Got my Cytronex!

[flecc]

It would be interesting to know what the Powabyke X is like o cycle without the assist. Does it use the same (Tongxin) motor as the Cytronex?

No it won't be. It uses Powabyke's own motor which is an internally geared hub, not free running by total disconnection which is unique to the Tongxin design. I suspect the Powabyke motor on the X bike will be the more powerful though, since their traditional models have the highest peak power on the market at 700 watts and their bikes have usually been exceptional climbers on motor power.
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[Rad]

I'm not sure what motor the x-bike has, though I believe it's something Powabyke developed themselves. The range for me isn't a problem. I'm buying it to commute. I've a 15 mile round trip but should be able to recharge at work once I've got the charger PAT tested. I don't know for sure but would imagine that a half discharged battery should only take half the time (or so) to recharge.

 

[Phil the drill]

I suspect the Powabyke motor on the X bike will be the more powerful though, since their traditional models have the highest peak power on the market at 700 watts and their bikes have usually been exceptional climbers on motor power.
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Hi Flecc

At the risk of going slightly off thread for a sec., I can concur that the Powabyke is an excellent hill climber, especially heavily loaded and that it could peak at 700w @ low speed. I thought however that some of the current Ezee models were capable of more than that? I'm sure I saw somewhere that some of them were capable of up to 1000w peak power?
P'raps I was mis-informed?

Cheers, Phil

 

[flecc]

The motor that the F series uses was the most powerful, intended for eZee's US market and rated as 350 watts. It's peak power was said to be 700 watts, but I made it more like 680 watts. The new motor that eZee claim is their own has had some extravagant claims made for it, but it's performance in the Torq 2 indicates that it's probably similar to the the F series motor.

If it really could make 1000 watts it would perform more like the Crystalyte or Puma motors and be very illegal, so I can't really see that as realistic.
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[Phil the drill]

Interesting... thanks Flecc.

 

[Barnowl]

Hi Rad

15 mile round trip sounds good. Don't forget the cost of replacement batteries though. The Cytronex NIMH battery, I think, costs £150. The Lithium ion costs more but probably takes a lot more charges before it fails. I can't find the details. The Cytronex I think, from memory, does about 200 charges. Looks like you'd be doing about 4 charges a week so I'd budget for a replacement once a year with the Cytronex (regular 5 day a week 15 mile round trip commute).
I'd try and find out how many charges the Powabyke would take. Maybe Flecc has a view on this. I suspect it's a lot more than the NIMH battery.

I'd also make sure I was reasonably happy with cycling the bike without power because at some point on your annual commute it's bound to happen.

 

[fishingpaul]

No it won't be. It uses Powabyke's own motor which is an internally geared hub, not free running by total disconnection which is unique to the Tongxin design. I suspect the Powabyke motor on the X bike will be the more powerful though, since their traditional models have the highest peak power on the market at 700 watts and their bikes have usually been exceptional climbers on motor power.
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Is the torq 2 motor free running.mine will continue to spin for over 20 seconds from 17.4 mph with the wheel held up,around the same as the nano motor from 16mph.

 

[flecc]

Is the torq 2 motor free running.mine will continue to spin for over 20 seconds from 17.4 mph with the wheel held up,around the same as the nano motor from 16mph.

I don't know the fine details Torq 2 motor internal drive arrangement Paul, but I understand it is geared so the epicyclic has to have the gears turned on overrun. The Tongxin is completely unique in that it's patented arrangement means that absolutely nothing is connected on overrun, so it's just like a normal bike wheel with only the bearings to consider. Therefore it has to be the most free running, though that doesn't stop a very well set up geared wheel from coming close. The trouble is that gears wear, grease gets old and gummy etc, so the free running could deteriorate on a geared hub motor.

Things change on the road too. My Torq 1 wheel would spin for ages like a normal bike with the front of the bike held up, but on the road it was a very different story and I always found it very unpleasant to pedal without power, at least 3 mph slower that the normally wheeled Twist when used without power.
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[Rad]

Hi Rad

15 mile round trip sounds good. Don't forget the cost of replacement batteries though. The Cytronex NIMH battery, I think, costs £150. The Lithium ion costs more but probably takes a lot more charges before it fails. I can't find the details. The Cytronex I think, from memory, does about 200 charges. Looks like you'd be doing about 4 charges a week so I'd budget for a replacement once a year with the Cytronex (regular 5 day a week 15 mile round trip commute).
I'd try and find out how many charges the Powabyke would take. Maybe Flecc has a view on this. I suspect it's a lot more than the NIMH battery.

I'd also make sure I was reasonably happy with cycling the bike without power because at some point on your annual commute it's bound to happen.

Cheers Barnowl, I believe the Powabyke battery is rated at about 500 charges but I think buying a back-up battery would be a must for these lower range machines anyway. I'm hoping to get shot of one of our two family cars which will more than compensate for the added cost of the additional battery.

 

[flecc]

I'd try and find out how many charges the Powabyke would take. Maybe Flecc has a view on this. I suspect it's a lot more than the NIMH battery.

Very much the other way round Barnowl. Both Li-ion and NiMh nominally take around 400 to 500 full charges, but experience with li-ion to date has usually shown them falling short by varying and often substantial amounts. In addition, lithium batteries age all the time from point of manufacture whether used or not, while NiMh don't.

I've kept two NiMh batteries on a Lafree running for 4.5 years, when I recelled one to increase it's range and gave the other to another forum member who has used it as a spare for at least another year. I've never heard of a large lithium battery lasting anything like that long in our high discharge e-bike use.

That said the NiMh cells in the battery have to be good quality to last, but I understand Mark at Cytronex makes a point of using the highest quality that can be bought. However, there is another factor which could shorten the Cytronex battery life which I'll explain if you want me to.

When we get reliably produced lithium-iron ( LiFePO4 ) batteries, lithium life will leap ahead with at least 2000 charges possible, but we are not quite there yet as a mass production proposition.
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[HarryB]

That said the NiMh cells in the battery have to be good quality to last, but I understand Mark at Cytronex makes a point of using the highest quality that can be bought. However, there is another factor which could shorten the Cytronex battery life which I'll explain if you want me to.

Yes please. I was wondering if there was a way of prolonging the life of the cells in much the same way as the prius does. So never fully charging and never fully discharging the cells - keeping them in the 50-80% range. It would be easier to never discharge the cells but more difficult to not fully charge. I suspect in the end it is not worth the hassle as the battery will last longer than most Li-ion batteries (and cheaper too).

 

[flecc]

You've answered yourself already Hal. As you know, the Prius battery is guaranteed for eight years, and in satellite use NiMh cells are used for ten years and remain serviceable after that. The key is partial use, in satellites only one seventh of the cell capacity is used and recharged every 24 hours.

And that's why I specifically mentioned this in relation to the Cytronex, since it's very small capacity battery means most users will have to quite fully discharge it all the time, leaving little chance for life extension.

For longest life the stress points at full discharge and full charge need to be avoided, but as you say that is very difficult to achieve on our bike batteries. Personally I just use the batteries and buy again as necessary as doing otherwise can be so much hassle.

To realistically achieve long NiMh battery life on mainstream e-bikes we'd need to at least double the capacity, the Wisper 905se needing 28 Ah and making old Powabykes look like lightweights! There's a self defeating aspect too. If we doubled up the Cytronex or any other bike batteries with them wired in parallel, it's very doubtful we'd double the life but it would double the cost, so no point.
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[Barnowl]

Flecc HarryB

Many Thanks. I really hadn't understood NIMH at all. This has corrected my view that it was better to recharge the battery when it ran out of power rather than keep it topped up. My commute is relatively short - 8 miles round trip at most. From what you say it seems it would be best to top it up every day or 2nd day at 8 or 16 miles rather than ever third day when the battery has drained. Thus avoiding the stress at the bottom end. Also at the top end switching the charger off after 1.5 hrs rather than leaving it on overnight.

 

[john]

Also at the top end switching the charger off after 1.5 hrs rather than leaving it on overnight.

I think a full charge is still needed at least from time to time though to prevent the cells going out of balance. I'm not sure how the Prius manage to keep its cells balanced though.

 

[flecc]

John's point is true, and it's one of the many reasons why I think the complexity of trying to extend battery life is probably hardly worthwhile.

My philosophy is use and enjoy.
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