My first day back here on Endless Sphere in a while (stepped away over the winter addressing health issues that are now behind me thankfully) and my first search turned up this amazing discussion.
Great to meet you all and I hope I can help out here as a fellow Dual Motorhead (haha!) ebike builder/rider.
Shoutout first however to amberwolf - We had some great discussions last summer when I built my first of two Dual motor setups and you were a TON of HELP. THANK YOU.
Matteo - I apologize if what I share here has already been discussed (tried to read the whole thread as best I could) but hope to add some gems and insights for you.
I'm also going to share about my second Dual Motor setup here as my first build is not quite done (much more complex) and will share about it when it's completely built and rolling/tested out properly.
First, here is a great video from Justin at Grin about Dual Motor setups:
From this video last year I learned of their dual controller cable for the CA3 which I was one of the first to ever order.
Here's the setup I went with and just last week got to take out for it's first test ride:
-2015 Surley Pugsley with front and rear 135mm wide mount points for the wheels/motors.
-Dual 9C RH212 (135mm width) 1500watt Hub Motors.
-Dual PhaseRunner Controllers
-CA3 Dual controller cable
-CA3 with multifunction switch, thumb throttle and ebrakes.
-Sempu 175mm bottom bracket torque sensing PAS
-EM3EV Jumbo Shark 14.8AH/52V battery - LG Cells capable of 44amp continuous, 55amp max, 60amp BMS cutout.
Notes about configuration
-Rshunt set to 0.500 mOhm and the battery consumption when compared to the bluetooth BMS is within 1-2% accurate.
-The Sempu BB PAS feeds the CA3 and it signals to the controllers/motors.
-Ebrakes are configured to only interrupt the controllers/motors when squeezed.
-Front wheel Phaserunner Regen settings are at Zero. I want manual braking of the front wheel only. Rear wheel Phaserunner is configured for gradual regen braking based on the throttle being used.
*Yes technically I can press the 'front' brake lever, not be pressing the rear brake lever and then apply regen braking to the rear wheel with the throttle. Real world I never press 'just' the front brake as I'm sure most others as well. This is why I added regen braking to the rear wheel only, as additional braking power basically.
-Each Phaserunner is set to 25amp max draw in respect to the single battery of this build. This still gives me up to 1,300watts per motor, 2,600watts total when needed.
-I picked up a Cycle Analogger (https://ebikes.ca/ca-log-gps.html
) with GPS to try out this year and will share my results once I have them.
Ride experience notes
-As Justin explains in the video linked at the top, the battery capacity running dual motors 'all the time' sharing the workload 50/50 can not only achieve the same range as trying to run a single motor mostly then add in another - it can extend ranges if the primary motor is getting too hot and losing efficiency.
On this note, in both of my dual motor setups, carrying my 270lb rider weight and the bike themselves are 80lbs (this build) and 160lbs (my other build) - I have never seen over 45-50C temps even on the hottest days going up 14% grades at 40kmph. Yeah...it's amazing.
-Why did I build this 80lb beast?
Mud. Beach Sand. SNOW.
I started beach and winter riding 5 years ago on an acoustic fat tire bike. Last year I picked up a RWD Bionx fat tire bike and wow what a difference. Sure I worked less but I enjoyed more and I also rode much 'longer' overall spending all day out riding going through the multiple batteries I have.
There was still one major issue. Front tire push, not roll. Sand gets too deep, too soft. Even worse in snow. With a motor on the back I still kept running into trails I was exploring where the snow got too deep and I had to walk it through because I couldn't keep the front wheel rolling and the rear wheel from spinning out.
Now I have 1,300watts of dig deep and let's gooo up front to try out this year and I'm excited.
-The torque based PAS to the CA then the 2 matching hub motors works...amazing. I use the digital Aux to control the Human Watts to Motor Watts ratio of 0.00 to 4.00 in 0.5 increments. Most of the time I'm running 1.5x on flats slight hills and then when I want more...4.0....and if need even more - press the throttle and keep turning the pedals, feeling like a chubby superman.
-Related note I use Polar M650 bike computers and heart rate monitors. Even with my bikes doing so much of the work, I ride in the 125-155bpm range all the time with a max heart rate of 171bpm. At 6'0 and 270lbs currently (topped out at 320lbs in March 2019 which lead me to ebikes) the ability to ride anywhere and as long as I want is my investment to finally losing the weight and unhealthy lifestyle I lived for 20 years sitting at the desk.
-Other technical notes from my first test ride:
--Human Watts input around 130-180watts on flats and 300-400 on hills.
--Dual motor draw around 250-400watts on flats, 1200-1400watts on steep hills using PAS and 2,300watts on steep hills with throttle.
--14.8Ah battery has given me a 28km range of trails with about 20% capacity left and no effort to conserve battery life.
I wish I could show you the size of the grin on my face from my first ride. I rode out into a dried riverbed, bouncing around like a bronco rider, never lost traction. Some short 15-20% grade trail climbs I previously would need to reach at speed to be sure I wouldn't spin out at the top...I purposely climbed at a joggers pace just to feel that front wheel pulling me up.
Any questions please reply. I will try to log in more often and regularly now that I'm back riding again and look forward to sharing full build details of my two dual motor setups with everyone as well.
Matteo, great to meet you. Thank you for starting this awesome discussion thread.