| Home |
| Search |
| Today's Posts |
|
#11
October 28th 06, 01:30 AM
posted to rec.radio.amateur.antenna,rec.radio.amateur.policy
|
|||
|
|||
ans calculations/ fuel cell battery buffer or cap?
Roy Lewallen wrote in
: Tom Ring wrote: . . . 1 week is 168 hours which gives us 403 ampere hours. . . . which at 13.6 volts is about 5480 watt-hours. This is the energy storage requirement. The OP asked about using a capacitor. The energy stored in a capacitor is C * V^2 / 2. For capacitance in farads and voltage in volts, the result is joules, or watt-seconds -- you need 5480 * 3600 ~ 20,000,000 joules in round numbers. So suppose you wanted to store this same amount of energy in a capacitor, and you had a switching regulator which would handle 50 volts maximum input voltage. Solving for C, assuming it's charged to 50 volts, C = 20,000,000 * 2 / (50^2) = 16,000 farads. This assumes you can get all the energy out of the capacitor, which requires your regulator to work down to zero volts. But you'll get 3/4 of the energy out of it if your regulator cuts off at 25 volts, 7/8 if it cuts off at 12.5 volts, etc. How does that sound? Roy Lewallen, W7EL Send that to me in CW and I'll have a look at it. SC |
| Thread Tools | Search this Thread |
| Display Modes | |
|
|
Similar Threads
|
||||
| Thread | Forum | |||
| Running a radio from a large rechargeable cell or battery | Shortwave | |||
| Running a radio from a large rechargeable cell or battery | Shortwave | |||
| MAHA MH-C777PlusII MAHA MH-C777 battery reconditioner recommendation? | General | |||
| Loose connection inside D cell battery | Homebrew | |||
| Loose connection inside D cell battery | Homebrew | |||
Threaded Mode
