Flit 16

Freddy Kruger

Just Joined
Oct 13, 2019
2
0
Hi,
I like the look of this folding bike but find it unusual that it uses a 220w motor as opposed to the 250w that seems more common.
They claimed it gives them much better acceleration and allows the use of maximum torque.
I'm struggling to understand and they are now being evasive in their answers.
Can anyone expand of the reason?
That aside I really like the look of it and fancy the ability to throw 2 of these into the car boot for trips off.
J
 

flecc

Member
Oct 25, 2006
46,514
23,348
I like the look of this folding bike but find it unusual that it uses a 220w motor as opposed to the 250w that seems more common.
Both figures are meaningless with regard to actual power, all e-bike motors deliver far more.

The EN15194 technical standard requires a motor can deliver 250 watts continuous without continuously heating to failure point. It's likely this motor can only deliver continuously to 220 watts without starting to heat up too much, so doesn't quite meet the standard.

In practical use on the road it won't make any difference since an e-bike is never continuously at full power and it's the controller that dictates the actual power level delivered. We've had a number in the past that were only 180 or 200 watts rated. For your casual use I'd say go ahead if everything else about the bike is ok, especially since small wheels place less demands on the motor due to mechanical advantage.

This is a complicated subject, which is why they are being cagey.
.
 
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Gavin

Esteemed Pedelecer
May 11, 2020
316
174
That's quite visually appealling and with a couple of interesting engineering details, however that's a lot of money for a single-speed folding bike.

Your money could go a lot further in such a competitive market sector with so many models to choose from....

P.S. Welcome Freddy!
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
6,938
2,674
Basildon
The motor has very little to do with how much power you get. The power is decided by how much current the controller gives it and the battery voltage. In simple terms, power = volts x amps. The motor is only a transducer. It converts that electrical power into motive power and waste some as heat. If you put a 200w or 500w motor in that bike, you'd experience the same power.

As said above, the watts written on the motor have very little significance. They're mainly stamped like that for legal compliance, depending on which countries they're sold in.
 

Dave@FLIT

Just Joined
Aug 4, 2020
1
0
Hi all,

Dave here from FLIT. Glad to hear you like the bike Freddy and sorry for any confusion!

We used this particular motor for a few reasons;
- it's made by Bafang who have a good reputation and good spare parts availability
- it was (and I believe still is) Bafang's lightest rear hub motor
- it has an unusually narrow OLD (120mm instead of the common 135mm) which helps when designing for a compact fold
- it has a 9T casette driver (like the type you'd find on a BMX) instead of the more common 13T freewheel which means we don't need such a large chain wheel to get a decent number of gear inches (less weight & better for fold design)

As other posters have mentioned, the 220W rating is the continuous power, not the peak power. The peak power is limited by the controller. In our case, the controller max current to 13A, so power peaks at 13*36= 468W.

So does this mean that a 250W Bafang motor will have better hill-climbing ability than our 220W motor? Yes and no. On a bench test, the 250W motor will almost certainly have higher torque but in real world riding other factors come into play.

Most of the weight of bike plus rider is acting over the rear wheel and this further increases on inclines - the steeper the incline, the less weight on the front wheel. To account for situations where the rider is on a steep incline with little traction (wet road + slick tires), we would have to be careful about how much current we send to a front wheel motor. With the motor on the rear wheel we don't have this limitation - the steeper the hill, the more weight on the rear wheel - so we can drive a rear hub motor and max controller current (i.e. max torque) without worrying about wheel slip.

I've probably rambled on enough already, but it was actually myself nearly flying off a front hub ebike whilst going over a steep bridge during early testing that convinced me we needed to design around a rear hub motor!

In conclusion, yes it's a small motor, but we don't restrict it so it performs surprisingly well on steep climbs. Probably the steepest I've tried personally was Constitution Hill in Bristol;

Freddy, if you're anywhere near Cambridge or London please let us know - I'd love for you to test ride the bike and answer any questions you have in person.

Thanks for your interest,
Dave
FLIT Co-founder