Liquid cooling pump for Nissan Leaf Electric motor

I test out a 12V water pump for liquid cooling the Nissan Leaf motor!

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To run the liquid cooling for the Leaf motor, I bought a Bosch water pump. I hooked it up to a 12V battery and tested the current draw and flow rate before hooking it up to the Leaf motor.

Tools & Materials used in this video:
Bosch pump –
silver shapie marker –
Craftsman 12V battery –
12V Automotive Fuses –
3/4″ radiator hose –
stainless hose clamps –
Crimp-on terminals –
Multimeter with DC Clamp –

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“Shaving Mirror” Kevin MacLeod (
Licensed under Creative Commons: By Attribution 3.0 License

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26 Replies to “Liquid cooling pump for Nissan Leaf Electric motor”

  1. BenjaminNelson

    Regarding the current draw….
    I recharged the battery and hooked it up to the pump connected to the motor again. The current was still about what it was before, and a little lower than it was on my test with the pump NOT hooked to the motor. The battery voltage did NOT make a difference.
    I believe the variable is that I did NOT have a hose on the outlet port when I tested the pump on my back porch. There was no need to, the water was just going right into the bucket. However, when the pump was connected to the motor, there was a hose from the outlet of the motor back to the bucket. The water in the outlet hose helps "pull" water behind it, making it easier for the pump to work. Essentially, I changed the setup from an open system, to a closed system.

  2. Whereswally606

    Hey Ben, great video. I am trying to upgrade my 2011 leaf for better winter range. One of my ideas is installing a 2000w electric parking preheater and a d3wz eberspacher diesel heater which will run in tandem with the original ptc heater when its driving (only using the diesel only for trips where I really need to when I need that extra range). The extra pump might help run the diesel heater when say at a campsite with no electric hookup or just to get that extra range as I can have the leafs oem heating totally off and rely on a toolpack battery for running the pump and powering the spark plug on the diesel heater. This way it would not be drawing down the 12v battery which I think gets quite abused by electric cars and shortens their life. Id be sure to attach a long exhaust if using the diesel for any time in a static location (I'll be honest I hardly want to ever use it but I want the backup). Already done heated seats but the car performs better generally when its warmer so getting the body of water up to temperature before setting off without using up battery energy makes some sense to me.

  3. Adamant Adam

    12:00 Well actually I'd have to disagree… I know it's just a saying and all but cooling a Nissan Leaf motor is more like Rocket Science than you might think. The amount of Heat Transfer calculations for the two of them were highly intensive. It's very difficult to model and design transient systems with complex geometry as the internals of that motor inevitably are. I understand it wasn't super hard to hook a pump up and some tubing, however I just wanted to know that what goes into making that motor feel as cold as it does with the coolant flowing through it was a highly strategic and laboreus process for an engineer. In the end though thank you so much for the interesting video!

  4. Stephen Alva Givens

    hey what happens when you replace the coil of a alternator with a motor coil that is equal to in total watts but not amperage and volts. Does it make it run cooler. and give you the correct energy without the huge motor expense.?

  5. Stephen Alva Givens

    (American Tech)(1000V+ High voltage generator from induction motor) try this with five on pole and some capacitors then how far will your car go. sorry benji but i had to show you. i don't hate you but this is my tech guy.

  6. Will R

    I just found your tractor project and just binge watched the episodes on it. I used to design electric industrial vehicles, and would like to build an electric farm tractor one day. I had some comments as I watched the videos, but figured I would just make one big comment at the latest video.
    1) Divorcing the hydraulic pump from the drive motor may allow for reversing using the drive motor (I think the TA transmission has an overrun clutch in one position). These old sliding gear transmission can be very clunky to shift gears. Forward to Reverse requires a complete stop with the tractor in gear to not grind a little. Being able to reverse the electric motor would be a huge help when doing loader work that doesn't require the PTO. This obviously wouldn't work when doing jobs requiring the PTO. PTO overrun clutches are available that would prevent damage by inadvertently reversing the PTO with an implement attached.
    2) Powertwist belts would be good to power the pump off the motor (of as a replacement in 15 years when a belt fails). This would allow replacing the belt without tearing the entire unit down.
    3) I would use a shelf industrial pump and not worry with trying to reuse the pump from the engine. There are belt drive, AC and DC pumps available off the shelf. Mount it low and use as few hydraulic fittings as possible on the suction side.
    4) do some calculations on the required hydraulic pump size. Frequently pumps are over sized on equipment because _ GPM is required to operate the steering from lock to lock at idle in a set time. This means at max RPM you are circulating a lot more fluid than is needed.
    5) I think there may be a design or part problem that caused the loader to drop as fast as it did. It could just be because the rod end of the lift cylinder has a smaller volume though. I would check though and make sure the system has something called a counterbalance valve. Typically these are mounted on the cylinders and prevent the loader from dropping if a line bursts.
    6) On your axle clearance, I wonder if you could space the mounting point in the back down a little. It doesn't look like you will have much interference with the frame on those axle supports, and I doubt the slight change in caster angle will make much difference in tractor driving performance.
    7) If you reuse the stock tractor radiator, I bet there is enough cooling capacity there not to need a cooling fan. The cooling fan will be the loudest thing on the tractor.

  7. kundan patel

    Hello sir
    My self Kundan patel a mechanical engineering student .sir I am working on a project to convert a petrol car maruti 800 (1998model) sir we are planning to put 48volts1000watt moter connected to gearbox .our total weight of car is 850KGS (including 1driver + 4 pessengers)
    Sir I am bit concerned about moter .sir my question is 1000watt moter is sufficient for our car or not and if not than for how much watt moter we should go for
    Please guide me sir

  8. Dinesh Pathak

    I need help!
    I'm a student and me and my other mates are converting a petrol car into EV!!
    CAR NAME: Maruti Suzuki 800 (1998 model). We're doing it on very low budget, as we're doing it with our savings and pocket money so don't have enough financial potential.
    I want suggestions on how much powerful motor will be needed, I'm thinking to use 48v 1000watts BLDC motor.
    Connected to gearbox, is it sufficient??
    On calculating total max load (with 5 people on board, 1 driver+4 passenger) it is around [ 940KGS]. Please help me !
    I'm in big confusion πŸ™
    Please help sir!

  9. Jack on the Farm

    Your electrical current dropped exactly as I expected. It may not be intuitive for some people, but on a centrifugal impeller pump, as resistance to flow increases, power decreases. This is because energy is being imparted to less water per unit of time. Your max power consumption will be with unrestricted flow at both suction and discharge. (Maximum flow rate, like your first test.) Your lowest power consumption will be when your flow approaches zero. At zero flow, the impeller is only stirring and heating the water in the pump. Moving gallons of water through the pump takes more energy.

  10. Sailorman6996

    Fun fact about centrifugal force pump is the smaller resistance the bigger the flow AND power. and vice versa. Try listen to your vacuum cleaner at full power, then block air inlet for a couple of seconds – then blocking it is maximum resistance and the RPM will clearly rise as the air trapped in the fan will just go round and round, less power is needed for fan motor.

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