I have been using a Losmandy GM8 with Gemini GoTo, powered by 2 x 30amp 12V deep cycle batteries. As the night goes on (usually after about 2 hours, I often get the dreaded "RA (or DEC) motor lags" error message in the hc. I have found this is usually attributed to lower voltage in my power supply. In fact:
The solutions I have found so far refer to power supplies converting 240V AC to 13.8V DC. Only one site I use has the luxury of 240V.
I have found an alternative. Snaptec Australia Pty Ltd make DC/DC converters. I rang them and, while my power request was not made by them normally, they agreed to provide a 12V to 18V converter. The serial number on mine is 0001. The model is GB60-1218 (
http://www.snaptec.com.au/dcdc/dcdc.htm#GB)
I have installed it into my battery box. When turned on, the amp meter does not move. While tracking power consumption is just below 1 amp, slewing about 2 amps. I wired the output through to a cig lighter socket mounted on the outside of the box.
The higher voltage has put an end to the "motor lags" errors