Why don't we have higher voltage 18650s?

st_burt

Newly Enlightened
Joined
Feb 20, 2009
Messages
16
I'm wondering why there aren't any higher voltage 18650 batteries available.



It seems to me that many of the 2x123/18650 lights on the market drop out of regulation on one 18650, so you have a tradeoff between higher capacity with one 18650 and full regulation with 2xcr123 or 2xrcr123. Alternatively, you can get a light with a buck/boost driver, but I think it'll be less efficient when it's boosting (when the 18650 is partly depleted), plus it'll be more expensive and complicated.



If the voltage when the 18650 was depleted was higher than the forward voltage of the LED and the loss from the circuit, couldn't you use those batteries in 2x123/18650 lights and get full regulation, rather than having the light drop out of regulation part way through? You wouldn't need a buck/boost driver to get full regulation on one 18650. You'd just use a buck driver, and the 18650 would be full at 6V and need recharging at 4V (off the top of my head; I don't know if those are the ideal values). That would be the most simplest way to get full regulation and maximum capacity from a one cell light.



The only problem I can see is that you'd need a new charger. Are hobby chargers able to charge at 6V? I don't know much of anything about batteries, so maybe there's some obvious reason why we can't have higher voltage 18650. Higher voltage 17670s would be great too, for Surefires and other lights that don't fit 18650s.
 
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