Converting bike with mid drive motor

[SandraL]

We have now coverted 2 bikes.
First was with a Bafang motor. Hardest part of conversion was removing existing pedals,arms and bottom bracket.
Some heat, extractor, hammer and wedge were involved here!
Assembly of motor into bottom bracket was straight forward. As this motor was fitted to a recumbent trike we had to stop motor rotating under heavy load, added wedge of wood to stop this . Fitted battery to existing rear rack.
Had to change brake levers with those in kit that have cutout switches for the motor when braking.

Second was a Tongsheng kit. Fitting was similar but as it senses pedal pressure the brake cutouts are not required, but were supplied in the kit.

The Bafang will add motor power as long as the pedals are moving. It powers to a set speed no matter how slow you pedal. These speeds increase as you increase the power setting on the screen. You can add a gear change button to cut power as you change gear which is kinder to the gear mechanism. Operating the brake gently would have the same effect.

The Tongsheng motor works when it senses effort on the pedals. The more effort the more help you get.
This means you can ride at any speed, useful to match others riding as a group rather than power on, off etc with the Bafang.
Only fitted this one today so not yet been anywhere on it. In the screen menu you can alter the pedal effort needed before assistance is given.
We have both got the same 48v 12.5ah battery. Idea being we can swap should one ( hers) run low.
Also intend to get dc dc buck converter with output set to around 12.5v. Idea being to use bike battery to assist the van leisure batteries should we run low, ie to take the load rather than charge the leisure battery.

Cost. Battery £190 each, motors £300 ish, Tongsheng tsdz2 slightly less Bafang bbs02 soughtly more.

Only other expense a set of wheels and tubes and a chain for my bike, couldnt get the freewheel off and wanted new cassette as teeth were knackered.

If you are reasonably handy then perfectly doable. Worst bit is extracting existing cranks and bottom bracket. Wiring is plug and play except possibly battery wiring depending on its location.

 

[Itsmcb]

Mine with a bafang motor, over 600 miles since March, including lots of off road, and rain, with no problems.

 

[Itsmcb]

I like the idea of using the battery as a back up for the leisure battery. Mines a 48v 17ah. Any links to the equipment needed?

 

[BuilderBob]

Like this idea. Can you change gear as normal with the device attached?

Which of the two would you recommend?

 

[SandraL]

Pardon our interruption...

I was thinking of something like this. Need to make sure that it is rated at least 60v input. A fully charged 48v bike battery could be 55v if just off charger.
Once again I intended to set voltage at say 12.5v, so as leisure battery came down to 12.5 the bike battery would take on the load but not charge the leisure battery. No plugging inverter in or any heavy loads!

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[LesW]

Do you need EHU/240v to charge the batteries?

 

[pappajohn]

Do you need EHU/240v to charge the batteries?

Yes..... Or a suitably rated inverter.

 

[SandraL]

Like this idea. Can you change gear as normal with the device attached?

Which of the two would you recommend?

We have derailleur gears on rear wheel.
Usually I would ease up on the pedals as I change gear but this does not work with the Bafang, unless you use the gear shift button or brakes to cut power briefly.
Having said that my wife has no trouble changing gear on her Bafang recumbent bike without these.

The Tongsheng s bright and shiny, not ridden out of our road yet. It seems better for "real" cyclists as more effort is more motor power.
But if like my wife you want assistance without effort the Bafang is better, ie as long as pedals are moving you get assistance.

Either motor can be fitted with a throttle, are both available in various motor sizes.
The Bafang recumbent has a throttle, useful on hill starts as you get power before the pedals move. ie normally half a rotation of crank before motor cuts in.

 

[SandraL]

Do you need EHU/240v to charge the batteries?

We have a dc dc boost unit. So takes in 12v and puts out the charging voltage. Last used when we had a 36v battery. We set the voltage to 41v and the current to a max 1.5amps. This worked ok with the solar panels covering it ok.

It was simlar to this

<Broken link removed>

 

[LesW]

We have a dc dc boost unit. So takes in 12v and puts out the charging voltage. Last used when we had a 36v battery. We set the voltage to 41v and the current to a max 1.5amps. This worked ok with the solar panels covering it ok.

It was simlar to this

<Broken link removed>

This looks better than fitting an inverter.

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[Itsmcb]

Like this idea. Can you change gear as normal with the device attached

Yep. I have a 9spd cassette on mine and a little gear change sensor which automatically cuts the power to the motor momentarily when changing gear. All works perfectly. I sometimes go on social rides then I just leave the battery home and use it as a normal 9 speed bike.

 

[DumfriesDik]

A bit late to this party. I have done a Bafang conversion on my Varna II handcycle. The motor is up quite high and wants to rotate back towards you. I needed to do a small conversion to the battery rack and extend the power lead. All in all I am very happy with it and can pootle along at 10mph quite easily or 30mph if I have my brown corduroy trousers on.

 

[Clipgate]

Has anyone fitted a centre motor kit to a five speed Sturmy Archer type gear change combination. If so what results please

 

[Metamorfosis]

Good resource for anyone considering a tsdz2 conversion

Tongsheng TSDZ2 review and build tips.

I have done this as a resource for novices like I am/ was who are attempting their first kit. Someone like me with no relevant tools, who has never even tightened brakes before. You can glean much of the following information on this forum but I wanted to bring it under one thread which would...

www.pedelecs.co.uk

 

[Itsmcb]

Has anyone fitted a centre motor kit to a five speed Sturmy Archer type gear change combination. If so what results please

I vaguely remember you need to pedal backwards to change gear, is that correct?

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[Clipgate]

No it changes conventionally, although a slight release of effort is required

 

[Itsmcb]

No it changes conventionally, although a slight release of effort is required

In that case a mid motor conversion should work ok. The motor just aids or replaces the effort required to push the pedals turning the crank, the chain drives the rear gears in the normal way. I have a small sensor that registers the gear cable movment then cuts the power to the motor momentarily when changing gear.

 

[SandraL]

Has anyone fitted a centre motor kit to a five speed Sturmy Archer type gear change combination. If so what results please

I guess you need to take power off as you change gear.

With the tsdz2 the torque sensor will react to less pressure on the pedals and cut power.

The bafang will need the gear sensor as in post 11

This link shows someone has done it with tsdz2

 

[Monty don]

anyone interested in doing a conversion on a commercial basis. IE a nice drink for doing it
I have a Scott mountain bike that would be a good conversion

 

[Itsmcb]

anyone interested in doing a conversion on a commercial basis. IE a nice drink for doing it
I have a Scott mountain bike that would be a good conversion

Be brave, it's quite straightforward.

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[Ditcha]

I converted our two Dutch bikes with the tsdz2 motors 3 years now only had to change one nylon gear for the metal version apart from that no other problems I also updated the software to the open source software which is much better although you have to change the display.

The motor on my bike is a little more noisy than my wife's and this is the one which had the gear change but my bike does have a coaster brake so not sure if this has any bearing it.

 

[Monty don]

Any links to the sites best to buy the kit
Ideally one stop buy the lot

 

[Itsmcb]

Any links to the sites best to buy the kit
Ideally one stop buy the lot

Besbike.co.uk
Eclipsebikes.com
Both UK based and excellent

 

[LesW]

Any links to the sites best to buy the kit
Ideally one stop buy the lot

I have no experience with this company, but have been looking at their website https://eclipsebikes.com/bafang-motor-kits-c-17_65/

 

[Ditcha]

I used these http://www.pswpower.com

Loads of info here

Endless Sphere - Index page

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[Itsmcb]

I have no experience with this company, but have been looking at their website https://eclipsebikes.com/bafang-motor-kits-c-17_65/

I bought my shark battery off eclipse. UK based, next day delivery. Excellent service.

 

[Vipar]

I take it the higher the wattage the more mileage you get.?
This is my Bronx Monsoon bike what would you recommend ( no onus on you ) for an 79 year old who just wants to go to the shops and a bit of fresh air?

 

[Neil Bedwin]

I take it the higher the wattage the more mileage you get.?

Your motor can only be a max of 250watts to be legal in the UK and Europe. If your battery has more watt/hours then you will get more mileage.

Watts/Volts=Amps so 250w/36v=nearenough 7amps. So a 15ah battery should last 2 hours. If for your 250watts you are doing the max allowed 15mph you will go 30 miles with very little peddling.

So turn down the power and pedal a bit more and you can easily increase the distance to 60 miles or more.......

 

[Vipar]

Need to find someone local to fit it for me.
Anyone near Bexley bored ?

 

[RustyRuss]

Ditcha tell us more about this open source software please. I’ve bought 2 tsdz2’s, one for the boss’s bike and one for mine. Due to arrive end of Feb, so looking forward to fitting them and getting out and about!

Cheers!

Russ

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