Electric Handcycle - Upgrade battery, motor, or whole system?

[smalltownboy]

Hi everyone, I'll try to make this concise:

I have a Stricker handcycle. It came with a 36v 250watt 10.4Ah system. After 2000miles, the battery is now shot and the mount is broken so I may as well put a whole new battery/mount on. I'm looking at greenbikekit.com's offerings for that.

My problem with just replacing the battery is that I am going to start going on camping adventures, and on my first one so far, with all my camp gear in tow, the 250watt motor really struggled on hills. The company that makes the handcycle also offers a "mountain" version that comes with a 350watt motor.

I found the 350watt motor on Aliexpress. I am unable to identify the controller as they had removed the labeling.

https://imgur.com/a/WKOf9W9 The circuit board had "kh306-a7" on it but I did not have any luck. Can anyone help me identify it? I am assuming (and willing to take the risk) that my current controller could handle a 36v 350watt motor.

I also need more range, so I was planning on adding a second battery.

Would you:

a. replace battery only

b. replace battery and motor, keep 36v and existing controller

c. convert to 48v and put in all new everything

Thank you for looking

[ncmired]

Hi, and welcome to the forum. Unfortunately, I don't think any Stricker owners have been on the forum in the past, nor anybody with anything quite like it.

I looked over the Stricker site a bit, and have the thoughts:

• what size drive wheel do you have - looks like 16" or 20" are available
• what's the traction like - would more power just end up spinning the wheel? More battery weight would plant the tire more, I'd guess
• I'm guessing the max safe speed is single digits, so I'm wondering if the (geared) hub ratio is key

I'm wondering if wheelbarrow hub motors would be a good fit, gear ratio-wise.

Just winging it ...

[smalltownboy]

I do have the 20" drive.

Traction is virtually never an issue on pavement, but I have not experimented much with gravel/dirt/grass. I have only used shwalbe marathons and I have a knobby tire in my garage waiting to be put on. Uphill, offroad, yes it becomes an issue. I also plan on putting extra weight in front and I have wide tires on my wheelchair.

Motor itself takes me to 15.5, and I regularly hit mid 20s mph downhill. Its very stable and has good brakes. That said, it does have a 44 tooth chainring, which I would like to reduce so I have more flexibility at lower speeds.


I appreciate the idea, but I do like to be able to keep up with my friends on their regular bicycles

[stts]

This is high risk stuff here. Service people may refuse to service stuff they didn't change. And the changes could add more risk for you at a very bad time. It all revolves around liability. So doing this means you and your helpers are solely on your own, probably from here on out.

That said, 250 watt motor is not much different than a 350 watt motor. Especially on a heavy bike. And that's alot of work to do all that stuff on your rig for a little bit of improvement. But we have no idea what kind of special software your bike uses for your situation. Software in the controller AND the control display. It could be tuned for slow acceleration so you don't have slip issues. And it could also mean why they use such a small motor. All that programmed into what you have.

That being said, I would love to dump all that and upgrade to 750 watts, huge knobby tires with tannus inserts and lower air pressure, big capacity battery and big wiring. and a display that shows you way more so you are better informed. Then you got a bike out in the boonies with plenty of battery and plenty of power for hills and plenty of resistence against overheating issues. But I got no clue how you are able to make all that happen.

So to answer your question, for all that work, 48v 500 watts is the minimum. Along with some premium knobby tires that people here are confident will serve you proudly. As for the controller, it looks typical of tons of eBike controllers. I can no doubt find one that should be plug and play for you. Unless you have special software loaded in your controller. You can likely swap out what I find with what you have to test it out before upgrading everything. Bigger controllers run small stuff fine as long as you don't try to drag race with it. Controllers are not very expensive, so you can buy and try to see if things seem possible. But Aliexpress is very slow delivery, so keep that in mind. Ill post a controller when I find it in a day or so.

[smalltownboy]

Thank you for responding to me, and in such detail. I am aware of and accept the risks. It's why I'm in the DIY forum :) The company makes a 1500watt version with a fat tire on it as well

The Stricker weighs approximately 70 pounds, my wheelchair 40, me 175, and my gear 20. So about 300 pounds total. Going up hills is where the small motor really feels it.

You are spot on noting the extra controller. There is a splice in the throttle wires that goes to an extra proprietary circuit board. It gives me 3 levels of assist, a fixed throttle dial, and a push throttle (that only goes to 3mph, for starting from a stop). That is why I am concerned about which type of controller I need, whether its sine or square wave. From what I can tell, it looks similar to the KT controllers. It was manufactured around 2016, if that helps.

And yes, I would LOVE to have a better display. I currently have a speedometer/odometer and a separate battery display.

Could you recommend a kit (I can handle spoking etc)? Would need to be a rear hub drive (like the Bafang H610), with a Hailong style battery, any kind of display, but the controller would need to be mostly plug and play with the existing controller.

If I knew that my current controller could handle 350watt, I would probably just put in the upgraded hub and remain humble

[Retrorockit]

A lot of places in the world have 250-350W legal limits on E bikes. I would guess that's what's going on here. I would definitely get in touch with Grin Technology.

https://ebikes.ca/

They're the hubmotor guys. They can help you work out motor rpm,tire size and speed considerations. 48V is pretty much the standard now, and 750W is the US legal limit. 28mph too. But that's moving right along for a wheelchair. Or even an MTB.
They're like Luna, they don't just sell other peoples stuff, they do R&D and make things themselves. For your situation one knowledgeable supplier is probably the way to go.
I think ideally a torque sensor at the hand crank running a motor driving the rear axle would be ideal. But IDK how much custom work would be required for that. Maybe 2x 250W hubmotors at the rear? You already have one.

[smalltownboy]

Thank you!! Yes, the bike was made in Germany so was made with that limit.

[ncmired]

Since we're (mostly) mid-drive motor drug pushers and if there's a standard bottom bracket spindle up at the hand crank, could you install a mid motor in place and have flexible gearing?

[Retrorockit]

WE're pretty much all rear wheel drive here too.