EB3A Failure As Uninterruptible Power Suppy

Last night I for the first time used my Bluetti EB3A as an uninterruptible power supply (UPS) for my CPAP. About 2-3 hours into my night’s sleep it shut down, showing an “overload” indication despite the fact that my CPAP only draws at most 40 watts. I contacted a friend who runs a computer-related business and was experimenting with two EB3A’s as UPS’s. He said that both had failed recently in exactly the same way under light loads, and that as a result he was no longer considering using them more widely for this purpose. Of the units I personally know of that’re being used in this way that’s a 100% failure rate, in my case on the very first night and on an important piece of medical equipment. (I have pretty severe apnea, and my head is still pounding as the direct result of this failure.) All three units involved were fully software-updated.
Bluetti specifically markets the EB3A as suitable for CPAP’s, and I’m far from the only CPAP user that can potentially die in the event of failure. (This is why I set up a power-outage backup in the first place.) think they have a Big, Big Problem here and may not be aware of it yet. I’m posting here both as a warning to others who may be depending on the EB3A a backup for various medical devices and in the hope that Bluetti will see this and act quickly.

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Hi @Rabbit , We felt deeply sorry for inconvenience caused.
Did you turn off ECO mode when you loaded CPAP? If ECO is on, the machine is likely to shut down automatically.

I tested 4 EB3As (latest firmware) in UPS mode, ECO off, Silent Mode charging, with very light AC loads, plugged into receptacles on 2 AC different phases, and all 4 tripped on “overload” daily on several successive days.
I then plugged all of them into surge-protected power strips and have had no “overload” trips for several weeks. I suspect the refrigerator (on a different branch circuit) compressor starting spikes were causing the problem.

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Thank you for replying. ECO was off.

ggnurps-- Thank you for replying as well. I’ve got a window air conditioner on the circuit, so I may have the situation you described. Still, I think this is urgent for Bluetti to address, because people will be using EB3A’s for medical devices.

Hi @Rabbit , Thanks for your confirmation.
The engineer replied as follows.
Please do not connect utility power with bypass mode to carry medical equipment and precision communication equipment and EB3A has a UPS switching time of 20ms.

You do realize that CPAP users are a large part of your market, right? And that the EB3A is being specifically marketed as appropriate for this exact use that you say here it’s actually not suitable for? For my part, yes. I’ve already ceased using the EB3A for this purpose and thank you for confirming that I was right to do so. My point here is that thousands of other EB3A owners don’t follow this forum and have no idea it’s unsafe to use this device with medical equipment. For that matter, HAM radio operators (is this what you mean by “precision communications equipment”?) are another large user-group. So, precisely what you’re saying not to do here is going to keep right on happening until either the problem is somehow fixed or there’s been some kind of large-scale recall or other appropriate corrective effort, having been specifically encouraged by your marketing efforts. And as I’ve stated elsewhere, a failed CPAP can (rarely, but it does happen) kill a patient with severe apnea. So… I’ve done my part by informing you. The rest is your lookout, not mine.

What engineer said that? Was it from Bluetti?

See the post above from “BLUETTI Admin”. I cut-and-paste here. Note that the term “engineer” was specified.

“Hi @Rabbit , Thanks for your confirmation.
The engineer replied as follows.
Please do not connect utility power with bypass mode to carry medical equipment and precision communication equipment and EB3A has a UPS switching time of 20ms.”

I bought EB3A and it had the same problem, AC output turning off randomly. I sent it back to Bluetti and they sent me a new one that must had been modified because its works. I use it with 10 watt fan, 25 watt fan and other combinations. It works great, so I bought two more EB3a from Amazon at $209.00 Guess what, both EB3A had the same problem of randomly turning off the AC output. I sent both of the EB3A back to Bluetti and got a full refund including shipping costs that Bluetti made me pay for. I have decided not to buy anymore until they fix the problem and the noisy fan.
When I sent the first EB3A back to Bluetti, I told them that a UPS AC output should never turn off until the battery is Zero and maybe that is what they did to fix the first EB3a.

Thank you.
Other than this one problem of the UPS feature not working properly I actually rather like both my EB3A and an EB70S I also own. You’re absolutely right about how a UPS should work and what the term UPS means. In my case I’ll keep mine and just not use the feature. But… You’re definitely right and Bluetti is definitely wrong. My only purpose for posting on this forum is to let Bluetti know that this particular flaw is genuinely a potentially health-damaging or even lethal one and doubly so in the context of their actively marketing to CPAP users. The reason I woke up with such a terrible headache after the UPS failure is that my blood oxygen fell far too low when my machine was cut off, and damage was done. It’s a statistical certainty that over the long haul eventually someone attempting to use the machine the same way won’t wake up at all, and Bluetti will in my layman’s opinion have serious liability. Both moral and financial.

Hi @Rabbit , Because EB3A as a backup UPS will have a 20ms switching time, it may be that this switching time causes the power to your CPAP to stop. We recommend that you use offline mode instead of bypass mode. Do not connect AC input, so that the machine can supply power to your CPAP normally.
We apologize again for the inconvenience.

Is is normal for the EB3A to show an “overload” error after a failure due to excessive switching time? Also… The utility power never went out. It didn’t even blink. I have other devices sensitive to this that would’ve revealed to me if there’d been a utility failure. Thanks!