Batteries specify reserve capacity as "so many minutes at 25 Ampere load" The mathematical formula is: "reserve capacity" times 25, divided by the current drain from the LEDs. Yields capacity in minutes. Here's some hipshot math with a fictitious battery. 120 minutes reserve capacity times 25 = 50 amphours. 120 leds draw about 2.4A. Could be 1.2A, could be 4.8A. That would yield a spread of 10 hours to 40 hours useful time. You could measure the current drain with a current meter, and get more accurate results. The reserve capacity of your battery might be written on it somewhere, probably in teeny tiny letters. Rick --- In dmcnews@xxxxxxxxxxxxxxx, "daviddelorean" <daviddelorean@...> wrote: > > I'm trying to figure out how long a fully charged battery will last. > What is the mathmatical formula for doing it? All my lights (except > headlights) are LEDs. The tail & front market lights have 45 diodes, > the side markers have 3 diodes, license plates have 6 diodes, door > markers (assuming I keep the doors open) have 6 diodes. > > So with doors open and parking lights on (headlights off) how long will > my batter last from a full charge? > To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/dmcnews/join (Yahoo! ID required) <*> To change settings via email: mailto:dmcnews-digest@xxxxxxxxxxxxxxx mailto:dmcnews-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/