AC200 Test Issues with AC inverter

[Recce]

So I have the AC200. Not the AC200P. Mine is 1700Wh. My first problem is with this email from the company with this quote:

"So the actual DC can use Wh=
1700Wh*75%=1275Wh.
AC200 AC efficiency is 88%
So the actual AC can be used
Wh=1700Wh*88%=1496Wh"

I want to believe that they mixed AC and DC. Please tell me if I am reading that wrong.

My second issue is my test results. After multiple test I am always pretty close to the same results. Some of my results are as follows:

DC powering a 400 Watt inverter (I know it’s strange but I was just playing with something)
1125Wh used = 66.18% efficiency = 33.82% loss (this is combined loss of DC + external inverter)

Everything under this for DC is based off the 12% loss quote above​

1125Wh + DC loss of 204Wh (quoted by the Bluetti if I reverse their AC and DC) = 1329Wh = 78.18% = 21.82% inverter Loss (this is external inverter loss)
Overall loss or 33.82% - Inverter loss of 21.82% = 12% DC loss on the AC200
(While the 21.82% is only from the quoted 12% loss. I believe that is pretty close and I don't have any issues on the DC side)

My other DC test (plugging directly into the 12Volt DC outlet) resulted in near perfect results. Pulling over 90% of the batteries power. So again nothing to worry about. My issue remains on the AC side where I am only getting between 55% to 58% capacity. The following is the last test I performed.

AC (internal 2000 Watt inverter)
990Wh drawn
58.24% = 41.76% inverter loss

I have run this test multiple times. Like the DC they are fairly consistent. This is the highest results for capacity and my lowest results come in at:

55% = 45% inverter loss.

While I am talking to the company right now. They are pretty slow on the draw with answers as it’s been a month of back and forth. And repeating the test in multiple different ways to make sure my results are accurate. I am placing this here to see if anyone else has had an issue with the AC inverter and if there was a solution other than sending it back in to be replaced. I truly feel like I’m getting a heavy loss here. I also tested the AC50S and got the following

AC (internal 300 Watt inverter)
410Wh drawn
82% - 18% inverter loss

I believe this was a good result. And not sure why I am losing so much from the AC200. In some of my test the AC50S was only a couple hours short of the AC200 powering the same device. The following was one test

AC200 lasted 21H50M
AC50S lasted 19H00M

A difference of 1H50M to run the same device. To me that is unacceptable. But please feel free to tell me otherwise if I am wrong somewhere.

Thank you for your time.
Jeff

 

[snoobler]

Welcome to the forum.

It depends on how they are producing the DC. If they are converting back to 12VDC from 120VAC, then 75% is a real number. I see this going from Solar batteries to 120VAC inverter to 120vAC to 12VDC RV converter - about 75% efficient. If DC-DC, should be around 90%.

Peak inverter efficiency is somewhere around 30% of peak power. It can be horrifically low at very low power, and it slowly drops off as you approach peak output rating. My Victron Quattro 48/5kW is only about 65% efficient below 100W.

Given that your tests are lasting for ~20 hours, I can only conclude that you are using a low load, and your efficiency is going to be notably lower than at higher power usage. I presume the test load for the AC50S is a notably larger % of its total output vs the AC200.

Recommend you use a ~500-600W AC load to confirm 85%+ efficiency.

 

[Recce]

It depends on how they are producing the DC. If they are converting back to 12VDC from 120VAC, then 75% is a real number. I see this going from Solar batteries to 120VAC inverter to 120vAC to 12VDC RV converter - about 75% efficient. If DC-DC, should be around 90%.

Recommend you use a ~500-600W AC load to confirm 85%+ efficiency.

-The DC results are near perfect to the 1700Wh. Yet they are claiming 75%. Thus just assuming. Not 100% That it must be DC-DC.
-Yes my test are with low loads. I will try higher loads this week and see what it gets me. And that would confirm my biggest fear. That the AC200 is only good on the AC side with large loads. As both the AC200 and AC50S did the same test. And ended up with near the same results. And that would mean I would be better off with two AC50S then one AC200. Meaning the only way to get most of the 1700Wh is to use them up quickly. Either way I will preform this test and get back to this after.

 

[snoobler]

Your fear is true for all inverters from all manufacturers. You size the device for the need. Bigger isn't always better.

 

[Recce]

Your fear is true for all inverters from all manufacturers. You size the device for the need. Bigger isn't always better.

Well that is good to know. Thank you for the help. Was hoping the inverter wouldn't use that much power. Now it would be amazing if I could take the 2000W inverter out and replace it with something smaller. Would make an interesting set up if you could switch out the inverter to the size needed so you can get what you need from the battery. On the good side of things. I use DC power for nearly everything I do so it will still work out. I'll do the test anyways to ensure that its proper and write back here once I have a result of sorts.

 

[Recce]

Recommend you use a ~500-600W AC load to confirm 85%+ efficiency.

The test is now completed. I kept the power draw to around 500 watts. I pulled 1370Wh of the 1700Wh. Giving me 19.41% loss. Much better then before. but they claim 88% on AC. Guess I'll be sticking to the DC power of this machine. Thanks for your input.