I’m not certain it’s fair to say they designed the VC4 “incorrectly” - as far as I can tell, it was released in early 2015.
For comparison, the USB-C specification was only finalized in August 2014, and 21700 cells began to see adoption in 2017.
So I’d actually say it had a perfectly reasonable design, considering what technologies were mature (or even in existence) at the time of its release.
Hooked my dad up with one of these…truly a step up!
1A max charge current? Looks like a bad joke for 5000mAh@21700 batteries, 5+ hours of charging! USB-C with no support for QC or PD - is it really 2021 now?
Oh ok, I thought 21700 existed in 2015.
I tried my vc8 with a generic usb c cable, and their ac adapter, it works but it would not charge at 1,2,3A currents, it was under 400ma, once i plugged their wire got 3A.
That is so dumb, they clearly can make a properly functional usb PD charger because the PB2s exists. If they could scale up the PB2s to 4 bay and add ni-mh support (even if the powerbank function was disabled) then I’d be buying one.
Make a 30W AC adaptor (and support USB PD), and make it to support 1.5A charging on all bays simultaneously (probably this would need a bit more advanced cooling mechanism to be implemented), then it will be a much more up to date design.
People nowadays are a bit less patient 
This VC4L charger supports USB-A to USB-C and also USB-C to USB-C cables. If your phone charging cord with Type C, can also be compatible.
Thanks! 
Thanks for your kind suggestions for the VC4S charger, we will feedback to engineers! :+1:
Just got my vc4L and it does not charge with a C to C cable. A to C works fine.
Will be returning it though because I wanted the c to c charging
Hi, the VC4L can also charge with C to C cable, pls check the pic below.
Both USB-A to USB-C and USB-C to USB-C cables are fine. May I know what kind of cable you use?
I bought one of these because I like the VC4. I’m charging some protected 21700 cells now. I like the new usbc plug too I wont have to worry about bringing an extra cable with me when I travel.
Ok so I’ve tried various usb c to c cables I’ve got.
Didn’t work with any 100w rated cables I own, Anker, choetech and Spigen. I can link the exact cables if needed when I’m on the computer.
It works with the 60w rated cables I have, various ones from ugreen, Anker, choetech, spigen. The only 60w cable it didn’t work with was a usb IF certified cable from choetech
So it does work with some cables but can’t seem to negotiate with a 100w rated cable so at the very least it would seem like the port hasn’t been implemented completely as it should still charge.
XTAR - can you please update your analyzing chargers to accept protected 21700.
There are our chargers compatible with protected 21700：
X2 extended version: https://www.xtar.cc/product/XTAR-X2-Charger-(Extended-Version)–128.html
X4 extended version: https://www.xtar.cc/product/XTAR-X4-Charger-(Extended-Version)–129.html
VC8: XTAR VC8 8-Bay Battery Charger & Capacity Tester
VC4L: XTAR VC4L USB-C 4 x 21700 Protected Battery Charger
FC2: XTAR FC2 Basic 2-Bay Li-ion NiMH Battery Charger
The Xtar SC1, SC2 and ST2 also accept protected 21700 batteries (but are not compatible with NiMh batteries).
The FC2 looks like the SC2, but now has user-selectable charge-current, and also supports NiMh in addition to Li-Ion, is that right?
Compatibility with protected 21700 looks nice, but with a max. charging current of only 1 A, it would take something like 6 hours to charge a fully depleted 5 Ah cell.
Nowadays, I consider 1 A unnecessarily slow even for most 18650 cells, and 2 A is the lowest charging current for 21700 in order to keep times on the charger reasonable.
Using the capabilities of QC and PD over USB-C, it would have been possible to design it with at least two slots capable of charging at 2A.
My guess is that having QC may make the charger more expensive?
The Xtar SC2 does use QuickCharge to allow 2 slots to charge at 2 Amps per slot.
while the Xtar ST2 requires USB-PD which allows 2 slots to charge at up to 4 Amps per slot.
I suppose the FC2 is supposed to be a more all-around entry-level but still versatile enough to handle both NiMh & Li-Ion battery types and also different charge currents.
Question:
So it doesnt support 2A or 3A charging?