mine was cancelled 
edit:
I just got a fan in the mail, addressed to just my first name. Thanks for the free fan. Couldn’t get it to run on battery even after charging for 10 minutes. Maybe it will take a charge overnight.
Wow……with $20 oopses and then free fans it might be hard for them to stay in business! lol.
Battery isn't taking a charge after 1 hour. See no battery indicator when unplugged no flashing when plugged in. Disassembled the unit. On the motherboard plugged the dc-in connector to the battery terminal and turned it on, verified that works so ruling out motherboard issue.
Guessing one of the batteries of the bunch is dead and its not giving enough juice. Reading 18.6 on multimeter where red/blue wire connector is on the battery. Removed battery cover. Here's some pictures. It is 7 cells total. 4 + 3.
My experience ends here, please advise what a good next step is toward the goal of getting battery power working. 
I got my two other fans today, for a total of three.
My order is complete.
I'm charging one of the fans right now.
(You have to charge them for four hours before you use them.)
Thank you, tammap, for the heads up on this deal.
I got to test my fans this afternoon when my grid power went out. My fans worked flawlessly for two hours until power was restored.
I am very pleased with my fans.
IIRC it read 13.4 on the board bat points, I’ll doublecheck later. I did plug the ac plug into bat plug and that worked fine. Here’s a bunch of photos. Any idea how to disassemble such a pack? I’ve solder and a rework station to work with but am weary of giving more than a short heat blast to the battery (which didn’t have effect).
This fan was free so that’s why I am bothering to do this. I’ve tested each cell and have the following values:
As my values are different than the numbers you propose and I am a noob I will explain that the way I got these values was by touching the black poker to the p- and the red poker to the B+, and later I stuck it underneath the cover to touch the battery directly as there’s only 6 points on the board but 7 batteries.
I presume I need to get the 04.4 battery charged and the rest will start working. But also I’m a noob and maybe that’s how it goes because of its position in the chain. I also and am not certain if the battery needs to be disconnected from the pack to be charged/conditioned or if that can be done by connecting leads directly to its ends.
Thanks for bearing with me I know I should learn this stuff and avoid a headache but until I do to keep things moving your assistance is appreciated.
Please enjoy your time here, lightsout!
That looks like three cells are overcharged and four cells are completely dead. All cells are definitely not recoverable and should be disposed safely.
Meanwhile the photo got updated. Please dispose the battery at a proper recycling station. It would be too dangerous trying to repair the battery pack for someone without the required knowledge.
So I’ve revived a few battery packs which have a BMS, and in my case the cells were severely discharged, but there wasn’t any single cell that was bad. Simply charging the entire pack slowly was sufficient to revive the pack.
The voltage values you have posted are not useful, because the BMS appears to be interfering with the readings, and they don’t really make sense.
I have found though that most BMS have a B+ and B- that complete a circuit with the battery, and if you can tap into those terminals, you can trickle charge the battery pack with the right charger. I have a few RC lipo chargers that are practical for this purpose, since they allow precise control of the amps and voltage.
Now based upon the picture of the BMS, I have an idea on where you would have to connect the charging leads, but without the right charger I’m not sure if it is a good idea.
Apologies I’m newbie with multimeter. I looked up how to do it correctly. Here are the correct values:
Think a car battery trickle charger could do the trick at 2amp?
ABSOLUTELY NOT!!!
You seem to have completely ignored or misunderstood the replies that I and others have given you. Please take the battery pack to a local recycling center and dispose of it responsibly. I removed my prior post, since your actions might prove dangerous to yourself and others around you.
When I asked a very specific question I did not ask you to write what you imagine about me nor to coerce me into destroying my property. If you’re going to spend the time to write three sentences following the answer make them worthwhile and elaborate on the answer or explain a concept instead of going where you don’t belong.
Anyway…
I disassembled the pack. Tack welds came off easy with pliers. Wrapping paper left a bunch of adhesive which it came off with wd40 and 99% alcohol. After placing the batteries in an Xtar VC8 it was immediately clear that one bad battery was the culprit.
I’m going to reassemble the pack with a non bad battery.
Question: I don’t have a tack weld machine nor those little metal strips, will I face issue using sufficiently thick copper wire with solder in the same layout?
You don’t need a university course to remove tape and desolder or pry connections. How ridiculous.
You’re making light of a serious situation — yeah yeah it can all work out — but there’s many instances where it works out really bad — If you’ve ever been around a venting Li-ion cell, then you’d understand
Good luck with your pack — using one oddball cell can be disastrous also
httphttps://www.youtube.com/watch?v=1qOM5ih0IHg://youtube.com/watch?v=
Your method of ripping off the welds might have introduced weak spots in the battery.
You cannot replace one battery with another one because all are in series. One might discharge earlier or later. Replace all seven batteries with new ones and use the old ones for safe applications if you like.
Soldering to Li-ion batteries is usually a bad idea. The heat will cause damages that you can’t directly see. There are people who do it successfully (not more than 2 seconds per cell, cool down immediately), but nobody knows the state of the batteries. One out of 100 might have gone bad and cause an explosion weeks later.
If you’re going to “experiment” with batteries be sure to take precautions; especially with lithium. (bucket of water nearby)?!
!
Pic shows what happened when I was experimenting with nimh and a camping shower; I still don’t know how it happened.
My guess is that the “the spirit of dum ass come on me.”
P,S, Big difference between venting and exploding. (face shield)? 
Even a button cell can go boom for no reason.
Anyone can throw together a bunch of 18650s into a battery pack.
You’ve gotta ask yourself one question: “Do I feel lucky?’ Well, do ya, punk?” :laughing:
Never Throw Venting Li-ion Cell in a bucket of water — It’s been proven that it accelerates the chemical reaction
I’ve mentioned this before — I fool with a lot of batteries — I have taken apart 1000s of 18650 cells with no problem — One afternoon sitting at my desk in the AC, I was taking apart a 60v pack of VTC6 cells — all of a sudden a cell started venting — Like a lit Roman Candles in the house — I was very lucky it was only one cell and I was able to grab the pack to get it outside — No burns to me or the house — Sooted up my desk and office some — I learned my lesson that day and I consider myself lucky—- I take them apart, build outside on the carport where I can throw them in the yard
All these products with Li-ion cells ( especially cheap surplus ) can be very dangerous —- especially when charging — most people don’t realize you shouldn’t charge these when they’re hot
LifePo4 cells are much safer , but have the same issues when charging in extreme heat or cold — But they only smoke , they don’t go BOOM
There was an Old Illustration Joke on the wall of a Tattoo Shop — It was a suicide bomber getting his lesson — The caption said ” I’m only Gonna Show You This Once ”