Complete bike or conversion?

[Cugel]

For what its worth I've had a Nano kit on my mk 3 Brompton for a number of years. Its powered by two Bosch 36v strimmer / lawn mower batteries.

The bike rides very well unpowered which means you can save the power for head winds and hills. Fitting was simple.

Three down sides are 1) the added weight, 2) don't let the batteries fully discharge by leaving the system switched on over night and 3) the controller which is mounted on the forward end of the frame would often slip and foul the fold adding another step in the folding process.

The kit use to come with three options of power control : twist grip throttle, thumb throttle and fixed assist with off/low/med/high . I found both the twist grip and thumb throttle hard to use because the springs were to strong. In the end I bodged the thumb throttle so that I could set it to a fixed setting.

A word about kits and batteries : both the quality of the cells and the construction of the battery should be your top priority when buying any kit or e-bike as you don't want to burn your garage or house down or kill you in a lift or other enclosed space . AVOID CHEAP BATTERIES!

S

Your post is a good match to the OP's requirement but it also illuminated what put me off the add-on kit approach: not easy to fit well and keep that way; worries about not just poor batteries but a poor match between the battery and the battery management gubbins (if any).

The battery fires, for example, are a danger but its not just cheap cells or poor construction that cause them but a poor or non-existent battery management process during charging.

I'm sure there are very good add-on solutions but it seems to require a very wide and up-to-date grasp of a lot of things, including the dangerous aspect of batteries and their management. Self-fitting will save money but having an expert do it is going to add a significant cost perhaps?

[stodd]

The battery fires, for example, are a danger but its not just cheap cells or poor construction that cause them but a poor or non-existent battery management process during charging.

I agree, but any half-decent e-bike battery will have an appropriate battery management system, as will respectable Lithium Ion powered batteries for lawn mowers etc.

[djnotts]

^Thanks @Skids and @Cugel.
The difficulty and risks of charging are probably the biggest obstacles to my making the leap. And yes especially so for add-ons. Pity Brompton's own electric seemingly pretty poor not to mention out of my price range.
Increasingly coming closer to just hanging up my wheels .......

[Vantage]

Not sure whether this would work from some quick googling I've done...but...would a Tongshen 250w kit work for the op? I've read that the additional securing bolt might interfere with the Bromptons prop stand and some sort sort of bracket on the bike but some say this can be overcome.
I switched to Tongshen about 3 months ago after using a Bafang motor and it's been an eye opener. It's a smaller, lighter motor than the Bafang and the resistance from the motor whilst pedalling unassisted is almost nothing...again compared to the Bafang.
My own 200wh battery can provide me with roughly 60 odd miles of reasonably hilly range. A similar power rack battery could be found with some googling.
It's been a life changer as I too was on the verge of hanging up my wheels prior to getting it.
Doesn't need apps etc. Wiring is easy peasy.

[Carlton green]

Not sure whether this would work from some quick googling I've done...but...would a Tongshen 250w kit work for the op? I've read that the additional securing bolt might interfere with the Bromptons prop stand and some sort sort of bracket on the bike but some say this can be overcome.
I switched to Tongshen about 3 months ago after using a Bafang motor and it's been an eye opener. It's a smaller, lighter motor than the Bafang and the resistance from the motor whilst pedalling unassisted is almost nothing...again compared to the Bafang.
My own 200wh battery can provide me with roughly 60 odd miles of reasonably hilly range. A similar power rack battery could be found with some googling.
It's been a life changer as I too was on the verge of hanging up my wheels prior to getting it.
Doesn't need apps etc. Wiring is easy peasy.

I was surprised to read that you were on the point of giving up and suspect that many others have similarly struggled with only some overcoming difficulties. Making the right choices is complex and doubtless there are a lot of broken dreams out there, it’s a ‘minefield’. You’re an experienced user and installer, how did you fall foul of an imperfect (for you) choice and educate yourself to be able to make better choices?

[Vantage]

If you've ever toured you may very well know that depressing feeling that follows when it's over. That feeling lasted forever with me. Returning to the same boring ridden a million times before roads just didn't cut it for me anymore. Lost a load of strength and health generally has been declining ever since.
I visited my dad a few months later and he'd bought himself an ebike. After a go on that I was a convert.
I didn't want to sell the Spa Wayfarer after all the effort I'd put into building it so a conversion was the choice there. The Bafang was the most commonly known ebike conversion then and probably still is. The 250w version did ok till dad and I started our 2nd tour when it's lack of muscle really hampered me on Wales's hills.
That tour ended with an accident and not long after the 750w version was fitted which was brilliant but all that power was again costing me leg strength.
That's where the Tongshen was swapped in. I've got the 500w version as Bolton is also quite hilly and even with that I struggle on some hills. But it does get me up them eventually!
I no longer have the 'lets get out for a ride for fun' feeling and these days it's just for getting me about but I do still enjoy cycling. Just not as much as I used to. I blame traffic volumes for that. Can't escape damn cars these days.

[Cowsham]

If the latter then first decision convert one of my 3 Bromptons or my 2 26"er ATBs

3 Bromptons ? -- sell one of those and you'll be able to afford an off the shelf electric bike.

The other and in my view better option is to put a Yose rear wheel kit into one of the 26" mountain bikes.

I have experience of two Yose power kits -- my brothers ( front wheel ) and my rear wheel kit. Both were very easy to instal, working perfectly 4 years on.

Mine took 1 hour to fit -- it was very easy. Don't worry about the crank sensor as they even give you the tools to remove the left crank arm and also the tool to swap the cassette from the old wheel to the new electric hub rear wheel.

It'll be a perfect fit for the 90's mountain or AT bike.

If you don't want to fit it yourself I'm sure you'll have someone who could fit it for you.

Fitting a kit to a Brompton to my mind is defeating the purpose of the Brompton cos it'll just make it heavier and less portable.

Also a 90's Kitted electric bike will be less attractive to thieves than an off the shelf one.

And off the shelf ebikes can become redundant when the parts are no longer available whereas I can buy any part for mine or just buy another kit.

It makes a heavy old bike into a useful tool. My brothers old town bike has a 17.5ah battery in and it'll do over 100 miles on one charge. Mine is 13ah and will do 60 miles easily. I could have bought the 17.5 ah battery cos they're interchangeable.

[PH]

Increasingly coming closer to just hanging up my wheels .......

Be a shame to do that, surely some cycling is better than none. Rather than chase your tail looking for the perfect bike to match your cycling, get the best you can find and match your cycling to it's capabilities. Chances are you're going to want to change it after a few weeks or months, you do with every other bike, what makes you think an E-bike will be different?

[UpWrong]

^Thanks @Skids and @Cugel.
The difficulty and risks of charging are probably the biggest obstacles to my making the leap. And yes especially so for add-ons. Pity Brompton's own electric seemingly pretty poor not to mention out of my price range.
Increasingly coming closer to just hanging up my wheels .......

Just get a Woosh Brompton front hub kit (from £499). What have you got to lose?
https://wooshbikes.co.uk/?hubkits#q70kit

[stodd]

Just get a Woosh Brompton front hub kit (from £499). What have you got to lose?
https://wooshbikes.co.uk/?hubkits#q70kit

Absolutely. (back to my initial reply)

[Cowsham]

If you can fix a puncture you can fit an ekit -- stick to the charging rules, proper batteries and chargers and all will be well. I charge mine in a box outside the garage so if the unthinkable happens the most I can lose is the battery. The box was an old electrical cabinet that would've went to scrap but any waterproof box will do the job.

[djnotts]

My thanks to all for all the above - much to digest and to ponder. Last 10 days in the heat of the Algarve seems to have significantly worsened my lung capacity. So a decision more pressing.

Electric all too complicated I fear. Pretty much decided I shall further lighten my custom part-Ti Brompton (and use public transport more when appropriate) for a few more months and then simply accept the inevitable and quit. An hour's walk every a.m. will have to suffice.

[Cowsham]

My thanks to all for all the above - much to digest and to ponder. Last 10 days in the heat of the Algarve seems to have significantly worsened my lung capacity. So a decision more pressing.

One of the main factors for me deciding to make myself an ebike ( from the second hand bike and yose kit ) was when we were on holiday and the temperature was up over 32°C my problem was what to do on such a warm day so I thought I'll hire a couple of ebikes.

Turned out to be a good idea -- really enjoyed the breeze and effortless travel through the lanes, hills and towpaths.

Don't give up something you enjoy and benefits your health.

[djnotts]

The most immediately attractive is the Yose rear wheel free hub kit mentioned above into my really quite light and vgc Univega Aluminium 702. I've owned it 3 times over last 15 years or so and it's a perfect fit.

They do seem very cheap - too good to be true?

[Cowsham]

The most immediately attractive is the Yose rear wheel free hub kit mentioned above into my really quite light and vgc Univega Aluminium 702. I've owned it 3 times over last 15 years or so and it's a perfect fit.

They do seem very cheap - too good to be true?

20250325_133404.jpg

They are about £400* so not that cheap but they work very well. My brothers has taken a lot of abuse over the last few years and still perfect.

*( £400 isn't cheap -- it's just that off the shelf ebikes are dear but for good reason -- the manufacturers and retailers have to make money cos the overheads in small business is prohibitive in this country.)