Is this UPS a fire hazard?

2 years ago by Magnetic_dud to c/ece

The batteries in this UPS lasted less than a year. It was because those battery were "no name" batteries, or because they were connected in series directly to the AC after the transformer? Shouldn't they have a rectifier and condenser before that? It seems that in this way the battery is connected to AC 24/7

hendrik 11 points 2 years ago

I'm fairly sure batteries can't be directly connected to AC or they wouldn't charge in the first place. It'd just heat them up. So if they charged at some point, there has to be something else going on.

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echutaaa 2 points 2 years ago

Looks like they have a half wave rectifier and maybe some sort of bms on top but it’s hard to say from one pic

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czardestructo 4 points 2 years ago

What is the make and model? Since it uses a full size transformer instead of switch mode supplies I'm going to guess its old and should be retired. Its old and inefficient, always consuming power to keep that large set of magnetics energized.

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Magnetic_dud 0 points 2 years ago

there's no make and model, just "1200VA UPS Made in China" and a what i suppose to be a fake CE logo

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czardestructo 3 points 2 years ago

As an electrical engineer I would advise you to recycle it. How much did you save buying no brand vs how much is the equipment you connected to it worth? How long would it take you to rebuild the connected equipment if the UPS threw out too much voltage and blew up everything downstream.? In my opinion the risk isn't worth the savings, don't cheap out on power equipment.

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RubberElectrons 1 point 2 years ago

Agreed. There are open source UPS projects out there if you want to know what's gone into your design, but be sure you have the time to do this right.

Physics doesn't give a fuck.

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PriorityMotif -5 points 2 years ago

Thats a transformer, it's outputting dc power. My main concern is that the batteries are sitting on end like that. They're filled with water, so if there's an air gap at the end the battery is not going to work as well.

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__Lost__ 11 points 2 years ago

Transformers change voltage, but they don't change AC to DC; you need a rectifier to do that.

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PriorityMotif -4 points 2 years ago

It looks like they put that on negative side of the batt.

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