YZXStudio 8 Power Bank Review (4x18650)

Weird - can’t find resistance measurement anywhere on my Contra SW. There is no setting 16.

Cannot check now, but did you make sure it wasn’t moved to the “Datum” calibration submenu in the 2.03 firmware?

Yes, silly me - its under Datum now. Thanks

Finally got mine today!

The install was tricky because the battery pack assembled by Nkon wasn’t properly done. The first problem was the batteries weren’t glued on a flat surface same as member swaan experienced, second problem was the battery tabs were off centre and they were shorting with the aluminium casing. With some dremel work and lots of krapton tape to avoid shorting everything was installed correctly.

My UI is in English, version 2.03.Some flaws/differences I noticed vs the unit maukka reviewed:
-LVP limited to 2.70V
-The resistance meter is hidden in the calibration submenu and still displaying double the true resistance, as mentioned above.
-Compass function doesn’t work, barometer over reads even when calibrated.
-Automatic charge current detection doesn’t work as consistently as I’d like, with the same QC2.0 charger it would choose 12V 1.5/1.75/2.0A randomly, but if I set it to manual it will always draw 2A.

It doesn’t seem to draw past 2A at any QC voltage, whereas the older yzxstudio 7 will draw up to 2.4A 12V or until the battery charge current hits the 4.56A limit.

Hopefully all these bugs or flaws can be fixed with future FW updates, but so far I’m happy with the construction and performance.

I was expecting Mario Bros power on logo, but got Contra instead. Not bad I guess?

Where did you order?
Which model did you buy?
How long was the shipping time from china to your country?
How much did you pay in $ for the Powerbank/shipping/customs?


Btw, booth of the domains http://franky.com and https://world.taobao.com didn’t work anymore.
Do anybody know more?


This is his E bay store.

So I’m curious, is the updating of this firmware for the batterythe same process as updating the USB battery monitors like in this video?


Nice, maybe it’s time I get a new battery pack since I have plenty of 18650 cells.
My only concern is the way the batteries seem to be wired. I don’t see any balancing between them? Or the pictures I looked at were wrong. I was looking at the 4 cell version.
Does it balance the batteries during charging?
I know it’s not needed as much as for a LiPo pack, plenty of laptop packs don’t do individual cell balanced charging, but charge them in clusters of cells instead.
I think I will get one anyway. It’s probably the one thing I haven’t reviewed or own from YZXStudio.

So I decided to order some parts for mine so I can build it since my one 10,000mAh pack had swelled up. Time to get the batteries, the best nickel strips I can get and find a way to spot weld them. So I went back to this review to read the rest of the thread and discovered mine is a version 2. Maybe I should at least power it on to make sure it works also.
Then I saw something about updating the firmware with with an STI programmer but using the micro USB port.
So I clicked on the link and just started laughing. That was he first time I ever clicked a link and it went to my own video. LoL that was funny to me for some reason.

Ok, so I ordered a way to spot weld the cells, should get it next week.
Any recommendations on what cells are the best to use with this. I lost the manual so I don’t remember what the max output is capable of doing. So I’m between the LG for the 15A out so they don’t run hot since it will probably never reach this level out, and the Panasonic ICR because they have 10A out, both comparable capacity but the panasonics are much more stable if something was to go wrong.

I ask about the max output because the nickel strips I use to spot weld and the resistance will matter. I’ll probably end up using 8mm wide pure (>96%) nickel but it’s hard to find with people saying its pure and shipping nickel coated steal. Not worried about the costs, I want this built correctly so it will last for a few years before I have to change the cells again for another few years.

Thank you,

I use GA in mine and they work great. After 30 cycles or so charging at 8A using a 50W laptop adapter and I still see 13.200mAh total capacity. It fully charges in less than 2 hours!

The powerbank gives you the option to charge up to 10A but it will drop when the core temp. reaches 55C.

I wouldn’t worry about output capability of the cell, even at the highest load you have it split into 4 cells.

Thanks for the reply Will.

I was about to pull the trigger on 4 Sanyo GA, but my thoughts changes slightly now. After looking at the data sheet on the GA being charged at 1.65A and discharged at 6 Amps for cycle life it seem to decline in capacity to 3000mah after about 75 charges.

So I’m looking for fast charging that will also last, yea it’s nice I can change the cells when they get low myself now with this pack.

Now looking at the Samsung 30Q it will also loose 300mah after 75 charges, the difference is the Samsung is being charged at 4 Amps and discharged at 15 Amps.
So the way I’m looking at it now is if I fast charge it with a laptop power supply it will be putting a percentage charge current to a battery that can take a 4 Amp charge and will degrade the cell slower with less loss leaving me with more capacity over a longer time and more charging cycles. But I guess this also depends on how often you fast charge it and use it, or even drain it all the way.

Both are great cells, I own a few Samsung 25R, and 3 other types from Samsung. I also own a few Panasonic 18650B and they are doing great also. The one tool pack I recently looked at for a friend that recently failed was running sanyo cells. It’s for the Weedwhacker and rated for 57watt hours at 24V. But when he told me it stayed on the charger in the garage for the last 4 winters and it just now failed. I was more impressed I only found one bad cell for being frozen a few joints out of the year.

Concidering I just had two USB packs fail (one 10,000mah that never did it’s claimed 2.1A out) and swell up in the last two months I’m tired of LiPo packs for USB portable power. Their still great for RC cars and drones, just not portable power.
The other great feature is the honest reporting of capacity, not some company saying it’s a 10000mah pack just because they put a 10000mah LiPo battery in it. They never concider the energy used by the boost ormghe efficiency of the ciurcut. So it will be nice to know how much power I really have left in the pack.

Soon, soon it will be built. I just need to make up my mind in the batteries, lol.

The displayed capacity is measured from the cells, before any conversion / efficiency loss. The difference is that it measures the real capacity vs spec capacity, which is only achievable in optimal lab testing conditions. e.g. a Sanyo GA only has about 3,350mAh real capacity.

I have the 7th gen YZX powerbank also with 4x Sanyo GA, this one has been heavily used for almost a year and the cells have over 200 cycles now. They charge at 1.1A to 4.2V and discharge down to 2.5V everytime. The capacity has dropped from 13,250mAh to 12,500mAh now, which is still 3,150mAh per cell, so I wouldn’t worry about cycle losses with the GA.

Keep in mind that the spec sheet is based on 6A output, in real use you will never see this kind of discharge rate. The max output is 15W on the 5V side and 24W on the QC side. Assuming 85% efficiency:

47W power draw / 3.7V = 12.7A / 4 = 3.1A per cell

If you’re still unsure about the GA, LG MJ1 and Samsung 35E are also good cells, recommended by the YZX guys themselves.

Thanks, I decided to go with the GA in the end.
I can’t trust that the nickel strips coming with the spot welder will be pure nickel, it’s probably plated steel. So another concideration was the temperature the batteries reach durring certain charge currents. I want to run this cool, and nickel plated steel will also heat up more. So I think I finally found a US seller for our nickel and maybe the whole thing will be up and running next week?
But it also might take a few days to test the nickel, and I want to load test each cell before I weld them together. But soon, soon it will charge things.
I did put one cell on it to make sure the electronics booted up today. It looks good. But I didn’t go over settings.

But you’d eqip the TOMO with low capacity batteries.
I use Panasonic NCR18650B 3,7V 3400mAh (PCB, Button Top) cells with 46g each.

So it’s just 86+(4x46)=270g for 50,32Wh; 186,37Wh/kg for the TOMO M4.

Check again. I used Sanyo NCR18650GA. The power bank output 31.8Wh with those 3500mAh cells.

Oh, so you mean the electronic circuit of the TOMO has high drain/low efficency?

Another question, how’s the YZXStudio Power Bank 8x (27600mAh) looking?
Whats the physical difference to the 4x18650?
Are there any pictures?

Yes, check the table. The Tomo is 67% efficient while the YZXStudio is 94% on the same 18650GA batteries.

It’s exactly the same as the 4x18650 one except for the case that is longer to house the four extra batteries. No difference in electronics.