Novice questions for Enduro build

[Balgaroth]

Hi guys,

First post here after spending a few weeks reading build threads and watching YT videos. I feel like I have a good understanding of the mechanical part of things and what to get (some alu Jap frame with normal intake, QS138 70h v3, lithium-king motor mounts). But it gets less clear when it comes to controller, throttles and batteries, which from what I understand makes of break your build.

In terms of what I expect, I'd like something like a 125 2 stroke with a bit more low end. The bike will be used for tech mountain trails, if it performs well maybe the occasional small MX track but that isn't the goal for now.

So here are my questions, lets hope some of you are kind enough to help me clarify this.
- I saw this kit from SIAEcosys which seems to fit the bill for that I want to do but the throttle seems very bulky and not adequate for Enduro/Mx riding. Does anyone has experience with this and would confirm if it can be used or if something would be better ? Same goes for the display, is it ok for that use or is there a better alternative, maybe less exposed ?

- This kit is with the EM200 but I've read that it is complicated to use. Do you have to change settings or can you use factory stuff ? It seems that the Fardriver controllers are more intuitive, any specific model to recommend and settings to looks for or change off the bat ?

- In terms of battery, I don't feel like building one for the moment. In France we don't have stuff like E&C to provide good kits and batteries either. But we can get upgraded parts for Surron, Talaria and all these. So can we use 72v batteries built for these ?

- I saw some batteries that seem interesting on AliExpress with what looks like decent casing and rating (like these). Does anyone has some experience with this ? They claim that they use eCar type of cell, what difference does it make ?

- Any recommendations about battery size and spec ? Ideally I'd like to be able to ride 50km in the mountains, climbs, logs, single trails etc.

 

[bengxe]

It kind of sounds like you want to build a surron. Are you sure you can build something better/ cheaper? I don't know how available they are in France, but here in the US I wouldn't be able to justify this kind of build. As for your last question, I think the answer should always be the most you can fit in your frame, at whatever voltage works best for your motor and gearing. Whether or not you can hit 50km/charge will depend on how slow/ steep and technical your trails are.

 

[Balgaroth]

It kind of sounds like you want to build a surron. Are you sure you can build something better/ cheaper? I don't know how available they are in France, but here in the US I wouldn't be able to justify this kind of build. As for your last question, I think the answer should always be the most you can fit in your frame, at whatever voltage works best for your motor and gearing. Whether or not you can hit 50km/charge will depend on how slow/ steep and technical your trails are.

Kinda but not really.

Surron are toys at best. You can't really be ridden properly standing up unless you start changing basically everything on them, plus you need to upgrade everything for them to be able to handle any kind of proper riding otherwise everything will break very quickly. My friends ridding Talarias broke everything within a few month after purchasing then new and I tried them and it is a big no no for me as I hate ridding seating down.

I can find a rolling chassis for less than 1000€, the SIAEcosys kits seem to go for around 1000€ and then motor mounts 130€. Even if you spend 3000€ for the battery you are still with something that is cheaper than a Surron and such but with a proper chassis that will have a good riding position, will be able to handle actual ridding without breaking stuff constantly.

Keep in mind that I already have my enduro 2 stroke for bigger rides and MX tracks. This will be more geared towards afterwork quick rides, go dig and maintain trails etc.

 

[E-HP]

- In terms of battery, I don't feel like building one for the moment. In France we don't have stuff like E&C to provide good kits and batteries either. But we can get upgraded parts for Surron, Talaria and all these. So can we use 72v batteries built for these ?

- I saw some batteries that seem interesting on AliExpress with what looks like decent casing and rating (like these). Does anyone has some experience with this ? They claim that they use eCar type of cell, what difference does it make ?

- Any recommendations about battery size and spec ? Ideally I'd like to be able to ride 50km in the mountains, climbs, logs, single trails etc.

I’d say as a general rule of thumb, expect to spend about 50% of your build cost on the battery. That battery looks like a piece of junk.

 

[Balgaroth]

I’d say as a general rule of thumb, expect to spend about 50% of your build cost on the battery. That battery looks like a piece of junk.

Ok thanks for the advice. This is kind of the reason why I asked if Surron type batteries could be used in a build like I plan to do. After a bit of research I found some options that are sold as Suron upgrade batteries, sold in EU from what seems like reputable shops.
For instance: Surron & Talaria 72V 56Ah Battery | Ultra Discharge

I also found these but I am not sure about the 80v rating as most systems are advertised as 72v or 86v. Do they advertise the fully charged voltage ? I am right to assume that these batteries won't work with the standard EM200 controller ?

 

[j bjork]

I get about 30km with 4kwh battery on enduro tracks. I suppose you can get more on easier tracks, but with my riding I suppose it would take closer to 7kwh to go 50km.

 

[Balgaroth]

I get about 30km with 4kwh battery on enduro tracks. I suppose you can get more on easier tracks, but with my riding I suppose it would take closer to 7kwh to go 50km.

By enduro track you mean something like the timed stages you do during enduro races ? Or something like an Endurance/Hare scramble track ? If that is the case, this isn't the program for this bike right now. It will be mostly single track trails where you can't really go above 30kmh, then hill climbs, logs, switchbacks, etc. Writing this I guess calling my program tech/hard enduro would be a better way of describing the intended purpose.

 

[dominik h]

The NP Battery looks like a battery that is made to last for the next years. Good cells, big enough bms and big connectors.
The surron garage battery is missing the information about cells and connectors.

 

[j bjork]

Im not sure I know what kind of tracks are what, the usual practice tracks mostly in the woods.. Sometimes there are races on them too..
Often about 8km long, some only 4km and some up to 12-15km maybe.
Not dirt roads or hiking trails, I haven't ridden enough on either one to say much about consumption there.
But if it is an easy trail where you go relatively slow to avoid running in to people or just exploring I would expect lower consumption, but I cant really say how much.

 

[Balgaroth]

The NP Battery looks like a battery that is made to last for the next years. Good cells, big enough bms and big connectors.
The surron garage battery is missing the information about cells and connectors.

I got in touch with them and they offer custom batteries so once I have a frame and can get dimensions I can work out the size I will need. Meanwhile I need to figure out what controller to use and then battery specs I guess.

Does anyone has some experience with the z6 throttle in the standard QS motor package ?

As for controller, can you achieve 25-30kw with the em200 or nd72680 ? If so which one is best for a novice ?

 

[dominik h]

The ND72680 can do 25kW , but I´m not shure if the QS138-70 V3 can achieve 25kW on 72V.
If you want more, raise the voltage and go for the ND96890 or ND 96850

 

[Balgaroth]

The ND72680 can do 25kW , but I´m not shure if the QS138-70 V3 can achieve 25kW on 72V.
If you want more, raise the voltage and go for the ND96890 or ND 96850

Strange since E&C advertise their qs138 kit as doing 28kw with the EM260. I will have a look at the controllers you suggested. Since I will probably have NP Batteries build a battery I don't have to stick to 72v I guess.

 

[dominik h]

I have done a scooter with the QS138-70H V3 and an ND72450. There the controller is the limiting factor.
Probably the QS138-70H V3 can do way more than 25kW, but I do not know it.
Probably someone else has done a 25kW built with 72V and the QS138-70.
With 96V you can reach higher rpm and higher power levels, and you can reduce gearing if high speed is not nececcary, which gives you more tourque at the wheel.

I had the ND72680 installed in my Hub-Motor scooter. I could raise the current until 350A for acceleration runs , without any problem. Phase current had to be slightly reduced , over 620A I always got overcurrent errors.
The Votol EM260 can do up to 700A peak battery current and for a few seconds up to 450A , that is more than the ND72680 can do.

 

[Balgaroth]

Ok thanks, the minimum to achieve 25kw with the Qs138v3 seem to be EM200 or ND72680 so not a surprise that you reached the limit of the ND72450. It seems that a good option could be the ND96680 which would leave a lot of room to get those 25Kw, or at least achieve them reliably. The goal is to have a bike that is easy to use and maintain as opposed to my 2 stroke that needs some frequent love.

Correct me if I am wrong but going from 72v to 96v would result in more RPM at the cost of some torque down low. Any idea of much torque would you sacrifice by doing so ? I imagine than even a "low" torque electric motor still has more torque than a 125/200cc 2 stroke or 250f right ?

 

[E-HP]

Ok thanks, the minimum to achieve 25kw with the Qs138v3 seem to be EM200 or ND72680 so not a surprise that you reached the limit of the ND72450. It seems that a good option could be the ND96680 which would leave a lot of room to get those 25Kw, or at least achieve them reliably. The goal is to have a bike that is easy to use and maintain as opposed to my 2 stroke that needs some frequent love.

Correct me if I am wrong but going from 72v to 96v would result in more RPM at the cost of some torque down low. Any idea of much torque would you sacrifice by doing so ? I imagine than even a "low" torque electric motor still has more torque than a 125/200cc 2 stroke or 250f right ?

You’ll have a lot more torque going to 96v, all else being equal.

 

[Balgaroth]

You’ll have a lot more torque going to 96v, all else being equal.

I had a little discussion with ChatGPT about it and the torque values at 500rpm are vastly superior to any ICE MX engine. Probably way too much to retain tracktability but it might be nice to hop over logs. I guess you can still limit current at low RPM in the controller to have something actually usable on the dirt ?
I remember riding a friend's Talaria and restarting on a hill was difficult as the thing would spin and doesn't have any clutch to modulate power. Let's hope this won't be a problem.

 

[E-HP]

You can control throttle ramping through controller programming, but practicing throttle control and technique is a must, and takes a while to master. You may want to spring for a Domino.

 

[Balgaroth]

You can control throttle ramping through controller programming, but practicing throttle control and technique is a must, and takes a while to master. You may want to spring for a Domino.

What do you mean by a Domino ? I noticed that you can also use a module that allows you to retain the standard MX cable throttle and connect the cable to it instead of the carburetor. Does that offer better throttle control ?

I tend to have a pretty good throttle control on normal ICE MX or Enduro bikes, especially combined with a clutch. The way the Talaria was hard to control was a surprise. No problem once it was moving or starting on flat ground or with better grip.

 

[E-HP]

Domino and Magura make resistance based throttles, while most typical units are hall sensor based. They have more predictable control over hall based units but are expensive.

 

[dominik h]

I have used both the "cable throttle" and the electronic one. There is no real difference. You can change throttle ramping and tourque at low revs.
I can either make a full power start or walk next to my scooter until it is parked in the garage, depends on how wide I open the throttle.

The more phase current the controller can give, the more tourque you will have from your motor. It is not completly linear, but that is how it works. With more phase amps you get also more heat in the motor, but only when you use it. With to much phase amps for to long time you can burn the winding and melt the phase wires. You can not crank your 3kW rated motor up to 50kw (probably for a second or two it will survive), but no one can tell you an exact limit for your use case.

So if you can afford it go for a controller that can give a lot phase amps for tourque and enough voltage for rpm, if it is too much you always can lower the settings.
If not start with the ND72680 and leave enough space for the next bigger one.
It all depends on how you will use your bike. For trails the 72680 will probably be enough. For tracks you need more power and speed.

There are builds with the QS138 here on ES, but only a few show how they are using there bikes.
Read in their threads and look which controller they have choosen. So you can estimate what will be a good starting point for you.

 

[Balgaroth]

I have used both the "cable throttle" and the electronic one. There is no real difference. You can change throttle ramping and tourque at low revs.
I can either make a full power start or walk next to my scooter until it is parked in the garage, depends on how wide I open the throttle.

The more phase current the controller can give, the more tourque you will have from your motor. It is not completly linear, but that is how it works. With more phase amps you get also more heat in the motor, but only when you use it. With to much phase amps for to long time you can burn the winding and melt the phase wires. You can not crank your 3kW rated motor up to 50kw (probably for a second or two it will survive), but no one can tell you an exact limit for your use case.

So if you can afford it go for a controller that can give a lot phase amps for tourque and enough voltage for rpm, if it is too much you always can lower the settings.
If not start with the ND72680 and leave enough space for the next bigger one.
It all depends on how you will use your bike. For trails the 72680 will probably be enough. For tracks you need more power and speed.

There are builds with the QS138 here on ES, but only a few show how they are using there bikes.
Read in their threads and look which controller they have choosen. So you can estimate what will be a good starting point for you.

Ok cool that's reassuring. Worst case scenario I could go with a Alta/Stark throttle if the hardware doesn't allow me to get the throttle feel I a looking for.

After a bit of reading I think I should go with a 96v system so I will probably go with the ND96680 which should be plenty for the kind of power and use I have in mind, while being more efficient than a 72v system. I guess another factor will be the size of the controller and the room I will have in the frame that I will pick.

Another question I have is about the other components. Do you have to have one of these bulky LCD screens or can you just go with a volt-meter and a key/on-off switch ? Any recommendation on that front ? I don't need to know my speed, I won't have indicators and whatnot so I don't see the benefit of having a fragile and bulky screen in the build.

 

[bananu7]

> Do you have to have one of these bulky LCD screens or can you just go with a volt-meter and a key/on-off switch
FWIW I'm not planning on any screen. You can talk to the controller via CAN or serial and get the data out into whatever form you want, like a microcontroller + LEDs, voltmeter (that can of course be done straight off of a battery), custom screen, or a BT dongle and a phone.

 

[E-HP]

Another question I have is about the other components. Do you have to have one of these bulky LCD screens or can you just go with a volt-meter and a key/on-off switch ? Any recommendation on that front ? I don't need to know my speed, I won't have indicators and whatnot so I don't see the benefit of having a fragile and bulky screen in the build.

If I was limited to one data point it would be voltage. But the minimum for where/how I ride, I’d want motor temp and speed, in that order. I know with my setup what speeds avoid cooking the motor on a long steep ascent. Faster or slower would require stopping to let the motor cool down. Without the speed readout, I’d just rely on the temp sensor to know when to pull over. For just hot rodding around, voltage and temp are sufficient.

 

[Balgaroth]

The bike purpose is going to be mostly enduro, hard enduro and maybe some MX depending on how well it works. So far all the builds I have seen skip the big display and some even skip the volt meter so I guess it is not a problem. I also did more research on wiring all the system and realised that the display has not other functions than showing the information from your controller so not having a display doesn't stop the controller from working.

 

[dominik h]

Yes , the display is only nice to have, you don´t need it to drive.
If you need infromation about voltage, you can either look in the app from the controller or the app from the BMS.
But it is nice to have a small volt meter, where you can look at while you are driving.

cheap voltmeter not the one with the best accuracy, but enough to know what is going on