According to the datasheet, the operating voltage of the servos. Are 4.8-6.0V. I ran one servo with 2 of the batteries I posted (14500 3.7V).
As far as the laser diode drivers go, they are set to output 1.25A of current to the laser diode. I've run these diodes with this driver before and I've needed 2 of these to run one diode. I would assume that the drivers require a voltages of 6V to operate.
That's the thing, I'm trying to figure out how much voltage and current is needed and what batteries could provide such power.
So your guesstimate for the servo looks ok. I assume
the laser driver may be a constant current source.
The battery is 900mAh. A quick approximation - if you use two of these in parallel, you would get 3.3V at 1.8Amps for 1 hour theoreticaly.
Now, this is important. I don't know too much about paralleling newer Lithium cells. In the past, I would use forward biased diodes attached to each positive terminal and then serialize the two parallel cells with the rest of the battery. Sounds like a lot of work, does'nt it ?
Using diodes reduces the effective voltage of the cell due to the voltage drop across the diode.
A better way is to serialise 2 cells and then connect a diode to each serialised positive terminal.
Someone else on this forum should verify the safety issues of paralleling without diodes, please.