Samsung 25R/LG 18650HE2/ Sony VTC5 high power 18650 battery

Green Machine said:
Has anyone bought and actually tested and cut apart those cells?

They seem too cheap...i dont know how someone can sale that cheap as a viable business model given what I think those cells cost. But i might be getting ripped off and someone is out there wholesaling samsung 25r for ridiculous cheap. A quick look on ebay and i cant find them for under $6 in any quantity.

When i see a battery priced too cheap i immediately think phony.

The other thing that makes me skeptical is why are they that green color? i have never seen samsung 25rs that color but maybe its an older model? What makes me weary is they are the same green color as the fony sonys.

Why did samsung choose the same color as sony to color their battery anyway? I am new the to the 18650 business so pardon my ignorance. I have always known samsung 25r batteries to be sweet baby blue.

I can confirm NKON has always sold authentic cells to me. The price is very good. Maybe it is because they are on the main container sea port in Europe, cell shipping through sea are the cheapest shipping nowadays, so they must have the lowest prices. Then the transport is all by terrain in EU, so we just pay 8$ ANY quantity
 
riba2233 said:
ridethelightning said:
i thought 25r was nca..in the link they are stated to be linimnco :?:


They are nca, dont worry. Just a simple error on their page.

25R are NCA??? :shock: :shock: :shock:

That would be very precious information. Anyone has the source to confirm that?
 
I am connecting my home made 25R cells together.
But too bad battery pack is too small to store all cells in this bag.
So I had to split the pack and using another bag for rest of the cells.

For the last cells wires (serie connection) are longer, is this harmful?
I mean using of different length of wires, cells may out balance/stressed not equal when under load?
 
BoomerChomsi said:
For the last cells wires (serie connection) are longer, is this harmful?
I mean using of different length of wires, cells may out balance/stressed not equal when under load?

current flow through total pack is equal, so its no problem if you have longer wire between s-groups. splitting a p-group needs more care (same wire length etc. for as equally as possible current flow)
 
My 25r's showed up today from evva. 5 packs of 4s9p. All in all I am pretty happy. They are shrink wrapped so Ill have to remove
some from the ends to add my balance taps. I also asked if they could give me 12 or 10 gauge wire (there's a 4 inch red/black on each end).
Looks like it came with 14 or 16 so not to bad. They did tell me their engineer said 10 gauge was not necessary so I expected that.

I did have to wait for them to get a new shipment of 25r's so hoping that's a good sign.

Will give an update once I get it wired up and hooked to my adappto.

+1 for Yvonne Chan at http://www.evvatech.com/ she was very helpful.
 
riba2233 said:
It's a well known fact. It says that it's NCA even in their datasheet... Even 20R are NCA.

Thank You very much for the clarification, that attribute passed over my sight!
 
ohzee said:
My 25r's showed up today from evva. 5 packs of 4s9p. All in all I am pretty happy. They are shrink wrapped so Ill have to remove
some from the ends to add my balance taps. I also asked if they could give me 12 or 10 gauge wire (there's a 4 inch red/black on each end).
Looks like it came with 14 or 16 so not to bad. They did tell me their engineer said 10 gauge was not necessary so I expected that.

I did have to wait for them to get a new shipment of 25r's so hoping that's a good sign.

Will give an update once I get it wired up and hooked to my adappto.

+1 for Yvonne Chan at http://www.evvatech.com/ she was very helpful.


pictures pls :)
 
ohzee said:
My 25r's showed up today from evva. 5 packs of 4s9p. All in all I am pretty happy. They are shrink wrapped so Ill have to remove
some from the ends to add my balance taps. I also asked if they could give me 12 or 10 gauge wire (there's a 4 inch red/black on each end).
Looks like it came with 14 or 16 so not to bad. They did tell me their engineer said 10 gauge was not necessary so I expected that.

I did have to wait for them to get a new shipment of 25r's so hoping that's a good sign.

Will give an update once I get it wired up and hooked to my adappto.

+1 for Yvonne Chan at http://www.evvatech.com/ she was very helpful.
i think evva is pretty good. very likely to be top notch cells.
 
Overclocker said:
ohzee said:
My 25r's showed up today from evva. 5 packs of 4s9p. All in all I am pretty happy. They are shrink wrapped so Ill have to remove
some from the ends to add my balance taps. I also asked if they could give me 12 or 10 gauge wire (there's a 4 inch red/black on each end).
Looks like it came with 14 or 16 so not to bad. They did tell me their engineer said 10 gauge was not necessary so I expected that.

I did have to wait for them to get a new shipment of 25r's so hoping that's a good sign.

Will give an update once I get it wired up and hooked to my adappto.

+1 for Yvonne Chan at http://www.evvatech.com/ she was very helpful.


pictures pls :)

Will take some when I get home from work. I was curious about the welds so ill get a close up of that also and post to the thread.

Thanks ride - felt like a gamble sending money via wire , but others on the board spoke well of them so I felt I had a 70% chance getting what I wanted.
I should have asked for them to put on balance taps , but not a huge deal. I need to source some shrink wrap to replace what I peeled back. evva is
going to tell me what size they used.
 
no probs ohzee.

here is some more "good evidence" :D

http://endless-sphere.com/forums/viewtopic.php?f=14&t=57291&p=978245&hilit=willow#p976595
 
No me gusta.

1. They used nickel for series connection. Each strip looks like it's 10 mm wide, and they are 5 of them. So if they are 0.1 mm that gives us equivalent copper area of 1.25 mm2, and if they are 0.15 mm thick, that gives us 1.85 mm2. Which is horrible, since all you battery current will pass there! You should add links made of copper wire, use 2 mm2 or similar solid wire and solder it between cells, not on the cells. You have 9 batteries in parallel, and each battery can give 20 A continuous, so that's 180 A. Even at 3C that's 67.5 A, which is far too much for this thin links. This is typical for chinese manufacturing. Imagine the voltage drop...

2. They used old cells. Ok, maybe not too old, but new ones are green, not blue.

3. They soldered output cables directly on cell top or bottom, so they heated cell too much. They should have soldered on nickel between two cells, that way they wouldn't heat cells at all. You can try that yourself, try melting solder directly in the middle of the cell, and on the nickel between two cells and you will see the difference.

4. They weld anywhere on the bottom of the cell, however there is a no weld zone in the center of the cell bottom.

http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=59438

Positive note - they use proper insulation.
 
riba2233 said:
3. They soldered output cables directly on cell top or bottom, so they heated cell too much. They should have soldered on nickel between two cells, that way they wouldn't heat cells at all. You can try that yourself, try melting solder directly in the middle of the cell, and on the nickel between two cells and you will see the difference.

not only this. the wire belongs to the middle of the group for evenly current flow. if its made like this there is higher current flow through the first cell with the wire attached and less on the last cell.
 
madin88 said:
not only this. the wire belongs to the middle of the group for evenly current flow. if its made like this there is higher current flow through the first cell with the wire attached and less on the last cell.

Actually you're wrong on that one. Look better, plus goes on the bottom, and minus wire goes on top, so current will flow equally. It's a diagonal arrangement. If both wires were in middle of parallel group, cells in the middle would give slightly higher current than ones on the ends.
 
riba2233 said:
Look better, plus goes on the bottom, and minus wire goes on top, so current will flow equally. It's a diagonal arrangement. If both wires were in middle of parallel group, cells in the middle would give slightly higher current than ones on the ends.
even if its diagonal arrangement, i doubt current flow is equal on this pack. i would not build the pack like this. further if you solder balancing wires at different places you get different voltage readings..
 
madin88 said:
even if its diagonal arrangement, i doubt current flow is equal on this pack. i would not build the pack like this. further if you solder balancing wires at different places you get different voltage readings..

Why not, everything is symmetrical. You can tap balance wires in the middle of parallel groups, that would work with more or less every symmetrical wire arrangement.
 
you probably have right riba, but would you build a pack like the way they did?
 
ohzee said:
Yea that picture made me feel better about purchasing from evva.

Here are a couple pics of 1 of the 5 packs.

file.php

I am agree with riba2233. The serial nickel conductors amount are not enough, but the main lead points are even worse.

Where the main battery wires are soldered, it that spots the nickel are completely in overcurrent. I don't see if they soldered more layers, in case that no, that points will heat the most in the battery, just check it.
 
Nobuo said:
Where the main battery wires are soldered, it that spots the nickel are completely in overcurrent.
exactly, and if they would have soldered to wire onto the middle of the group, it would at least only produce half the heat..
 
Thanks for the good advice. I will do as advised.

Pretty dissapointing.

I gave them the specs for my maxe and explained how many amps I was hoping to possibly pull from these.
 
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