battery power for origin live DC motor?

I've started using the Origin Live DC motor kit with my Linn LP12. Aside from the noticeably louder brush noise from the DC motor, I like the effect it has on the music from the LP12. It's also much nicer to be able to easily switch to 45rpm.

However, since the DC motor speed is a function of the voltage, my speed varies from day to day. I have to readjust the speed to 33/45 before each listening session. The voltage stays constant over the few hours. Maybe it's just my San Diego Gas and Electric Power, but I know that home power companies regulate the 60Hz freqency VERY well, but not the voltage. Anything 110-120 is OK, they say.

The motor kit uses a 8 or 9 volt transformer, so it should be possible to use a big old 9 volt rechargeable battery, say like the ones used for model cars. This would provide a rock solid voltage, at least until it drops to zero and needs to be recharged. Has anyone tried this approach?

I don't think that battery power will help with your
speed calibration problem. Any speed control that does
not incorporate some type of feedback will be subject to
speed drift. I found that that with a high quality regulator
circuit it was difficult to keep the speed within +- 3% long
enough to play a record side. As the turntable and motor
warms up the speed will change slightly even if the
voltage remains constant. Fortunately our ears are not very
sensitive to this slow drift so the problem is not nearly as
bad as it might seem.

However, I do think that battery power will notably improve
the sound of your turntable.

I have not really noticed a change over the course of one listening session. Fortunately, I don't have perfect pitch ;) The changes were from day to day - and I can measure these at the wall with my multimeter! Once the motor, etc. warms up (an hour or less), I'm hoping a DC battery will help things. I'll keep y'all posted. By the way, this all has pushed me enough to want to DC power my entire setup, using a big'ol battery and a DC/AC inverter. Thanks Tom for the advice :)