China E-Bike Sleeper Project

**GT250** · 26-09-23, 05:59 AM

Hi all,
No update. Parts issue.
Might - might, have the rear disc brake and disc mounted before i'm away (Thursday).
Back in middle OCT.

Cheers,
GT250.

**GT250** · 19-10-23, 05:57 AM

Hi everyone,
Hope all is well...

Back from Indonesia and after 2 days back the Battery arrives. Yippee!!

Now that we have a 'proper' 72v power supply (and it fits perfectly into the old battery bay), we started to get things sorted out.

However, I need some help or advice on how to convert 72v to 48v and the, not so cheapest, but "is there another way" sort of thing...?

But back to the China Bike:
Once the batt was hooked up (going to convert the XT60 connections to XT90's), we spun it up and the speedo (Hand digital thumb control), went to 130kph!
Took it out on the cul-de-sac and got it to 55kph (Phone GPS 55kph and speedo 58kph), before the road ran out - and it was still pulling...
Only have the front brake, so mucho hand use and feet sliding along at the end of the road

Going to weld/fix bracket a 180mm rear disc (change from the 140mm supplied one), and a hydraulic caliper. Caliper will be cable, but the hydro part is on the caliper itself.

It looks like I have to retain the digital speedo - mainly for the MODE 1-2-3 options. Had ideas to somehow integrate the MODE function into the original 'mode' 'switch on the bars, btu it's not looking that way so far. Which is a shame as it would have been perfect as in keeping the China bike original.

48v Lights, horn, indicators etc and most importantly the front brake lever to cut the power supply off the motor, is looking as though we certainly have to have a 48v power supply that will feed into some of the original cabling.

I thought about the 7805 12v to 5V, and wondered if there was a similar 72v-48v option. I don't need more than 2A really. I've seen 72v-12v step down bucky things and 12v to 48v step up's and thought about getting those two and do it that way. 72v to 12 - 12v to 48v.
I've seen 10A 72v-48v converters, but I don't think I need 10A and the cost was over $200!

Was hoping to find a suitable 'cheaper' and quicker (not ordering from Ali-Express - snail postage!), more locally.

Managed to change the 3000w motor tire and put the original 400w motor tire on - so now the wheels look completely the same.

Anyway, the 'workshop' last night

My P/S mockup changed from 72v to 48v as to find all the original loom to test the lights etc at 48v.
All good fun

**lsemmens** · 19-10-23, 02:42 PM

When you've finished this, what are you hoping to do, I, somehow, think that the "authorities" may take a dim view of the top speed of this thing, or are you going to hide a switch on it that means it is street legal.

**hoe** · 19-10-23, 02:55 PM

Originally Posted by lsemmens

When you've finished this, what are you hoping to do, I, somehow, think that the "authorities" may take a dim view of the top speed of this thing, or are you going to hide a switch on it that means it is street legal.

never going to be street legal in australia, unless they change the rules.........

no pedals, so its an electric motorcycle, not en ebike. so it needs a vin and adr approval and registration....

**lsemmens** · 20-10-23, 07:38 PM

So, when you finish this, what are you gonna do with it? Seems like a pointless exercise if you can't enjoy the benefits.

**GT250** · 21-10-23, 06:32 AM

Hi all,
I have visions of using it for the occasional run to work (7 kms). Or the occasional run to the shops for those items you don't have in the larder you need for tea

I could put the PAS back on I guess, at least some pedals (as the shaft is still there), to keep a keen eyed officer at calm...

Is just a fun project for a little China Bike. Such a cute little thing. All things becoming electric and a way to learn about Wheel motors/hubs, AMPS, voltages and the wiring options that come with Controllers.
It was either spend 4x12v 7ah batts and a charger for say $350+ or spend $1200. or throw it away. In my fuddled mind I have spent '$800' to have a brand new zippy little e-bike.

I've ordered a 72v to 48v converter. $50 delivery in mid NOV

Have a problem with the controller I think. On another run I took it out on, I went up an 'ok' hill (200mtrs), and back down etc, doing about 2kms and it started to cut out. Huh oh, I thought to myself!
After a few seconds with throttle off, it would go again for about 10mtrs then cut out, then back again. The longer the throttle was closed, the longer the distance again...
It appears the controller has a thermal cut out. It was fairly warm, getting too 'hot'. Hard to describe.
I had it placed in the open battery tray wrapped in bubble wrap (as the battery), so no direct air flow.
And of course, I've had it WOT all the time

It will sit in the area behind the seat in the same area as the original old 48v one - with air flow from the underneath of the rear wheel above the rear wheel guard.
So hopefully this 'cutting out' won't be an issue!
If it does (and I assume the controller supplied in the kit, is as cheap as it is), keep doing this, I might look at getting a better 72v controller..

Anyway, all good fun

Cheers,
GT250.

**loopyloo** · 21-10-23, 05:43 PM

Sounds like a good spot for the controller. You could eat some beans before your ride to supply more air flow for the controller. That may even provide some direct thrust.

**GT250** · 05-11-23, 04:18 PM

Hi all,
Yeah, been a while...

The 72v to 48v controller has arrived. Heavy little thing!

Input is (as the sticker says), 58v to 85v.
Output 48v.

So hopefully I can get things moving on

Still waiting on confirmation for the upgraded rear brake 'piston' caliper to arrive as well.

Not much of an update, but I'll keep those beans in mind Loopy

Cheers,
GT250.

**GT250** · 12-11-23, 07:46 PM

Hi guys.
Bit of an update - the end might be in sight!

OK. Rear brake is on. A big mechanical step!
Friend came over today and brought his mini TIG with him.

Made a bracket out of 4mm steel and with a bit of tacking, got the bracket in the right place.

The original kit came with a 140mm disc and now a 180mm disc is on.

The caliper $50 - long time to come in - is a side by side caliper, not the push on one side cheapo ones. Apparently, it's hydraulic internally, yet still has the cable from the bars.

Took it out for a test drive to see if this super-duper 180mm disc will work...

And boy does it brake!

Wil lock the wheel up - blue puff of smoke - at 60kph...!
So I think that the stopping power of 3000W@72V on a 20kg (batts and Scooter), weight bike, is going to be ok..

Also changed the original scooters 48v 350W-400W motor XT60's and the 72V Batts original XT60 connections to XT90's.
So now all Power and Motor connectors are XT90's, with upgraded cable.

Next stage is to get the electrical work polished off.
Get the 72v to 48v convertor to control the original 48v lights, horn, indicators, rear brake light etc.

Also a bit of fiddling to get the hall effect wires out of the colour display thumb control thing - to work with the original twist throttle grip.

It's looking like that I will have to retain the LCD controller to Power on (whilst retaining the original key ignition switch) - so without the key one can't 'steal' the China Bike as it won't power up - Hopefully!

Have to make compromises with what I can do. I wasn't interested in any speed indication. But there are 'MODE' options (1 Low/2 Med/3 High), built in as well.

I can't work out in my fuddled mind how to make it power on in Mode 3 - from pressing the Power button (after key ignition), and twisting the throttle., and away...

Anyway,
All good fun.

Cheers,
GT250.

**wotnot** · 12-11-23, 10:10 PM

Get the 72v to 48v convertor to control the original 48v lights, horn, indicators, rear brake light etc.

48v lights? Seriously?....I would've thought the original controller would've had a 12volt BEC (battery elimination circuit)?

**GT250** · 13-11-23, 05:03 PM

Yeah, Wotnot,
I thought so at least, but no. Would have been a lot easier and more choice and cheaper to have had the option to put 12v lights etc on it.
I'm pretty sure that when I measured the V off the orij controller, they were all 48v and 5v's, no 12v.

The lights/bulbs (Well, Indicators), on board are stamped 55v...

To save me the hassle of converting these in case of needing replacements - I found out that you can buy them...!

My main problem (and trying to keep the China Bika as original as possible), was the front headlight. Be a nightmare to change it for round, square etc and fill in the gaps etc...
It's a matrix of many LED's (not sure if there's a photo of the front), I think I had a look to see if there was any voltage info but could not find any. So to keep the existing wiring and the original lights etc, I just decided to cough up the $ to get 72-48 convertor. I am 'Assuming' that the front light is 48v (55v)...!

I've ordered (for contingencies), a 48v to 12v 2A convertor. The 72v-48v convertor can handle 10A - way more than I need, so can happily supply the 48v to 12v invertor/convertor...

So next step is the wiring. Have to take apart the Hall effect (5v I think), wire out of the LCD digital thumb and connect it to the orig twist throttle.

Actually, Wotnot, I'll have to check the V's on the horn.. - which might v independent low v's low beep etc....

Anyway, all good fun.
Cheers,
GT250.

**GT250** · 16-11-23, 06:01 AM

Hi Guys,

Need some help..

All the lights are working (headlight was definitely 48v-55v), horn, indicators (with Beep, Beep, Beep).
72v to 48v convertor fitted fine (as per orig lights etc working) - The Dash lights up fine and mirror the indicators etc.

Problem is; after removing the Hall from the LCD display unit to have the Orig handlebar twist grip (which is working fine), the Scooter will not Power up - WITHOUT - shorting two connections on the LCD Display unit - where the Hall IC came from...!

Start up procedure 'should be' is:

1) Turn Ignition key on. Everything lights up fine.
2) Press LCD Power ON - LCD Display Powers up.
3) Press Mode (defaults to 1), goto 3 (fastest Speed).
4) Twist throttle and go.

Problem is with 2

The LCD Display panel has a tiny red light - NOW APPEARED - just above the mode digit.
With this Red light on the twist grip (hall), doesn't work.
Red light off - twist grip works fine and away the scooter goes!

The only way, and - AFTER an HOUR - of scratching heads, we found the only way to get rid of the Red light was to SHORT two pins from the LCD display Hall IC (now removed).

So now to have to scooter work (like the last 1% of the job!), is to have;

1) Turn Ignition key on. Everything lights up fine.
2) Press LCD Power ON - LCD Display Powers up - With Red Light Dot.
2.5) Short the two pins (red light dot goes away).
3) Press Mode (defaults to 1), goto 3 (fastest Speed).
4) Twist throttle and go.

Does anyone know of a solenoid/momentary - pulls down on power and then releases, sort of switch we can put in line to create this SHORT when Power is sent to the LCD Display...?

Only 'unusual' thing that - didn't seem - to be an issue, is that the Hall on the twist grip, starts at 5.0v and decreases to 1.0v - like Reverse/Negative...!

So close, yet so far. My minds all over the place at something, that should be so simple

Anyway,
All good fun. Nearly there...

Cheers,
GT250.

**wotnot** · 16-11-23, 02:58 PM

Sounds like a safety device, like 'must be seated before starter works' on a rideon mower...how was it used originally?...ie; twist grip position? Front brake on?...probably the former ...ie; twist grip must be in off position (close hall effect switch) before controller gets armed... r/c gear is like this. A lot depends on what the controller wants...ie; if those contacts just need to be closed for initialization I'd think about fitting a switch to brake ---- if those contacts need to be continuously closed, it's a bit more fickle, as this'll be a safety feature to disarm the controller should you have an endo, but if you aside that you could fit a secret anti-theft switch somewhere which must be on for the thing to work.

**GT250** · 16-11-23, 07:10 PM

Hi Wotnot,
I think you might be on the right lines...

As for asking "How was it used originally', it's hard to say as that the China Bike was ever first started when I did my Battery P/S (PHD in Electrical Science), in joining 4x12v P/S's up and it spun the rear wheel without (from memory), pressing any brake/safety switch. I guess I Was just standing by the side and - it all worked, at the time!

The only physical ride was when I got hold of a 48v lith batt and - again - I can't remember if I had any brake on, it just went...

On another day, I took it out with the LCD Display Thumb and the 72v 20ah, and I'm pretty sure that I didn't need any brakes as (at that time), there was no rear brake (disc) set up then. Only the front tiny drum brake, LOL!

Now, after a bit more work this afternoon, I found this out about the RED LIGHT - after I decided to put my glasses on and with the right lighting and camera no glare angle!

It's a Twist grip! OMG! So at least the LCD display is telling me something...!

Another - link to the issue - is that:

When the Ignition is turned on (Orig Dash lights up ok).
And then pressing down on the LCD Power button - I get the 'Red Light'
I short the Blue and Black leads (have ran Red and Black and Blue lead wires from those original Hall pads). And the Red Light goes away - and the twist grip works fine.

BUT - BUT - If I power down the LCD Display (with the Ignition/Dash lights still on), and then Power back up - the 'Red light' is not there, and the twist grip works fine!!

It's only when the Ignition key is turned off, then it all resets. A funny thing is that when the Ignition Key is turned off some lights on the dash stay on for a bit and the horn goes "bup" as the bikes last dying breath of power dissipates...

I must admit though - not sure if it linked (but who knows LOL!), haven't worked out the (any), brake lever action to cut the power to the motor. Tested it a few times, but no good. The 72v controller does (of course), support it, but I am using the orig brake levers and cables etc - But I can't see any reason why that would make a difference!

Then that's me

As for your good recommendation of a 'secret switch', I didn't want a big sequence in starting it up. The original was 'Turn Ignition Key' and go!
I opted for the now - Turn Ignition Key on (As security, because you can't Power up, without having a key), power up, Mode 1 default and go - besides the current 'red light' issue.

There were talks about how to just turn on the Ignition Key and it would power up and be in Mode 3 automatically...
After some readings I did, it got very involved in hexdec programming the IC and so on... It can be done. But, and not necessarily beyond my skills (would have 'freshen up' a bit LOL!), but really at this time and frankly now, it's not worth going down that path.

Anyway, time to think. Getting close now.
All good fun.

Cheers,
GT250.

**GT250** · 23-11-23, 05:42 AM

Update:
IT IS DONE!!! - FINITO!!!
Yep, done!

Put the plastics back on last night.

Managed to solve the 'Red Light' problem - Did have a push button switch - ready to go (As Wotnot suggested as a 'Secret Switch' - Which would have worked great as in testing it was good in way to see the scooter fired up (Origdash on-Lights on-LCD Powered up-Mode 1 there - yet, Nothing!! But just a 10th sec push on the black button and away it would go - Nice anti theft thing...), just in case as a final last resort.
Put back the Hall IC on the other side of the controller. Sounds simple now but there ya go...!

Managed to get the Front and Rear brake levers when operated to cut the power to the motor.

China Bike starts in Mode 1, which max's out at 25kph - but boy does it get there fast LOL!
I think it maxed out at 40kph in Mode 2 - but too many beers too remember.

Will do a few photo's and I might do a small video of it running (I think One Drive links work on this site?).

Can now see 'another' red light bottom left of the display - with what looks like to be a Powercord Plug!
Have a feeling it's for Re-Gen...?
Can't find any documentation for the "Red Lights' anywhere. I wonder how many 'Red Lights' are built in..?
But I'm not going to worry too much about re-gen - or should I ..? NOOOOOOO!!!! LOL!

Might not even be possible (Humm, would be in the wiring on the controller, would it?). NOOOO,,,!!

Got the 48v to 12v convertor (only 2A mind you), so I can play around with common 12v bit's and bobs.

Over the weekend I'll get some Show and Tell stuff done.

All good fun!
Cheers,
GT250.

**GT250** · 27-11-23, 05:46 AM

Hi all,
Well, took her out for a maiden run - and had a bit of a sphincter moment

Zooming down the road at about 65pkh (in the bicycle inside area (car 70kph speed limit)), I had a *lady* driver in a silver car in front/side of me and a Hilux ahead of that. As a bus starts to indicates out, the Hilux moves out to bypass the bus - and I - thinking the lady is going to follow the Hilux - pull out behind her and I WOT...

She starts to go with the Hilux, the bus edges out a tad more, she goes with the Hilux, and then - decides not to!! I'm full WOT and she starts to brake, hard! ... I go Gulp!

Yanking on the brakes, I'm slowing down quick. But not quick enough! I pull harder on the front! Now it's for real!! The rear brake is on, no good. I pull harder - and - lock up! SQUEALLLLLL.... Rear snaking away...!!! I come within 50cm of her car...!

After checking my pulse, I continued and did about 5kms. There was a slight hill of about 200mtrs and I tucked down reaching a good speed

The wind resistance is massive! As it's so small in height, I'm sat there full flat chested. Even a slight forwards angle, the scooter increases in speed (little torque I think?).

Taking off is slower than I thought. There's no whoomph at first twist. Just a gradual takeoff. But then after about 5kph, it starts to pull and easily matches traffic up to about 50kph, then it's gradual after that.

I'm guessing with the locking up on the rear wheel; it's too light, and too little rubber for the weight (moving mass of me, 94kgs).

So, there we are

I - *might* have a crazy 'out of the park plan' - that a member did mention! But I have to wait a few weeks to even dare look at it more closely. SHE WILL NOT BE HAPPY!!!

So at this stage, I'd like to thank everyone who had an insight/view and comment of who has watched this saga. I have learned a lot about the E-bike/scooter motor/battery/controller world, and I hope that some of my post has been a good read.

A few photo's.

All good fun!
Cheers,
GT250.

**lsemmens** · 27-11-23, 10:55 AM

What did the missus have to say about the skidmarks inside your jocks? As a teen, I managed to hit 80kph on a deadly treadly once coming down a hill in the Adelaide Hills, Can't remember where I was now, but the T junction at the bottom had me concerned. I managed to get around the corner somehow scaring the cr*p out of a car that I would have cleaned up had he been a little faster, I remember hitting the gutter side on and staying upright as he passed me on MY left. Skid marks time there, too!