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Tinkerer

New member
Joined
Apr 7, 2021
Messages
14
Hey everyone,

I got roped into a project involving a 2013 Nissan Leaf and a bunch of 18650s. The car is getting older, so the range is understandably decreased by a bit. Gets about 65 miles and need it to go 80. The idea is to try and build a cheaper “range extender” and seeing if it works rather than drop a lot of money into a new car. I already have the cells, like-new MH1 cells, 868 of them. My idea is to use those heavy duty tool cases to enclose all this along with an inverter/BMS/charging circuitry. Battery will be 14s 62p, or about 10kwh. That should extend the range~ 25 miles, perfect. I plan to have cell fuses, temp sensors, high gauge cables, more fuses, and ammunition cans to hold the raw cells. DALY bms, expensive but worth it. Multiple tool boxes might be needed, depends on what I can fit. The car’s charger will plug into the battery, then route into the front of the car. This is to not have to modify the car and mess with the high voltage system, basically using its stock level 1 charger to charge it off an external battery. Can anyone think of anything I’m missing? I’ve got temperature shut offs handled, balancing I’ve got, ammo cans as protection and safety, good thick cables, fuses, cell level fuses, bms, and padding for physical stress/vibrations.

only pulls ~1500w, so around 30amps, nothing crazy.

it’s going to be a heck of a battery, but I want to be sure I’m not missing something or forgetting a key part somewhere.

thanks for reading.
 

Oberfail

Member
Joined
Jun 22, 2021
Messages
103
Can anyone think of anything I’m missing?
Conversion losses. You have to convert the 48ish volts up to whatever AC voltage you need, for it to be converted again internally by the car to charge its battery.

I'd give it a overall efficiency rating of 60-70%. Reducing the useable capacity of the battery quiet a bit.
It also probably charges the car slower, then it actually needs to get a fair share of extended range.
 

OffGridInTheCity

Active member
Joined
Dec 15, 2018
Messages
1,785
Here's a guy that actually did a 'serious' Nissan battery extender - shows how he connected it and some workarounds to get it to work properly. In addition, he started with some 'extra battery power' - just search his channel for "Nissan". Don't know my Nissan years or details or if it will apply in your case - but it might :)
View: https://youtu.be/ckrhref5V-c

I remember now - you want to see Part 2 as well. This is where he had to drop the battery for the 2nd time and re-connect on the motor side of the 'shunt' as the shunt will only allow 22kwh to flow thru. In Pt1 he connected downstream of the shunt.
View: https://youtu.be/Dd0qeoDwEmY
 
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Crimp Daddy

Member
Joined
Feb 21, 2018
Messages
963
The used car market is so incredibly hot right now... personally I would just sell the car and buying something else. But I also don't want my daily driver to be a science project.
 
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BatGroupCraft

New member
Joined
Oct 12, 2021
Messages
14
Woah Tinkerer, that's very courageous. MH1 are awesome, I was suprised to find that NASA selected the MJ1 as the best when they compared batteries for jovian missions. That many batteries is beyond my imagination for welding, I expect you have a pretty amazing welding rig. Please check out my new technology page if you want for some future projects.
 
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