Hi everyone, a little intro here but if you want to skip to the heart of the problem see below.
Here in Montreal, we go through all possible seasons, including long and often humid winters (November to April). People's biggest expense here is related to car fueling and maintenance. Since COVID19 started, we've been trying to cut down on expenses and my solution has been to place all bets on ebike technology. Some people think I'm crazy to ride in -20 temps but to them I say, there are no bad temperatures if you have the right gear. With a North Face jacket, a BBSHD equipped ebike and quality studded winter tires, believe me everything is possible! I even built a very simple super wide rear rack extension with thick plywood and ratchet straps allowing me to mount a huge storage box to carry quite a lot of groceries. The experience has been great and winter riding is super fun!
***I can make a post with pictures on how to build this easy, cheap and super efficient upgrade if you guys are interested.***
I now do 100% of all my transportation by ebike, thus saving us on avg 4500$ of car expenses this year over : Insurance, gas, general maintenance, anti-rust treatment, mandatory winter tire swapping, car part breaking down due to our very OH SO shitty asphalt roads and so on... Incredible!
Pictures of my bike when in normal and "cargo mode"
https://ibb.co/qB9GY9j
https://ibb.co/sj1VQFd
https://ibb.co/cQKd9VY
https://ibb.co/wY3rFfr
https://ibb.co/TKK7Cgt
https://ibb.co/bdJWpqR
Heart of the problem
My next challenge is to find the right configuration for inter-city winter commuting in very cold temperatures (-20 ish, 25 to 50 km ride).
My strategy is to hookup 2x 52v17.5ah batteries (Home made with LG MJ1 3500mah cells) in parallel and use as little throttle as possible for better range. After testing this setup, I realised that plugging 2 batteries in parrallel helps reducing heating which is normally a good thing. The drawback is that in -20 temperatures the cells get even colder which translates into even more rangeloss.
My idea is to program the BBSHD in a way that the battery heats up just enough to bring the cells back to a suitable internal temperature. I use settings similar to Karl's special sauce and other than the standard 30a limit, I make sure the controller and motor never have to perform more than a 1500w workload. I know that the BBSHD can easily do 2000w without any issues so considering my riding style, I'm not worried about smoking the motor. The concerns is the stock controller... of course.
With the added wind factor, the mosfet's heatsink gets super cold during -20 commuting. With this in mind, do you think I can push the drive's amp limit to maybe 32 or 35amp without overheating the FETs ? The cells wouldn't even need to be very hot to the touch... just a bit of heat at the core of the cell would already be an improvement I think.
I'd love to have your thoughts on that!
Here in Montreal, we go through all possible seasons, including long and often humid winters (November to April). People's biggest expense here is related to car fueling and maintenance. Since COVID19 started, we've been trying to cut down on expenses and my solution has been to place all bets on ebike technology. Some people think I'm crazy to ride in -20 temps but to them I say, there are no bad temperatures if you have the right gear. With a North Face jacket, a BBSHD equipped ebike and quality studded winter tires, believe me everything is possible! I even built a very simple super wide rear rack extension with thick plywood and ratchet straps allowing me to mount a huge storage box to carry quite a lot of groceries. The experience has been great and winter riding is super fun!
***I can make a post with pictures on how to build this easy, cheap and super efficient upgrade if you guys are interested.***
I now do 100% of all my transportation by ebike, thus saving us on avg 4500$ of car expenses this year over : Insurance, gas, general maintenance, anti-rust treatment, mandatory winter tire swapping, car part breaking down due to our very OH SO shitty asphalt roads and so on... Incredible!
Pictures of my bike when in normal and "cargo mode"
https://ibb.co/qB9GY9j
https://ibb.co/sj1VQFd
https://ibb.co/cQKd9VY
https://ibb.co/wY3rFfr
https://ibb.co/TKK7Cgt
https://ibb.co/bdJWpqR
Heart of the problem
My next challenge is to find the right configuration for inter-city winter commuting in very cold temperatures (-20 ish, 25 to 50 km ride).
My strategy is to hookup 2x 52v17.5ah batteries (Home made with LG MJ1 3500mah cells) in parallel and use as little throttle as possible for better range. After testing this setup, I realised that plugging 2 batteries in parrallel helps reducing heating which is normally a good thing. The drawback is that in -20 temperatures the cells get even colder which translates into even more rangeloss.
My idea is to program the BBSHD in a way that the battery heats up just enough to bring the cells back to a suitable internal temperature. I use settings similar to Karl's special sauce and other than the standard 30a limit, I make sure the controller and motor never have to perform more than a 1500w workload. I know that the BBSHD can easily do 2000w without any issues so considering my riding style, I'm not worried about smoking the motor. The concerns is the stock controller... of course.
With the added wind factor, the mosfet's heatsink gets super cold during -20 commuting. With this in mind, do you think I can push the drive's amp limit to maybe 32 or 35amp without overheating the FETs ? The cells wouldn't even need to be very hot to the touch... just a bit of heat at the core of the cell would already be an improvement I think.
I'd love to have your thoughts on that!