|
Post by bupkis on Aug 10, 2019 1:43:45 GMT
buck is the two features, ohms law. 60v x 5A = 300 watts bucked to 15v x 20A (ignoring eff). Power is the term or quantity to compare, power = power. Notice they talk about stepping down voltage while stepping up current. Stick to what you know please! en.wikipedia.org/wiki/Buck_converter
|
|
|
Post by mediadogg on Aug 10, 2019 12:31:38 GMT
buck is the two features, ohms law. 60v x 5A = 300 watts bucked to 15v x 20A (ignoring eff). Power is the term or quantity to compare, power = power. Notice they talk about stepping down voltage while stepping up current. Stick to what you know please! en.wikipedia.org/wiki/Buck_converterOk, but I thought that was what I was saying. I thought that was exactly my point, and I agree that is correct. No need to be rude, especially when we agree and are saying pretty much the same thing. What did I miss? Out of curiosity, what did you think I was trying to say? In fact, I didn't ignore efficiency, I took it into account by saying "(power out + losses = power in)".
|
|
russ
Solar Advocate
Posts: 63
|
Post by russ on Aug 10, 2019 20:26:55 GMT
Notice they talk about "stepping down" a high voltage from the PV to a lower voltage used for charging the battery, and then "boosting" the current to compensate for the lower voltage (power out + losses = power in) at over 90% efficiency. This task, at that efficiency is typically done today by what are called buck converters. There may be other ways to do it. Boost converters do the opposite: they convert a lower DC voltage to a higher DC voltage, at a reduced current (again, Power out = approximately Power In). MPPT controllers for battery voltages greater than 48 Volts might need both "buck" and "boost" circuits (this use of the word "boost" is totally different from "boost mode" as a stage of charging a battery). That is a very good explanation of buck and boost conversion.
In the interest of improving efficiency I use a buck converter to drop a 12 volt battery to 5 volts for charging my phone, tablet, and other usb charged devices. Because it is a buck converter rather than pulse width modulation it increases the current (with respect to the input current) as well as steps down the voltage with a minimal loss from conversion in the form of heat given off by the circuitry.
Also in the interest of efficiency, I use a small boost converter to raise the voltage of a 12 volt battery to 19 volts to charge or power my notebook computer. While the boost converter raises the voltage of the 12 volt battery at it's output to 19 volts, the current at the output is reduced with respect to the current at the input of the boost converter. But, considering the battery capacity is only 50 amp hours this is much more efficient than using the 115 volt notebook computer power supply and an inverter, making better use of the limited battery capacity.
|
|
|
Post by mediadogg on Aug 11, 2019 22:04:57 GMT
That is a very good explanation of buck and boost conversion. Thanks and right back at ya!!
|
|