Can I run my KX1 on two cells?

I swap my old KL1 back and forth from a one cell body to a two cell body just depending on what I need at the moment. Can the KX1 head be interchanged like the KL1 head or will I fry something if I do?

It doesn't work.

More info here: https://www.candlepowerforums.com/threads/169222

KX1 has a boost constant current regulator, so voltage in should be lower than voltage forward of individual LED. The regulator will boost the single 3+ volt CR123 to the vf of the LED. Any voltage significantly above the vf of the led, about 3.2- 3.5 volts, will cause the circuit to not regulate and the LED will be directly driven by the battery(s). This is a simple answer, because the added voltage can have an efect on the driver also, but no, not a good idea to run the KX1 on 2XCR123. You will probably get away with it using a single LiIon, but your will still be overdriving the LED until the voltage drops below 3.2 volts or so.

The KL1, having a buck/boost constant current regulator is ok with one CR123, 2X CR123, and 3X CR123, or two LiIons.

Bill

Bullzeyebill said:

Any voltage significantly above the vf of the led, about 3.2- 3.5 volts, will cause the circuit to not regulate and the LED will be directly driven by the battery(s).

Click to expand...

Have you seen this in action? I don't have a KX1, but the reports I've read say it's even worse than what you describe. The circuit appears to go into some kind of overvoltage protection mode, and the light flashes on and off periodically.

When I run my KX1 on a 3.7V lithium rechargeable, It goes really bright, then normal, then really bright, then normal, cycling every two seconds.

If I throw a McClicky two stage twisty on it (with an Aleph 1x123 body) and set it to the low position, it will strobe about 12 times a second until the voltage drops...on high. It's very nauseating after a while.

My KX1 unit is now attached to a 1x123 body and is a primary only unit now. I've even debated selling it.

-Steve

Ty_Bower said:

Have you seen this in action? I don't have a KX1, but the reports I've read say it's even worse than what you describe. The circuit appears to go into some kind of overvoltage protection mode, and the light flashes on and off rapidly.

Click to expand...

Wow, thanks for the quick answers. I'll not do it. Reminds me of one time I bought an L1 head with a green LED here on CPF. I put it on an E2E body and it was AWESOME for about a week. Then it quit working. So I sent it back to Surefire and they fixed it. It lasted again about a week. I called Surefire and told the CSR what I was doing with it and he explained that I was overdriving the LED and this time it would cost me to get it repaired. I wound up selling it on the BST to someone for $20. I'm glad I asked about the KX1 before I done something stupid again.