I do not see much idea in using this charger as a power bank, it is way to big. A dedicated four cell power bank would be much smaller
The two cell chargers are more fit for travel usage and this makes it more useful to have a secondary function as usb power bank.
Dale, thank you so much for your hope to Efest, we are always listening the bad and good sides, your suggestion is our progress, we are so sorry for this issues, actually we have been adjusting voltage back ( 4.2V±0.05V ) when we started to get some not good feedback from customers some days ago ( we decided to make little bit higher voltage charger to make all cells full charged,seems it is not good for most cells ), all chargers get to adjusted voltage ( 4.2V±0.05V ) already. Thanks HK.J to take the time to test updated chargers for us again. We will be waiting for the new testing report. Thank you all.
Jone
Glad to see you here Jone, welcome to the BLF family! 
Good business for you is good for me, I need your IMR10440 for some very special lights to me, so making sure you are doing well guarantees I get the cells I need. 
I use your IMR10440 daily (I have a minimum of 3 of these with me at all times), and regularly use your IMR18350, IMR18650 V1 and V2. Also will be building a light to utilize your 26500 in the very near future. So yes, I wish to keep you happy so you can keep me happy.
Merry Christmas!
so about ~0.12% tolerance
That's fantastic efficiency!! H)
i'm in jone. group buy? :)
Do you label the new chargers different?
How totell the difference between the two types of charger?
Or is it programmable through the user?
Perhaps a gold star sticker beside the name on the adjusted models? Something to show both you and us that it has made the grade, so to speak?
I always wondered when the manufactures quote HKJ or even made a holographic sticker “Recommend by HKJ”
A gold thumbs-up sticker simply stating HKJ. Henrik, how would you like that?
Everyone the world over that got a charger with a gold thumbs up on it with your initials would know it has been reviewed and passed muster as a good charger, right out of the box.
(Then we’d have to start watching out for “fake” gold thumbs-up stickers)
No thanks, I am not doing any quality control.
If they want to put a QR code on the box linking to the review, it would be fine.
Only problem is if the charger is "improved" later on and the sticker stays, without a new review.
But I do not believe that will happen, my reviews are way to technical for the average consumer, even for many consumers that are smart enough to know about LiIon batteries and chargers.
From our own contact with Efest there won't be a change in packaging. I assume you'll have to ask the retailer if they have the updated version directly. We actually received the LUC V4 with our original Efest cells but did not list them due to our own findings regarding the higher than normal charge voltage. Our quick tests of the Efest LUC V2, Bio V2, and Smart charger are within spec of 4.2 +- 0.05V
Do you recall how long ago the Bio V2 versions came? Do you think we can presume that any that ship now will be the revised version? Is there a way to tell that it’s got the Bio V2 upgrade? Are you doing Turkey or Ham for Christmas? What? I figured I was asking enough questions I might as well get an idea if it was your house for lunch or not!
Appreciate the insights,
Merry Christmas!
Hello Calvin,
Thank you for updating this news for us , we will not change the LUC V4 gift box, but we will change the manual from 4.23 - 0.05V ( current manual ) to 4.2- 0.05V .
Hello Calvin,
Thank you for updating this news for us , we will not change the LUC V4 gift box, but we will change the manual from 4.23 - 0.05V ( current manual ) to 4.2- 0.05V .
Jone
The Bio V2 has been around for at least half a year, the V2 part of the chargers isn't a version number, it refers to how many bays the charger has. I'll be running another quick check on the chargers we have on hand to be sure they terminate too high but we tested all the Efest ones we had on hand after we noted that the LUC V4 terminated too high and they others we carry seem to terminate at spec.
EDIT: I made a mistake, the Bio V2 actually happens to be a change in version, there existed a Bio V1, but the LUC V4 refers to number of bays. Sorry!
Calvin, here is the BIO : Review of Charger Efest BIO we updated V2 that can charge big cells like 26650 batteries.
Jone
Thanks for the correction.
Thank you, Calvin, it is so nice to meet you here.
So like 4 months later, how can one make a difference from old vs new version with fixed charging?
Buy from a good vendor like Illumination Supply or Mtn Electronics.
20$ shipping, that’s too much 
And Mtn electronics, out of stock…