Taking a chance on Alibaba (K Power battery)

Batteries, Chargers, and Battery Management Systems.
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dogman dan   100 GW

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Taking a chance on Alibaba (K Power battery)

Post by dogman dan » Jul 17 2015 7:47am

Edit. Review thread over here. http://endless-sphere.com/forums/viewto ... =4&t=71499

I've sworn for years that no way I'd ever send a pile of money to China, on Alibaba.

But yesterday, I just couldn't resist on this one.

http://www.aliexpress.com/store/product ... cycle-have the certificate. That is one reason I stopped buying shipped from china batteries a few years ago.
1500W/1714144_32371948308.html

Obviously not going to be the very best Samsung cells. But the price is just too good for that size, and the shipping appears to even be legal! They seem to
All the specs seem legit, it's not crazy too low weight for that Ah, or any red flags like that. Cut the claimed discharge rate in half of course, so it should have no problems running a 22 amps E bike kit. Paralleled with my 13 ah allcell, it should run ok on my big motor cargo bike if I set the controller for 30 amps. I'll finally have about 1500 real actual wh of range, without carrying any hobby king shit.

If this works out, it will be even cheaper than my first pingbattery, back when they were extra cheap with the 1c pouches. 1000wh for four hundred bucks. That ping was $400, but only 750 wh.

Supposed to come in less than two weeks, We'll see....

EDIT

It came in less than a week. Nice! But it was not shipped legally.

Box in good shape, well packed.

$398 including the shipping, no message later saying send more money for shipping.

Charger the piece of shit I expected, but I was able to fix it and it does work. It's fan was flopping around loose in there.

First try riding, and 900w load did not make it sag like crazy. Only 2v sag under load. I call that ok. So at least average decent cells inside. Not .5c laptop cells. Maybe laptop cells, but good enough ones. Performs better than my allcell, and at least as good as my pingbattery.

Third cycle, a deeper discharge of 16 ah. End voltage 45.5v, so I don't think I'll really get 20 ah from it. 18 ah will satisfy me. This cycle was done at about 600-800w. Max 1000w. 20mph is the max speed of the longtail cruiser, since it uses the EBK heavy duty kits low rpm motor. I'd hoped to get the full 20 ah at such an easy discharge rate, but figured I might not on a pack this cheap.

Voltage sag still only 2v, even climbing back up the big hill with lower voltage. At no time did the pack get any warmer than body temp. Not like my allcell pack, that gets much hotter by 45v. Clearly, 20 ah size has a lot to do with that, the allcell is only 13 ah.

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cycborg   1 kW

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Re: Taking a chance on Alibaba

Post by cycborg » Jul 17 2015 8:06am

Well, it's always great for the rest of us when someone decides to be the Guinea pig for a new product or vendor. Thanks and keep us posted!

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spinningmagnets   100 GW

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Re: Taking a chance on Alibaba

Post by spinningmagnets » Jul 17 2015 8:25am

With all the new cells that have come out this past few months, the old models have come down in price, and I'm sure a lot of whole-salers are wanting to clear out less-exciting "old model" inventory...looks like a safe bet to me on a legit pack.

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Re: Taking a chance on Alibaba

Post by whatever » Jul 17 2015 8:26am

does that price include shipping?
I've been buying things from aliexpress for years, never had a problem.

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Re: Taking a chance on Alibaba

Post by dbaker » Jul 17 2015 11:35am

20ah / 9p = 2.2ah/cell :mrgreen:

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cycborg   1 kW

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Re: Taking a chance on Alibaba

Post by cycborg » Jul 17 2015 12:23pm

dbaker wrote:20ah / 9p = 2.2ah/cell :mrgreen:
I'm sure this is meant as some sort of revelation, but I'm afraid I'm too dense to get it...

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Re: Taking a chance on Alibaba

Post by Ykick » Jul 17 2015 12:29pm

I like those dual PCB sandwiched BMS. They’re sturdier and seem to provide better temperature dissipation than single PCB.

Good price, will be interesting to hear your experience.
Talent must not be wasted.... Those who have talent must hug it, embrace it, nurture it and share it lest it be taken away from you as fast as it was loaned to you.

- Frank Sinatra

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riba2233   1 MW

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Re: Taking a chance on Alibaba

Post by riba2233 » Jul 17 2015 4:13pm

I'm kind of skeptic, they didn't even write the cell model, and that is absolutely the most important fact! in the end, it determines the performance of whole pack. Don't buy unless you are 100% on cell model that goes in, because they could be some shitty latpop cells (samsung makes lot of them) with 100 mohm IR, and they will die very soon!
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dogman dan   100 GW

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Re: Taking a chance on Alibaba

Post by dogman dan » Jul 18 2015 10:06am

They may well be some shitty laptop cells good for only .5c. But they will only die soon if I flog them.

If so, at least I don't have to solder up a shitload of em. 8) I'm not such a fool as to think they are going to be good for much more than 1c, whatever the spec sheet says.

If they are only good for .5c, then at least it's big enough to still run at 10 amps. Or 25 amps easy, paralleled with my allcell pack. Or if I must, I can parallel it with 5 ah of Hobby King packs. That will buffer the amp spikes, and insure I stop at a higher voltage for the sanyo's. I'm hoping they can take at least .75c continuous without getting too hot, which would get me a nice 15-18mph cruise speed out of it.

The $400 seems to include the shipping. We'll see if I get the message this week, " so sorry, we make mistake in ad, please to submit additional $350 payment for shipping" . :(

For those that weren't around, I was one of the first dozen or so guys to buy a bike battery in China from Li Ping. So it's about time I did the guinea pig duty again.

It's just duct taped, so I'm planning to immediately peel it just enough to see if I can find a cell label to identify what they are.

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Re: Taking a chance on Alibaba

Post by spinningmagnets » Jul 18 2015 12:32pm

dbaker wrote:20ah / 9p = 2.2ah/cell

I'm sure this is meant as some sort of revelation, but I'm afraid I'm too dense to get it...
We are trying to figure out what cells are being used. If you have a 20-Ah pack that is configured with 9 cells per parallel group (9P), then each cell in this pack has 2200-mAh per cell (2.2-Ah). Also, its listed as a 48V (average) and the top voltage listed hot off the charger is 54.6V

Most of these types of batteries charge to 4.2V per cell, so 54.6V / 4.2V = 13, meaning it is a 13S / 9P pack, 13 cells in series, 9 cells in parallel, 13 X 9 = 117 cells.

We have deduced that this pack is
117 cells in a 13S / 9P configuration
each cell has 2200-mAh

We want more information than this, but...it is a start. To be fair, most customers don't care about this info, so there isn't any pressure on the vendors to accurately list it.

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Re: Taking a chance on Alibaba

Post by riba2233 » Jul 18 2015 3:30pm

Samsung has two 2.2 ah cells, 22F (100 mohm laptop shitty cell) and 22P (excellent 4C contionus cell). Both are cheap, but who knows...

http://eu.nkon.nl/rechargeable/18650-si ... 0-22p.html

117 pieces = 266 eur, and you need to count assembly, bms, shipping... Seems to cheap, i would skip...
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dogman dan   100 GW

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Re: Taking a chance on Alibaba

Post by dogman dan » Jul 19 2015 7:03am

Well, you know perhaps only 1% of ebike riders can handle assembling their own battery.

We'll see what's inside when/ If it gets here. That's the whole point of one of us taking the plunge.

What really interested me about this company, was that the pack seems certified to ship by air.

For a long time, you bought a battery in china, you got shipped something labeled "toys" or "bike parts". No certification, getting the stink eye from your postman when you sign for it. Risk of it simply being destroyed at customs. Yuk.

So while this cheapo pack is obviously going to have less that stellar cells inside, finding out if you can trust them to ship at the price they say, and ship it legally, is what we really need to know about K battery. If they zing you for extra to ship it like BMS Battery, screw em. Same if the box doesn't come with proper hazmat shipping labels too.

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Re: Taking a chance on Alibaba

Post by Rodney64 » Jul 19 2015 7:38am

Buying from China's always a risk. Not only have you taken that risk but you're sharing which allot of us wouldn't. Hope it works out ok.

Do you look at aliexpress dogman.

http://www.aliexpress.com/item/Free-shi ... 36454.html

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Re: Taking a chance on Alibaba

Post by imorton » Jul 19 2015 8:53am

Dogman Dan, I personally am pleased that you are sharing your experience with Alibaba, since there's many potential suppliers of very reasonably priced battery packs.

I also am eagerly waiting to hear and see what you get, and I wish you receive a good battery that gives you years of great service... IAN :)

Thanks for sharing.
IAN from http://www.all-about-houseboats.com
GIO 500w scooter, LifePo4 48v 15Ah, WattsUp meter,

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Alan B   100 GW

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Re: Taking a chance on Alibaba

Post by Alan B » Jul 19 2015 9:17am

The only way to learn is for someone to try it, thanks for testing and sharing.

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riba2233   1 MW

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Re: Taking a chance on Alibaba

Post by riba2233 » Jul 19 2015 9:31am

At least bmsbattery offers packs with real panasonic Pf cells, one of the best ev cells (at least for their cost).
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dogman dan   100 GW

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Re: Taking a chance on Alibaba

Post by dogman dan » Jul 19 2015 12:13pm

Hadn't looked at what BMS battery was offering lately. Do they ship legal? Are the batts certified?

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riba2233   1 MW

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Re: Taking a chance on Alibaba

Post by riba2233 » Jul 19 2015 1:22pm

I don't know, I've only been buying cases and bms's. You should ask cwah and friendly1uk, they have been buying.

Also, you must know that lot of chinese certificates are fake, especially those CE ones :)
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Re: Taking a chance on Alibaba

Post by chilledoutuk » Jul 19 2015 2:33pm

riba2233 wrote:I'm kind of skeptic, they didn't even write the cell model, and that is absolutely the most important fact! in the end, it determines the performance of whole pack. Don't buy unless you are 100% on cell model that goes in, because they could be some shitty latpop cells (samsung makes lot of them) with 100 mohm IR, and they will die very soon!
You haven't a clue what your talking about!!
laptop cells from genuine battery's are better quality than anything else out there. I have had my sanyo 18650 8p10s battery for 3 years now and i have noticed virtually no loss of capacity over that time.

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riba2233   1 MW

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Re: Taking a chance on Alibaba

Post by riba2233 » Jul 19 2015 3:33pm

I know very well, laptop cells are high impedance low cost, usually 1C rate or less. They *CAN* be used as an ebike pack, no doubt about that, but knowing how most people here use them...
My electric moped: http://www.evalbum.com/4966

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Re: Taking a chance on Alibaba

Post by markz » Jul 19 2015 9:43pm

Me personally, I would much rather buy known cells and figure out how to connect them properly.
For the prices of cells, VTC4 2.1Ah 15C, at 2.49euros, at ~100 cells, factor in currency exchange ~1.5 then its $375, $410 shipped.
Cant go wrong with 30A discharges, I think also this cell is 100A for 5seconds.

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dogman dan   100 GW

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Re: Taking a chance on Alibaba

Post by dogman dan » Jul 20 2015 5:33am

Damn guys, you act like I just endorsed this seller. All I have done so far is explain why I was willing to STUPIDLY RISK MY LIMITED MONEY. Can you guys just calm down for a few weeks, and see how this deal goes first?

They call it 2c discharge, 3c for 5 seconds. So that's not going to be a stellar cell in there. Cut the c rate they claim in half, as always!!!

But in 20 ah size, it should have no difficulty at all running my typicaly 22 amps bikes. NO THIS IS NOT YOUR BATTERY FOR A STRONGER CONTROLLER. But if it works out, 40 ah of this would run my 40 amps cargo bike, and have up to 100 miles of range. So there is potential there, for somebody who wants to tour, but does not have $1500- $2000 for a huge battery, nor the time and experience to assemble 2000 wh worth of 18650's.


Again, buying known to be best quality loose cells is fine for the 1% who are competent to tab weld and assemble their own pack. But despite my years of experience, I'm not competent to do that. Oh, I could learn if I had a tab welder but I don't. Mostly though, I want to ride my bike, not build batteries. Fun for some, just tedium to me frocking around with the battery part of the bike. I like to buy something, charge it, and roar off on a fun ride.

Bear in mind guys, ES is not 100% guys as talented as you are. Thousands read who never become a member.

RE the possibly fake certificate, works for me as long as FedEx and customs is buying that it's legit. :twisted: There's a REASON I stopped buying hobby king packs in lots bigger than two or three packs, and never ever again from the china warehouse. I sure hope this package doesn't arrive labeled "toys".

Again, we'll see how this goes. THATS THE POINT, TEST THIS VENDOR. Soon as that package comes, we'll all know how they ship it, how they pack it, and soon after that, we'll see if I can read labels on the cells and find out what's inside,,,,,this week. Next week, it could be anything inside that pack. So that's always a risk with any battery assembler. That's why dealing with a guy you can trust, like Paul at EM3ev is so important. But I don't have that much $$ this time.

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Re: Taking a chance on Alibaba

Post by imorton » Jul 20 2015 6:40am

Amen... :)
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Re: Taking a chance on Alibaba

Post by 999zip999 » Jul 20 2015 10:18am

Dogman why are the shipping certification important to you ? The receiver of goods ? Is there a liability on your side ? Are E.S. members liable for hobbyking lipo batteries being shipped without proper certification ?

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Re: Taking a chance on Alibaba

Post by Alan B » Jul 20 2015 11:23am

Hobbyking Lipo shipments have the proper labelling these days, at least from the US warehouses.

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