# Review: Xeccon 2S2P Battery packs with Samsung and Lishen 18650 cells



## ledoman (Apr 17, 2012)

From the mtbRevolution | Xeccon mtb Racing Bike Lights | Road & Commuter LED Lights I've got two Xeccon battery packs to test. Both packs looks from outside the same but one has *Samsung ICR18650 26F* and the other *Lishen LS1865SK* Li-Ion battery cells. The first is Koreian and the other China manufactured. Since we mostly have bad experience with China made Li-Ion cells this is chance to see if those are any good.

Both packs are 8.4V and are declared to 5200mAh nominal capacity.

First let describe the outer look. Xeccon has made very nice pouch I've never seen before. It is rather thick with wide strap and very nice soft feeling. It should also protect the pack thermaly. New pouch has rather strong smell which should slowly fade away.























The connector is square from outside, but inside it is same tipical 5.5x2.1mm sized compatible with most chargers we use. So no problem for charging or using with Magicshine style male connectors. It is only they won't be water tight. There is also adapter cable avalaible from square to round shape. Probably Xeccon wanted to tighten up their packs to their lights and/or make them distinctive to others.
Cable is about 40cm long and quite thick. It is soft enough so it won't break soon.









When we take pack out of the pouch we can see very nice ruberized protection shell we have seen also with some otherpacks. Shurely it looks more classy with its Xeccon title on it.









Dismantling is tipical with "window" poped out at the bottom.









*INTERNALS*

Now from here one we can see some differencies. The Samsung pack had broken shrinkwrap and patched with capton tape.








On the other hand Lishen (LS) had double shrinkwrap.








Both had same PCM, though. It is funny oriented so you need to desolder middle wire in order to see the board which is not the case with the other packs.
















PCM was cropped with some paint.









It uses some tipical FETs 8205A and looks like very precise controller chip 21DB6.









*MEASURMENTS*

Now to the most interesting part, capacity measurments. Both packs came balanced within 0.01V, but Samsung pack had 8.31V while LS had 7.33V. So it looks like Samsung pack has been at least charged before I've got it. Have no info about its prior usage. LS on the other hand came at proper storage voltage. Both pack very fully topped charged with 8.43V charger and prior discharge double checked with my hobby charger.









As always I was using Lilo setting to discharge down to 2.8V per cell and 2A current. 
What was interesting and different from all previous tests was the *overdischarge* limit triggered already at *3.02V* so I couldn't run test down to 2.8V. This is very conservative aproach from Xeccon. Also the *overcharge* protection kicked in at *4.258V* per cell which is very good.

*Discharge curves for Samsung 26F pack.*








I've got barely *4800 mAh* out of it. This is somewhat dissapointing. I was expecting about 5000mAh, at least. Then again I don't know how it was used prior this test and PCM has kicked in. From the curve direction I would say I would get another 200mAh down to 2.8V. The good side was both curves maches very well, so the quaity of the cells is pretty even.

*EDIT*: After thinking I might got the pack which has been overheated. If you look broken shrinkwrap picture you can see it has been cracked. This might happen if exposed for some time to very high heat. Maybe the manufacturer was aware of that and give it as a test pack to the seller. Accidentialy I've just got that one to test. Who knows but I has been prommised to get new one in a month or two repeat the test.

*Discharge curves for Lishen pack.*








Here I've got *5100 mAh* which is very good for China branded cells. Both curves were pretty close till the end.

*Comparing curves from both packs*. 
I've taken results of both tests and put them in Excell spreadsheet. It took me some time to make a proper graph. On X axis there is capacity readed every 2 seconds. On Y axis there is Voltage as usual.









As can be seen both packs has somewhat similar curves. LS has higher beggining and lower middle part, but keeps running longer. Of course comparation is somewhat unfair as I don't know what was hapening with Samsung pack before I've got it to test. If I would get another pack I could tell for shure. Based on my previous tests of single Samsung 26F cells I would say they should be more like Lishen or even better and we should get full 5200 mAh discharged down to 2.8V.

Last test was made on PCM to check how much current it holds. I've connected two powerful lights with 10step drivers and I've got *6.7A* before if cuts off the power. So I can assume it can stand somewhere up to 7A.

*CONCLUSIONS*

*Pro:*

Very good pouch - much above the average
Watertight rubber shell
Very precise PCM and good overcharge threshold at 4.26V 
High quality cells - specialy Lishen is nice surprise
Good capacity on Lishen and very likey the same on Samsung
Good thick cable

*Con:*

Overdischarge treshold on PCM is set to conservative, 2.8V would be better, specialy if the Xeccon have choosen to use the same PCM with higher capacity Panasonic cells. Shurely 3.0V treshold is better for the cells lifetime 
Some welding stripes to the PCM could be wider
Square connector (though it is compatible with 5.5x2.1mm)


All in all we have proven not all China Li-Ion cells are bad. Lishen is suprisingly good. Hopefuly we would see more and more quality cells produced in China. Of course we don't know how they behave on long term use, we can just hope they are doing good.

And at last but not least I'll have to wait for another (new) Samsung pack to correct this review if it proves better.

Some links:
Lishen: 
??LR1865SK 2600mAh????-???
MTBRevolution: 
Xeccon LS 8.4V 5200mAh Li-ion Battery
Xeccon Samsung 8.4V 5200mAh Li-ion Soft Shell Battery


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## tigris99 (Aug 26, 2012)

Surprised your Samsung pack came out so low on capacity. I ran mine down (using a light) and got 5100mah on recharge.

Im wondering if they accidently sent you a test pack.

The Lishen pack looks really promising! Seems they can make useable cells over there.


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## ledoman (Apr 17, 2012)

Yes, as I've written in text I don't know what has happened to this Samsung pack in the past. The fact is it came almost fully charged. It may be stored fully charged for longer time or whatever. Based on my previous Samsung 26F tests the pack should give full 5200mAh minus some looses in PCM and cabling. I just wanted to make honest review so I've described it as I've measured it. Maybe I should test another one to prove things. 

Otherwise both packs are much above average chinese ones. They might be more atractive to the USA based people who wants to get away from their crappy packs having them "localy" avalaible at MTBRevolution.


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## Cat-man-do (May 16, 2004)

Very nice review. I think the difference in capacity between the two was the difference in PCM cut-off ( as you said ). It doesn't surprise me that the Chinese can make a good 2600mAh Li-ion cell. BAK makes a good 2600mAh cell and they are Chinese. Whether they can make a good 18650 cell over 3000mah though remains to be seen.

It seems that Xeccon might be shopping around for cells that are less expensive but still perform well. They need to lower their cost if they want to stay competitive selling batteries.


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## ledoman (Apr 17, 2012)

Thanks Cat. Right now I'm discharging Lishen pack from behind of PCM so I'll try to see what influence the PCM has.


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## ledoman (Apr 17, 2012)

Another interesting thing. I've done additional discharge test *bypassing the PCM, connector and cabling* part of the Lishen battery pack. OK not everything rest was left identical as I had to use aligator clips directly connected to the battery stripes, but anyway just to give you an idea on voltage drop might happen over those three elements.








Graph is showing voltages of the whole pack and the X axis is the capacity. X numbers are bit off and don't know why. At 2A load I've got 5149mAh without PCM.

You can see the voltage curve is somewhat higher when running discharge right off the cells. Don't know which element is the worst, but I'm shure connectors we are mostly using are outdated. Cabling itself used in this pack is good about 20AWG and not to long. The PCM is more or less standard.


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