Dunlop said:
I have been trying to figure how to answer all this, but here goes: The lake is at 450ft (above sea level), My house is at 1300 ft. The straight line distance is about 4 miles. That is average 3.8% grade... Some parts of the hills are steeper than others so the town is made up of ups and downs from 5% to 1%... LOL Ya, there is nothing truly level around here!!
The bike was purchased in July, from BPM Imports... It is a full suspension, 24" fat tire bike: 1000W Bafang Hub motor, 21A-H Battery made with samsung cells, durado type battery. (Seemed pretty bad-azz on paper anyway).
Ok. So, with the info provided, and a guess of 120kg (230ish lbs) for bike plus rider weight, then this
https://ebikes.ca/tools/simulator.html?motor=MMAC10T&batt=B4823_AC&cont=C25&wheel=24i&frame=fat&mass=120&grade=5&axis=mph
simulates your bike/situation using a mac 10t motor that may be similar to yours (grin doesn't have your motor in the simulator) and a "custom" 15A controller to approximate yours. The simulation results could be very different from your bike, but you can play with that simulator to see if various simulations match the equivelent actual ride; if they don't, you can change simulator equipment settings until they come close for the same ride parameters.
It says you could ride 17mph at full throttle (or full assist level with PAS) up that 5% grade without overheating, with a 15A controller. (the motor will be over boiling, 110c, for the mac 10t, no idea what temperature your actual motor would be, or if it would overheat). If you don't get that speed on your ride under those conditions, then it doesn't match your system, and we can figure out what might better fit.
The 15A (at 48v) would be only 720w, so if it's a 1000w motor then as long as you're able to maintain near full speed up a hill, the motor should be ablet ot ake it. If it slows way down on the hill it can overheat the motor as it won't be in it's effficient range.
You could use a 20A controller for 1000w if it's really able to handle 1000w, and push harder up the hills to maintain the speed. The simulation gives about 20mph for a 20A controller (with the mac 10t motor).
On the flats, your actual max speed will depend first on the voltage of the battery, for the same wheel size and motor winding, the higher the voltage the faster the speed (above about 20mph the wind resistance also matters so you need more power to compensate, and thus a higher A controller and possilby more capable battery depending on how many A (not Ah) the battery is designed to handle (C-rate)).
My style of riding: Theoretically, the throttle is just used to get going, or move quickly through intersections, otherwise I need the PAS working all the time!! I rode my wife's bike, and some of the longer up hills found myself using the throttle to keep up the speed, and take some load off!
That usually means the bike doesn't have a low enough gear, or you didn't shift down enough to keep your pedal cadence fast enough, or the assist level was set too low in the controller/display. Depends on how her controller works.
On the downhills, I am wishing for higher rearing so I can go faster... momentum helps get up the next hill, and a fat tire bike has some serious stability, like a small motorcycle, rather than a bicycle. Her bike is a 750 no-name hub motor, but I get 35mph on a good downhill.
You can get higher pedal gearing, by changing out either front chainrings (for larger rings) or rear cluster (for smaller sprockets), depending on frame design and what gearing you have now, but this may decrease the ability to ride at slower speeds up hills by pedal power if the motor system has an issue for whatever reason.
If you need faster *motor* speed downhill, you either need a faster wind of motor, or you need a higher voltage battery and controller system, by proportionally however much speed you want vs the speed you get now, by pure motor power on the flats. Meaning, if you get 20mph on the flats under just motor power, and you want 40mph, you would need twice the battery voltage that you have now, and a controller that can also handle that. And a new motor that can handle the power needs of going that fast, whcih will probably be twice as much power as your existing motor is meant for.
The downhill pure motor speed will also be dependent on the same kind of things. If you get 35mph downhill by pedalling hard / full throttle then basically coasting (your motor and pedals probably can't contribute past 20mph or so, based on typical fatbike stuff I've seen for your wheelsize/etc), then to go faster you need to also be able to do that speed on the flats. (wind resistance is a major factor at those speeds.
To be clear, I bought this bike to get some exercise!! in an area where bicycle riding is just not very popular, because of the hills. I am always pedaling (as time goes on hopefully pedaling harder and longer).
In that case, you would want to be able to turn down the assist level as time goes on, usually by just changning which level you use on the display. So if you have say, 7 levels on there now, and level 0 is no assist, 1 is min, and 6 is max, with 7 being throttle only, then you'd use level 6 to start with, as long as it lets you put some pedal force in at the gear you shifted to on the bike for that speed and terrain. Later as it is easier to pedal, you use level 5, and so on down until you are at teh balance of pedal vs motor power you really want.
There are also systems that let you use a torque sensor, so that it requires a certain amount of pedal force to even activate the assist, and then the motor provides proportionally only as much assist as you have chosen , for the specific amount of force you put into the pedals.
One of these solutions doesn't require you to replace your controller at all, and uses the Cycle Analyst v3 from Grin Tech, along with a compatible torque sensor (usually these replace the whole bottom bracket unit that the pedals are bolted to, like the Erider, etc, so you have to get one as wide as your current one so your pedals clear your frame).
The CAv3 outputs a plain throttle signal so your PAS on the controller doesn't have to work, and the torque sensor replaces your whole pedal and PAS thing, so taht doesn't ahve to work either.
Even if you just use cadence PAS for it, the CAv3 will still replace the broken PAS function of your controller.
The downside is that it is not plug-and-play, and requires configuration and then tuning for your specific usage scenario, which can take some time to get just right. You can have Grin preconfigure it for you for the basic setup, but you'll still probably need to tune that as you use it to get it "just right" for all the situations you use the bike in.
It can be setup for three presets, and one function (of a few) can be setup to be incremented via buttons (like the assist level on your controller does now). You would turn your bike on, set the exisitng assist level for throttle control to max if needed, then set the CA's buttons to desired level, and ride.
The actual CA doesn't have to be on the handlebars with your exisitng display; you can run it remotely with just buttons on the bars. (you probably do need your existing display to turn the controller on and set it to the right assist level each time it's turned on).
I use just cadence PAS with the CAv3 to run my SB Cruiser trike (eventually I'll use the torque sensor but need to modify things for my specific needs first).
