Comments on: power convert calculation. 3000 mAh backup battery and 5watt CF bulb? http://www.batterybackupguide.com/blog/power-convert-calculation-3000-mah-backup-battery-and-5watt-cf-bulb/ Thu, 17 May 2012 23:08:37 +0000 http://wordpress.org/?v=2.7 hourly 1 By: sergio p http://www.batterybackupguide.com/blog/power-convert-calculation-3000-mah-backup-battery-and-5watt-cf-bulb/comment-page-1/#comment-200 sergio p Sat, 17 Jan 2009 05:13:32 +0000 http://www.batterybackupguide.com/blog/power-convert-calculation-3000-mah-backup-battery-and-5watt-cf-bulb/#comment-200 P=I*V I=P/V P=5 watt if V=110 Vca then I=5/110 I=.045 Amp=45 mA -->3000/45=66.66 hrs P=I*V
I=P/V
P=5 watt
if V=110 Vca
then I=5/110
I=.045 Amp=45 mA
–>3000/45=66.66 hrs

]]> By: AJ http://www.batterybackupguide.com/blog/power-convert-calculation-3000-mah-backup-battery-and-5watt-cf-bulb/comment-page-1/#comment-199 AJ Wed, 14 Jan 2009 11:28:17 +0000 http://www.batterybackupguide.com/blog/power-convert-calculation-3000-mah-backup-battery-and-5watt-cf-bulb/#comment-199 You are missing one important information. What is the voltage of the CF bulb. Once you know that number, divide watts/volts and result will be the current (in Amps). Now divide 3 Ah (3000 mAh) by the current. The result will be the numbers of hours the battery will last. You are missing one important information. What is the voltage of the CF bulb. Once you know that number, divide watts/volts and result will be the current (in Amps). Now divide 3 Ah (3000 mAh) by the current. The result will be the numbers of hours the battery will last.

]]> By: billrussell42 http://www.batterybackupguide.com/blog/power-convert-calculation-3000-mah-backup-battery-and-5watt-cf-bulb/comment-page-1/#comment-198 billrussell42 Wed, 14 Jan 2009 01:15:08 +0000 http://www.batterybackupguide.com/blog/power-convert-calculation-3000-mah-backup-battery-and-5watt-cf-bulb/#comment-198 5 watts is 5 joules per second 3000mAh or 3A-hr battery Need the voltage on the battery. Assuming it is 12 volts, then 3 A-hrs is 36 watt-hours 36 watt-hour x 3600sec/hr = 130000 watt-sec or 130000 Joules 130000 Joules / 5 joules/sec = 26000 seconds or 7 hours. But ratings on batteries vary a lot depending on discharge rate. Plus there are losses to consider, so count on half that time. . 5 watts is 5 joules per second

3000mAh or 3A-hr battery

Need the voltage on the battery.

Assuming it is 12 volts, then 3 A-hrs is 36 watt-hours
36 watt-hour x 3600sec/hr = 130000 watt-sec or 130000 Joules

130000 Joules / 5 joules/sec = 26000 seconds or 7 hours.

But ratings on batteries vary a lot depending on discharge rate. Plus there are losses to consider, so count on half that time.

.

]]>