On my bike I have an voltage meter on my handlebars and noticed lately that it wasn't showing the power that it used too, since adding my home made light-bar. I still need to do some checks but I thought you may be interested to know what I have found out so far.
We have approximately 350w of total power output generated by our Stator and the draw of the bike at bog standard (no accessories) is around 220w, so you only have approximately 130w available. My light-bar is running 2 x 55w bulbs = 110w. This leaves leaves only 40w for all accessories, including full beam, LED lights, satnav, heated gear, radio/mp3 player or whatever else you may wish to use. So be careful that you don't overload your system and find that your bike won't start one day because you have used all the electrical power that your bike has to offer. If you are running at or near peak power you really need to ensure that you have the ability to switch things off such as your light-bar when using things like heated vests or gloves that are running off the power from your bike. Also pop your bike on to a trickle charger whenever you can to keep your battery in tip top condition. I have a lead that is permanently attached to my battery and comes out from under my seat so that attaching the trickle charger is not an issue & because its so easy to plug in, I plug it in every time I park my bike up.