New 18650 with tag

My first thought is that RS is expensive - literally three times the price of the popular supplier, NKON in Holland: http://eu.nkon.nl/rechargeable/18650-size/samsung-icr18650-26f.html

I see they've started offering a tagging option on many of their 18650 cells. There isn't a price next to the tag options in the above link, but for other cells it's an additional 0.40 euros per cell (£0.30).
 
Punx0r said:
My first thought is that RS is expensive - literally three times the price of the popular supplier, NKON in Holland: http://eu.nkon.nl/rechargeable/18650-size/samsung-icr18650-26f.html

I see they've started offering a tagging option on many of their 18650 cells. There isn't a price next to the tag options in the above link, but for other cells it's an additional 0.40 euros per cell (£0.30).
Click to expand...

Thanks, that is a great find, especially being in Europe. I didnt realise that tagged batteries are an option post manufacture. £0.30 is very reasonable considering the learning curve doing it myself with a spot welder (although I really do like the JP welder and may still get one for the busbars etc). Anyway, looks like RS wont be getting our business on those tagged 18650's.
 
The 26F is a 2c max battery. Even with only a 20A controller, the sag will be significant, and that's all all a 4p pack will be rated for. I wouldn't give $2 each for them for a small pack. They're just too weak.
http://www.oomipood.ee/kasutusjuhend/ICR18650-26FM.pdf
 
So I've made a list of the 18650 cells that NKON offer with a tag option, to see if one stands out above the rest, but of course its a tradeoff,

1. Samsung INR18650-25R 2500mAh €3.95 http://eu.nkon.nl/rechargeable/18650-size/samsung-18650-inr18650-25r.html
2. Samsung ICR18650-26F 2600mAh €2.75 http://eu.nkon.nl/rechargeable/18650-size/samsung-icr18650-26f.html
3. Samsung ICR18650-26F 2600mAh €4.30 http://eu.nkon.nl/rechargeable/18650-size/samsung-icr18650-26f-with-z-tags.html
4. Panasonic NCR18650B 3400mAh €4.25+0.40 http://eu.nkon.nl/rechargeable/18650-size/panasonic-ncr18650b-made-in-japan.html
5. Panasonic NCR18650PF 2900mAh €4.90 http://eu.nkon.nl/rechargeable/18650-size/panasonic-ncr18650pf-3-7v-2900mah-with-utags.html
6. Sanyo NCR18650GA 3500mAh €4.99+0.40 http://eu.nkon.nl/rechargeable/18650-size/sanyo-18650ga.html
7. Sony Konion US18650VTC5 2600mAh €4.45+0.40 http://eu.nkon.nl/rechargeable/18650-size/sony-us18650vtc5-flat-top.html

But from comments I've ready in other threads I'm leaning towards number 6.Sanyo GA. Is that the best choice in this list? Or maybe 4.Panasonic? (ps: We need a European supplier for our university purchasing dept so cant use FastTech)
 
The Samsung 25R is a popular high-power cell. It's almost identical to the Sony VTC5 but cheaper.

The rest depends on what your discharge/charge requirements are for the pack...
 
Punx0r said:
The rest depends on what your discharge/charge requirements are for the pack...
Click to expand...

I hope i've worked this out correctly:
250W maximum continuous power (this is the UK and its an old ebike I'm restoring :( ).
Pack will either be 8S4P or 8S8P construction
So around 30V and 10A continuous from the whole pack , i.e. 2.5A per cell for 8S4P or 1.25A per cell for the 8S8P
Does this limit the choice? Or would any of these tagged 18650 batteries be ok?
 
The 25r is rated at 8C, 20A. The vtc5 is rated at 15C, almost 40A. So if the vtc5 rating is accurate, the vtc5 would be a much better choice. I wouldn't waste my money on any rated for less than 5C.
 
nippynoo said:
I hope i've worked this out correctly:
250W maximum continuous power (this is the UK and its an old ebike I'm restoring :( ).
Pack will either be 8S4P or 8S8P construction
So around 30V and 10A continuous from the whole pack , i.e. 2.5A per cell for 8S4P or 1.25A per cell for the 8S8P
Does this limit the choice? Or would any of these tagged 18650 batteries be ok?
Click to expand...
That's all meaningless. The only thing that matters is the max amp draw of the controller you use. For an 8s pack I'd want at least a 25A controller for better acceleration. I've never seen a controller as low as 10A.
 
wesnewell said:
nippynoo said:
I hope i've worked this out correctly:
250W maximum continuous power (this is the UK and its an old ebike I'm restoring :( ).
Pack will either be 8S4P or 8S8P construction
So around 30V and 10A continuous from the whole pack , i.e. 2.5A per cell for 8S4P or 1.25A per cell for the 8S8P
Does this limit the choice? Or would any of these tagged 18650 batteries be ok?
Click to expand...
That's all meaningless. The only thing that matters is the max amp draw of the controller you use. For an 8s pack I'd want at least a 25A controller for better acceleration. I've never seen a controller as low as 10A.
Click to expand...

Yes , but the controller is already in the ebike (Panasonic mid-drive, 250W, from 2011 era) so I'm stuck with that I'm afraid - unless there's a way of upgrading it, hmmm, maybe, but sounds difficult. At the moment I'm wanting to build a battery pack to replace the 26V 8AH unit on the bike. So the Panasonic controller will be limiting max amp draw to 10A.
 
Ok, I was getting off topic, but looks like any of the tagged 18650's from NKON in the above list will do for my 26V 8Ah replacement pack. With the Sanyo/Panasonic I could get up to 32Ah in the same physical volume (100mm x 100mm x 200mm) with a 7S11P arrangement (77 batteries). So thats four times the range. Not that I need it..

Next prob is to figure out BMS and charger for 7S11P (or maybe 7S10P).... but I'll do some forum reading first.
 
The 3400 / 3500 mAh are 1C max cells, so you'd be ok (just) at 2.5A per cell. But that assumes your 250W bike really does only draw 250W from the battery. Some will draw more, especially for short periods. However, if you use an 8P pack you should be fine.

That said, the 2900mAh cells are a popular choice and have considerably more headroom. Have a search on this forum for "NCR18650PF" for a datasheet and to see what people have done to test them. They are what I would go for, unless you really need the extra capacity of the 3400/3500s and know you won't lean on them too hard. The 25r and VTC5 are overkill for your application and sacrifice too much capacity for their high output current capabilities.
 
nippynoo said:
Yes , but the controller is already in the ebike (Panasonic mid-drive, 250W, from 2011 era) so I'm stuck with that I'm afraid - unless there's a way of upgrading it, hmmm, maybe, but sounds difficult. At the moment I'm wanting to build a battery pack to replace the 26V 8AH unit on the bike. So the Panasonic controller will be limiting max amp draw to 10A.
Click to expand...
I would be surprised if 10A is the actual max amp draw of the controller. 15A is the weakest I've seen. Where did you get that info on it. Again, kit watt ratings don't mean a thing. A 250W rated motor will happily take 1000W in short burst.
 
Punx0r said:
The 3400 / 3500 mAh are 1C max cells, so you'd be ok (just) at 2.5A per cell. But that assumes your 250W bike really does only draw 250W from the battery. Some will draw more, especially for short periods. However, if you use an 8P pack you should be fine.

That said, the 2900mAh cells are a popular choice and have considerably more headroom. Have a search on this forum for "NCR18650PF" for a datasheet and to see what people have done to test them. They are what I would go for, unless you really need the extra capacity of the 3400/3500s and know you won't lean on them too hard. The 25r and VTC5 are overkill for your application and sacrifice too much capacity for their high output current capabilities.
Click to expand...

Thanks for the great advice, that is very useful. I'll go for the 2900mAh. I see NCR18650PF batteries feature in this assembly video on spinningmagnets website so must be good.. https://youtu.be/w0j3wKii9ZQ?t=154
 
wesnewell said:
nippynoo said:
Yes , but the controller is already in the ebike (Panasonic mid-drive, 250W, from 2011 era) so I'm stuck with that I'm afraid - unless there's a way of upgrading it, hmmm, maybe, but sounds difficult. At the moment I'm wanting to build a battery pack to replace the 26V 8AH unit on the bike. So the Panasonic controller will be limiting max amp draw to 10A.
Click to expand...
I would be surprised if 10A is the actual max amp draw of the controller. 15A is the weakest I've seen. Where did you get that info on it. Again, kit watt ratings don't mean a thing. A 250W rated motor will happily take 1000W in short burst.
Click to expand...

Ooops sorry, I was just guessing it was 10A (from 250W and 26V), I didnt have any info.
 
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