Got a eZee Sprint 7 - it is fantastic

[Jim]

This e-mail is from ken from eZee bikes reguarding the cutting out of the sprint motors. Unfortunatley we got this the e-mail the day after I spoke to mick reguarding his concerns with his sprint. I will check out your bike when it comes back to us and I will test it's replacement before we send it back to you to make sure that it is just the cut out coming in.

Anyone who knows a little about electric motor will know there is a very high amps draw when a motor starts even with zero load in the works, not to mention that our little 250 watt needs to pull a guy 80 kgs ? + bike 30 kgs total 110 kgs from start.

We already have 20 amps overload protection with 36V that is the highest , nobody has higher, and you know very well that our software programe in the controller try to make the best of the situation to accelerate slowly for the sake of safety.

If those people sit on it and pull a full throttle to race ahead causing a very high amps draw
the overload protection MUST come in.

You just need to take it a bit more gently when setting off and you won't have a problem.

Cheers Jim

 

[zammo]

This e-mail is from ken from eZee bikes regarding the cutting out of the sprint motors. Unfortunately we got this the e-mail the day after I spoke to mick regarding his concerns with his sprint. I will check out your bike when it comes back to us and I will test it's replacement before we send it back to you to make sure that it is just the cut out coming in.

Anyone who knows a little about electric motor will know there is a very high amps draw when a motor starts even with zero load in the works, not to mention that our little 250 watt needs to pull a guy 80 kgs ? + bike 30 kgs total 110 kgs from start.​

We already have 20 amps overload protection with 36V that is the highest , nobody has higher, and you know very well that our software programe in the controller try to make the best of the situation to accelerate slowly for the sake of safety.

If those people sit on it and pull a full throttle to race ahead causing a very high amps draw the overload protection MUST come in.

You just need to take it a bit more gently when setting off and you won't have a problem.

Cheers Jim

I agree with you in principle; the motor has to do a *lot* of work when pulling away from a standstill and the powerful motor and battery mean that there's a high current flowing which needs to be monitored to protect the motor/battery/wires/controller.

But if I were to show you it happening I think you'd agree that there's something not quite right:

From a stand-still I turn the throttle gently up to about half way and it cuts out (I do not whack open the throttle all the way in one go). I have enough of a physics background (and mechanical+electrical sympathy) to know what the system is trying to do when I set off from a stand-still.

The other reasons why I think it's a fault and not designed to work that way:

• I'm only 70Kg so I assume below the average weight used to calculate tolerances for load
• The cut-out happens *after* the motor actually does some work and moves the bike a few feet
• It does not happen due to high load at any other time (hills for example) only when starting from a standstill

I completely understand that if I were carrying a bag of cement on the back, at a standstill, pulling on both brakes, with my feet on the ground and holding the throttle open all the way holding the bike back (so the motor is fighting me+inertia+brakes) then something has got to give. But that's not what is happening at all.

Hopefully now that Tim at the London branch has the bike you can experience (and verify) the problem for yourselves.

 

[zammo]

it's back

The bike is back (I think it's a different one) and it works perfectly.

After Tim from 50cycles kindly brought round the charger and battery (which had not been returned with the bike) I went for a blast around the parks and it works perfectly:

• the take-off is much smoother and less 'notchy' than the original (in retrospect the 'notchyness' may have been connected with the fault that made it cut out)
• no cut outs at all, even at full open from stand-still
• nice power delivery all the way up to the top
• nicely sprung ride

I'm very happy with it.

Thanks to 50 cycles for sorting out the problem so graciously. I promised some pictures and will take some as soon as it stops raining

 

[coops]

Glad to hear that you are back on two wheels again zammo and that the cut-out problem you had (which I hope didn't "dampen" too much the enjoyment of the first ebike experience) seems happily resolved, though I admit I'm a little envious as I'm not yet motorised and do feel I'm missing all the fun to be had on electric bikes but hopefully it won't be long now

Still, as you say, its not exactly fair-weather cyclist conditions at the moment, so that eases the wait oh well, back to planning, & tinkering with my still non-motorised bike for now...

Stuart.

 

[zammo]

coops,

Good luck, if you go electric you won't regret it. I'm quite physically lazy and would not be cycling *at all* were it not for the electric assist. That way I get some fresh air, 'some' excercise and it's a far more pleasant way to travel.

The upright position of the Sprint is a joy - I have cycled quite a lot in Italy around an island and i loved the non-macho/non-competitive sit-up-and beg easy gliding of the bikes rather than racing about bum-in-the-air (to each their own). I think that's what I was looking for in a bike and the Sprint definitely has that stately feel.

 

[Tim]

The bike is back (I think it's a different one) and it works perfectly.

Yes, it's a new one. Your original Sprint is being taught a lesson in our workshop!

 

[zammo]

Yes, it's a new one. Your original Sprint is being taught a lesson in our workshop!

Please give it a spanking from me and thanks again for your efforts in replacing it.

 

[zammo]

Question: raising handlebar height

A quick question, how do you raise the handlebar height?

I have increased (or decreased depending on your point of view) the angle of the handlebar holder (the diagonal piece that links the handlebar post and the handlebars themselves) so it is pointing upwards but would like to know if it is possible to raise the post height. I only need it to go higher by a centimeter or so.

Any advice before I start stripping the chrome off the nuts?

 

[flecc]

This looks like a conventional headstock Zammo. The large nut is the headstock bearing adjustment lock nut, there's a pair against each other, the lower one tightens the bearings, the upper locks it.

It's the allen bolt at the top which adjusts the handlebar stem height. Using the right allen key, slacken this and it takes pressure off the cone in the bottom of the stem tube that clamps the stem.

Then twist the handlebars from side to side, working them up that centimetre. Finally align the handlebars and tighten the allen bolt again. If it's almost impossible to twist it up, give the top of that allen bolt a sharp tap to free the tapered cone in the bottom of the stem tube.
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