Lithium Battery Reports & Tests' 9/08

kilowatt said:
I took apart a 36 volt 20 amp cammy to divide it in two for panniers. I found two 18 volt 20 amp batteries series connected into a 2S19P configuration. If your thinking about getting two 36 volt 10 amp out of it, then forget it. The number of individual cells is staggering but dividing it in two is fairly easy as long as your careful not to lift a spot weld while removing the duct tape; I did. Another thing to watch is your BMS sense wires. On my BMS I have two connectors; looking at the two connectors head on the pinout is from left to right. The large connector is on top and starts with pin 1 (channel 1) on the left through channel 8 on the right. The 4 pin connector on bottom is left to right channel 9-12. I got this info from cammy. :D :D

I ran into problems trying to find a low voltage cell (within a large bank) so I decided to remove 60 cells to bring it down to 15 amps (I think). I'm still working on it but have decided to move to 48 Volts with 4 ea 12V 12Amp SLAs. I don't think I will invest in another battery from China, especially the cylindrical type; we need a US supplier! I hope this helps you out.

Dave


Cheers Dave. It sounds..."fun"...... :D
 
Battboy said:
Just responding to the above Poster as far as finding a U.S. supplier.

DH

?? Are you confirming that your new cells are made by CammyCC? Or did I misunderstand to which 'above poster' you were responding?

I'm a 'US supplier' of cells - when I talk tech, I post on the forum. When I want to post something for sale I use one of the 'sale forums'. What am I doing wrong?

Andy
 
Responing to Kilowatt (Dave): I ran into problems trying to find a low voltage cell (within a large bank) so I decided to remove 60 cells to bring it down to 15 amps (I think). I'm still working on it but have decided to move to 48 Volts with 4 ea 12V 12Amp SLAs. I don't think I will invest in another battery from China, especially the cylindrical type; we need a US supplier! I hope this helps you out.

Has nothing to do with Cammy.

DH
 
Anyone know anything about FullRiver (Fent Battery) LiFePO4 packs? (Thinking about the 48 V 12ah to 20ah packs)
http://www.fentbattery.com/en/Cylindrical.asp?id=452
Thanks
 
AndyH said:
Battboy said:
Just responding to the above Poster as far as finding a U.S. supplier.

DH

?? Are you confirming that your new cells are made by CammyCC? Or did I misunderstand to which 'above poster' you were responding?

I'm a 'US supplier' of cells - when I talk tech, I post on the forum. When I want to post something for sale I use one of the 'sale forums'. What am I doing wrong?

Andy

Hi Andy....I advise you check this out with the other forum members but it is my belief that "Cammy_CC" is a mere vessel for some greater power in the LifePo world. Cammy, Volgood, 1448Elephant, Vtac etc are all, it seems to me, working for the same person, or may well be the same person.

While we are on the subject, I chased down a sample from one of the people whom I feel is behind all of this and here is what I came up with:

4579172130_8237cac7e9.jpg


and

4579243676_9fa7b3d2e7.jpg



and, for comparison sake, a genuine A123 M1 has been added, just to provide a visual aid.

4579242804_561ac9f13c.jpg


But from my own experience, neither of those cells in the cardboard sleeve are identical to the ones in the CAMMY/VOLGOOD packs.

For what it is worth, I have weighed both of the batteries and come out with 38g and 82g for the 18650 and 2665 respectively.

That means a Cammy_CC 36v 20Ah would weigh, using the 18650 cells, around 7.6Kg and I know for a fact it weighs a lot more. I would like to know where they are getting their cells, they are obviously paying very little for them, by and by.
 
Ordered from CammyC on ebay - was labeled with V-Power sticker 48V 15Ah model.
Got mine for $325 incl. expedited shipping (at extra $50).
Shipping was more than battery closing at $132.50.

DSC00172.jpg

DSC00173.jpg

DSC00174.jpg


Not pretty up in there, indeed. I used the same black duct tape (Home Hardware) but I'm worried now that it won't come off as easily when I test the suspect cell I touched with a knife.
Had my first good run today and it didn't get hot at all I marked the outside where bad cell is with a couple of red stickers. I want to get a few charges on it then I'll think about how it will get permenantly arranged, prob in a plexiglass enclosure but it's so prone to scratches, maybe fibreglass but it's so dirty to work with, something better but it fits really snug into my padded rear carrier bag, for now.
 
Hi there great pics Chillboy- can you possibly show some photos of how the BMS was wired up.

From what I recall, Cammy uses two of those sprockets with the ribbon wires, but I forget how he had them wired up.
 
I've had my Ping 2.0 24V 20AH battery for about 1.5 years now, and the current draw on it averaged at 35 amps over 90 cycles. I discharged it on average to about 60% SOC on average, while completely draining the pack about twice. The second drain was a discharge test.

My amp meter measured the discharge to be about 19.3 Ah, though it was really slowing down and was "impractically usable" at 18.5 amp-hour due to the voltage drop. I measured the pack's internal resistance near the beginning and calculated .1 ohms, and near the end (Around 17 AH of discharge), it was at around .2 Ohms.

This suggests a decline to 95% capacity over 1.5 years. This suggests it may take 4.5 more years at this rate to reach 80% capacity, assuming it isn't destroyed in an accident first. So, all in all, this suggests a practical lifespan for ping's type of lifepo4 of maybe 6-7 years in terms of calendar life. It may be shorter from a cycle life perspective if you use it more frequently than I do.
 
HIGH-POWER LITHIUM POLYMER BATTERY
with build-in balancers
37V/27Ah/66C/1000Wh
Terminal clamp 2XPLUS 16mm² / 2XMINUS 16mm²
designed for the LOWRACER HYBRID SPEEDBIKE

The battery pack is made from 20pcs 11.1V/4500mAh KOKAM-cells, normally it's used for RC-models.
Inside the battery the powered branch hasn't got any cables, here are power rails!
Charging:
Fast charging with 45V/54A in about 30minutes, but then you'll need a charger with 2500Watt. In all cases THE HOUSE GETS DARK.....
Normal charging with 45V/4A in 7hours, that's OK, the battery don't need to cooled and the cell has got a much longer live!!

WORK: about 60hours
MATERIAL PRICE:
20pcsX125€ Kokam cell 4500mAh/11.1V
+20pcsX15€ Balancers
+2 pcsX20€ 120X120X25 thermal controlled fans
+100€ incidentals
---------------------------------------------------------
# 2940€ result


!!!!!DANGER!!!!!DANGER!!!!!DANGER!!!!!DANGER!!!!!DANGER!!!!!
PLEASE DO NOT SHORT-CIRCUIT IT or you get a copper-coated visage in milliseconds!!!


[youtube]ysr9HgIY4A4[/youtube]
 
I like that those cells have a tab on each end. That makes a lot of sense from a design and performance perspective in a pouch cell. Kokam makes good stuff, I bet you will be happy with that pack for a long time. :)

That pack cost you a fortune though, both in labor and materials!

That's $4.20 per Watt-hour.

If I was looking to do a no-expense-spared 1KW-hr battery, I would use these cells:
http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=11956

Then you would have 45-90C rated cells, and all the LiPo packs would cost about $1200 shipped.

Or, if you were looking to have the same 1,700amp peak discharge ability, but wanting to have over twice the pack capacity, you could go with these guys:

http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=8586

Arranged 10 in parallel, 2x6s in series, and have a 44v 50Ah pack with 1,700amp discharge ability, for under $1,000 in battery cost (+$~200 in shipping). Then with 2,200watt-hours rather than 1,000watt-hours, you could have about 2x the range. :)
 
liveforphysics said:
I like that those cells have a tab on each end. That makes a lot of sense from a design and performance perspective in a pouch cell. Kokam makes good stuff, I bet you will be happy with that pack for a long time. :)

That pack cost you a fortune though, both in labor and materials!

That's $4.20 per Watt-hour.

If I was looking to do a no-expense-spared 1KW-hr battery, I would use these cells:
http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=11956

Then you would have 45-90C rated cells, and all the LiPo packs would cost about $1200 shipped.

Or, if you were looking to have the same 1,700amp peak discharge ability, but wanting to have over twice the pack capacity, you could go with these guys:

http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=8586

Arranged 10 in parallel, 2x6s in series, and have a 44v 50Ah pack with 1,700amp discharge ability, for under $1,000 in battery cost (+$~200 in shipping). Then with 2,200watt-hours rather than 1,000watt-hours, you could have about 2x the range. :)


Ok, 1000Watt-Hours is much stuff for an E-Bike. Also I charge it with my pedal alternator.
If I am not lazy I've got an unlimited range...

BUT, ANOTHER THING:
I've got seen that the marked "C" isn't the reality!!!
I'd taken my informations from the german page http://www.TrueC.org
The results are on this page: http://www.truec.org/tc-tested.html
 
LOWRACER said:
.... Also I charge it with my pedal alternator.
If I am not lazy I've got an unlimited range...

Wow! You da man! :shock:

...uh, sorry... didn't mean to interrupt the thread.
couldn't help myself.. anyone who makes a comment
like that on an eBike forum....nevermind.... Carry on.
:oops:
 
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