2011 Nissan Leaf modifications (efficiency and utility)

[ME_Andy]

Or tint the windows

[Isaac Zackary]

Originally Posted by vskid3

Has anyone added better thermal management to the battery pack? I looked into it a bit in the past but didn't find anything.

Not that I know of.

Existing TMS
From what I understand the existing "thermal management" works like this. On 2011 and 2012 cars a battery heater is optional, and on all 2013 and later cars this battery heater is a standard feature. When extremely cold the battery heater uses some 300 watts, but only to keep the battery from being damaged from freezing. I've noticed in the bitter cold that my Leaf has terrible performance and range in spite of having a battery heater. The winter package also comes with a thin wrap of insulation around the battery.

For cooling the battery there is a space above and below it that air passes through as the car drives down the road. Some of the car's climate control also exhausts on the battery. This has been noticed because the battery will slightly cool if you use the AC and slightly heat if you use the heater. However, the cooling and heating effects are minimal. You can get better results by simply parking in or out of the shade.

TMS ideas

1. One idea would be to just blow more air around the battery. There is some space behind the motor and controller where some blowers could be installed and blow more air around the battery. Of course this will only help bring battery temperatures closer to ambient, but that's better than nothing.
   
2. Another idea would be to do the above but with some sort of water spray for cooling. Or cool the air some other way.
   
3. A third idea would be to apply cooled seat technology to the battery. The battery is one big box. But if wrapped in some sort of tubing then cooled (or even heated) coolant could be pumped around the battery.
   
4. The best TMS idea would be to redesign the whole battery. The battery has enough space to hold some 72kWh of electricity if you replace the Leaf's modules with the right cells (like LG MJ1 18650 cells). Even replacing the Leaf modules with Tesla/Panasonic cells you'd get some 50kWh. Since most other cells are cylindrical (like 18650's) that leaves space between them for tubing. Of course this would not be the kind of project for the faint of heart.

[Isaac Zackary]

Another thought for Oil Pan 4. The 2012 Leaf has a water-coolant based heater. If you use the heater much one thing that can be done to improve heater efficiency is to wrap the exposed heater lines with insulation. Also the 2011 and 2012 Leafs were designed so that you can't turn on the climate control fan without engaging the heater or AC. But with the right knowhow, you can set up a switch that will allow you to use your fan but turn off the heater when you simply want air, like for defogging.

[oil pan 4]

This pack will have to get weak enough for me to want to replace it then I will consider some kind of major upgrade that involves tearing into the battery.

Until then I may drop the pack and coat it with A•B sprayed foam. But I would probably save that till it gets cold, after I see how it does during the summer. If I insulate it too well it may not want to cool during the summer.
Constant driving and charging like I did yesterday heated it up some.

It may just need an air conditioned garage lol.

Because right now, the plan is to drive the firebird if it's going to be exceptionally hot or cold out and save the battery.

[oil pan 4]

The leaf is getting the alignment checked now.
I told them to go for 0 toe in even if it's toe in is with spec.
Even if going to 0 toe in only adds a half mile of range, ha try pushing that thing for a half of a mile. I would rather not.

[ldjessee00]

I wanted to figure out a way to pull a trailer of batteries and/or small generator and charge our Leaf while out and about so we can do longer trips.
But, i would need to run high voltage lines from the front to the back...
Also, with the limited thermal management, would charging and discharging at the same time cause too much heat?

[Isaac Zackary]

Originally Posted by ldjessee00

I wanted to figure out a way to pull a trailer of batteries and/or small generator and charge our Leaf while out and about so we can do longer trips.
But, i would need to run high voltage lines from the front to the back...
Also, with the limited thermal management, would charging and discharging at the same time cause too much heat?

This is perfectly possible and has been done several times. Basically you connect the extra battery or generator to the main bus on the car and then match the voltage and then feed current into the main bus.

However, there is no such thing as charging and discharging at the same time. Either current is going into the battery or it is coming out. A river can only flow one way, and the same is true of electrical current. There's likely only one thing that would happen with an extra battery and three possibilities with a generator.

1. If the motor is pulling X amount of current the current will be divided between all the batteries. For an example, if your trailer battery is twice the size of the Leaf's main battery then 1/3 of the current will come out of the main battery and 2/3 from the trailer battery. If the generator is small. less than 15kW, then you will normally be using some current from the main battery and some from the generator as the car goes down the road.
2. If the generator puts out about 15kW or 20hp, then at highway speeds the battery may not be charged nor discharged while driving, except a little when going up or down small hills or when accelerating and decelerating. But overall, the battery's level of charge will stay roughly the same during the trip.
3. If the generator is big enough, like 30kW or 40hp, then it will be able to both charge the battery and drive the car at the same time. Basically current from the generator will come to the main bus and split, part going to the motor and part going to the battery. Of course once the battery is full you'd have to turn down the power output of the generator so as to not overcharge the battery.

The effect of adding another battery or a generator will be a cooler main battery because it will be under less load.

[oil pan 4]

I already have a mobile 17.5kw generator trailer.
If there is a way to put 240v power to the car while driving I would like to know. I already have the main component to pull that off.

[oil pan 4]

Turns out the alignment was off a little.

[ldjessee00]

Overcharging is another concern... being able to automate turning down or off the generator once the battery was at 80% would be great... I guess I could just rig up some remote and turn off the generator, but would really prefer it to happen automagically, in case I was distracted or otherwise preoccupied.