PD Converters and Water Usage
For Dry Campers Only No secret I've been a fan of PD converters for 15 yrs or more, and for more than one reason. The PD maintains my batteries every day of the year, except for the 4-5 months that...
Forum Discussion
Sounds like you got a very good understanding of what's going on. I welcome you aboard.
Glad you're taking some time to take measurements. As mentioned before, PD performance is dependent on the ac voltage. It's been documented that the PD does poorly with a 3500W Onan Microquiet. The greater the ac voltage, the better the performance. See my equation from earlier.
The standard test procedure is to discharge battery down to 50%. You can discharge the battery using an inverter and a given load. Note discharge current and total time. Once taking measurements by turning on the converter circuit breaker, current and voltage may drop fast. It can be difficult to record manually. I like to take a video (with meters located together) to get accurate results.
As you mentioned, you don't have to have 3 meters. If line resistance is known, an amp and one voltmeter will work.
An accurate method to measure line resistance is to take a differential voltage measurement across the cable. Place one lead of meter (set meter on 2V scale, or lower) on the positive output of the converter and the other lead on the positive battery terminal. Given a know current, resistance is V/I. Do same measurement for the ground lead.
Glad you're taking some time to take measurements. As mentioned before, PD performance is dependent on the ac voltage. It's been documented that the PD does poorly with a 3500W Onan Microquiet. The greater the ac voltage, the better the performance. See my equation from earlier.
The standard test procedure is to discharge battery down to 50%. You can discharge the battery using an inverter and a given load. Note discharge current and total time. Once taking measurements by turning on the converter circuit breaker, current and voltage may drop fast. It can be difficult to record manually. I like to take a video (with meters located together) to get accurate results.
As you mentioned, you don't have to have 3 meters. If line resistance is known, an amp and one voltmeter will work.
An accurate method to measure line resistance is to take a differential voltage measurement across the cable. Place one lead of meter (set meter on 2V scale, or lower) on the positive output of the converter and the other lead on the positive battery terminal. Given a know current, resistance is V/I. Do same measurement for the ground lead.
DrewE wrote:
(The claim is that the PD converters often are at neither the full output voltage nor the full output current, but fail to put forth their rated power at the "boost" setting.
I have not run any specific experiments on mine in this regard; with luck this weekend I'll be able to finish wiring up a proper battery voltmeter and ammeter and finish up some other electrical upgrades I'm making, and then be able to do perform experiments in my "copious free time.")
If you determine the resistance of the wiring, it would in theory be possible to measure any two of the three measurements (current, battery voltage, and converter output voltage) and compute the third.
