Batteries draining with "0w" output?

We’ve been running our AC300/B300 setup and remote monitoring it via wifi - the batteries are dropping much faster than expected. Every time we check in (because it’s new, i’ve been keeping a log over the past day or so to figure out what we can expect), the AC output on the app shows 0w, but I definitely have a couple devices plugged in that are drawing power, like a router. According to the little AC20, these devices consume around 7-10w, but the battery capacity is dropping at an average rate of 55-70w/hour (calculated based upon the reported battery percentages, assuming 90% accessible capacity of the advertised 3072wH, due to the 10% reserved by the system). I know there’s some overhead to running the AC300 screen & BMS & wifi access & whatnot, but this is really high considering it keeps reporting 0w being consumed.

Any ideas on what might be causing this? Clearly, the display is reporting is wrong (note: The prior firmware displayed 4w output when I tested it running a fan, but the new firmware has never shown anything <100w output), but with numbers like this, I’m worried about what’s going to happen when we add more things to the load. :face_with_raised_eyebrow:

I guess the first thing I would say is that the AC300 is massively overkill for keeping a couple of very low wattage items powered. I believe that the AC output reported needs a certain load (something like 20-30 watts? I don’t recall) to show something greater than zero.

Keeping the unit powered on and turning on the outputs will definitely chew up a fair bit of power with a 3000 watt inverter. Frankly, for small things like a router and modem for Internet access, I’d use one with a much smaller inverter (something like an AC50S?) or just use a UPS if you’re primarily interested in keeping it up during power outages.

Another alternative might be to get a 100-300 watt inverter (not drawing more than about 100W) and hook it directly into the B300’s 12V DC cig lighter output to power these low wattage devices – turning the AC300 off until you need it to power heftier things.

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:stuck_out_tongue_winking_eye: i know it’s overkill for just some small devices - we’re just in the setup & test phase, but it will be eventually powering an off-grid cabin. So yeah, it’s going to power a lot more than just a few devices, including an Air Conditioner, but I want to be confident that the system won’t quickly drop to 0 before I depend on it to power appliances & whatnot.

Thank you for the point about the 3000 watt inverter, that’s the type of overhead that I was trying to figure out if I was missing in figuring out my calculations.

Typically an pure wine inverter takes about 1% of its rated power just to be on with no load. So for the AC300, that’s about 30W. The unit itself with probably takes maybe 10-15W to keep active, add your load of 10W which requires 13W due to 80% efficiency then you are draining 55-60w.

It is a shame that the power output indicator is not more accurate. I wish it showed you total power used rather than what it is outputting.


Thanks, that makes a lot of sense & is a good breakdown of what I’m seeing! Since this is going to be our primary power source, there’s lots of calculations going on to figure out what we can & can’t add to the load. And of course it’s our first venture into solar, so I’m learning a ton as I go along.

And agree, I wish it would show the total power consumption. Hopefully the app will continue to mature as more people & products use it.

I will say though - despite a learning curve, it still feels a lot easier to set up & use than some other DIY solutions we were looking at, so I’m thankful for that!!

If you are charging the AC300 and B300 with PV, then the loss is acceptable as that lost energy was free. But if you are using the setup as an UPS , then you will be paying for the utility cost, and that cost is worth it for a continuous (uninterruptable) power source.

A similar question about power drain on the AC300, I understand that having the AC “ON” will drain power (inverter being on). However, I noticed a drop of 15 percent over 3 days (for 4x B300 batteries) , with both the AC & DC off, but the Wifi and Bluetooth are on and nothing is plugged in. I did not expect an 1800 watt power drain when the system is left on (600watts/day), but both the AC and DC are left off. I would only expect this amount if I left the AC inverter “ON”. I have the latest Firmware for all items.
Note: As @avlena originally mentioned, I, too, am just running a test; while I wait until I have my panels up (hopefully this weekend). When it gets down to 50%, I plan to shut the AC300 completely off until the panels are up and connected.