Reviews of Sony Konion US18650V3

[cwah]

Hello all,

I've decided to get some Sony Konion US18650V3 cells rated at 2250 mAH and see what they have in the stomach:

You can find them in europe here:
http://cgi.ebay.fr/ws/eBayISAPI.dll?ViewItem&item=181227591293

First, they weight 44g as advertised:

In term of resistance, my icharger found 58mOhm. Doesn't seem bad, but not as good as lipo.

Single cell at 2A charge (1C):

Cell is a little bit warn, not too much. What's surprised me was that the cell reaches very quickly 4.2V, however it was only 60% full. Yes, only 60% full at 4.2V under load. I think A123 perform much better in this area and are fully charged when they reach 4.2V. So please be careful to let your charger pluged in for at least 30mn more to be sure your pack is charged.

Single cell discharge at 2A (1C):

The cell gives a nice discharge curve. Voltage goes down under 1C load but it's not too much. Cell is little warm and gives 2048mAH capacity.

Single cell discharge at 4A (2C):

The voltage literally collapse. The cell is still able to give 1850mAH until it reaches 3V. The cell gets very warm at the end of the discharge, but it looks able to handle 2C current without too much stress.

 

[district9prawn]

Funny charge graph. Can you put one with the charge current on top as well?

 

[schwibsi]

The resistance is 4 times as high as it should be.
That's why you have such a high voltage drop. The cells are either broken or fakes.
The 2250mAh capacity are for a full cycle of 4.2V down to 2.5V per cell.

Did you buy them from that ebay source? I've never seen that large print on original Sony cells.

 

[wojtek]

subscribed.

 

[cwah]

Thanks schwibsi,

yes from the shop, I've let before the connections a bit loose and what you told me made me think it was probably the reason resistance is so high.

I decided to clamp the cell properly:

Now it reads 58mOhm. Still far from lipo at few ohm, but much better. Let's test them again.

 

[Teh Stork]

These should be around 30mOhm internal resistance. I don't know if your measurement is inaccurate or if you've been delivered bad cells. Ebay has provided me with some crap Panasonic ones.

 

[schwibsi]

That's still almost twice as high as the datasheet.

You should read a lot less. Also, what puzzles me is the print on the cells. Mine have never had that. There is small print on the cells for the model number etc. and a barcode but I've never seen that large fat print before.

 

[cwah]

Yeah specs mention 30mOhm (average measured by AC1kHz)

Now the resistance I'm having has been measured with my iCharger 1010B+ and have have consistently between 55-65mOhm resistance.

Do you mention the 30mOhm from the specs or did you measure it?

 

[cwah]

And as I said before.... many times.

I do not trust manufacturer data sheet. They always put the best condition ever to test resistance.

Anyone tested their resistance apart from me?

 

[skeetab5780]

Did you buy them from that ebay source? I've never seen that large print on original Sony cells.

Thats the first thing i thought when i saw the picture of the cells.

 

[voicecoils]

And as I said before.... many times.

I do not trust manufacturer data sheet. They always put the best condition ever to test resistance.

Anyone tested their resistance apart from me?

The iCharger is not at all accurate at low resistance for measuring single cell IR. That's been discussed many times on E-S previously. You'd need a 4 wire IR meter for reasonable accuracy.
[youtube]yohD2mtLYbQ[/youtube]

 

[christosser]

The laser tagged cells Do Not look like mine. This can be everything, but i am almost sure that this is no original Sony stuff.

By the way, as mentioned before, I was driving chinese A123 for years and i can definetley recommed to NOT use them:

1. A heavy battery per Ah is killing:
Your bike (tires, brakes others) - expensive If you Drive a lot
Your Bike Fun
2. A123 needs BMS - causing a lot of issues
3. A123 has a bad packaging - hard to handle the seize of it.

Sony Konion Seems to be the best choice.

 

[schwibsi]

Well, to be honest, I don't know, how you measure the internal resistance, impedance etc.
Whether you do continuous DC, DC bursts, AC etc... and I also don't know the equipment you use.

I already posted that the cells don't look like the original Sony's that I've seen so far, so I would imagine, they might be fakes. When it comes to battery cells, you really want to look for a reliable source, that's not going to cheat you. In my book, sourcing from China or shady ebay sources is more than a gamble. I would consider the risk as too great. I say that possessing the facilities to make my own pack, checking cell balance etc and treat this as a hobby. And still I just want a carefree, reliable solution, when it comes to battery packs.


Also, the comparisons between Sony, A123 and Headway aren't done in a way that's appropriate for electic vehicles.
Power, internal resisstance, current and capacity are all values that are important in relation to the weight of the cells.
A C-rating of the cells on its own is relatively unimportant and says nothing about how the cells will fare on a bike.

I care about:
- Wh / kg
- Maximum current per kg
- Voltage drop at given voltage per kg at 10-30A for a reasonably sized pack
- ease of use (cell drift, bms requirements etc.)
- reasonable cycle life for e-bike purposes (I care about the capacity over 3-4 years, not the 10 years)
- last not least price, factoring in all of the above

I just don't see the A123 beating new Sony cells (I'm not talking about packs made from old power tools and put together)
If you're going to compare them. Make a reasonable 1-5kg pack each and check out the values.

Measuring and comparing individual cells to me is a little like masturbation. It may be fun for a while, but it doesn't get you anywhere and it especially doesn't give you what you wanted in the first place.

However, if you want to look at an original Sony cell, I'll send you one.
Or better yet, I could make you a nice pack, and you'll see how it performs.

 

[cwah]

Ok, can you send me 2 cells so I can double check what they worth compared to my ones?

I'll mp you my address and of course pay for the cells and shipping cost

 

[schwibsi]

I shipped the cells the day before yesterday.

I wanted to include the sticker from the outside of the V3 boxes so you see, what the original sticker says, but the cells will have to do.
I'm curious what you'll measure for the V3 and the VTC4 cells, oh and how long shipping a letter to France actually takes

 

[cwah]

I'm definitely curious too.

On my icharger I've got 2150mAH at 0.4A capacity to 3V and 50-70mOhm resistance. 1800mAH to 3V at 6A.

I'm guessing they should be real but let's compare them.

 

[migueralliart]

Are these cells protected ? having the protection pcb will probably explain the increase in resistance.

 

[cwah]

I don't think these cells are protected. How do you know it?

 

[Doctorbass]

Guys, pay attention to the way you measure the voltage these cells have while dishcarging them... if you have too much loss in the wires and conections you use the discharge will cut too soon due to false LVC measure due to voltage drop.

4 wires measurement is essential! for internal resistance, dishcharge and charge to get TRUE results.

Doc

 

[cwah]

Thanks Doc. What is the 4 wires measurement?

 

[schwibsi]

Just watch the video posted above. he explains it nicely.

Measuring the impedance and resistance of a battery is not as simple as it may seem.
Techniques vary greatly and the manufacturers will employ other methods than what's important to us.

We care about the voltage drop from a continuous DC load. The manufacturers oftentimes use an AC load and measure the voltage drop from that, which tells us close to nothing, for what we want to know. Your results will be mostly interesting to determine, if the other cells you have are fakes or genuine. The absolute values you get, will not tell us a lot, for what we need.

 

[John in CR]

Those aren't Sony US18650V cells.

 

[cwah]

How do you know they are not??? Is it just by the cover?

 

[cwah]

Ok, just to answer some assumption, the bigger writting has been adding to meet shipping regulation that requires voltage and capacity to be written on each cell:

I started to peel of the writing.... pfiiouuu. No it's no faaake!

 

[John in CR]

No it's no faaake!

It's not fake that it's a battery. From the capacity test, it doesn't look fake for the written capacity. If someone is telling you it's a Sony US18650V of any generation, then yes it's a fake. More accurately, they are mistaken or simply lying.