Converting Electric Ripstik from wireless to wired (and overvolting)

[Jarza]

I have taken the important parts out of my Ripstik (Version 3) to build a new electric scooter, but it uses a remote for throttle, and I would like a hardwired throttle. I have things like raspberry pis laying around that I can use to probe with GPIO pins, but that's about it. I've been seeing E300 overvolt kits, upgrading 24V to 36V, and I was wondering if I could do something similar with my new scooter, as the Ripstik takes 22V (close enough? ). These kits also come with handles that allow for variable speed, which is something I want, and also being able to see the amount of battery left. Thanks in advance!

 

[Jarza]

I'm thinking I'll buy this controller and throttle (Amazon Link) and get everything hooked up. This should work even though the ripstik motor is only supposed to take 100W, not 350, because I'm going to be using max power in little bursts, not full throttle the whole time. I'm also going to add a little bit of passive cooling to my motor, because the passing air from the movement of the scooter should keep it cool with a few heatsinks due to the motor being in the front. If you have any advice for batteries I would appreciate it!

 

[E-HP]

What will the specs of the new battery be? That’s the most important component so you need to start there before you can build something that meets your requirements.

 

[Jarza]

What will the specs of the new battery be? That’s the most important component so you need to start there before you can build something that meets your requirements.

I will need a 36V battery with preferably 10-15Ah or more. I would like a longer ride time.

 

[E-HP]

I will need a 36V battery with preferably 10-15Ah or more. I would like a longer ride time.

So you need room for 30 or 40 cells. You current pack is 6 cells. Are you going to use a backpack?

 

[Jarza]

So you need room for 30 or 40 cells. You current pack is 6 cells. Are you going to use a backpack?

I'm not sure exactly how I'm going to place the batteries, but I know I have a decent amount of room on the new scooter. I guess I'm just looking for a cheaper option for a battery that won't blow up.

 

[E-HP]

I’m not sure what is being moved from the ripstik to the new scooter. If you’re replacing almost everything, why not convert to a brushless motor while you’re at it.

 

[Jarza]

I’m not sure what is being moved from the ripstik to the new scooter. If you’re replacing almost everything, why not convert to a brushless motor while you’re at it.

I am putting the motor into the new scooter, and I was intending on using the battery and control board too, but seeing as the board is wireless and the battery is rather low-powered, I was going to replace those too. I have already welded the wheel well for the ripstik wheel, so I'd like to use that motor if possible. Is it really more cost effective to get a different motor?

 

[fill]

Perhaps detail your requirements for the finished scooter speed/range? and include details about your mass and the motor you are set on using. So specific viable options can be suggested.

an ex scooter or hoverboard bldc could provide a budget friendly motor option that would be compatible with the majority of cheap ebike/scooter control systems and provide you with a metric (peak draw) to match with a suitable overhead to a suitable batteries max drain to ensure system safety.

there is a reason only a few aimed a children ev's and historical options employ brushed motors and most modern ev's use BLDC motors.

 

[Jarza]

Perhaps detail your requirements for the finished scooter speed/range? and include details about your mass and the motor you are set on using. So specific viable options can be suggested.

an ex scooter or hoverboard bldc could provide a budget friendly motor option that would be compatible with the majority of cheap ebike/scooter control systems and provide you with a metric (peak draw) to match with a suitable overhead to a suitable batteries max drain to ensure system safety.

there is a reason only a few aimed a children ev's and historical options employ brushed motors and most modern ev's use BLDC motors.

I would like the scooter to be able to reach ~15mph, but more is always welcome. I am, like I said, planning to use the motor from the electric ripstik as my propulsion, but I am open to changes if they are relatively cheap. I don't want to spend too much, as this is just a personal project.

 

[Jarza]

I'm thinking I'll just use a 22-24V boost controller and use a 24V controller with my existing battery. Thank you all for your help!

 

[glennb]

You don’t strictly need a controller or throttle of any kind for a brushed motor at these power levels on a kick scooter - an all or nothing power delivery method is perfectly rideable.

A high power switch or relay in-between battery and motor is acceptable, but you can instead hook battery directly to motor and use a BMS with enable pins. I.e. BMS is asleep until you press a button. There’s no discernible delay in the BMS waking up, the power delivery feels instant.

Either way, best to put a couple of strides in to have the scooter underway before activating the motor, to lessen spikes and stress on the components, as well as reduce the intensity of the jolt.

(With a powerful motor and large gear reduction, from a standstill you need to lean forward and hang on tight or it’ll jump out of your hands, but you’re not going to have that issue with your setup, and you should be moving before applying power. If you’re already rolling along beyond walking pace you’ll barely feel a jolt, it’s bugger all different to what a quickly rotated throttle feels like.)

 

[Jarza]

You don’t strictly need a controller or throttle of any kind for a brushed motor at these power levels on a kick scooter - an all or nothing power delivery method is perfectly rideable.

A high power switch or relay in-between battery and motor is acceptable, but you can instead hook battery directly to motor and use a BMS with enable pins. I.e. BMS is asleep until you press a button. There’s no discernible delay in the BMS waking up, the power delivery feels instant.

Either way, best to put a couple of strides in to have the scooter underway before activating the motor, to lessen spikes and stress on the components, as well as reduce the intensity of the jolt.

(With a powerful motor and large gear reduction, from a standstill you need to lean forward and hang on tight or it’ll jump out of your hands, but you’re not going to have that issue with your setup, and you should be moving before applying power. If you’re already rolling along beyond walking pace you’ll barely feel a jolt, it’s bugger all different to what a quickly rotated throttle feels like.)

I feel it would be a little bit easier to have a controller, as I could implement things like throttle control and brakes that can work for both physical brakes on the rear wheels and also braking for the motor. I also may want some of the additional features later, so I want extensibility. If I build another scooter with less requirements, I may take this approach, as I didn't know about this solution at all.

Where could I find one of these BMS modules? Where would I find buttons or throttles that go on the handlebars to control it?

 

[glennb]

I see.

Re throttle control … with low power setups you don’t use the throttle range, it’s full gas all the time. For low speed manoeuvring, and around pedestrians and the like, you should not be applying motor power, even partial throttle, that’s how accidents happen. Use your legs for those situations.

Re motor braking … I wouldn’t recommend it with a little motor, because it heats the motor too much. And if there’s a gear reduction via belt or chain or helical cut gears, I really really wouldn’t recommend it. If you want brake cutoff, you can have that without a controller, you just use an ebike brake lever with its switch in series with the power switch (BMS or relay activation). It’s kind of pointless, but does add some safety, because pulling the brake lever will cut power in the event that your momentary power switch seizes in the on position.

Re additional controller features … I can’t think of any that I’d want on a little scooter. What are you thinking? Perhaps a VESC has additional cool stuff, but typical little brushed motor controllers have none. Stuff like rear brake lights, horns, indicators … again you don’t need a controller for any of that, it’s just wires and buttons.

Re sourcing parts … Aliexpress, Amazon, Temu, other smaller online stores, electronics suppliers, or scrap equipment. Any old normally open momentary switch is all you need, and tiny is possible because it won’t carry significant current. If you want a quick easy install with minimum fuss, any of the 22.2mm clamp style ones with a “horn” button will do the job. The horn button is momentary. They often have a headlight switch, and often indicator switches incorporated, but I’m sure you can find one for horn only, which will only have two wires hanging out of it. For BMS, I salvage them out of old batteries, but buying from Chinese online stores should be doable. If you want fancy, the JBD ones are great and cheap, but somewhat large. You can use a relay instead of the BMS enable feature, but it’s nice if your BMS can perform the task - less components and wiring.

Anyway, all the best with it. Sometimes less is more. I’ve used homemade heel switches, where you kick off with your preferred leg, then literally step on the “throttle”. With rear mounted motors and batteries it’s very neat, with no wiring at all to the front of the scooter.

 

[Jarza]

Thanks for the info. I've never had much success with wiring, but maybe this will be a fun way to get into it and have some experience. I want to start electrical work, and such a project would definitely help understanding.

 

[glennb]

Yeah, I suppose. Might as well learn on the job.

You’ll want a high quality wire stripper, and high quality sprung side-cutters. For stripper I use and highly recommend Kinchrome K4001. Affordable, but there’s Chinese clones of it that might be ok too.