# Chennic single cell LiFePO4 charger



## mora (Nov 11, 2009)

I got myself one of these chargers. I bought it from eBay though. It was 25$ + shipping which I thought isn't bad for a single cell charger.

Here is a link to the product
http://www.chennic.com/show-products.asp?id=87&JCSC10

and eBay auction
http://www.ebay.com/itm/Charger-Sin...&otn=5&po=LVI&ps=63&clkid=5424364785805818417

Product ID is the same on both sites (JCSC10). Even product description is copy-pasted to eBay. I believe it is the same guy/company behind sales in both sites. 

Then the main thing: product description doesn't match with real product. It seems to work but doesn't really do CC/CV at all. It starts at 10A nicely but amps drop soon as voltage rises a bit. When voltage is at about 3.5V charge current is less than amp and charger "finishes". I thought CC phase is 10A until voltage is 3.65V (or whatever set voltage level) and then amps start lowering when it is CV phase.

I opened the charger and it seems 100% analog. At least I didn't spot any ICs on circuit board. It has a small single cooling fan which is pretty noisy.

I thought I'd post my experiences here. I've tried contacting eBay seller and Chennic via email but haven't received any replies.

Does anyone else have this chager? Does your unit work as it is supposed to?


----------



## brainzel (Jun 15, 2009)

The charger is OK and seems to charge as it should.
When your battery rises up to the end of charge and the constant currant phase changes to constant voltage, the cell can not swallow so much current anymore.
The charger reduces the current to match your endvoltage.

So, everything is OK


----------



## mora (Nov 11, 2009)

but why doesn't current stay at 10A until cell hits 3.65V? It takes over 20 hours to charge one single 90Ah cell. Current drops in 15min after connecting the charger.


----------



## brainzel (Jun 15, 2009)

to charge your cell up to 3,6V @ 10 amps, you have to raise your voltage much higher than the cehnnic single cell charger might could.

F.ex. I charged a single 130Ah CALB cell manually @13A by increase the power supply output voltage up to ~6V to get such a high current @3.45V cell teminal voltage.


----------



## rwaudio (May 22, 2008)

mora said:


> but why doesn't current stay at 10A until cell hits 3.65V? It takes over 20 hours to charge one single 90Ah cell. Current drops in 15min after connecting the charger.


Although it's not in the same ballpark for price, I've been using the Cellpro Powerlab 6 to charge/discharge A123 20Ah cells and it works great. My cells are around 19Ah so I'm charging/discharging at 38A (2C) which is just under the chargers maximum of 40A charge or discharge. 

It will hold 38A till the cell hits 3.65V then tapers the current as expected and terminates at C/20.
Charging at 40A you could easily charge empty cells in under 2 1/2 hours. It will also tell you the internal impedance of the cells while charging. You do need a decent power supply or 12v battery to power it, and if discharging above 8A you need power it from a 12v battery so it can dump the current back in.

It connects via USB and lets you control the charger in software and gives you graphs and tons of info. Attached are some graphs it produces on a top up then full discharge and then recharge of a cell.


----------



## mora (Nov 11, 2009)

Now that's a single cell charger.

What's a single cell charger if it can't charge a single cell properly? If it couldn't push high enough voltage to a cell to keep amps high then it is bad charger, right? I'm still saying this Chennic single cell charger doesn't work right.

Luckily I have only 15 cells to cycle now.


----------



## brainzel (Jun 15, 2009)

To push the last 10%/15% Energy in my battery (130Ah) @ ~ 10A charge current, I have to raise the voltage up to ~6V.
So if the chennic goes into the CV phase (3,65V), there is only 35W taper down to 3.7W of energy floating into the cell.
That isn't a reason to complain, it's the normal behavior of a charge curve 

What did you expect to get for $25 bucks? ;-)
In this cheap class of charger, I would be lucky if it hits the right end voltage.


----------



## mora (Nov 11, 2009)

I don't care about the last 20%. This charger does not hold 10A for more than 5 minutes on completely empty cell. There is no CC phase at all. I noticed this when using clamp-style meter on charge leads.

Somebody else might also buy this charger because it is that cheap. I hope they find this thread before they decide to put their 25$ on this. If someone already got this charger I'd like them to share their experiences too. Because if I have faulty unit I might try my luck and buy another one.

I attached a picture of what I mean. First image represents current (hehe) situation. Last one is correct CC behaviour, right? See the difference?

Still I haven't found single cell chargers for lithium cells that do 10A or more. I've tried few RC chargers but haven't had good luck with them either.


----------



## brainzel (Jun 15, 2009)

Don't get me wrong, I think it's great to swap experiences.

I was just about to buy one myself, wrote to chennic and asked about adjustments, because I would not charge to 3,65V.
So it wasn't a single charger for me.

I expected a longer or any CC Phase ... the course you describe would disappoint me too.

Seems to be the same behavior as my Junsi iCharger 3010B. The internal voltage is 3,65V and the charger taper down the current.
No matter how the real cell voltage is ...


----------



## mora (Nov 11, 2009)

Yes, there must be something like that going on inside of that thing.

I'll replace those alligator clips with big ring terminals or 10mm^2 lugs. I'll also replace those charging leads with a bit thicker cable there if PCB allows. If not I'll just cut current leads as short as possible and solder bit thicker cable to the remaining lenght of original charge lead. Wires don't seem to get warm now but maximizing contact area can't be bad.


----------



## brainzel (Jun 15, 2009)

If you want to push 10A into your cell, get a power supply f.ex. a MeanWell S-100-5 or S-40-5. The 40-5 will provide ~9A of power, until you take it of your battery. The 100-5 about 20 amps (~$20 - $30).
An arduino board, a current sensor and e relay and you can terminate the process at your personell point of charge.
That's the way I do it at the moment.


----------



## Yukon_Shane (Jul 15, 2010)

I used this charger to complete a top balance for my 50 100ah cells. I wired them all in parrell and left the charger on for just over 2 weeks before the current had dropped down to 1 amps and the pack was resting at around 3.35V. It worked fine but I would also question the manufaturers CC 10 amp claim.

From what I observed the charger seemed to provide no more then 4 amps at the beggining of charge (cells half full) and dropped down from there which says to me that it's really just a constant voltage charger set at 3.65 V.

Not the quickest way to top balance a pack but realistically a person may only do this set-up once so I couldn't really justify purchasing a high current power supply that I'd probably never use again.

In my opinion this charger is a reasonable good tool at a good price but certainly nothing special and likely not a true CC/CV charger.


----------



## vilkas2004 (Apr 25, 2013)

hello i have 4 of this chargers and looks they work great i m charging thundersky 100ah cells 26 of them and amp meter shows 10 amps to 15 amps at moments even when cell has 3.75 volts. yes one of them chargers was bad so i got one more and till now don,t have any problems.i use them to balance my pack and fully charge 2 cells so it takes me 6 to 7 hr to charge but looks like they have all the capacity.


----------



## mora (Nov 11, 2009)

I put my Chennic unit to trash bin and got myself a Powerlab 6. This happened months ago already. I power it using 5x 90Ah old Winston cells. Now I got what I wanted and should have got it right from the start. ~200$ price tag sounds bad but it is all worth it. Makes balancing whole army of cells fast. And it will also help analyzing a suspected bad cell. I also have other use for it as hotwire cutter power supply (there is even a factory program for this purpose). Oh, and I also charge small rc lipos with it. I really like the internal resistance measurement feature it has. Enough of marketing speech for Powerlab.

My Chennic was propably bad or vilkas2004 got lucky. It just seemed a simple transformer with some additional protection circuitry.


----------



## dillond666 (Dec 27, 2010)

I bought the 20a version of that charger from ev-power in Prague.
It works quite well in the CC phase but on the CV phase it charges until the current is annoyingly low and takes forever.

I am going to use a Picaxe or Arduino to terminate the charge at about 4 amps to save time.


----------

