silly question?

[KeithH]

Following on from the cyclotricity upgrade and 48v battery threads I've been wondering what would happen if I put 48v through my bog standard LED cyclotricity kit.
My thoughts so far on possible outcomes.
1 smoke/bang from the controller
2 smoke/bang from the motor
3 Dead LED dashboard
4 More torque
5 More speed
6 longer range
and of course no warranty
From my point of view range followed by torque are the priorities but there are times when a little more speed would be useful.
Anyone tried this? A forum search proved barren
Ta
Keith

 

[trex]

I asked myself the same questions and never have the courage to try it out.
KirstinS has tried something similar on an 8-Fun kit and got higher speed.

 

[Deleted member 4366]

If you mean a 48v battery that is typically 54.6v fully charged, there's risks.

If you have 53v capacitors in the controller, they'll be working above their theoretical limit. If you over-volt them they can go "pop" and make a lot of smoke. They're easy and cheap to replace, so best to do it first.

You can also have problems with the 12v regulator. The 36v comes into the controller and goes through a big resistor that cuts the voltage down. It then goes to the 12v regulator, which cuts it down further to a steady 12V (sometimes 14v). Anything that happens after that can't be affected by the battery. For 48v, the value of the big resistor is higher to stop too much current flowing through the 12v regulator, so, ideally, that should be replaced as well. They're also cheap and easy to replace.

Most people that try a 48v battery on their 36v controller report that it works OK, but we never hear long-term reports. One guy told me that he tried it twice, and they both packed up after a couple of months.

If you mean that you want to run with 12S lipos or a 2-cell booster pack, which are round about 48v most of the time (50.4v max), it should work OK without modification.

 

[D C]

there are times when a little more speed would be useful.

Just out of interest my Cyclotricity doesn't cut the power till I'm over 21 mph, I didn't do any mods, it did this from the day I fitted it and I assumed this is how it's meant to be. Maybe it's because it's thumb throttle only.

 

[KirstinS]

Hi KeithH

As mentioned I added a booster battery to my 8fun kit. I get about 22/23mph hot off charger. Range is reduced by about 30%. Motor is niosier

Initially I went with 7.2v (2s)booster but after a while I upped it to 11.1v (3s)

I am using a BMS battery ku65 and was happy to risk blowing it up as I could always stick the stock controller back in .

However - I commute 15 daily and nothing has blown up . I've had no issues at all and it's been at least 9months

Hope this helps

I've actually got 2 controllers spare so you can have one for a nominal sum and postage

You can even have a bunch of 18650 cells to make up a booster pack if you like. You can have those for free - just postage

Just pm me if keen

Cheers

 

[Deleted member 4366]

Just out of interest my Cyclotricity doesn't cut the power till I'm over 21 mph, I didn't do any mods, it did this from the day I fitted it and I assumed this is how it's meant to be. Maybe it's because it's thumb throttle only.

It's nothing to do with the throttle. How fast a motor goes depends on it's coil windings and the voltage applied to it. yours is a 260 rpm motor at 36v., which is 22 mph (no load) with a fully charged battery, so about 19 to 20 mph on the road.

if you want 15 mph, you have to join the speed limit wires on the controller or in the settings in the LCD if you have one.

 

[D C]

It's nothing to do with the throttle. How fast a motor goes depends on it's coil windings and the voltage applied to it. yours is a 260 rpm motor at 36v., which is 22 mph (no load) with a fully charged battery, so about 19 to 20 mph on the road.

if you want 15 mph, you have to join the speed limit wires on the controller or in the settings in the LCD if you have one.

Sounds like it would be simple for Keith to get more speed from his existing set up?

 

[Tangsoo]

if you want 15 mph, you have to join the speed limit wires on the controller or in the settings in the LCD if you have one.

I've dropped your controller in it's place now but out of interest which wires are the speed limit on that controller?

 

[Deleted member 4366]

The speed limit is in the LCD. Press and hold + and - to enter set-up.

 

[Tangsoo]

The speed limit is in the LCD. Press and hold + and - to enter set-up.

Sorry, I wasn't clear, I meant my old MXUS controller as the OP referred to, you mentioned there are wires that limited the speed?

 

[D C]

This is a controller wiring diagram that came with my Cyclotricity kit if it helps anyone

 

[D C]

easier to see this way up!

 

[Deleted member 4366]

Most controllers without LCD have two wires to join to set the 15 mph limit because there is no other way to communicate with the controller.

The LCDs normally have software in them to set the speed limit, so they don't need the two wires. The LCD communicates with the controller.

The Cyclotricity controller, according to the wiring diagram above, is designed for a LCD, so it doesn't have the two wires, but it can run without the LCD by joining the red and blue wires that normally go to the LCD. Hence the need for the special cap on the connector when running without the LCD, but this would mean no means of setting the speed limit, although some controllers default to 15 mph if they don't get the wheel-speed signal. They normally have the speed sensor connector directly on the controller, which the Cyclotricity one has.

Perhaps someone from Cyclotricity could explain how to limit the speed to 15mph, or someone could ask them.

 

[trex]

does it matter if they don't limit the speed to 25kph?
lots of bikes being sold today are easy to derestrict, even Bosch do not close down the 'tuning' dongles.
BTW, I can't see how an SWX motor can do 21mph on 26" tyres unless going downhill.

 

[KeithH]

Hi all
Thanks for the prompt helpful responses. Lots to think about.
KirstenS I like the idea of playing using a spare controller and I like the idea of a additional battery in parallel so I may well PM you. Thanks for the offer.
Trouble is I have a working bike that I don't want to wreck and my physics is way out of date (A level 1966, the wheatstone bridge is about all I can remember about electricity). I was hoping for a simple "slot in" solution.
The range I'm getting at the moment is about 6 miles short of optimal (and a little more speed wouldn't go amiss!)
Typo in my OP, I have the LED version not LCD.
Ta
K
ps why does the range drop if you have 48v surely 10ah at 48 is more watt hours than at 36? (silly question no2?)

 

[Geebee]

You go faster so more aerodynamic drag, IF you rode at the same speed range would be longer due to the extra watt hours

 

[D C]

does it matter if they don't limit the speed to 25kph?
lots of bikes being sold today are easy to derestrict, even Bosch do not close down the 'tuning' dongles.
BTW, I can't see how an SWX motor can do 21mph on 26" tyres unless going downhill.

i don't know what's meant by SWX, this is my motor and gives over 21 mph before cutting out. I'm quite happy with that.

 

[Deleted member 4366]

It's a MXUS motor, not Bafang SWX.