Do Kill a watts work properly On the output of Inverter?
Even if they do, they will not account for the inverter losses or line losses from ther battery.
Get the battery to 14.7ish, twist pot to hold it at 14.7ish when charging.
Not being familiar with the Megawatt, I can only relate that with my meanwell rsp-500-15. I only have to account for voltage drop difference on my wiring at 40 amps, compared to 0.4 amps. I only bother to turn mine higher loaded or unloaded when i want 40 amps to last for longer while battery is climbing to 14.7v. If time is not an issue and max amps for max duration is not an issue, then if I set my Meanwell unloaded to 14.7, it will get to 14.7v by the time amps taper to the single digits. Somewhat slower to just set it to 14.7v and let it go, compared to setting it to 15.3v to hold 40 amps until battery terminals getto 14.7v( accounting for voltage drop, but no constant pot fiddlement is required.
For the load test, Amp draw at beginning of test, just before ending test, the duration of the test, and voltage readings at those endmarks can reveal enough info for us to make edu mun cated guesses as to the health of each battery you test. The same load and the same duration test will allow
valid comparisons between batteries.
How many KWH or AH actually pass out of the battery can be inferred close enough from the amperage at the beginning of test, and the end of the test, and how long the test was performed, minimizing all variables.
Meaning do not start test, stop test, goto bed for 8 hours and then restart test as that will reveal nothing helpful.
Throw a 4 to 8 am pload on each battery individually for a set period of time, record initial battery voltage unloaded, then loaded, record amperage, then after X amount of time, record amperage flowing record voltage at battery terminals, then remove load, record voltage at 30 seconds, 5 minutes then and hour then 5 hours.
Seek to perform the same test on subsequent batteries keeping all variables as close as possible, and then there IS a basis for comparison, not only from battery to battery, but then again on the same battery if one is going to rechrge it again and load test it again, and compare the voltages/ results to the previous test.
Measure and time the load, return the battery to full charge recording the charging amps and duration and voltage, then load it again.
Do this a few times and it removes nearly ALL the mystery of how a battery stores and releases the energy it has the ability to contain.
Do this a few times and you can look back on this thread in a year and wonder how it was not so obvious to you then.
Ammeter, voltmeter, load and a clock. You have those tools and the sources.
If your battery is not going to accept much more than 25 amps, this tool will record Amp hours and watt hours, upto 64AH with about 90% accuracy.
Sorry no direct link, copy and paste:
https://www.amazon.com/GT-Power-Analyzer-Consumption-Performance/dp/B00C1BZSYO
I feel all ~ 25 amp charging sources should have one.
I modify mine with 8awg and push 40 amps thorough it without concern and it is almost shockingly revealing as to what the battery is accepting/has accepted from the charging source. not 100% accurate by any means but a zillion times better than 'it has held 12.92v for a week now, is it good?'
