New BS LiCo --> LiFePO4 Charging Adapter

[xyster]

Found these "smart cable" lithium charger adapters:

https://2339072343.monstercommercesites.com/index.asp?PageAction=VIEWPROD&ProdID=3285

* The smart cable is designed for converting a 3.7V smart charger' into a smart charger for 3.2V Li-Fe-PO4 cell at lower cost.
* Just plug the cable's two hole connector into 3.7V smart charger' s two pins plug ( big hole or / pin is positive )
* Specifications
o One DC regulator is installed inside cable and provide 3.8V cut-off voltage.
o Max. charging current : 1 Amp
o Cut-off power when battery pack ( 1 cells) is full
o Red wire / clip is positive polarity.
o Please sure charger's polarity match with battery pack's before charging.

They sell them for one to four cell chargers for their 3.2V 1.3AH A123-like high-rate LiFePO4 batteries (which they've just dropped the price of too):
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=3071

(note the different domain names of the two BS links-- wonder what's up with that?)

Too bad max charging current is 1 amp. Would a couple work in parallel with my single-cell 1.5A lithium chargers in order to charge subpacks of A123 cells (that I may, over time, replace my lithium cobalt cells with subpack-by-subpack)?

Could these little voltage regulators be over-amped without damage or a change in the output voltage?

 

[bobmcree]

the so-called "smart cable" is obviously just a Schottky diode with a .5V drop which you can buy for less than a buck for 3A parts. if you had these diodes in the outputs of the chargers you could connect the cathodes together and each would still regulate its voltage so it should work fine to parallel them and increase charge current.

i have been lusting after A123 cells for months now, and their developer packs are a total ripoff at $120/6 cells. I have tried to buy 100 cells from them but they are not interested in little guys. I did not want to fool around buying a pack at a time at different prices on ebay, so i waited til now, and there are finally enough packs around that ebay prices have stabilized at about $115 for the 10 cell DeWalt packs.

I just bought 7 packs and I will be making a 10 lb 53V 9.2 Ah pack for one of my bikes. Total cost with shipping for the 7 will total about $900 compared with about $1400 from A123 just for the cells in developer packs. These guys are missing out on people developing applications for their cells by being so stingy with the small quantity buyer, but they don't want their cells getting a bad rap from unqualified users, so i can understand it. If the cells give me the promised 1000+ cycles to 90% DOD it will be $900 well spent.

I know you and others have made some posts on the A123 cells, the BMS, etc. i bought one of their chargers to see how the 3 stage system works. If you could point me to the threads with the latest info on the cells i would appreciate it.

The pack and BMS should fit easily into one of the Pelican cases i am using on the Cruzbike.

-bob

 

[jondoh]

Hi Bob,

I've been following your thread on the powerassist yahoo groups. You have quite a ride there-- very nice!

Anyway, I'm using e-moli milwaukee batteries but I do understand from users from the old voltage forum that you'll have to bypass the BMS from the battery outputs. You'll have to get the special tool to open the packs and then solder AWG#10 wires somewhere inside before the BMS. The problem is that the BMS will blow up when they see voltages greater than intended.

 

[xyster]

the so-called "smart cable" is obviously just a Schottky diode with a .5V drop which you can buy for less than a buck for 3A parts. if you had these diodes in the outputs of the chargers you could connect the cathodes together and each would still regulate its voltage so it should work fine to parallel them and increase charge current.

Thanks, Bob! I would've never caught on to that myself...

I just bought 7 packs and I will be making a 10 lb 53V 9.2 Ah pack for one of my bikes. Total cost with shipping for the 7 will total about $900 compared with about $1400 from A123 just for the cells in developer packs. These guys are missing out on people developing applications for their cells by being so stingy with the small quantity buyer, but they don't want their cells getting a bad rap from unqualified users, so i can understand it. If the cells give me the promised 1000+ cycles to 90% DOD it will be $900 well spent.

Too bad they won't sell in quantity to get people hooked on their product...suppose production isn't yet ramped up enough to meet demand from their big, contracted clients of the powertool market...

I know you and others have made some posts on the A123 cells, the BMS, etc. i bought one of their chargers to see how the 3 stage system works. If you could point me to the threads with the latest info on the cells i would appreciate it.

I don't recall any threads here with great a123 info. There's some discussion here:
http://endless-sphere.com/forums/viewtopic.php?t=547
Mike sells packs of emoli's and a123's he gets from suppliers without breaking into powertool packs:
http://www.bigerc.com/

At the old V there was a great thread from a member who installed four dewalt packs in his scooter. I recall he needed to bypass the dewalt BMS by tapping the main power leads on the cells.

The pack and BMS should fit easily into one of the Pelican cases i am using on the Cruzbike.

I really look forward to your review.

 

[knoxie]

Hi Bob

Bikes looking nice, I have e-mailed you a few times with no reply? you got some spam filter going on me :lol:

How you finding the BMC?

Knoxie