Can I use a D-tap cable with my 500 or 700 series monitor?
You need to be careful when attaching a third party power source to your 502 monitor. It has an input range of 6.2V to 8.4V if you exceed 10v you can damage your monitor.
Here is a good dtap to lp-e6 option that you can use with your 502 monitor: http://store.smallhd.com/store/500-accessories/DCA5-KIT
How do I power the 500/700 series monitors?
500 Series monitors are compatible LP-E6 style batteries and the DCA5 D-tap Power Adapter
. 700 Series monitors are compatible with LP-E6, Sony L Series batteries, and theDCA5 D-tap Power Adapter
Please note, monitor only kits do not ship with a battery or power cable.