BFL13 wrote:
I am confused about the "replace" part. I can see it takes about 900w of AC to "make" 50 amps of DC and over time it would take so many KWH to make so many AH.
Usually we talk about "replacing" after the DC amps are "made" and used through a battery in AH. In that case, you run the battery down by say 100AH and then "replace" that, which takes maybe 110AH.
No way does it take 1.87 to "replace" 1.0 in the battery.
I can see how the watt meter would measure the amount of 120v from gen or shore power to run the charger during a recharge. How do you use it to measure what is drawn from the battery?
I did/do not measure AHs drawn, only how much 120V energy is needed to lower charging Watts to below 200. When dry camping, I shut the genny down under 200W because the solar can take over. I now know that when morning Volts are 12.33, I will be charging nearly three hours before I can let solar take over.
I stopped charging at 126W. Using my estimates of Dividing 126W by 16.8 or 20, I get 7.5 or 6.3 ending charging Amps into the 270AH bank. That says the bank is very near recharged without ever knowing how many AHs were taken/returned. I'm sure we can agree I was 95% SOC. :)
I suspect far more than 1KWH was drawn from the bank. 1KWH is the energy that arrived at the heater. I could guess the AHs by using 12.5V as the average during the 1KWH draw. That gives roughly 80AH plus efficiency losses of ?. There was a good amount of heat inside the inverter as evidenced by the 15min cool down time. How much of that was AHs that never made it to the KAW?
There was also heat generated in the charger as evidenced by the thermal antics. How much of that were Watts that never made it to the bank.
Both of these factors should make both of the 1 and 1.87 readings closer. I wonder how close we were to the 110% after all?
What I would like to see is a comparable test run with other brands of inverters and chargers.
HTH;
John
