Anyone know anything about these LiFePO4 battery packs?

[Russell]

They are being offered on eBay at what first looks like attractive prices however apparently there is NO BMS or charger included and no spec's whatsoever are given. I've emailed the seller asking that he update his ads.





http://stores.ebay.com/e-dittoditto_Battery_W0QQcolZ4QQdirZ1QQfsubZ336379017QQftidZ2QQtZkm


-R

 

[dogman dan]

A bunch of money for a box with unknown contents. Are we at the carnival?

 

[Russell]

Well the answer I received to my email query was neither complete or very informative. They don't seem to realize that people want to know what they are buying

-R

 

[davespicer]

A bunch of money for a box with unknown contents. Are we at the carnival?

If they were SLAs, the old trick of substituting an actual brick would work. Don't know what weighs the same as the newer stuff...

 

[Miles]

The specifications seem to be there now.....

Otherwise: http://www.tenergybattery.com/index.php?page=shop.product_details&flypage=shop.flypage&product_id=350&category_id=23&manufacturer_id=0&option=com_virtuemart&Itemid=27

 

[Russell]

A bit more info is on the Tenergy website;

http://www.tenergybattery.com/index...art&page=shop.browse&category_id=23&Itemid=27

For example the 36V/10AH pack;






Item Number: 31516

Features and Benefits

36V 10Ah LiFePO4 Rechargeable Battery.
Maximum discharge rate: 2C.
Maximum charge current: 10A.
Maximum burst of: 30A.
Recommended charging rate: 0.3C.
Dimensions(L x W x T): 281mm x 123mm x 96mm
Weight: 4.04kg (8.9lbs)


And I'm GUESSING it uses these cells;



Item Number: 30207

Features and Benefits

3.2V 10Ah LiFePO4 Rechargeable Battery.
Maximum discharge rate: 2C.
Maximum charge current: 10A.
Maximum burst of: 30A.
Recommended charging rate: 0.3C.
Dimensions(L x W x T): 231mm x 83mm x 7.5mm
Weight: 278 grams



-R

 

[Russell]

The specifications seem to be there now.....

Otherwise: http://www.tenergybattery.com/index.php?page=shop.product_details&flypage=shop.flypage&product_id=350&category_id=23&manufacturer_id=0&option=com_virtuemart&Itemid=27

Oops I didn't see your post

-R

 

[Russell]

So it looks like the cost for the 36V/10AH battery pack, BMS and charger is as follows;

Purchase price: $231.66
Shipping to USA: $44.00
BMS and 3A charger: $150.00 (and whatever extra shipping they might charge)
Extra fees: $62.00 (they mention these under "payment details")

TOTAL: $487.66

http://cgi.ebay.com/LiFePO4-36V10ah...photoQQcmdZViewItemQQ_trksidZp1742.m153.l1262

-R

 

[dogman dan]

About 419 gets you a 12 ah pingbattery, with about fifty to spare to buy a good box. The cells inside are presumably comparable, so that looks like a pretty good deal there now that we know what must be inside it. I just figured it might be another crappy round cell pack in the box. In the same class, the battery Ypedal is testing looks pretty good too. Those are at Ebikekit.com 10 ah shoud be enough size for your motor.

 

[Russell]

About 419 gets you a 12 ah pingbattery, with about fifty to spare to buy a good box. The cells inside are presumably comparable, so that looks like a pretty good deal there now that we know what must be inside it. I just figured it might be another crappy round cell pack in the box. In the same class, the battery Ypedal is testing looks pretty good too. Those are at Ebikekit.com 10 ah shoud be enough size for your motor.

The problem I see with Ping packs is that he uses 4AH cells which means he needs to use a lot of them when constructing a battery pack. Each connection means another possible point of failure. Also having so many soft cells bound together with only duct tape (c'mon duct tape, really ) lowers the physical integrity especially on bigger packs. Sure you can put it in a case of your own design but I would still prefer to have a battery pack made with 10AH cells fitted to an enclosure made for it and assembled using modern methods. Frankly I don't think Ping will be around at the end of this year either unless he upgrades his product.

The pack Ypedal is testing looks pretty good however I don't care for the size of the thing. I want something which fits in my rear trunk bag leaving me the spare room, compartments/pockets for all of the other stuff I carry along, that or a battery which fits elsewhere on the frame, like in the triangle.

-R

 

[John in CR]

Don't knock the duct tape...lithium batteries change size with status of charge. Rigid packs will prove to be problems, because either they are too loose or too tight. I got some LiFePo$ pack in steel boxes, and they are definitely coming out, and not just due to that unnecessary weight. Also the duct tape is connected better thermally to the cells, and transfers heat better to the exterior than anything with any airspace can. Some kind of plastic will probably prove to be the proper packaging, but in the meantime I'm going to settle for boxes made of 3mm thick epoxy impregnated plywood...flexible enough and strong enough, while still allowing a good finish. The method I'm using comes very close to advanced composite structures in terms of weight, but is a snap to work. Think boats and work backwards instead of bikes made of steel tubing and working forward, then you'll find much better and easier solutions with little weight penalty.

John

 

[dogman dan]

Cut open a 10 ah cell, and you find some subcells inside connected paralell. So it's really still smaller cells. Pings may have subcells inside the pop tart, sombody cut open a ruined one and tell us. Like I said, it's as good a deal as ping, and for 50 bucks, the box is nice. My box is nice too, and cost about 10 bucks, so I was able to shave a few off. Nobody should run a naked ping. It looks like a decent deal, the only question is CS if there is a problem. We know about ping, so that would tend to make me go for that. I just wanted to point out that it wasn't cheaper than ping. Pings prices were better last year, but now he may have to lower the price with this kind of competitor.