EB3A IN UPS mode dead and smoking.

I used the EB3A as a UPS (Uninterruptible Power Supply) for my Ender 7 3D printer, as well as a Raspberry Pi to control it using Kipper. Today, there was a power outage, and the circuit breaker tripped.

Upon reaching the 3D printer downstairs, I detected a burning smell, initially attributing it to the 3D printer itself. However, it wasn’t caused by the printer but by the EB3A UPS. As I attempted to disconnect the 3D printer from the UPS, I noticed smoke emanating from it.

It turned out that instead of safeguarding me from power failures, the EB3A caused the power failure. Fortunately, my circuit breaker activated, preventing further damage.


Hi @3d2d

Thanks for sharing your issue with us.

I watched your picture from imgur and see that you EB3A is located directly beside the radiator. In UPS Mode, the unit produce a lot of heat. Especially when hook up to something that need a lot of energy over a long time (Datasheet says about 350W draw). Like you 3D Printer. In this case, the unit may dont get cool enough air to actual cool down.

Dont want to point with my finger on you. Dont get me wrong.

It also can be some sort of technical defect too, where you dont have any influence on.


@3d2d I’m sorry for the inconvenience. Can you provide me with the order number? We can help you arrange a return. We will check the specific reasons after the machine is returned to the warehouse.

The Radiator is/was not on and the printer draws under 200W when printing low temperature material like PLA.

It is also rated -20 to 40C and it was maybe 15C
And power draw was only 1/3 of the rating

Also the UPS is not double conversion so there is no reason for it to have more load as loang as its not actually running.

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Is this unit really meant to operate as an UPS? It seems to have only DC in, so I understand it needs to constantly invert whatever the scenario (on grid, off grid);

There is something as a double conversion online UPS. But these units are usually more expensive.
Double conversion UPS units always convert from AC to an internal DC bus that charges the battery and powers the inverter that always runs to provide power to the load.

With a regular standby or line-interactive UPS, AC utility power is directly fed through the UPS to the load and the UPS only intervenes when there is a power cut or when the AC utility power voltage is too high/too low.


Thanks. How fast does the UPS react to a power cut? I have a desktop computer that sometimes reboots when the grid has a sudden, short, voltage drop. In rural Italy, this is happening quite often and I don’t want to buy a laptop just because of regular voltage drops messing with my PC.

Hi @Puffi

I see many users here in the forum that use the EB3A as UPS for their computer. It should work, but for what i see, it sometimes depends on the computer.

If you dont have a PC with a super high powerdraw, the switch from grid to battery shouldnt be noteable. What can happen for some screens is, they turn of when switch to “backup” mode. But as for the PC. It depends.

Try it for yourself, and if it doesnt work for you, return it :slight_smile:


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Honestly I might go for a larger unit, that new AC200L seems to have it all in a single package. I have a camper with a lot of DIY still to be done, so I still need to decide what kind of powerplant to install in there; EB3A might be to “light duty”. I’m just concerned by the vibrations and how it would affect the health of the device.

The bigger Units are designed for beeing in a Van for example. Cables are fixed inside the unit. So there shouldnt be a problem with taking them on the road!


Agreed, and youtube has teardown videos to confirm this indeed, as @Selfmadestrom lays it out, they’re solid inside. Epoxy, glue, and all it needs to be vibration resistant. There’s been an AC300 in my car for a few months in a row. I just make sure to not turn on the inverter “AC ON” feature, as that is sensitive to vibration.
Keep in mind that all Bluetti devices have a DC in plug, and come with a car 12V lighter plug to Bluetti in adapter. This suggests they encourage you to recharge you car while driving, so you can recharge your device between stops.

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“The UPS?” What do you mean. A regular UPS is always fast enough. Around 10ms. (Solar) Power stations are a bit slower. The Bluetti AC300 has been tested to be around 20ms. It is still fast enough to keep my power hungry gaming PC on when I yank the power cable of my Bluetti AC300 when it feeds my equipment in UPS mode.

When you have any problems with power stations of Bluetti or other brands in UPS mode: Consider the following: Buy a regular computer UPS with pure sine-wave output, such as an APC Smart-UPS. Connect your computer to that. Keep your Bluetti charged up and use it for whatever purposes except for UPS. When there is a power cut, just switch on your fully charged Bluetti power station, enable AC output and plug your (APC) UPS into that.

Then you solved any possible problems with switching time, idle power drain, battery wear or fear about spontaneous smoke output.

In short, if you need a solid UPS, buy a computer or server UPS with pure sine-wave output from a company that has been making UPS systems for decades.

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Good point, thanks…!