Looking at your 6kw inverter

Thx Sid!

Sid, there's a serious issue in your inverter. I would like to talk with you privately about it. let me know what means that can be done.

Ummm...via private message??

On 7/16/2021 at 6:10 AM, Bossrox said:

Sid, there's a serious issue in your inverter. I would like to talk with you privately about it. let me know what means that can be done.

Since I have just ordered a 6K, is there something here that should be of concern?

Ha, not really.  The "serious" issues were significant moire/speckling in an analog CCTV camera system...and a washing machine that wouldn't wash when connected to the inverter.  In my book...those would classify as "annoying", not "serious problem with the inverter."  Heck, I've found forums complaining about washing machine issues on Magnasine and Victron inverters!  (That doesn't give us a pass, though it does hint that modern washing machines can be very particular about their input AC power.)

In testing, Bossrox was able to determine that adding more AC output filter caps to the output of the inverter reasonably solved both problems.

We have had one other customer report a washing machine compatibility issue (seems that usually the washer will abort midway through the job, but work perfectly on AC mains).  Similarly, this issue was solved by increasing the AC output filtration.

As a result of these discoveries, the Rev. C control boards (which are planned to go into all the next shipment inverters, assuming we can get them soon enough) double the size of the AC output filter capacitors.  This has a side effect of notably increasing the inverter's no-load current (the latter customer went from 18W no load to 36W--but the cap was grossly oversized.  I expect a no-load somewhere between those 2 numbers).  However, if increasing the filter cap size solves equipment compatibility issues, then I won't complain.

Sorry for the slow response; there's been little activity on the forum lately, I got out of the habit of regularly checking it...

I did some reading on the washing machine issue when you mentioned it.  Honestly thought it would have been more a problem with line connected AC motors and electronic control with the electronics getting upset, not the modern setup with VFD style operation.  I did read one thread attributing it all to motor inductance causing terrible power factor and the inverter not being able to cope but to me that only makes sense with an improperly compensated motor direct across the mains.  Maybe there are AC motor designs that (dear god) use phase angle switching of the motor for control?

I'm definitely no washing machine expert of course.

Unfortunately, having never personally experienced this, I don't have any way of diagnosing the root of the issue.  Throwing more caps onto the inverter output seems to alleviate the issue, which I'm thankful for.

I personally have a Maytag Bravos XL (HE) washing machine...got it for free on CL 'cause it wouldn't turn on.  Found that the touch control panel was the issue...cracked it open, it started working, so I put it back together--and it works just fine.  Never had any issues with it complaining about the AC power from the inverter (with an A.1 control board and original caps), or failing to run a cycle.

Sean experienced a few compatibility issues with the washing machine at his prior residence--but the new place got a new washing machine (no issues), so that benchmark is not available anymore.

Got another ? Sid. On the inverters kw tally indicator, does it read from the final output load or the total amount including the power the inverter uses? I have 1 of those chinese kw meters coming off the inverter & just noticed the difference between the inverters tally & the outboard meter have quite a different spread being the outboard is lower than the inverters. I've suspected the outboard meter wasn't recording an accurate measurement. Just wondering if you've run an outboard test to see if it lines up with your inverters #'s?

The kwh reading is from the AC output only; there is no DC-side sensing on the inverter.  It is worth noting that there are 7 different wattage calculations available in the dedicated power sense IC, as follows:

• Active (Real) Power -> this is probably what your Chinese meter is using, and also used by most PoCo meters for billing
• Average Reactive Power
• Reactive Power calculated from Power Triangle
• Apparent Power -> this is the one the LCD reads from, as it matches up with W = V * A
• Harmonic Active Power
• Fundamental Active Power
• Fundamental Reactive Power

It's anyone's guess what methodology the Chinese KWH meter is using, but likely if it's got any smarts, it's "Active (Real) Power."

I am aware that "Active (Real) Power" is basically "Apparent Power" x Power Factor.  In other words, loads with a poor Power Factor will register considerably lower on the "Active (Real) Power" than they will on the "Apparent Power."  The difference in cumulative readings may well just be differing methods of calculating the power used between the inverter and the Chinese meter.

If you have a clamp-on AC ammeter, we could verify this hypotheses--or  determine if the inverter's readout is miscalibrated.

It is worth noting that on the up-and-coming Rev. C systems, I am (currently) planning to ditch the power monitor IC altogether.  Not only has the current IC gone up in price by over 6 times, it's also very difficult to find for purchase anywhere worldwide.

I didn't expect it to read from the dc side, I was just wondering if the kw tally was somehow factoring in the power used by the inverters consumption. Just something I needed to know to get a better grip on the efficiency stats.

The difference between the inverter kw tally & the outboard kw meter got me to taking a closer look at it & being its a feed thru hookup, i discovered its also directional & I've had it reversed which likely explains the wacky difference. Seems there's always some kinda kink in the chain to figure out.

I wouldn't put a significant difference past different wattage calculation algorithms.  Some time back, I had had another customer point out that the inverter was reading significantly higher wattage than a Kill-A-Watt running the load--this would have to do with the Apparent Power vs Real Power calculations.