpers directly to the Pos/Neg terminals of the dead car's battery first, then connect the red directly to the LEAF's Pos battery terminal, and then finally, connect the black jumper lead to the case of the DC-DC. The DC-DC is the large aluminum box behind the "engine looking" inverter. You can easily see the black negative terminal on top of it, which is a good place to grab. Once jumping is complete, disconnect in reverse order. Be very careful not to short the jumpers together when removing them from the LEAF.

The LEAF's DC-DC converter is about as powerful as an alternator on any normal car, and should charge a dead ICE battery enough to start it in a few minutes. No need to "rev" the LEAF! =)

-Phil

So you are saying that using the jump leads while the vehicle is turned on is the best way to go, given one hooks up the jump leads appropriately? No need to upgrade the 12v battery either.
 
JPWhite said:
Ingineer said:
While Nissan doesn't condone it, you should have no issues jumping another car with the LEAF. Be absolutely sure to get the polarity correct, and connect the ground on the LEAF to the DC-DC converter, NOT THE BATTERY (-) TERMINAL!

Procedure: Connect the red/black jumpers directly to the Pos/Neg terminals of the dead car's battery first, then connect the red directly to the LEAF's Pos battery terminal, and then finally, connect the black jumper lead to the case of the DC-DC. The DC-DC is the large aluminum box behind the "engine looking" inverter. You can easily see the black negative terminal on top of it, which is a good place to grab. Once jumping is complete, disconnect in reverse order. Be very careful not to short the jumpers together when removing them from the LEAF.

The LEAF's DC-DC converter is about as powerful as an alternator on any normal car, and should charge a dead ICE battery enough to start it in a few minutes. No need to "rev" the LEAF! =)

-Phil

So you are saying that using the jump leads while the vehicle is turned on is the best way to go, given one hooks up the jump leads appropriately? No need to upgrade the 12v battery either.
Yes. Putting high loads on the little battery without the DC-DC converter is not a good idea. In fact, The DC-DC is powerful and yet current-limited, and since it is liquid-cooled, it can handle high loads much better than most car alternators. Without having the LEAF in ready, you aren't going to get much across the jumper cables from the small battery alone.

-Phil
 
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