YZXStudio 8 Power Bank Review (4x18650)

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.
Scott

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.

I would love a BLF group-buy on a powerbank like this!

Me too!
Could be an EU groupbuy maybe.
Perfect would be if someone can solder good cells into the powerbank, since shipping from Hong Kong is prohibited or expensive.
Franky Tongs price for 4/8cell version is $73/$76 per piece including shipping. So groupbuy could be less.

Franky also wrote me:

Creating a new thread for the groupbuy would be a good one too separate the topics.
http://budgetlightforum.com/forum/marketplace/commercial/liaisons

As I said, a groupbuy on this charger and I´m superinterested, seems to be very difficult to import to Europe.

Hello guys.
I just got my powerbank and its just awesome!
I’ve soldered inside 4*3500 Sanyo cells and it shows 13.400mAh capacity. By the way it was pretty hard to put inside even not soldered cells - enclosure was too tiny. And after I solder it with usual 80w soldedrer it wasalmosy impossible to put it inside with pcb, but I did it wit a some cell tube scratching. I think its not a problem that “-” will be on case.

Language of interface was not a problem to understand what is what, but I prefer English one. Tell me please where I can get firmware? Franky’s store don’t work anymore. My current firmware is 8t-2.11-0916.

And one more question: How I can enter menu with calibrations? Long press for any but to just power off bank :\

Thank you for help.
Regards, Sergii.

Long press the rightmost button on the last information screen to enter settings and calibrate the battery capacity.

Thank you maukka, now I got it. Also I discovered that I have 7more submenu points in 16th menu. And main menu order not as yours.

Tell me please where I can ask for eng firmware?

Hello, where can i purchase this powerbank

I got it from here taobao | 淘寶

Woooooooo! There is English language inside!

To enable open menu by long press right button on the screen with version
Scroll down with right button to 16th point
Long press right button
Choose 25th menu point
Long press right button
Choose “En” by right button
Long press right button
PROFIT!

That’s cool! Before you had to get hold of the English firmware and flash it.

Yeah. That’s why I bought stm programmer, but looks it’s useless now.

Sorry guys. My store was closed for about a week as I was very busy packing stuff up at home to prepare for my move overseas. The store is now open again. Unfortunately I will not be carrying any YZXstudio products anymore. I made a post on the EEVBlog forum a while ago explaining the reason: Starting a new chapter - Page 1

—Franky

The concept is exciting, but the batteries are put in parallel, or without ORing MOSFET control, the weaker battery will kill the others. The iPad batteries are connected via ORing MOSFET control, which is the “secret” for battery longevity.

How can I buy this power bank?