For any one interested in the

 

Im not so thrilled with the cosmetics , but if it does the job well, why not ?

The Tongxin is very quiet, down to its roller bearings rather than cog gear drives. In fact the Tongxin makes a louder whiring sound when not being powered, than when it is engaged.

 

It also has an excellent free wheel.

 

As far as I know it is much quiter than any other geared motor option, although some have had reliability issues.

 

Regards

 

Jerry

 

What do you think of the ezee then ?

 

Has any one here tried using DIY Battery Setup with it, or would it post more problems ?

 

t

Does seem good value and I see no reason why it would not work fine with a Tongxin.

 

Points to consider :

 

1. Import duty ?

2. Returns/Failure ?

3. If it fails especially the BMS, then the battery is pretty much useless unless you feel confident you could get and fit a new BMS yourself. Replacing a single failed cell might also be difficult.

 

For the prices of the 10Ah listed I could easily build two A123, 36v, 2.4Ah packs albeit 1/2 of the capacity of the one shown, but the beauty of these DIY packs, is that the do not seem to require balancing (although I have added taps) and thus no need for a BMS. If a cell does fail, they are also easily replaced and the packed saved.

 

However if you want a quick solution and need the capacity, it does seem like VERY good value

 

PS note some of the negative feedback, though mainly for the motors they sell. Said they have sold 6 * 10Ah batteries to date and don't see any negative feedback about those.

 

Ping batteries seem to have a better well respected reputation, but then they cost more. Pays your money takes your choice I guess.

 

Regards

 

Jerry

 

Are there any kits this has been proven to work well with ?

 

I was thinking about Ezee again , but I remember their being some sort of problem with some of their batteries i.e. Id feel more comfortable trying it , if I knew it already worked with one rather than taking a leap of blind faith .

 

t

I've bought 2 of these direct from this supplier in China which I've connected in series to give the equivalent of Jerrys & the Freedom solution:

6S1P 19.8V2300mah A123 systems original Li RC battery on eBay (end time 16-Aug-10 10:19:44 BST)

 

which is slightly simpler than putting together individual batteries.

 

I ordered them too (now awaiting delivery ...)

How long did postage take in your case ?

 

Note: ElectricWingman sells them too from UK stock...albeit at twice the price point. I say it's worth taking the risk* ordering direct from China.

(*) delivery, delays, warranty, taxes, etc.

 

6s A123 Battery Packs - 19.8V

 

They are much lower capacity than the the battery from EWC though so it's a case of you pays your money and you takes your choice!

 

(BTW I think EWC did mention they will be making smaller battery options available in future)

 

I contacted Li Ping about making a LifePo4 5Ah pack (which is not on their official catalog). No problems, it costs about half as much as my 10Ah Ping battery, and it's literally half the thickness.

 

The Li Ping packs use prismatic pouches, not cylindrical cells, and they come with a balancing circuit. The Li Ping electronics are top-notch, but in practice, the A123 packs (although based on the same LiFe "nano" chemistry), do not need balancing.

 

For me the main problem with the Li Ping packs is that the shape is constrained by the size of a single pouch (150mm x 105mm x 15mm), so my 10-cell 150mm-deep 10Ah pack would reduce down to 75mm, but still with a 150x105 face that is not very pocketable (in terms of Brompton luggage). That's why I went for the lower-capacity A123 pack based on cylindrical cells (just under 2.5Ah), which also happens to be less fragile than the more exposed sheets in a prismatic pouch cell.

 

http://www.pedelecs.co.uk/forum/electric-bicycles/4734-diy-stage-2-received-li-ping-lifepo4-battery-photos.html#post59988

 

They seem heavier than the Ping batteries. e.g. for 10Ah 36V, the weight is 4.9kg against 3.5kg for the Ping.

 

Yes, that's the difference betwen cylindrical cells (A123 or 26650) and LiFePO4 prismatic pouch cells.

 

Cheers, Dan

Edited October 6, 201015 yr by daniel.weck

 

I was thinking about Ezee again , but I remember their being some sort of problem with some of their batteries

 

The first generation of Li-ion e-bike batteries were prone to premature failures, and this showed up first on the most powerful motors such as eZee's which used the most current.

 

That no longer applies, eZee use one of the best battery manufacturers currently, a firm that also supplies some of the best Wisper batteries.

.

I ordered them too (now awaiting delivery ...)

How long did postage take in your case ?

 

It took about a week. It did occur to me that by buying individual cells in a number of seperate orders, and putting the cells together yourself you would avoid the import tax. As it was I was lucky and they got through without attracting any duty anyway. Hopefully yours will be the same!

The first generation of Li-ion e-bike batteries were prone to premature failures, and this showed up first on the most powerful motors such as eZee's which used the most current.

 

That no longer applies, eZee use one of the best battery manufacturers currently, a firm that also supplies some of the best Wisper batteries.

.

 

Thank for the update Flecc,

 

I read yesterday about some serious developments being made in hydrogen cells and it got me rethinking the whole electric motor thing- mainly because its so darn expensive to replace , and of course the fact id be using it more like a scooter.

 

I thought i could use it more on assist but its looking less likely now after trying my downtube and phyiscal woes its giving me , mainly knees.

 

Its great bike though , very light , but it would of been better I think If id gone possibly with the crank forward instead- then again ( given the weight ) it would probably also mean a kit

It took about a week. It did occur to me that by buying individual cells in a number of seperate orders, and putting the cells together yourself you would avoid the import tax. As it was I was lucky and they got through without attracting any duty anyway. Hopefully yours will be the same!

 

I've now got a tracking number (Hong-Kong post).

Smaller batteries

 

Hi Dan

 

The 5ah battery from ping. Is it still rated to deliver 17-18 amps. We have a 4ah pack which firs in the back pouch of the brompton bag. Buy we had to use higher power and more expensive base cells to get the current

 

I ordered them too (now awaiting delivery ...)

How long did postage take in your case ?

 

Note: ElectricWingman sells them too from UK stock...albeit at twice the price point. I say it's worth taking the risk* ordering direct from China.

(*) delivery, delays, warranty, taxes, etc.

 

6s A123 Battery Packs - 19.8V

 

 

 

I contacted Li Ping about making a LifePo4 5Ah pack (which is not on their official catalog). No problems, it costs about half as much as my 10Ah Ping battery, and it's literally half the thickness.

 

The Li Ping packs use prismatic pouches, not cylindrical cells, and they come with a balancing circuit. The Li Ping electronics are top-notch, but in practice, the A123 packs (although based on the same LiFe "nano" chemistry), do not need balancing.

 

For me the main problem with the Li Ping packs is that the shape is constrained by the size of a single pouch (150mm x 105mm x 15mm), so my 10-cell 150mm-deep 10Ah pack would reduce down to 75mm, but still with a 150x105 face that is not very pocketable (in terms of Brompton luggage). That's why I went for the lower-capacity A123 pack based on cylindrical cells (just under 2.5Ah), which also happens to be less fragile than the more exposed sheets in a prismatic pouch cell.

 

http://www.pedelecs.co.uk/forum/electric-bicycles/4734-diy-stage-2-received-li-ping-lifepo4-battery-photos.html#post59988

 

 

 

Yes, that's the difference betwen cylindrical cells (A123 or 26650) and LiFePO4 prismatic pouch cells.

 

Cheers, Dan

The 5ah battery from ping. Is it still rated to deliver 17-18 amps. We have a 4ah pack which firs in the back pouch of the brompton bag. Buy we had to use higher power and more expensive base cells to get the current

 

http://daniel.weck.free.fr/BromptonBafangTongxin/IMG_3875.jpg

 

The Li Ping battery (v2.5) is made of LiFePO4 prismatic pouch cells (lithium iron phosphate), each of which has a nominal voltage of 3.2V. My 10Ah battery is made of 12 individual cells (12S1P pack, 12x3.2=38.4V nominal), so the individual capacity of each cell is 10Ah. EDIT: actually, I think each cell is 5Ah (according to the Li-Ping website), so they must be paralleled in pairs, then pairs are chained in series (2P12S). So a single red LED on the BMS would correspond to a single pair (to be verified). Their optimal use is 1C discharge rate (continuous), although they can safely be used at 2C, and are rated to 4C max. The cut-off protection is between 25-30A for the 10Ah pack, and it happily delivers between 10-20A continuously.

 

http://farm3.static.flickr.com/2683/4241171404_ba98f354f2_o.jpg

http://taistor.wippiespace.com/images/view/dewalt/DSCN0445.jpg

 

The small A123 pack (2.3Ah) is also 12S1P (or more exactly, 2x 6S1P packs connected in series), but each cylindrical cell is rated 3.3V 2.3Ah. Although the chemistry is more or less the same, the C discharge rate is much higher for the A123 pack than for the LiFePO4 one. As a result, this tiny 2.3Ah pack will deliver the 10-15A I normally use continuously from the much larger 10Ah battery, without negative side effects. Furthermore, the A123 cells rarely need balancing, and are very tolerant to over-discharge and over-charge (although of course it is not recommended). These benefits largely offset the inconvenience of a lower capacity/weight ratio, so these batteries are perfect for any - moderately hilly - ride under 10 miles.

 

Now, with that in mind, and knowing that the aforementioned A123 pack fits (just) in the rear pocket of the Brompton bag, I wonder what 4.6Ah you are talking about ? Can you please explain ?

 

http://farm5.static.flickr.com/4063/4240402497_e3ef70920d_o.jpg

Edited October 8, 201015 yr by daniel.weck

Hey some of those pics look familiar

 

Just past 1000 miles (150 charge cyles approx) on my DIY A123 12s1p (2*6s1p) pack. No BMS and each cells remains within 50mv balance of each other. No drop in capacity or range yet.

 

Regards

 

Jerry

Edited October 8, 201015 yr by jerrysimon

Just past 1000 miles (150 charge cyles approx) on my DIY A123 12s1p (2*6s1p) pack. No BMS and each cells remains within 50mv balance of each other. No drop in capacity or range yet.

What is it about A123 cells that make them so uniform that a BMS is not needed?

Hey some of those pics look familiar

 

I found them on the internet.

What is it about A123 cells that make them so uniform that a BMS is not needed?

 

If I was selling them I guess I would say they have nano technology built in BMS facilities in the chemistry/construction themselves

 

I don't know they are just a DIYers dream battery of choice

 

Google A123 and you will find all sorts of interesting info. They seem to be made to be abused way outside their specs. Not the best capacity to weight ratio you can buy, but in my application pretty much perfeck!

 

PS check out my battery build thread for info.

 

Regards

 

Jerry

Edited October 8, 201015 yr by jerrysimon

4Ah Battery

 

http://daniel.weck.free.fr/BromptonBafangTongxin/IMG_3875.jpg

 

The Li Ping battery (v2.5) is made of LiFePO4 prismatic pouch cells (lithium iron phosphate), each of which has a nominal voltage of 3.2V. My 10Ah battery is made of 12 individual cells (12S1P pack, 12x3.2=38.4V nominal), so the individual capacity of each cell is 10Ah. EDIT: actually, I think each cell is 5Ah (according to the Li-Ping website), so they must be paralleled in pairs, then pairs are chained in series (2P12S). So a single red LED on the BMS would correspond to a single pair (to be verified). Their optimal use is 1C discharge rate (continuous), although they can safely be used at 2C, and are rated to 4C max. The cut-off protection is between 25-30A for the 10Ah pack, and it happily delivers between 10-20A continuously.

 

http://farm3.static.flickr.com/2683/4241171404_ba98f354f2_o.jpg

http://taistor.wippiespace.com/images/view/dewalt/DSCN0445.jpg

 

The small A123 pack (2.3Ah) is also 12S1P (or more exactly, 2x 6S1P packs connected in series), but each cylindrical cell is rated 3.3V 2.3Ah. Although the chemistry is more or less the same, the C discharge rate is much higher for the A123 pack than for the LiFePO4 one. As a result, this tiny 2.3Ah pack will deliver the 10-15A I normally use continuously from the much larger 10Ah battery, without negative side effects. Furthermore, the A123 cells rarely need balancing, and are very tolerant to over-discharge and over-charge (although of course it is not recommended). These benefits largely offset the inconvenience of a lower capacity/weight ratio, so these batteries are perfect for any - moderately hilly - ride under 10 miles.

 

Now, with that in mind, and knowing that the aforementioned A123 pack fits (just) in the rear pocket of the Brompton bag, I wonder what 4.6Ah you are talking about ? Can you please explain ?

 

http://farm5.static.flickr.com/4063/4240402497_e3ef70920d_o.jpg

 

 

Ours is a 4AH Lithium Iron Phosphate - using 5c rated prismatic cells (x 12) to give up to 20A discharge. Looks like the ping battery with blue heatshrink and includes BMS. Will take and post a picture - but fits perfectly in brompton rear pocket.

Ours is a 4AH Lithium Iron Phosphate - using 5c rated prismatic cells (x 12) to give up to 20A discharge. Looks like the ping battery with blue heatshrink and includes BMS. Will take and post a picture - but fits perfectly in brompton rear pocket.

 

Intriguing. LiFePO4 (Lithium Iron Phosphate) prismatic "pouch" cells normally deliver 3.2V per unit, so a 12S pack would provide the required 38.4V nominal voltage for a typical 36V pack, and based on what you are saying each cell has a capacity of 4Ah (unusual, as I've only seen 5Ah and 10Ah cells). My Li Ping cells measure 150x105mm (and about 6.25mm thick), for a 5Ah battery (12S) the whole pack is 75mm deep. My 10Ah (2P12S) battery is 150mm deep.

 

So I'm looking forward to seeing photos of your battery in the rear pocket of the Brompton luggage Any idea of the price, and where to source it from ?

 

Cheers, Dan