Irony

[awallis]

With the LEAF OFF, the HUGE discharge rate on the LEAF's 12v battery might damage it.

In fact, if I was receiving a jump-start in the Leaf (from a tow truck or ICE car), I would ensure that the donor car is OFF to keep the power rails quiet. Automotive electricity is a nasty place.

The LEAF does not have or need a starter motor/alternator. When a 12v dies it's usually dead so the LEAFs 12v system is off until it's replaced... or is it? Does raise a question of what does the LEAF do when it's 12v system fails. Will its 12v functions run off of the propulsion battery and tell you to replace the 12v??? I think it's going to be a bit of an adjustment for everyone regarding the simple anatomy of Electric Cars. The people with Owners Manuels might be able to verify more on this and if jump starting is recommended for gas cars.

Agreed. Since the leaf doesn't have a starter or motor, the 12v is likely too weak to safely start anything but a smaller vehicle. It's all about the amps, and the LEAF's 12v will be fairly week, I think.

In regards to what happens when the LEAF is dead, my guess is that electric cars, when dead, will have to be towed home OR be recharged from a significant battery bank on a tow truck to get have enough power to get home. This is assuming the car has been driven to its range-limit, or 100% depth of discharge, at which point the car will shut down to protect the batteries.

I have no idea what will happen when the 12v dies, but a good guess would be that you simply replace the battery and the car's auxiliary systems will come back to life. If you're talking about reacharging the 12v, its probably safest to disconnect the terminals and charge the 12v without its connections to the car.

Just guessing...

 

[evnow]

I have no idea what will happen when the 12v dies, but a good guess would be that you simply replace the battery and the car's auxiliary systems will come back to life. If you're talking about reacharging the 12v, its probably safest to disconnect the terminals and charge the 12v without its connections to the car.

Or if you have SL - and happen to be in the Sun - just wait a bit. You will be able to start the car ;-)

 

[awallis]

Or if you have SL - and happen to be in the Sun - just wait a bit. You will be able to start the car ;-)

Exactly! Can't wait to get mine!

Pending...pending...pending

 

[Coffee_Slurry]

Agreed. Since the leaf doesn't have a starter or motor, the 12v is likely too weak to safely start anything but a smaller vehicle. It's all about the amps, and the LEAF's 12v will be fairly week, I think.

Um, no. Have a look under the hood. I too expected a small/weak/motorcycle 12v battery.

Instead, you'll find a very average sized car battery. Maybe even a bit on the large side for a compact 4cyl car.

 

[garygid]

The Owner's Manual (that we do not have yet) should explain exactly what to do if the 12v battery is "too discharged" to "start" (boot up) the LEAF.

 

[garygid]

Starting a "big" ICE through "long" cables, poor contacts, and "thin" wires is sometimes too much added Resistance for the "donor" battery to be able to supply the needed current. Even 0.1 ohm limits the current to about 120 amps, and sometimes 300 or 400 amps are needed.

 

[EVDRIVER]

The Leaf likely has a 100A DC/DC so when on it could jump another car, even when off as the battery is adequate. If the 12v battery were dead a tiny 12v charger is enough to trip the contactor and drive the car even if the 12v battery is dead or needs replacing, it's not needed to drive the car.

 

[TRONZ]

I have no idea what will happen when the 12v dies, but a good guess would be that you simply replace the battery and the car's auxiliary systems will come back to life. If you're talking about reacharging the 12v, its probably safest to disconnect the terminals and charge the 12v without its connections to the car.

Or if you have SL - and happen to be in the Sun - just wait a bit. You will be able to start the car ;-)

If the battery is dead due to chemistry then I really do wonder what happens. Your solar will have no place to go since the 12v storage is inop. You get in and push the Start button and.... nothing? Or does the propulsion batt share a little? It will be very interesting to see what powers what, when, and if this fails then what, when??? It's a brave new world!

 

[driveleaf]

All of these comments about the physical size of the 12v battery are irrelevant.

You are looking for cold cranking amps, and I would be willing to wager the leafs cranking ability to be near zero.

That 12v battery under the hood is the equivalent to your CMOS battery in your computer. And the main power supply equivalent to the 120v.

I think it would be quite foolish to use the little leaf boot up battery to try and start a real engine.

You live in the future now. Cranking a gasoline powered engine is sooooo 20th century.

 

[turbo2ltr]

All of these comments about the physical size of the 12v battery are irrelevant.

You are looking for cold cranking amps, and I would be willing to wager the leafs cranking ability to be near zero.

That 12v battery under the hood is the equivalent to your CMOS battery in your computer. And the main power supply equivalent to the 120v.

I think it would be quite foolish to use the little leaf boot up battery to try and start a real engine.

You live in the future now. Cranking a gasoline powered engine is sooooo 20th century.

Right, because when they chose a battery, availability of a standard car battery played no roll in the decision. Cmon. Why would they put anything BUT a standard readily available automotive battery in there?

 

[awallis]

The Leaf likely has a 100A DC/DC so when on it could jump another car, even when off as the battery is adequate. If the 12v battery were dead a tiny 12v charger is enough to trip the contactor and drive the car even if the 12v battery is dead or needs replacing, it's not needed to drive the car.

Sounds right to me. It could even be that the solar panel alone (in full sun) would allow you to press the start button and go.

We're making all of this sound complicated. What makes me happy is that this is all actually MUCH simpler than dealing with the various scenarios of a non-starting ICE engine (battery, starter, coil, distributor, injectors, O2 sensors, crank sensors, mass air-flow sensors...)

 

[garygid]

In the Prius, the 12v has to supply "boot-up" power for the electronics (including the brake-pressure system), and it appears that the software, if satisfied that "enough" is OK, will close the traction-battery relay, and start the DC-to-DC converter to supply the 12v system from the traction battery.

It is likely that the LEAF is similar.

The LEAF 12v battery is NOT like a CMOS battery, it is a SUBSTANTIAL power source, apparently used in Accessory Mode to power anything you have on: lights, radio, etc.

 

[EVDRIVER]

All of these comments about the physical size of the 12v battery are irrelevant.

You are looking for cold cranking amps, and I would be willing to wager the leafs cranking ability to be near zero.

That 12v battery under the hood is the equivalent to your CMOS battery in your computer. And the main power supply equivalent to the 120v.

I think it would be quite foolish to use the little leaf boot up battery to try and start a real engine.

You live in the future now. Cranking a gasoline powered engine is sooooo 20th century.

Nothing you said makes any sense, batteries half the size of the Leaf battery can crank out more amps then many stock car batteries. That battery is twice the size of the ones on both of my EVs and the power from a 100A DC/DC can certainly to some work on a weak battery. EVs have been built basically the same way for years, there is no mystery and anyone can read a bit and get the facts. Comparing the Leaf battery to a computer battery shows a complete lack of understanding of electronics and I have no Idea what you mean by main power supply but is it is the pack you are citing it is no where near 120V.

 

[awallis]

In the Prius, the 12v has to supply "boot-up" power for the electronics (including the brake-pressure system), and it appears that the software, if satisfied that "enough" is OK, will close the traction-battery relay, and start the DC-to-DC converter to supply the 12v system from the traction battery.

It is likely that the LEAF is similar.

The LEAF 12v battery is NOT like a CMOS battery, it is a SUBSTANTIAL power source, apparently used in Accessory Mode to power anything you have on: lights, radio, etc.

Good info. Thanks!

 

[jhm614]

Right, because when they chose a battery, availability of a standard car battery played no roll in the decision. Cmon. Why would they put anything BUT a standard readily available automotive battery in there?

I've had a couple of cars that had something other than what I would consider a standard automotive battery. My Miata had some unusual battery -- a gel? based one? I know I wasn't able to replace it at NTB. Same thing with my first MINI, had to get the replacement from the dealer.

Based on what I saw at the test drive, the LEAF's 12v looked about half the "width" of a normal 12 volt. It definitely looked smaller than the last couple of car batteries that I have replaced.

 

[garygid]

Optical delusion?

 

[Coffee_Slurry]

You are looking for cold cranking amps, and I would be willing to wager the leafs cranking ability to be near zero.

That 12v battery under the hood is the equivalent to your CMOS battery in your computer. And the main power supply equivalent to the 120v.

I think it would be quite foolish to use the little leaf boot up battery to try and start a real engine.

You will probably want to LOOK under the hood of a Leaf:

CMOS battery? Zero cranking amps? Are you just making this up as you go?

 

[taztaz]

I would check it with nissan or check the manual first.

My guess is that it will work just fine. I would connect your battery with the other cars battery when your nissan is OFF. Then i would turn it on to make it charge the other battery. If you want to be safe i would turn of the nissan again before the ICE car tries to start. If you want to be EXTRA safe i would remove connection to your battery before trying to start the ice car..

But i think it will be no problem even to have the two cars connected together when started. The DC/DC converter/charger must have a high amp safty built in. Nothing will probably happen, it will not deliver more than 100A .. And doing that for a couple of seconds is nothing .. But I would not risk any of this without first checking with Nissan!

 

[gascant]

garygid makes a good point about the Prius--many of you may have seen that some creative folks have used the Prius to power their home during a grid outage. The brave ones tap into the traction battery and hook it into the house breaker panel through a backup power supply (uninterruptable). A simpler thing to do is hook a 1000W inverter to the 12V battery and just run the fridge, computer and some lights directly from that. The latter is possible because the 12V battery is fed by the traction battery. For both scenarios, the ICE kicks on when it senses that the traction battery charge is low.

Does anyone know if the LEAF has a similar arrangement? Wouldn't it be cool to have a few lights on in your house when everyone else is sitting in the dark? If you try to do this, though, I'd recommend buying a pure sine wave inverter.
------------------------------
LEAF SL brilliant silver + Level 3
Reserved 4/20 3:20pm PDT
Ordered 10/1 1PM
Pending

 

[taztaz]

garygid makes a good point about the Prius--many of you may have seen that some creative folks have used the Prius to power their home during a grid outage. The brave ones tap into the traction battery and hook it into the house breaker panel through a backup power supply (uninterruptable). A simpler thing to do is hook a 1000W inverter to the 12V battery and just run the fridge, computer and some lights directly from that. The latter is possible because the 12V battery is fed by the traction battery. For both scenarios, the ICE kicks on when it senses that the traction battery charge is low.

Does anyone know if the LEAF has a similar arrangement? Wouldn't it be cool to have a few lights on in your house when everyone else is sitting in the dark? If you try to do this, though, I'd recommend buying a pure sine wave inverter.
------------------------------
LEAF SL brilliant silver + Level 3
Reserved 4/20 3:20pm PDT
Ordered 10/1 1PM
Pending

I already have a 7,5kWh battery bank in my house ... 12v @ 600A / 24v @ 300A .. Have no problem power my house if i have a power failiure.. wich i never had so far ... Been living here for 1,5 years..

If they are going to do that you write about.. They have to have the LEAF turned on for the 12v to be charged.. Better would be to connect directly to the batteries.. But then you must know the system voltage (measure).. And have a separate DC/DC converter or a UPS that is made for that DC system voltage