Irony

[AndyH]

Here is the rewrite ...

If you use LEAF as a booster vehicle, the electricity for jump starting ICE vehicle is not enough due to the amount of electric power needed at jump starting is larger than the power available in the Leaf 12-volt battery. However it is no problem using gasoline engine vehicle to supply power to the LEAF battery.

It might take 200A to start a gasoline engine if the engine has been off for a while. My 2L turbodiesel can pull more than 600A first start of the day. After that, either engine will only need 50-100A to start.

Last summer I tossed-together a 12V 20Ah LiFePO4 pack and used it to start my VW turbodiesel. Here's a voltage plot from the start. It didn't catch the first time I turned the key so it took two starter-events to get the engine running (I'm used to it starting very quickly so released the key too soon).

The numbers on the bottom are time hacks in seconds. The total two-key-turn start event -- from first key turn to engine running -- took 7.25 seconds.

The ragged up curve is the voltage rising when the alternator came on-line. (Notice how ragged the alternator output is? We're not talking computer-grade power in cars here!)

Now - jump up to the youtube videos posted above. The LiPo pack that's cranking and cranking the Integra? That's THREE lithium cobalt polymer cells in series and a total capacity of 4Ah.

It doesn't take a lot of total energy to start an ICE - but we have to be able to move enough current quickly enough to run the starter motor. And that's more about the quality of the jumper cables than the capability of the battery.

The DC-DC in the Leaf is not designed to jump start a car on its own - it's only sized to keep the 12V lead-acid battery charged. And that's just fine! Saying that we can't use the Leaf to jump start another car because the DC-DC is small is just like saying that we can't start a car with a dead battery because our trickle charger is only 2A. DUH!

 

[Nubo]

A couple of things.. you guys are assuming that because the LEAFs battery looks like a normal battery that it is, perhaps its not designed to deliver the hundreds of cold cranking amps that normal cars need.. the battery may have been optimized for high capacity and low self discharge (similar to the battery used in a UPS or an alarm)

Perfection is the enemy of "good enough". I can't see any need to get too fancy with the Aux battery. Perhaps they'd spec a deep-cycle construction, but beyond that there'd be little need to get fancy; much more cost-effective to select a mainstream (albeit small) car battery. The fact that they chose a "flooded" battery suggests "standard" as well. I was surprised by that choice and would have thought they'd at least have chosen an AGM design, to save a few pounds and completely eliminate maintenance hassles. Corroded terminals on my EV? How 20th-Century!! :?

 

[smkettner]

Do we know the group size yet for the 12v battery?
I did not see it in the manual

 

[johnr]

The manual says you can't do it cause either the Leaf's 12V battery is too small or its DC-DC converter is too small, not sure which, but Nissan says it just doesn't have the current to turn over a starter motor. But if needed, you can safely jump the Leaf's 12V battery from any other 12V battery - even using an ICE car.

Not sure about the 12V battery size either, but from the pictures it looks to be about half the size of a regular car battery.

LOL - from the manual (off-topic)"

CAUTION: Do not substitute anti-freeze coolant for window washer solution. This may result in damage to the paint.

No duh! I guess it's already been done by some idiot or they wouldn't have to put in a warning :shock: :lol:

 

[Coffee_Slurry]

Not sure about the 12V battery size either, but from the pictures it looks to be about half the size of a regular car battery.

It's a standard car battery. I don't know what pictures you're looking at, but compare the battery here to the whole "engine block".
Why are so many people insisting the battery is small/undersized/low-current/unusual? I give up.

Last try:

 

[jhm614]

Not sure about the 12V battery size either, but from the pictures it looks to be about half the size of a regular car battery.

It's a standard car battery. I don't know what pictures you're looking at, but compare the battery here to the whole "engine block".
Why are so many people insisting the battery is small/undersized/low-current/unusual? I give up.

Last try:

GL-

I just looked at the battery during the demo in Austin. It's as long (right to left) as regular battery but it only looked half as deep (front to back) to me. I'll throw the tape measure on at the Dallas demo.

Actually, the whole area under the hood looked smaller to me than it does in the pictures.

J.

 

[Coffee_Slurry]

Batteries come in different (Group) sizes. This one seems pretty typical for a compact car.
An 8cyl or diesel will have something bigger, but this one isn't mini.

If I wasn't leasing, I'd make some measurements (parasitic, boot, etc) and select an appropriate Hawker/Odyssey battery of much less weight.

 

[smkettner]

Considering the warning of paint damage using coolent for wash fluid I would similarly expect a warning on jump starting another car with leaf if there was a probable risk of damage. Usually it is just a boost the donor car needs and not the full power of a battery to start a V-8. I say help the guy out and give the jump.

 

[garygid]

WARNING:

I believe that the "rewrite" of the "do not use the LEAF to start other [ICE] cars" warning is incorrect.

It is not the LEAF's 12v battery that does not have enough power [and might be damaged], but the DC-to-DC converter that does not handle [pass] enough power to do the job [and thus might be damaged].

So, even if you don't like my "translation",
it DOES say ... DON'T do it.

 

[garygid]

IF I HAD to start another car, due to some substantial emergency,
I would first try it with the LEAF turned OFF, I think.

But, probably better to use your [working] LEAF to handle the emergency (getting that woman to the OBGYN), rather than trying to start her car.

 

[smkettner]

It is not the LEAF's 12v battery that does not have enough power [and might be damaged], but the DC-to-DC converter that does not handle [pass] enough power to do the job [and thus might be damaged

Rather than "and thus might be damaged" should simply be "and thus a fair chance you will just be unsuccessful"
If the doner car did not spin up and fire quickly I would tell them sorry and move on.

If a diesel truck or big block asked for a jump I would probably pass.
Otherwise I would give it a go. But I will not be carrying jump cables.

I just do not believe the LEAF system would be designed so fragile that it would be damaged

 

[taztaz]

If you are too afraid to jumpstart a ICE car there is alternatives. Buy a cigarett lighter cable that is made for connecting two cars together. That cable wont use more than 5-10A i think. That way you don't have to mess around with jumpstart cables and its a lot safer. There is also indicators on that cigarett-plug device that shows when ICE driver can start his car...

Problem solved! No more need for discussion .. Just ask Nissan about the jump start thing.. If they say ok its ok!

Here is an example of such device..
http://www.amazon.com/Wagan-EL9796-Quick-Jumper-Jumpstarter/dp/B00005OWK2

ANd then sit there for hours to equalize the charge. You can't jump a dead battery via a cig plug. All this jump start discussion is silly. If one wants to jump another car so be it if not call AAA. A leaf could easily charge the hell out of another car battery when on.

OfCourse you can.. Depending on the engine and how hard to start the car is it takes from 2 - 10 minutes.. I agree with you that thick cables from the battery is better. But this is a sollution for people that dont want that..

To give you some figures.

If the cigplug adapter transfer 10A you need it connected 5 minutes to be able to start a car that requires 600A for 5 seconds... To be on safe side give it 10 minutes and he should be able to crank the car for 10 seconds and thats a really long time..

 

[taztaz]

WARNING:

I believe that the "rewrite" of the "do not use the LEAF to start other [ICE] cars" warning is incorrect.

It is not the LEAF's 12v battery that does not have enough power [and might be damaged], but the DC-to-DC converter that does not handle [pass] enough power to do the job [and thus might be damaged]

So, even if you don't like my "translation",
it DOES say ... DON'T do it.

I don't believe what you say... I cant imagine Nissan building a car with a DC/DC converter without current limit in it.. If there would be no current limit in it there might be a fire because overload if they dont have it fused at 100A or something.. I would say either a fuse or a current limit is existing..

And.. I can say without knowing the Ah rating of the battery that that battery will be sufficient to start a ICE car without the Nissan turned on... If you have thick enough starter cables...

Can someone find this about about the DC/DC converter? If it has a current limit and/or a fuse? If it is rated at 100A it usally can deliver much more than that for a couple of seconds too.. If it is not current limited...

 

[garygid]

I am not trying to describe how it actually works, because I do not know. Yes, I know ways that it could / should be designed.

I was just trying to properly "translate" the statement that THEY wrote about their own stuff.

Yes, they might not have made an entirely correct statement. I consider that an entirely different issue.

 

[awallis]

The question to me is not merely how much energy the battery or the DC/DC converter can put out, but whether it can take a power surge going the other way. Sure, they probably put some protections in, it's probably great, but why risk it? One would think everything is solid--and it probably is for its purpose--but you never know, and I don't want to blow up a 1000 dollar electronic component, so, if I really wanted to jump start someone, I would remove the cables from the 12v before proceeding, then I wouldn't worry too much. Seems like an easy step...

In all of this, I'm thinking of Jack Rickard's Mini and how many times he kept blowing up the A/C (as in air conditioning) unit controller (a 400-500 part) because the manufacturer of this expensive, high-end controller didn't put in a $2 diode to block power surges from the pack during acceleration.

 

[EVDRIVER]

If you are too afraid to jumpstart a ICE car there is alternatives. Buy a cigarett lighter cable that is made for connecting two cars together. That cable wont use more than 5-10A i think. That way you don't have to mess around with jumpstart cables and its a lot safer. There is also indicators on that cigarett-plug device that shows when ICE driver can start his car...

Problem solved! No more need for discussion .. Just ask Nissan about the jump start thing.. If they say ok its ok!

Here is an example of such device..
http://www.amazon.com/Wagan-EL9796-Quick-Jumper-Jumpstarter/dp/B00005OWK2

ANd then sit there for hours to equalize the charge. You can't jump a dead battery via a cig plug. All this jump start discussion is silly. If one wants to jump another car so be it if not call AAA. A leaf could easily charge the hell out of another car battery when on.

OfCourse you can.. Depending on the engine and how hard to start the car is it takes from 2 - 10 minutes.. I agree with you that thick cables from the battery is better. But this is a sollution for people that dont want that..

To give you some figures.

If the cigplug adapter transfer 10A you need it connected 5 minutes to be able to start a car that requires 600A for 5 seconds... To be on safe side give it 10 minutes and he should be able to crank the car for 10 seconds and thats a really long time..

The point is you can't jump a car with a low battery, sure you can sit there for a long time and trickle charge it but you can't jump one straight off. I have done this on many cars and even decent cables heat up. Try this- I=E/R.

 

[AndyH]

In all of this, I'm thinking of Jack Rickard's Mini and how many times he kept blowing up the A/C (as in air conditioning) unit controller (a 400-500 part) because the manufacturer of this expensive, high-end controller didn't put in a $2 diode to block power surges from the pack during acceleration.

Nissan and other car manufacturers have real engineers and technicians that specialize in designing these systems to automotive requirements. The retired publisher from Missouri is- and does-not. Apples and oranges.

I ordered a Leaf specifically because I do not want to have a half-vast car kludged together by folks with half-vast skills, knowledge, and/or experience.

 

[Coffee_Slurry]

If you use LEAF as a booster vehicle, the electricity for jump starting vehicle is not enough due to the amount of electric power at jump starting is larger than the power Liion battery charges 12-volt battery.

There you go.. clear as mud.


Rumor is that the Chevy Volt has a 175 Amp DC/DC 12v converter, and the GM techs have said "Sure go ahead!" for powering other things from it. Their own crew used it run large 120v inverters for tools.

All we know about the Leaf DC/DC is that it's at least enough to power a 10A cigarette outlet.

 

[taztaz]

OfCourse you can.. Depending on the engine and how hard to start the car is it takes from 2 - 10 minutes.. I agree with you that thick cables from the battery is better. But this is a sollution for people that dont want that..

To give you some figures.

If the cigplug adapter transfer 10A you need it connected 5 minutes to be able to start a car that requires 600A for 5 seconds... To be on safe side give it 10 minutes and he should be able to crank the car for 10 seconds and thats a really long time..

The point is you can't jump a car with a low battery, sure you can sit there for a long time and trickle charge it but you can't jump one straight off. I have done this on many cars and even decent cables heat up. Try this- I=E/R.

Are you talking about what i wrote now? Or starter cables in general?
If we talk starter cables in general, you can connect them and the second after start the car.. Thats no problem, i do that all the time. Maybe my cables are thicker than yours, mine dont heat up...

Its I=U/R in my language.. And yes.. I work with batteries and cable area dimensioning in my work so i know what i talk about It's all about thickness and length

If you talk about the cigplug adapter.. When you connect it it starts to tricklecharge the battery.. So you can start the car when you have transferred enough energy to the other battery that the start motor needs to start the engine... Then it also depends on the other cars battery.. Maybe the battery itself is not okay anymore? If you deepcycle a starter battery to many times you have to change it. It's not made to deepcycle...

 

[DaveEV]

The weak part of most jumper cables is the clamps. Most are not able to clamp the terminals/block/etc to transfer large amounts of power. Very often to get sufficient power from the donor vehicle to the dead vehicle you have to mess with the clamps to make sure they are clamped down very well, otherwise it does not help much. Starting the donor vehicle and holding engine revs at 1500-2000rpm also helps make sure that the alternator is putting out maximum voltage which helps reduce current requirements...

Anyway, I didn't read the owners manual as saying that you should NOT attempt to start another vehicle with the LEAF, but only that it's not likely to supply enough power. I've jumped other cars with my Prius without issue... Nice to know that GM over-engineered their AC/DC inverter - I bet they pulled that part from one of their hybrid trucks where having lots of 12V DC power is important.