Rubber caps are mostly useless in a light meant for rough use in the dirt.
I am sure most USB built in charging ports are very reliable and the chances of one failing is low if you only have 10-15 lights. Everything is great when its built right. I just have trust issues with quality control sometimes. Just having work with so many lights over the years with bad USB charging port causing issues I choose not to use them whenever I don’t have to.
–1 on usb charging. I seldom use it.
Hey Vinh, Nice to see a Viet Bro in Engineering Design mode like myself. Are you doing the CAD, Catia, Solid Works drawings, CNC millings, from beginning to final product? OR will you be completely out sourcing project? Engineering minds want to know.
BTW, having both USB and removable battery will be a plus man.
Well, adding USB C charging might be too much for this ‘high durability’ flashlight, but it would be nice to see in future flashlights.
There are several flashlight brands that are doing USB charging well, and if it can work with regular batteries (no proprietary bs) then there really is no downside.
Charging the flashlight conveniently in places outside of home is very useful 
It is nice to have the option of an on board charger when out & about as most everyone has one you can borrow.
You can use your main charger at home still if you want.
Keeping the port hidden behind threads & o-ring is the best way to do it, not those daft rubber flaps.
100% agree
Olight UC and a spare cell. I tend to use my lights.
Edit, I might be interested in on board cell charging. I have a WowTac light that has usb mini in the cell itself. I find this usable.
I agree I stray away from lights that have built in charging as much as possible (I know this isn’t possible on lights that have built in battery packs, however anything else I shy away). I would say most people going to drop $150-300 on a light will want to charge their cells at a rate they desire. Instead of worrying about carrying a cable with me or finding somewhere to place my light to charge for awhile I usually just carry a 2ea spare batteries. A lot easier to deal with and not have to worry about down time. This is something to each their own, people have their own reasons and likes.
Very much agree with this - use usb charging on something not intended for rough service
Why do you say that as if it was one or the other?
You can have built in charging and still take the battery out and use a dedicated charger if you want.
It’s literally just an extra option, you don’t have to use it.
A foolproof no-BS design is cheaper and more reliable.
I won’t use it - for me its just something to make the light needlessly longer weakening the threads if placed there and added complexity and cost for something I will never use - it’s only function will be to make the light less desirable for me.
Other peoples opinions are just as valid but this is my reasoning
As stated below your post is exactly why, I think it adds more headache than they are worth. If a person is not going to use it, why have it? It gives just another point of failure to a product most want to know will work when they need it to. You are correct that it is another option however this option can potentially add reliability issues that a lot of us don’t want to deal with. Added to that I stand by what I said most people who are going to drop the dime on this light are not going to even think about using a built in charger.
This is funny slightly because in bigger threads such as the DX80, MS12, and X70 people complain about the built in packs and built in chargers and no options on cell charge rate or option to discharge for long periods of storage. I understand why they do this on the bigger lights, but I do not like it.
IMO if you’re going after extreme duty less is more. It appears this is an intertwined design/fabrication/price objective. KISS and all that.
If I were to EDC this and depending on its expected usage I would practically carry an extra batt in a separate well fitting belt holster if need be. And if I were adamant to have charging abilities outside of a dedicated desk-top style charger I would get a batt that has a USB port. Put the cable and extra batt together in said holster. Done. Would be plenty good enuff for me at least.
JMO.
- well because a lot of people will use it. Just because some people won’t use it doesn’t mean you should completely remove the feature.
“oh I only use one mode on my flashlight, we should just eliminate the driver because it’s another point of failure, a single physical switch is much more reliable. I don’t need 5 modes so nobody else should either.”
2) As I already said 3 times, if it is designed correctly, it does not have any more chance of failure than a regular flashlight driver does. It’s just an electrical circuit. It would also only add a couple mm to the length. If you care about a few mm that much then you should design the flashlight to use non-protected cells only and that will cut down on like 5mm+ of length.
3) What do you not understand about “non-proprietary” ?? We’re not talking about those horrible custom battery packs used in those flashlights you mentioned, that’s stupid.
You even need a special wall wart to charge those, not just a simple USB cable.
What we are talking about here is a USB port on the flashlight that allows you to charge through that if you want, but otherwise everything else is the same.
Uses standard batteries, which you can swap yourself, or charge them outside the flashlight.
No custom battery packs, no proprietary batteries, no custom chargers.
Literally the exact same thing as a regular flashlight but with a USB port on it.
from this —-> to this 
No proprietary batteries, no loss of reliability, just the same thing but with the option to charge it without carrying a bulky charger around.
A USB port with electronics that add to the chances of failure.
Get rid of your flashlight drivers then.
They add to the chances of failure.
Use a physical switch only.
Just because you can add features (or potential failure points) to every light no matter it’s intended purpose does not inherently make it a good idea.
Of course they do. And I accept that risk. I don’t want to add to the risk with something I wont use.