Using a Battery Backup on your GF (Problem/Solution)

Hello everyone,
Got my GF yesterday and have proven that “proper” setup within an hour is impossible unless you have some minor (major) details already taken into consideration such as, safely powering and protecting your $4000 investment.

I was getting ready to plug it in and then this Step through me for a loop:

Plug in your Glowforge
Plug the Glowforge into a grounded wall outlet with 800 watts of power available. Make sure you connect the printer directly to a wall outlet and not a surge protector or power strip.

Problem: I live in Florida, brown and black outs all the time. So the internal surge protector from the GF is ok… but being in Florida I don’t want to have to start/stop jobs all the time nor beat up on the internal surge protector. No idea what the GF warranty on the surge protector is but I’d rather not have to find out the hard way. (And even if it is covered, it’s only for 6-12 months)

Due Diligence in a nutshell:
-Read through GF community posts
-Google’d technical info & best practices with UPS’s
-I can’t find any battery backups that don’t have outlets without surge protection.
-I HAVE to have battery backup ability.
-I HAVE to accommodate both the internal GF surge protector and the external one bought separately.
-My conclusion on issue with daisy chaining UPC/Surge Protector:
-If you daisy chain two surge protectors you MUST consider that the 1st Surge Protector (In this example, the internal GF unit) can mask the actual power output of the unit it’s protecting.
-Making it so the secondary Surge Protector (External UPC) can be overloaded beyond it’s capacity which can cause serious damage/fire, possibly immediate if the UPC enters batter backup mode AND is overloaded. This issue is intensified if the UPC is dispersing available power to multiple plugged-in electronics.

So the resolution to my dilemma is:
-Bought a 1500va (900 watt) UPC ONLY. Again, UPC ONLY for the Glowforge. Nothing else will ever be plugged into this UPS. Guaranteed to accommodate the 800watt GF rating & leave room for error between both Surge Protectors. If the UPS is dedicating all 800 watts to the GF, unless the GF has the ability to spike over 900 watts and hold it, I don’t see why this would ever be a concern.

-Unplug the machine when not in use.
-After using GF, check for any sort of abnormal overheating of the UPC, power cables and outlet.

I by no means am an expert in electrical work. But by reading numerous posts in the GF community and doing my own research on UPS’s I feel confident about my conclusion here.

Please provide your feedback and/or support. I’d love to get more affirmation on this solution.

Maybe GF can also confirm a black & white method where a user can safely and effectively use their GF with an external battery supply.


You’ve posted in the official support forum, the official support answer will not be any different than what you’ve already read.

In reality, using a (quality) UPS and/or powerstrip won’t harm the machine or affect its operation in any way. It’s no different than a computer or similar device, it doesn’t have any special or particularly sensitive power-related components. It also only draws aprox. 150W in-use, 25-45W at idle, but a higher rated supply is needed as it can spike higher for brief periods.


Yeah, since support is not going to be able to comment on this, I’ll shift it to the Beyond the Manual section for you so that other customers can give you input. :slightly_smiling_face:

BTW: We also live in a place where frequent line surges and power outages are a BIG concern. We finally had enough and installed a Generac. Best damned decision we ever made, because as soon as we finished the last payment, we knew that there would never be another major power outage or hurricane come our way again.

And so far… :sweat_smile:


I moved you over to Beyond the Manual as GF support will not elaborate beyond the “official” word. I have a Battery backup for mine, but I got that all rigged up over a year ago and now I forget the details. :crazy_face: Your homework seems well reasoned and your precautions seem pretty comprehensive. I’m gonna check my rig tonight and see if I have anything to add.

Also: welcome to the community!

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Beat ya to it! :wink:

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Oh, maaaaannnn… You ALWAYS get to recatagorize! :pleading_face:
That was gonna be my first one!

I’m going to have to start looking in at weird hours. You have to sleep some time…

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Wait…wait…I can’t stomp on that…

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Okay…it’s all yours! :wink:

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Since 2 hours has passed and it was still in P&S, I moved it to BTM :wink:


@UrJac must have moved on before seeing my post. :joy:
(I’ll try to refrain next time.)

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Here is a thread about surge protectors/UPS and glowforge:

The 800W rating for the glowforge seems to be a conservative max surge rating. When the first units were delivered there was some posting from folks who metered it finding nothing really close to that power usage.


:rofl: I KNEW it was a bad idea for me to get back to work! I missed everything!


A UPS isn’t the same thing as a surge protector. A UPS isolates the mains input from the UPS outputs. They’re not directly connected. The UPS’s backed-up outputs don’t have surge protection because they can’t surge. These outputs are actively regulated by the UPS circuitry. The input to the UPS has a surge protector true, but that’s invisible to the devices plugged in to the backed-up outputs of the UPS.

It’s not like a home generator with a transfer switch that disconnects the mains and connects the generator. The UPS takes the AC input and it converts it to a lower DC voltage, which it then converts back to AC to power the UPS outputs. It’s like it has its own miniature generator inside (it’s called an “inverter”) and that’s what powers what’s plugged in. The DC also charges the battery, which is basically connected in parallel, and when the AC at the input starts to drop, the converted DC voltage also starts to drop and the battery is there seamlessly providing replacement juice. The UPS clicks because there’s a relay it uses to disconnect itself from the mains input when the input drops below some threshold (it’d be something like 80V), and only reconnects when the input is stable again (or if you run a test on your UPS).

If the UPS has surge protected but not-UPS outlets, then those are just connected in parallel across the input to the UPS, transferring the UPS’s surge protection to the devices plugged in to those outlets. It’d be inadvisable to connect a GF to a surge protected UPS outlet (because it’s not UPS if it’s labelled “surge protected”).

I’ve been running my GF off a 1500VA UPS since new and it hasn’t shown a single issue going on better than a year now. And I have had the lights flicker enough the UPS kept things running (though I suspect to actually matter, your computer equipment needs to be on a UPS, too. I think the GF needs an active network connection to work at all. Lose the network and the print stops. My computer stuff is on a UPS, too).


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