We have a new AC200Max that performs marvelously, but has (what we consider) the enormous overhead battery drain to keep the AC unit “on”, even without any active load. There are plenty of other board postings on this site and others that address/confirm the situation. For now, all we need is the ability to run 24 hours with very modest, continuous AC load (let’s say <10w). Our AC200 is hooked up to 2x200w panels in parallel… which even with the winter sun and all inefficiencies should be more than enough to meet our power needs… but the Bluetti “overhead” seems to be a fixed cost that we’re not able to overcome. The battery is nearly drained after 2-2.5 days of use. One wouldn’t have thought we needed to add so many additional panels just to keep the Bluetti idling in neutral. Is this an issue that can ever be resolved? Since this is a Bluetti site, is there some other Bluetti unit that we should have purchased instead that is better suited for continuous, lower draws?
@Kilgore234 the high power of the ac200max’s inverter is where all that overhead is coming from. And unfortunately, you’re gonna have that with most high powered inverters. If you’re looking for something to power those lower draw items, you could get an EB55. I use more eb55 for my overnight trips where I don’t been to be using any high wattage appliances and it works perfect for my needs.
The EB150 and EB240 both have high wattage inverters (1000w) and have much less of an idle draw when not in use also. But it’s because they are simpler units without all the fancy stuff. (App connectivity/RV plug/etc.)
Hope this helps!
If it is only 10 watts, you could try a car inverter of 100 watts and plug it in the DC socket of the AC200Max. I heard the DC circuit does not have a high overhead.
PS Use a pure sine wave inverter, it works better with most devices. Here is one:
Wow, I am surprise that it drains that much even with 2x200w panel. Does the display shows the total wattage including idle drain? Or just the actual output and the idle drain is on top of that but not visible?
One thing I liked about my ancient lead acid goal zero power station is that the output is raw battery output, so idle drain or any other drain (external to the battery) is visible.
@snowstorm The display does not show total drain when AC is on. I can put on a rather small load (<10w) and the unit will show that there is some AC load (the blinking little periods that graphically show current flowing from Bluetti out) but still reads as “0”. When there is no exterior load, the unit sits idle and shows no AC activity… but we now know there’s quite a bit going on internally with that inverter.
@hey That is a really good idea. I’m going to give a DC car inverter a try and report back.
Plugging an inverter will use more power because it draws from a regulated DC source that is then converted back to an AC source. This sounds great, but does not result in lower electrical consumption.
@hey Just for fun I tried out your suggestion. Plugging in this Bestek DC adapter and turning it on draws 10w from the Bluetti. Running my internet modem/router through the Bestek pulls a total of 25w. Adding approx 12w from Mike’s posting above would suggest a total Bluetti draw of about 37w.
When I run the same internet modem/router through the Bluetti AC inverter, it works well and shows that there is current draw, but the screen shows 0w output. Assuming this router draws no more than 10w and adding the 32w of AC inverter “overhead” this sums to approximately 42w.
Thus, there is no free lunch here, or not enough to really make a long term difference (37w vs. 42w). Hopefully this posting proves educational to folks out there even if it still hasn’t yet solved my problem.
There is one more option that may be most efficient, but it depends on the voltage and adapter…
Almost all routers actually use DC. It may accept 110V and then converts it to DC inside, or it has a power brick that converts the AC to DC before going into the router. Some options can be considered which will be more efficient as they skip the DC-AC inverter stage:
1- Has power brick, brick output is 12-14V DC. Great, rig up a wire and connect directly to the DC output, skip the power brick.
2 - Has power brick, brick output is not 12-14V DC. Say it is 18V… use a DC DC converter that can accept 12V and output whatever voltage and current your router brick supplies. Connect that and bypass the original power brick.
3 - No power brick the AC wire goes right inside the router. This is the hardest option, but still possible (though I won’t recommend this…)Open up router and find out how it diverts to DC, measure voltage. Use amp meter to check how much current it is pulling when in use or read the wattage. Wire DC DC converter into the router and bypass the internal rectifier.
All regulated DC outputs have overhead losses to regulate the output. The higher the output capacity, the greater the losses in general
Yep no free lunch as stated
Very true. There is no free conversion. However typically DC->DC is more efficient than DC->AC. Especially when the load is small relative to max power capability.
Also, the DC output of these power station is typically much lower powered than the AC output, which may explain the lower losses.
We don’t have to guess…
The DC output overhead (with no load drawn) is 11 watts.
The AC inverter overhead (with no load drawn) is 15 watts.
After converting the 58 volt DC to a regulated 13 volt DC output the 4 watt difference in AC vs DC will be consumed and a moot point. After plugging in a small 12 volt to 120 volt AC inverter to think it will be more efficient, you will actually be consuming more power than using the main AC inverter.
Hi - I’m new to bluetti family, so trying to catch up on this conversation. First, I love the bluetti - THANKs for the great design. I have been a bit surprised by how fast the battery drains, as others in this conversation. First, I ran a fan all night with a 90% charged AC200Max, and it was almost dead in the morning. Like someone else on this topic, I would have thought a fan would have run for days. So, I plugged my kill-a-watt meter into the AC200Max, and my load into the meter to try and see exactly what was going on. The AC200Max was charged to 98%, the load on the panel said 76-80 watts, and the meter said 70 watts (or less):
I’m assuming that approx. 10 watt difference of what I’m seeing the AC200Max shows as the load and what the kill-a-watt meter shows is the inverter overhead folks are talking about - is that correct.
Again, by morning, the meter showed 1.21 Kwatt usage, but the AC200Max was at less than 20%, when I expected to see it at least 50%.
Is the AC200Max performing like it should? I’m surprised a single fan would run a 2400Wh system down.
One other thing: when the actual load is about 60+ watt, the AC200Max panel shows about 70+ watt; however, when the actual load went below 15 watt, the panel showed 40+ watts. In other words, there was a big jump in the reading of the load watts on the AC200Max panel when the actual load was low. Is there a reason for that?
The displays are approximations and not multimeter accurate. The % remaining is also not linear as the % drops and is also an approximation very similar to a vehicle analog fuel gauge. For example, I took a trip to Miami over the weekend and filled my fuel tank up. I drove almost 100 miles before the needle dropped below the full mark. The next quarter tank on the gauge only lasted about 60 miles but even at the 3/4 mark, I did not have 3/4 of a tank of fuel left but something less.
When using the AC200 Max or any unit of any brand, there is a certain amount of power required just to have the equipment turned on. When you turn on the AC inverter you have the amount of electricity required to turn the main unit on plus the amount required to turn on the inverter and have it sitting in standby mode. This is all before you have attached or operated any AC load at all. Now when you power the AC load device, you have the before loads plus the AC load which requires additional electricity to convert the DC battery voltage to AC higher voltage. All this is what your actual power consumption is. You will not get the best results battery capacity wise when you use a small load attached to a big machine like you are doing. A small machine running a small inverter powering a small load is going to use less battery capacity than using a large machine with a large inverter powering the same small load. As an example: a bicycle is more energy efficient to go two blocks to get a pack of skittles than to hop in an 18 wheel semi truck to perform the same task. Both machines are capable and will perform the same task, but with different energy consumption results. But…a bicycle will have difficulty hauling a 2,500 lb. pallet of those same skittles and the semi truck will not.
When you are measuring outputted electrical energy, you are only seeing the delivered electricity and not the power required to produce it. In short, I would expect 80 to 85% of the total battery watt hours as an absolute capacity.
Thank you - everything you say makes sense. Can we translate the wealth of information to the AC200Max: If I’m camping and want to run A/C or heater during the night, will I be able to do that (don’t want to leave for camping with the grandkids before we know we can keep them warm). I can do the math (80 watts for 1 hour is 80 watt hours, etc.), just need to know the reality of what I’ll be able to get.
Are you saying that I should be able to “realize” 80% of the battery. So, just under 2KWh? If I’m drawing 100W, I should run be able to run that for 20 hours before having to charge again? Or have I missed it (please be patient, just want to understand).
As a side note: I built an off-grid system about 12 years ago, with the help of the Arizona Sun folks (via a community like this). At that time, the HOA wouldn’t allow panels on the roof, so I put them in the driveway (funny, no HOA laws against that). As a result, I had to build my own power station: I started with 1 car battery and 1 solar panel, and my goal was just to brew 1 cup of coffee. I learned a ton, ended up with 8 car batteries and 8 solar panels (medium size), and went to cold brew - which I highly recommend for everyone. This seems like a long story, but stay with me.
When we moved, no HOA, and we purchased a grid-tie on the roof system, with 18 large panels, and no car batteries. My solar panels were fine, but we didn’t have much space on the roof and didn’t want to waste the real estate with the older, lower performing solar panels, so they have been sitting in my garage for almost 10 years, just waiting for Bluetti to do their magic. I did a bunch of research, and decided to start with the AC200Max (would have gone with the AC300, but they weren’t available yet, and I may be glad I ended up with the 200). I’m so excited to be using the solar panels again, now that I have a way to store the power.
Originally I was hoping to use this to power my out building, but I’m wondering if that will be doable. I’ll need to run pumps and fans, and charge batteries for yard equipment. There are times I may need to run a large fan all night - I’m confident I can keept the AC200 charged during the day, but, obviously, not at night.
Thoughts? And, thanks again for your comments. Also, I’m looking at building a panel so I can plug the Bluetti into my home in case of power outage. Just some thoughts.
You should be able to get around 80% of the battery capacity. But…remember when you are using a low wattage load (100 Watts) for 20 hours, you are also using the amount of power that the Bluetti takes to turn on and operate as well as your load. Basically every minute you turn the Bluetti on, you are consuming some power. You will get the most battery (usable capacity) life when you run larger loads for shorter periods of time.
With regards to running a heater or air conditioner during the night. You can, but you will not be able to run it very long. For example: If you ran an electric space heater that consumes 1500 watts, you will exhaust your battery in approx. 75 minutes. If you ran a smaller window type AC that used 500 watts you should be able to run it about 3 hours and 45 minutes. If the AC type your are referring to is the RV AC unit then you will get about 1 hour of use.