Has anyone used the charge feature with lithium batterys? The manual says to use lead-acid. I'm planning to use the CR206 with a very small enclousre so small battery will be needed. I've not had the best luck with small lead-acid batterys in the past so I'd like to go lithium.
You won't have good luck with lithium batteries and the built in charge regulator. You should buy a charger built for the lithium batteries.
The CR206 charger will output about 13.6VDC, with adjustment for temperature. That is good for lead acid batteries. On hot days or cold days, it could be outside the acceptable range for the lithium battery.