Apkungen wrote:I have gotten a deal on some 18650 Li ion batteries at 200dollar/kWh so i would like to buy an used Nissan leaf and extend its battery with about 24kWh which would cost 4800dollar (weigh 130kg)and extend its range with more than doubble of todays since i can depleat them more the few times i actually have to use the full range. Usually i get 100km from the leafes i have driven. With this i could easily get 200km.
I read something about this being done by a company in The US. Does anyone know of it has ben done by a private person, how Hard it is and if i can get any information on "how to" somewhere?
Please do not play with 18650 cells on such "high" voltage (you need at least 96 volts if it is any use on 24 kwh). To make a pack at 24 kwh you will need over 2000 cells, and every connection is a hazard, and you will need a BMS that can handle at least 500 series. Or use a many BMS
I do not think 18650s are suitable for such a Rex, even if you play it safe and only make a pack at 4 kwh. This should be done at a factory where every connection is perfect.
I think that the best you can do with 18650 and LEAF is to make a micro-REX. Make a 500 wh pack(about 45 pieces of 18650 cells) with nom 20,4 v and connect it to a stepdown to 13,5 or 14 v and connect it to the battery or 12v outlet. That would eliminate the wattage the main battery pack need to give to the 12v system. That should give you about 4 km more range... If you add another 45 more 18650 cells, and drive really slow and efficient you could probably get at total of 10 km extra.... But your trip will take 3 hours to deplete all battery packs...
I am playing with this idea myself. Since I am sometimes out of range and the last 20 km I often drive very very slow, and often get close to 9 km per kwh. With such low speeds the 12 v system is a lot larger factor. In such "emergencies" it would be nice to use the few hundred watt hours on moving the car, not on lights etc. This is the same route every time, and there are no QC or normal charge nearby. So I either got to QC about 30 km before my end destination, or drive very slowly. That QC charges in 15 minute intervals, so I often chose to just to use the scenic route and lower my speed.
So for me that extra 500 wh would help quite a lot. And another 500 wh could be used for seat heaters!
Based on you nick I assume that you are from Sweden... I live in Norway. If you still have a lot of 18650 cells available I would be interested in buying some of them.