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--- blog:2024-09-28:estimating_cost_of_electricity [2024/09/28 10:20] – [Here's why that works...] va7fi
+++ blog:2024-09-28:estimating_cost_of_electricity [2024/11/24 12:48] (current) – va7fi
@@ Line 1: / Line 1: @@
+~~DISCUSSION~~
+~~NOTOC~~
 ====== Estimating Cost of Electricity ======
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 If you look at the units carefully, you'll notice that they almost all cancel out except for \$\frac{\text{\$}}{\text{month}\cdot\text{W}}\$ ((The "hrs" of "24 hrs" cancels with the "h" of "kWh" since kWh means kW \$ \times\$ hr .))
-That number means that it costs 0.102784 \$ per month for each Watt that's on 24/7.  So if you multiply that number by the power consumption of the device, you'll get a result in \$\frac{\text{\$}}{\text{month}}\$, which is the monthly electricity price for that device.  For example:
+That number means that it costs %%$%%0.102784 per month for each Watt of power that's continuously drawn.  So if you multiply that number by the power consumption of the device, the \$\text{W}\$ will cancel out and you'll get a result in \$\frac{\text{\$}}{\text{month}}\$, which is the monthly electricity price for that device.  For example:
 \$$
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 \$$
-The trick to simply divide by 10 instead of multiplying by 0.102784 works because \$\tfrac{1}{0.102784} \approx 9.729... \quad\$  So a better approximation would be to divide by 9.7, but dividing by 10 is so much easier to do in your head, and the result is not that far off, specially since we already over estimated the cost of electricity to full //tier 2// instead of a combination of //tier 1// and //tier 2//.
+The trick to simply divide by 10 instead of multiplying by 0.102784 works because \$\tfrac{1}{0.102784} = 9.729... \approx 10\$ .  So a better approximation would be to divide by 9.7, but dividing by 10 is so much easier to do in your head, and the result is not that far off, specially since we already over estimated the cost of electricity to full //tier 2// instead of a combination of //tier 1// and //tier 2//.
 ===== A Concrete Example =====
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 Equipment on dedicated 12 V system that's on 24/7:
   * Internet modem, switches, and Wifi Boosts
-  * [[https://scarcs.ca/howto/echolink#sysop |Echolink radio and computer]]
+  * [[https://scarcs.ca/links/echolink#sysop |Echolink radio and computer]]
   * [[https://wcaredn.ca/setups/va7fi/home |AREDN hAP, two AREDN dishes, one AREDN VOIP Phone]]
 ))
-on a dedicated 12V system.  The system is fed with a high quality / high power 12 V charger with backup batteries and solar panels.  In the winter, the solar panels don't get any sun and the charger puts out a constant 75 W (and goes up when I'm transmitting).  In the summer, the solar panels provide about half the electricity needed.
+on a dedicated 12V system.  The system is fed with a high quality, high power 12 V charger with backup batteries and solar panels.  In the winter, the solar panels don't get any sun and the charger puts out a constant 75 W (which goes up when I'm transmitting).  In the summer, the solar panels provide all the electricity needed for up to 16 hours.
-That means that my internet and radio system costs me about $7.50 / month of electricity in the winter, and half that in the summer.
+That means that my internet and radio system costs me about $7.50 / month of electricity in the winter, a third of that in the summer.