A sort of beastmatic !!!

[OldBob1]

I aquired a cheap folder at a low price, it was fitted with a 24 volt NiHm battery which was on its last legs.
After reading the many inputs about the beastmatic, I thought what can I do to this folder?



This is how it looks at the moment fitted rear rack with 36 Volt 10 Ah battery, new brush controller and twistgrip controls, fitted larger chaingear but still cannot keep up with it!
The original brushed motor is very powerful and must have a free-wheel fitted as you can hear the motor winding up to speed like a jet engine!!!
Still tinkering with it, might have a go at fitting d8veh cruise control to it and a PAS to it.
But its great fun to ride and given the old bike a new lease of life.

Bob

 

[johnc461165]

Interesting times ahead then Bob.

 

[Deleted member 4366]

Great work, Bob. I wouldn't bother with PAS because it'll probably just give full power as soon as you start pedalling. A cruise control will be a better solution (once you get used to it.

 

[OldBob1]

Dave whats the nack of getting into the twist grip to reduce the spring tension?
Also how are these brush motors on taking the extra power have been up a few hills with it and the motor and controller are just warm.
Suspension seat post and gel seat the next addition.
John this is getting more fun the more I tinker.

Bob.

 

[Deleted member 4366]

You can't change the throttle spring tension because it's a coil spring, but you can remove the spring completely. You remove the throttle from the handlebars. There's three retainers on the inner diameter (barbs) that hold the throttle together. You need three very thin knives or similar to hold the barbs up while you pull it apart. Fairly easy on a thumb throttle, but tricky on a full or half throttle. You just have to persevere.

Brush motors are normally fairly strong. 600w from the battery will probably be OK. I'd guess 900w the limit. To avoid burning the commutator, higher voltage is probably better than higher current. It should be OK at 36v and 15 amps. Do you know the rating of the original controller?

 

[OldBob1]

Not been able to get at the original its inside the bottom bracket and was worked off the torque put on the pedels.
Replaced with a Yiyun YK 31 C controller for 36 volts 350 watts brushed motor.

 

[jackhandy]

Just won an auction for a 24v folder & should pick it up tomorrow:

Seller thinks the battery's dead (lithium, I think) so it'll be interesting to see what I can do with it

Comes with battery & charger...

 

[OldBob1]

Hi, well I have fitted a suspension post to the seat wow what a difference, soaks up the crap road conditions we have around here, even after having a new cheapo wearing surface replacement( bull****) for wasting more tax payers money.
Son came over today, saw bike and had to take it for an evaluation, dissappeared for 30 minutes and then came back with a Big smile on his face, (yep overtook a lycra possey climbing a hill).
Jackhandy what model is it? 24 or 36 volts?

Bob

 

[Deleted member 4366]

Just won an auction for a 24v folder & should pick it up tomorrow:

Seller thinks the battery's dead (lithium, I think) so it'll be interesting to see what I can do with it

Comes with battery & charger...

Should go well with a 36v battery, or even better with 12S lipos (44v). For 12S lipos, you'll need a new 36v controller.

 

[jackhandy]

Well... Got it home (140 mile round trip - inthe heatwave).. Turns out it's a 24v 200w, generic Chinese folder; lithium battery which is intermittently showing full charge or no leds lit. 3 wires to the motor, so brushless?

Started working through connections & found a connector off in the "manifold" box on the head tube.

Replaced the pedelec disc, which was busted, & it goes!

Trundles my bulk up our road without pedalling, is very low geared, but there's still an intermittent fault which is fixed by turning off, lifting the battery & replacing.

Controller is quite chunky & labelled 16a, I think, so I'll have a bash at soldering the shunt: 20a seem sensible?

I feel rather guilty now, as I bought it as "for parts, not working" from a lovely 3rd age couple, although I suspect the lady rather fancied a new bike, anyway.

Wonder if it'll go on my record as ripping-off a retired reverend & his lovely wife? No pearly gates for Jack, then.

 

[OldBob1]

but there's still an intermittent fault which is fixed by turning off, lifting the battery & replacing.
Jack that sounds like the usuall dodgy contacts in the base of the battery? put a piece of inner tube on the bottom of my Cyclamatic battery to stop it moving about.
Sounds like a good buy.

Bob.

 

[Deleted member 4366]

Soldering the shunt won't make a lot of difference because the battery will struggle to give that current. Much better would be to go up to 36v if you can.