If you're driving a 12v halogen at 11.1v, you'll be losing A LOT of light, much more than -9%, probably closer to -15%. Better to run another cell to get 14.8v and use an efficient, nearly-lossless regulator to keep it around 13v. Then you'll get brighter light and longer capacity due to the extra cell and the regulator will provide a longer run-time of a fixed brightness. Rather than super-bright at first that fades faster into a dim 2nd half of the charge.
I got 13.2v so that I can overdrive the halogen light by about 10% and get 20% more light out of it. :) The charger I use is a Battery Tender that detects full-charge through a voltage-plateau I believe. So it stops at 12v or 13.2v or 13.8v for SLA batteries, varies depending upon what's hooked up. Another source for smart-chargers are the Black & Decker chargers for cordless-drill batteries. Some of the smart-chargers even have an adjustable trigger-point for when they switch from charge to trickle mode.Quote:
Originally Posted by wmgardner