Well, I also have a Li-Polymer pouch 13Amp that I purchased from Andy of Oxygen bikes and a cracking battery it is but the cheap one from China seems every bit as powerful and mileage eating so far.

 

The real test is going to be how many cycles you knock out of it, unfortunately it is impossible, obviously, to determine that so early on.

 

LiPo is more powerful than LiFePo4 in terms of power-weight, but A123 when paralleled in large enough groups is seriously powerful.

 

20Ah of 1C cheap LiFePo4 is good for 20Amps, at only 24v that is still well over a half-horsepower.

Old Timer - I have sent an e-mail asking them to make the pack flatter and more suitable for rack mounting - just hope they tie the two things together - the order placed earlier in the day and the e-mail.

 

They should connect the two if you put the details on the E mail and I make you right to make the battery flat for rack fitting. I E mailed them twice about other things and they replied both times. Although we speak different languages I`ve always found the Chinese to be right on top of the game.

I`m sure these batteries will be fine, you might not have been a member when I wrote that my son had been to China on a buying trip for his engineering company and witnessed several production lines under one roof making the same products for different companies and packaging them differently although they were basically the same products (I`d better not mention the names on them but they spanned the top to the bottom of the UK price range made in the same place from same materials.)

There are different grades in products (we all know that) but I`ve always said that in general people would not set up a plant to make really poor items ( I`m talking engineering and electrical type of stuff) there will always be the exception of course and thats where these forums come in.

Let us know how it goes

 

Dave

The Chinese Duct-Tape people have come on in leaps and bounds over the last few years, it has to be said, and their communications have improved no end.

 

I bought two of their batteries- heavy blighters, but they both worked and both provided a lot of power.

As we are digressing a little. I'll ask "Electric Avenues" - or anyone else come to that - any ideas for re-celling an Ezee battery pack?

 

I am well aware that the stock answer is that it can't be done. However I have always thought that surely it is only a box and should be able to accommodate cells of whatever type. If cells to the value of 36v, 10a can't be squeezed in then couldn't a small aux pack be made up to piggy back it?

 

Thanks, Dave

 

However I have always thought that surely it is only a box and should be able to accommodate cells of whatever type. If cells to the value of 36v, 10a can't be squeezed in then couldn't a small aux pack be made up to piggy back it?

 

That's the point Dave, the case is only a box so low value. For an example from the past, an eZee NiMh battery, same case, cost £200 new in 2006/2007. To re-cell it needed 30 top quality tagless cells which retailed at around £8 to £9 each at the time, so at least £240 to recell, which in any case was particularly difficult with that cell type and case.

 

As for cells of any type with lithium, they must be compatible with the existing BMS or that would have to be replaced as well.

 

LiFePO4 cells are larger for a given capacity and current delivery so haven't been able to go into an existing case normally, but that shows signs of changing.

 

Auxilliary packs of any chemistry and piggy-backed are practical and many of us have done it. Mixing types can mean the need for isolation diodes which normally entail slight voltage losses, but virtual diode lossless circuits are possible as described by Tiberius in this forum.

 

A practical alternative to attempting recelling is to just buy a cheap alternative battery from another bike maker who prices them much lower. Thirty-seven volt lithium batteries range from about £200 to £600. There's some risk in doing that of course, but some cheaper batteries have been proving to be not too bad to date. In some instances the whole content of a cheaper lithium battery could be swapped into your existing case with connections re-made.

.

Pings battery will be lighter, as it is made from pouch cells. Pings build quality is also better.

 

And yet, curiously Ping and Old Timer's suppliers quote almost exactly the same dimensions for the same spec of battery.

 

Weight:5.50 kg ( 12.3 lbs)

Dimension:220x105x150 mm ( 8.7x4.2x5.9 inch )

 

And from Ping

 

Light Weight: 5.6 kg / 12.3 lbs

Small Size: 225x105x150 mm / 8.9x4.1x5.9 inches

 

That led me to think that the individual cells are very similar if not identical.

Li Ping's batteries have prove to be very reliable to date and his support service is good. I suspect that some of the price difference is due to the obvious care that goes into his production and his personal attention to customers.

.

Are you sure about that? Aren't they the same Prismatic (rectangular) LiFePo cells that Li Ping uses? Or was this an earlier version?

 

It seems you were right. another email to the seller requesting a photo of the cells used clearly shows pouches , not cylindrical cells as he first advised me.

Edited November 10, 201015 yr by onmebike

It seems you were right. another email to the seller requesting a photo of the cells used clearly shows pouches , not cylindrical cells as he first advised me.

 

 

Isn`t this better though? I thought these pouches were later technology and therefore makes the battery not old hat at all?

Isn`t this better though? I thought these pouches were later technology and therefore makes the battery not old hat at all?

 

There must be an advantage in using pouches if only the weight saving aspect.

Old Timer - I have sent an e-mail asking them to make the pack flatter and more suitable for rack mounting - just hope they tie the two things together - the order placed earlier in the day and the e-mail.

I'd be interested to know what dimensions their "flat" version for rack mounting is.

 

Colin

I'd be interested to know what dimensions their "flat" version for rack mounting is.

 

Colin

 

E mail him, he will answer you. I seem to remember him saying he could make almost any shape.

As soon as I get an e-mail back from him I'll post the information.

 

I have asked him what size the new configuration will be.

Thanks.

As I don't know whether I want one, or where to fit it if I do get one, I'd rather possibly waste your time rather than the guy that builds them. He can be making your battery instead of taking time out to answer my email asking the same question as you.

 

Colin

Once charged and left alone for at least 24hrs the battery seems to settle on 40.7V for those interested.

Once charged and left alone for at least 24hrs the battery seems to settle on 40.7V for those interested.

 

Mine was last charged a month ago and is currently 40.1volts. I dare say the BMS being permanently connected, consume's some miniscule amount

Edited November 11, 201015 yr by onmebike

Very low capacity?

 

I only use my bike back and forth to the railway station - 4 miles each way with a big hill in the way. I have a 10Ah battery - this seems to be overkill.

 

Is it possible,do you think, to ask for a 2/3 Ah battery?

That would be a bad idea. You will be using the extreme ends of the charge/discharge cycle, and shorten its life. Always better to have a higher capacity and only use a bit of the charge.

I use a DIY 36v, 2.3Ah, A123 battery which gets me to work and home about 8-10 miles.

 

I have been using it nearly a year with no problems. I am of the opinion too, that it is pointless carrying more battery weight than you actually need.

 

Regards

 

Jerry

I use a DIY 36v, 2.3Ah, A123 battery which gets me to work and home about 8-10 miles.

 

 

That's the sort of thing I was thinking of - what does it weigh?

Hi

I have made DIY battery packs with 26650 tagged cells, copper strip for bus bar and bms's supplied programmed to order by BMS battery in China. The last one was a LiFePO4 24v 12Ah one for my wifes Saracen e-bike conversion. It has worked fine for the last 6m. The cells were glued together, shrink wrapped, and put in a home made neoprene 'sock' (made from an old wet suit).

I'm currently about to start on re-celling my old Wisper 905 battery using 26650 tagged batteries and a BMS (same source), this time using Li-ion cells now rated as 800 cycles (individual cells) and 2C (continuous). I can't get enough cells in the original case to get the original 14Ah capacity, but I can get in enough cells to get a 12Ah rated battery plus the BMS in. The cost of the cells and BMS, including shipping to the UK works out at about £165.

It is lower capacity and heavier than the original plus it involves a fair bit of effort and time to make. It does save you £350.00, however... .

When I bought the bike, replacement batteries were quoted as £299-00. I could live with that (just). When it suddenly jumped to £500+, well that seemed like rampant inflation. I don't blame Wisper, I understand their reasoning, I just can't justify that on a three year old bike, which is now of intrinsically low value.

I should add, however, please don't do this yourself if you don't know what you're doing, you could have a BIG accident (you'd be surprised how big), so give it a go if your sure, or else find someone who does know what they are doing to do it for you and keep them in beers whilst they do it !

Phil

That's the sort of thing I was thinking of - what does it weigh?

 

Details in this thread

 

Regards

 

Jerry

Small battery packs. One solution here.

http://www.pedelecs.co.uk/forum/electric-bicycles/6956-diy-stage-9-a123-nano-battery-pack-photos.html#post88165

That's the sort of thing I was thinking of - what does it weigh?

 

Be careful, Jerry is very economical over his 10mile ride, <8Wh / Mile from an 83Wh pack.

 

I think you'll have to try and workout how much Wh you use over your journey, I'm reasonably fit but I struggle to get under 8Wh when hills are involved and my 'consumption' is more like 12~14Wh which would mean a 6 miles range.

 

Going with A123 cells is a good idea as they recover from deep discharge well without the associated fireworks and keep balance exceptionally well.

Be careful, Jerry is very economical over his 10mile ride, <8Wh / Mile from an 83Wh pack.

 

 

Yes valid point if you have steep hills then you may find that 8-10 mile range is halved. A simple watt meter (Turnigy) connected up will tell you how much charge you are using so test it out first.

 

A charger at work is also an option so you can charge both ways.

 

Regards

 

Jerry