Anybody have any experience with Foxx power

[sabb]

I am still building my bike but as a test a while ago I put a cheap kit on my girlfriends bike it works and came with SLA so she wont ride it because its too heavy. my response was to buy 12 * 10amp hr cells from Foxx power.

This week I started testing them to get ready to put the pack on the bike and I am getting really horrible results

My CBA wanted to test a lifepo4 cell at 1c down to 2 volts, and at first I thought that was too low, but these cells sag so much that 2 volts seems correct even at 1/2c

after charging to 3.6 until charge current dropped to .2 amps I assumed the cells would put out roughly 10 amp hrs

but at 5 amp discharge down to 2 volts

my best cell has given me 8.4 amphrs and the worst was 5.9 amphrs

now what i am wondering is do I finish to build this pack hoping these cells will get better over the next few cycles or do I throw them in the bin

Thanks in advance for any advice
Stephen

 

[mwkeefer]

Hello and welcome!

Most LiFePo4 packs will develop a bit, or break in over the first 10-20 cycles I suppose... if your still seeing low capacity from the pack after this many cycles... then you have your answers:

> my best cell has given me 8.4 amphrs and the worst was 5.9 amphrs

And honestly your running 12S LiFePo4 for 36v nominal - at 3.3v per cell nominal it's actually 39.6v nominal..

How are you charging / balancing this pack? Are you relying on the stock Foxx BMS and Charger?

-Mike

 

[sabb]

I have not assembled the pack yet so I am charging single cells on a turnigy 8150.

I bought but have not wired a signallabs 12s bms to maintain balance and protect for lvc.

No charger sourced yet but I know I need to get voltage up high enough to balance so I cant use old sla charger that came with the kit.

I am going to retry the worst of the cells and see if it gets better.

Thanks
Stephen

 

[sabb]

So I cycled the cell again that only went 5.9 amp hours at 5 amps and at 10 amps the cell managed 5.7 amp hours and was warm at the end of discharge.

Should I keep cycling it and if yes should I charge fast or slow and discharge fast or slow trying to get it to come to life.

btw i found new highs of 9 amp hours from some of the last to cycle so they are not all bad

Stephen

 

[kriskros]

i have a foxx 36v 20amp pack... with their cell balancing charger[no bms]... took about 12 cycles to get the pack to 3,64- 3.65v fresh off the charger... using an infineon26v 35amp with CA... recumbent trike,total weight of rider and trike approx 220lbs puma motor.... CA reading, max speed 24.6mph,vmax 39.9,vmin33.6 .8.5a....total miles 22.6 no major hills, paved trail... have made this run several times with very similar results... have 43cycles on battery

 

[The Mighty Volt]

I don't have any personal experience of Foxx but they are selling on Ebay and some of their feedback is negative.

http://cgi.ebay.co.uk/Foxx-Power-LiFePo4-20a-Cell-/140349959859?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item20ad826eb3

 

[biohazardman]

Foxpower I remember them. Got my first e-bike batts 36V 10AH there a couple years back. I had no trouble with it on my 500W GM motor so after near 2K miles I upgraded and bought a 48V. It had a couple bad cells and they replaced them promptly. It was about that time that I had enough A123 dewalt packs to build my first pack. Foxpowers have been sitting on the shelf ever since. I have a considerable amount of investment there so probly should look into getting a few more batts and going 20AH as they suggested. Alot of bulk and weight though so needs to be in a trailer I have been thinking.
I think you may have a bad cell or two. You might want to charge them all up evenly and just put them together and use them for a bit at 1.5-2C. The cell ballancing charger should take care of things from there on out. If it does not e-mail Zane and ask him what you should do. Things can go slow with e-mail so maybe call him like I should do shortly.

Here is the post on my dealing with Foxpower and the batts themselves.

http://endless-sphere.com/forums/viewtopic.php?f=14&t=6586&p=140425#p125502

 

[liveforphysics]

Foxx power = fail.

Jumped into the market years ago ripping everybody off with dirt cheap cells that performed like dirt. Also sold over priced chargers that many failed in minutes of use.

IMHO, stay away from those guys.

 

[sabb]

Thank you all for the advice

I dont think at this point I would recommend this kind of cell for anyone who wanted a small pack on an ebike they claim they are a 2C cell and on the best cell at 1.5C they droop and get hot. Luke is right "FAIL"

I will prob ask the vendor about the 5 amp hour cells but I now do not think this pack will ever see a bike.

Since I bought these I decided to try batteries with some real power so I bought some 8s 5.8 amp lipo for one of the bikes I am building and a 16s 20 amp hour pack on its way from cell_man for the other bike

Stephen