AC200Max - Excessive AC Overhead?

Reading in these forums, other people have cited AC overhead of maybe 10-30w, but what I’m experiencing (with my new AC200Max) seems like too much!

245w drain minus 165w load = 80w lost to overhead
143w drain minus 8w load = 135w lost to overhead

Any thoughts?


Hi @coherentfield , The reason for the difference in the displayed power is that the AC200MAX shows the apparent power and the meter may show the active power

That still seems like a really big discrepancy.

Can any other users confirm whether my unit is behaving in a normal way?

To fully explain, the Bluetti had a belkin surge protector plugged in with a few power adapters plugged into it and a PC. The low power situation was with the PC off & the high power situation was with the PC on.
Thanks in advance!

Trust your power meter not the Bluetti display, my AC200P can be off by over a hundred watts sometimes.

Hi @coherentfield, Your AC200Max is likely displaying apparent power (VA) but you’re measuring real power on your Kill-A-Watt… See my response to a similar question: AC200 vs AC50S watts totally different for same appliance - #2 by bxm6306

There are two ways to measure electricity consumption: real power and apparent power (VA or volt-ampere)… You can measure both metrics with your kill-a-watt by switching between the Watts (real power) and apparent power (VA).

Fun fact, power stations (and real world power generation plants) must produce power equivalent to the apparent, NOT real power. So for example if your kill-a-watt measures your air pump as consuming 12 watts of real and 70 VA of apparent power then it will need to generate 70 VA of power which might show as 70 “watts” on your AC200’s display.

Purely resistive loads (like heaters) have apparent and real power equal to each other. The difference between these two figures is known as the Power Factor.

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Thanks for the info! I had never tried resistive only load on my AC200P before and when I did with a heater the AC200P display and my power meter were very close.

I have exactly the same with my new AC200Max.
I also wondered about the high power values at low AC load.
Then I used a measuring socket, too.
The result of some testings (measuring socket/AC200Max Display):
Laptop+Monitor: 58W/150W
PC+Monitor: 228W/290W
Toaster: 1068W / 1080W
Soldering station heating up: 47W/0W
Dremel on different speeds: 15-35W/0W

I agree the AC200Max seems to show the apparent and not the true power, but below 50W true power it further shows 0W.
In this cases the devices have maybe nearly the same apparent power as true power and it is only 0 if the apparent power is also extreme low, I don’t know. I have to check it again.
But my measuring socket is further showing the power factor, which is the the ratio between true and apparent power and for the example with laptop+monitor it showed a power factor of 0.39.
58W true power divided by 150W apparent power results in 0.387 power factor, wich is the same value what the measuring socket showed.

Thanks @bxm6306 for bringing up the purely-resistive loads. I tested with an electric heater and the numbers matched super-close (see pic)

I guess this is a clear reflection that the power factor on this other equipment is pretty bad. Is it safe to assume in those cases, that the amount of energy listed on the Bluetti is a more-accurate reflection of how its battery is being depleted? (and that the external power meter isn’t super-relevant?)
Thanks to all of you for giving this topic some attention.

@viper your experience with loads below 50w isn’t the same for me - at least with this digital power adapter stuff, my 9w of usage on the power meter showed as 143w on the Bluetti. It must be because the dremel and soldering iron have a different power factor. The fact that it shows you 0w is sadly too good to be true!

Yes, exactly, and power factors are an important consideration when generating your own power because the generator must produce the apparent (VA), not the real power (Watts). The apparent power will always be higher. If your device has a poor power factor then it means more work for your generator/inverter. Devices with active power factor correction will be more efficient and draw less apparent power from your generator/inverter.

Absolutely. Most power meters (like the Kill A Watt) can display apparent power and real power, you just need to know which one you need to pay attention to for what you’re measuring. So in the case of Bluetti power stations, you should really only be looking at apparent power (VA) and not real power (Watts) on your power meter to determine the amount of power the inverter needs to produce.

Thanks for all the details! That helps. I’m going to check for the VA option on the Kill A Watt…

Hi Community. similar issue.

But horrible.

Since several month I run my fridge on a AC 200P off grid. I‘m charging with PV and sometimes from the grid. Usually in the evening I start from 100% or closets that.

In the morning I usually reach 30-38%.

Fridge was measured by me with different equipment to 60W and 90VA. AC200P usually shows 115W.

But in general The Iland works.

No I made an Upgrade to AC200Max with 1x B230. I thought that by this I have some more buffer and maybe can attach some more devices such as Wi-Fi Router, Network Swith.

So I simply unplugged AC200P and installed AC200 MAX +B230. Charged to 100% and … go.

First issue. AC 200 MAX shows power output of 155W. This is far away from 60 or 90. So I‘ was confused.

But ok. With 4000Wh:155W I still expected a runtime of 25h.

In the morning I was shocked. Already at 6 am when I was awake, System was off. It shut down somehow in the night after less than 12h.

I gave it a second try realizing that when I started B230 it was already 66% SOC.

After charging again to 100% second night was similar. Only 5% left at 6am.

Third night, without load but AC inverter on, nearly 50% loss in 12h. Does that mean the inverter consumes 166VA per hour? Is this serious?

And now the question, why does it work with AC200P?

OK, I’ve figured out why my equipment was causing so much of an draw of apparent power. I use Graham-Stetzer filters to soak up “dirty electricity” (or “high voltage transients” basically static on the line that can come from the power plant or from household sources - esp switching transformers). It looks like these filters result in a pretty decent 80-140VA draw (while only 1-2 watts in actual power). I’m not an expert so if I’m describing these things inaccurately, I’m open to correction.

In this process, using my Graham-Stetzer meter, it appears that my Bluetti AC200Max puts out a very “dirty” AC current (but so to did a smaller Anker box I have). Obviously, if I’m in need of the juice, I won’t care, but it makes me think twice of integrating this equipment into my life on an ongoing basis.

If you’re wondering “what the F is this guy talking about”, this is one resource by an epidemiologist Samuel Milham MD MPH: Books, Biography, Blog, Audiobooks, Kindle

Those filters likely just have a large capacitor in them between live and neutral and nothing else of significance which consumes apparent power but not real power. Check this video out of a similar device: Power saver plugs just got a bit darker - YouTube. He actually calculates the apparent power at 8:10. In effect, this filter is just correcting for inductive loads by adding capacitance which should bring the power factor closer to 1.

I think you’re completely correct about these basically just being capacitors.
Thanks for sharing…
Like mentioned in the video, if power meters measure apparent power are used to judge electricity usage, these filters can have a big impact on costs. At my office, the landlord has individual meters for each unit (that presumably measure the apparent power). After installing these filters, my bill went up a huge amount. I couldn’t figure it out since I was using my meter to just measure the real power and saw no increase. Instead of removing the filters, I have chosen to turn off all the circuit breakers when not using the office & the cost is tolerable.