Duotts C29 48V 15Ah cheap bike

[Peter.Bridge]

So I thought I would try out one of these cheapo Chinese 250W 48V bikes as a bike that I could leave at my sisters and use when I go to visit. It would only be a daytime fair weather bike that I would use on rides with my sister and nieces for rides on generally empty roads and light trails in the North Yorkshire Moors and store in my sisters garage.

I initially was looking at the Varun M27.1 which has a 48V 13Ah battery. I checked out Amazon, Ebay , AliExpress, Varun itself and then the Varun store on Alibaba

VARUN M27-1

VARUN Ebike for Adults - 250W Motor & 48V 13Ah Battery. Up to 100km Range at 25km/h. Smart Version Equipped with APP. Suitable for Riders 160-195cm Tall.

www.varunebike.com

That was £550 on Amazon, and the cheapest I could find it was on Alibaba for £432 delivered. I looked around at any alternatives and ended up buying this Duotts C29 with 48V 15Ah battery

https://www.amazon.co.uk/Electric-Mountain-Removable-Powerful-Professional/dp/B0FMFDXMY6?

That was $675 from Duotts store on Alibaba, so, ended up costing £497 including delivery. I ordered it on Friday and it turned up at my sisters today
So, will be at my sisters on Thursday evening - will try and assemble it then.

After I bought it , I did a bit of reading up on it (I know!)

• Latest model limited to 25 km/h, I saw some people had tried to change the top speed in the settings, but it had no effect.
• Has 250 stamped on the hub motor (earlier versions had 750 stamped on the motor)
• 3*7 speed freewheel, Shimano Tourney derailleur with 14t smallest gear - may change this for a 11t DNP freewheel. I know its very low end but I've used the Tourney gears on lots of e-bikes and its been fine for me, given that there's a lot less changing gear and it doesn't have to be as slick as a normal pedal bike - the hub motor is powering the bike during the gear change.
• Cable disc brakes (with brake cut outs) - need to do something with these !
• Controller sounds very crude - sounds like significant delay for the pedal assist to kick in and significant motor overrun after stop pedalling. Speed based assist levels (so full power until your reach the speed for that level.)
• Power supplied is 48V 20 Amps - sounds a bit OTT ! On earlier versions you could de-tune it in the parameters and set the maximum between 10 and 20 amps but I think that setting is locked in the latest version (I would have set it to 15 amps)
• With that motor overrun I think I either need to just change the calipers or have fully hydraulic brakes with cut outs
• Not sure I can live with that controller - I do have a 9 mosfet KT controller with display that I could use, maybe I'll see how bad it is.

 

[saneagle]

I think you're going to hate the controller, especially with 48v and 20A. Speed control is tolerable with low power, but you can't control you're pedalling with 1000w from the battery that you can't turn down. That brings me to the second point. You might as well order the DNP freewheel today because I can absolutely guarantee that you won't want to keep that 14T one. You'll just be air-pedalling all the time, except on level 1.

It's a shame that the controller is in the battery base because that makes it a bit more complicated to change, but if you looked at that bike as a sort of project, you got a nice motor and battery plus most of a bike for £500. £100 for a KT controller, freewheel and a bag to put the controller in gives you a really nice powerful and legal bike for around £600.

I look forward to the next episode to see if I'm right and what you're going to do with it. I love projects like this.

 

[Peter.Bridge]

I think you're going to hate the controller, especially with 48v and 20A. Speed control is tolerable with low power, but you can't control you're pedalling with 1000w from the battery that you can't turn down. That brings me to the second point. You might as well order the DNP freewheel today because I can absolutely guarantee that you won't want to keep that 14T one. You'll just be air-pedalling all the time, except on level 1.

It's a shame that the controller is in the battery base because that makes it a bit more complicated to change, but if you looked at that bike as a sort of project, you got a nice motor and battery plus most of a bike for £500. £100 for a KT controller, freewheel and a bag to put the controller in gives you a really nice powerful and legal bike for around £600.

I look forward to the next episode to see if I'm right and what you're going to do with it. I love projects like this.

Yes, absolutely happy to look at this as a project. As I said in my bag of bike bits I have a KT controller and display. I will undo the battery compartment that holds the controller, see how difficult it would be to swap over and put the kt controller in a bag

Will order the DNP freewheel and a couple of tyres (the standard ones look awful)

(Didn't have a DNP tool, I know I'll only need it when I take off a DNP freewheel, but add to my collection)

 

[saneagle]

I will undo the battery compartment that holds the controller, see how difficult it would be to swap over and put the kt controller in a bag

It might be an idea to order a complete new battery base if you can get the right one with the right connector. The battery wires are very short and go straight to the controller, which will probably be potted, so you can't easily remove it and it doesn't normally leave enough room to join new wires and run them through leaving the controller in place. Also, you'd have all the wires hanging out the back of the battery attached to the old controller. With a new base, you can either keep the old stuff for emergency use or testing, or you could sell it on Ebay and get some of your money back. With the LCD, it's got to be worth £30 to £50 to someone.

 

[Peter.Bridge]

I think you're going to hate the controller, especially with 48v and 20A. Speed control is tolerable with low power, but you can't control you're pedalling with 1000w from the battery that you can't turn down.

Yes - if I was recommending a cheap 48V bike on here to someone that didn't want to build their own, I think I would suggest the Varun. It has a slightly smaller battery (48V 13Ah) but plenty big enough. The controller is, I think 48V 15A, which is enough for any hills but would be slightly better with speed control, and I think the new batch of UK compliant bikes have 48V / 201rpm motors (people complaining when they unlock them they only does 17 mph ! - but this would help up very steep hills !) Would probably still have to do something with the brakes (change to cable actuated hydraulic ?) and the freewheel for relaxed pedalling. And only £432 delivered if you order direct from the Varun store on Alibaba (Shenzhen Haibaike Technology Co, Ltd.)

The other thing I was thinking was using a KT controller on the Duotts bike is likely to increase the range, rather than it accelerating to its speed levels under full power all the time. (I know when it gets to the set speed level it only uses enough power to keep it at that speed.) And less strain on the battery and motor too.

I notice somebody on the Duotts C29 facebook group claims to have ridden 10,000 km , so maybe it is better than I am expecting !

Anyway off to my sisters tonight - I can take a look at the bike !

 

[saneagle]

Yes - if I was recommending a cheap 48V bike on here to someone that didn't want to build their own, I think I would suggest the Varun. It has a slightly smaller battery (48V 13Ah) but plenty big enough. The controller is, I think 48V 15A, which is enough for any hills but would be slightly better with speed control, and I think the new batch of UK compliant bikes have 48V / 201rpm motors (people complaining when they unlock them they only does 17 mph ! - but this would help up very steep hills !) Would probably still have to do something with the brakes (change to cable actuated hydraulic ?) and the freewheel for relaxed pedalling. And only £432 delivered if you order direct from the Varun store on Alibaba (Shenzhen Haibaike Technology Co, Ltd.)

The other thing I was thinking was using a KT controller on the Duotts bike is likely to increase the range, rather than it accelerating to its speed levels under full power all the time. (I know when it gets to the set speed level it only uses enough power to keep it at that speed.) And less strain on the battery and motor too.

I notice somebody on the Duotts C29 facebook group claims to have ridden 10,000 km , so maybe it is better than I am expecting !

Anyway off to my sisters tonight - I can take a look at the bike !

Let us know how you get on. You might like it. I reckon these bikes are very good for delivery riders. You just turn the pedals and off they go.

 

[Peter.Bridge]

OK - unwrapped it all (but not assembled) - Looks good, came with mudguards, rear rack, front and rear lights, solid looking kick stand, horn, pump , waterproof phone holder. Not sure whether to assemble it as is or change the controller / display before hand. The display has some parameters locked (e.g. controller current = 20A * 48V), which is a pity, because I would like to have experimented say with !5A, to see how that altered the behaviour. Wonder if I could get an unlocked display !

Here are photos of the battery / battery cradle / controller. Are these a standard Hailong size ? Are they torx heads on the controller cover ? (didn't have my socket set with torx heads with me) - I'd be interested to see what is beneath the cover. Anyway, they are on holiday for a week, so plenty of time for me decide on my next steps.

 

[saneagle]

There are 4 different bases that have 3 or 4 different batteries that connect to them, and there are three different connectors, which makes a lot of possible different combinations; however, one of the bases doesn't have a controller, so can be eliminated. There are definitely two different controller compartments. I'm not to sure whether the base without the aluminium rail has a different controller compartment. Out of the two with aluminium rails, yours is the least common.

Basically, if you want a base that fits your battery, you need to get the same type with the same connector, then see if you can find a controller to fit. Hailong battery controllers are normally more expensive than the aluminium box type, so probably better to use an external one.

This looks like your one:

Ebike Battery 4 Pin Mounting Plate Bracket Rail for Amyet EB26 Ridstar Q20 OUXI V8 H9 RCB RK29M Mukkpet GL Electric Bike - AliExpress 18

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com