Have a 3.8V storage charge and 4.0V working charge. And of course 4.2V like every other charger.
The 4.0V is to allow charging to 80% for those who want to extend battery life but still have good battery capacity for everyday use. I have never seen a 4.0V feature on a charger so this would be an innovative feature.
Also the ability to show voltage or percent on the display, so the user change choose which one they prefer, i want voltage being an enthusiast but someone else might prefer percent.
The problem (of course) is that to stretch the slots to fit 800s and 980s, that means the slider-spring needs to be made of some miracle material to also grab onto 340s and 350s (ie, 16340s and 18350s).
Even in my Ope that only stretches to baaaaaaarely fit 21700s, it also barely rests against the case of 18350s/16340s, and to make good contact I typically also have to wedge something in the open area to push the slider more firmly against the cell.
I’m glad to see this development. 
Can it be easier to make an adapter for the 26800?
(This is not my adapter.)
I'm thinking it would be easier, but if I wanted to get into 26800 cells, I would want a proper charger that doesn't require an adapter. 
I would take the adapter, its very spiffy and can be customized to many sizes!
Well, one adapter for one 26800 would probably be cheaper than an entirely new charger. 
Indeed, plus its future proofing, whatever new size comes out just buy an adapter.
I like that ….
I would also like to have an adapter to use with my existing chargers.
An inexpensive 2x 26800 charger (starting at 2Amps or higher), which means if it is USB-powered, this may have to use USB-PD (maybe only use QC3.0 if the price difference is going to be really big for USB-PD vs QC2/3).
As for a full-featured charger (capacity testing), I think a higher discharge current (maybe 0.75A or 1A) would be desired to grade large capacity batteries (a 6800mAh battery at 300mA discharge current is going to take around 23 hours to discharge, and that does not include the charging phase yet). Although 1A may need proper cooling (cooling fan may add cost)
Too True.
I’d say make 18650 the smallest battery it will take. Trying to make a charger that fits everything - means it’s a poor choice at the ends of the size range.
Consider this a charger for larger higher capacity batteries. The world is full of chargers for smaller batteries and NiMh.
Don’t cripple the design by trying to be a one size fits all device.
As far as power supplies - A 12v-14.4v power supply included with the charger would be ideal.
Then the charger could be connected to a cars 12~14v power for charging in an Auto or other 12v portable source.
All the Best,
Jeff
I’m going to say no to adapters at this point it’s a bad idea. Look we have a company that is the largest builder of Lithium-ion battery chargers. That company with a really great reputation came here and said “We would like to build a charger for you, give us some ideas.” We’re already offering a compromise instead of a from the ground up new product. Lets be bold and take them up on the offer.
1. Single bay stretched ANT-MC1 Plus just stretched to 90mm’s
2. Dual bay, 2A each channel, battery voltage, charge mAh, compatible with 18650 - 26800, test battery real capacity.
USB C PD - Absolutely MUST HAVE.
Charge current up to 4A
Don’t worry about trying to fit any cell under 500mm length
If 1 slot, make it as compact, simple and lightweight as possible.
If 2 or 4 slots, do more fancy screens, discharge meter, internal resistance measurements, etc.
The best solution is two chargers.
As these batteries become more prevalent. The low end chargers will start to appear from other makers.
A famous saying: “There’s always room at the bottom”
Meaning that a cheaper charger will always be the choice of many (even if it’s not the same quality).
I suspect most of the lights will have built in charging - limiting the customer base for external chargers to enthusiasts who will want to test batteries or have multiple batteries charged and ready for use.
Or need to charge the batteries at a faster rate.
Hence the 5a charge rate I recommend.
Build a charger that sets your brand apart from the rest.
All the Best,
Jeff
I’d go for an extra large version of the PB2S that covers down to 18650. My PB2S is probably the best flashlight-related product I’ve bought, including the actual lights. It’s perfect. Everything else has some major weakness, but not the PB2S.
The ribbon makes it super easy to remove the batteries, so there shouldn’t be a problem squeezing your fingers between cells or damaging wrappers.
USB-PD is an absolute must. I can’t think of a new product that should be charged with anything but USB-C PD. A portable charger with 2 26800s and power bank support would be pretty awesome.
A longer ANT MC1 Plus with USB-C PD input. Would it allow unstable solar power input with less than 500mA?
It might be better to upgrade one of your flagship 4 slot chargers instead so that those who are willing to pay for extra features will also get 26800 support.
What I want in a charger…
Display for each slot including voltage, current, mah charged (and discharged if feature present) / Internal resistance of the battery
Proper LED indicator coloring. Red = Charge, Green = Full, Blue=Discharge? I just don’t want to see Red charge Blue full etc.
Temperature sensing to cut off charging on overtemperature of cell
Capacity test, discharge test, charge / discharge & measure / charge test… Basically what the Opus chargers do for testing batteries
Minimum of 1 amp on all slots
Dual stage spring so small cells have sufficient tension.
Ability to handle NiMHs (Talking about D sized batteries here)
Multiple power inputs. USB-C is ok, but also have like 12v in to provide higher charge rates and mobile charging from vehicles, solar generators, etc.
Discharge to storage charge option
2, 4, and 8 slot options, with all features available in all slots (i.e. not like the VC8 with only 4 slots having most of the functions. I would pay more to have all 8 slots work the same as the left 4)
If you really wanted to go over the top you could have some PC connectivity options.
Obviously fits all the batteries, just got a protected 21700 which fits in none of my chargers but at least has USB charging on the cell. Still, I can’t do a capacity test and label the battery to later compare it’s initial capacity after years.
Audible tones like the Dragon VC4 has are useful. Also power bank function might be useful, though I’ve only used it to drain cells down to a storage charge manually.
I have > 300 lights and about as many batteries, so the semi annual battery maintenance chores have me wanting multiple good 8 slot chargers.