[Nut-upsuser] Bluetti as a UPS?
Bill Gee
bgee at campercaver.net
Wed Sep 9 00:57:09 BST 2026
(breaking into song while everyone covers their ears ...)
"There'll be a hot time in the old town tonight!"
My needs are nothing that fancy. This is just me and my personal home
servers. With a base load of 350 watts I am not doing fancy stuff. I
just want to make sure it keeps on going. Indeed, looking at the stuff
I have running, I am amazed that it is only 350 watts.
Back in the days when I worked for a paycheck, we had a bunch of those
APC managed power strips. They were very useful in that situation and
well worth the high price. Not so much for just me. The two devices
mentioned below both require either Alexa or a smartphone to be useful.
Those are - in my opinion - worse than BlueTooth Disease.
I do have a Kil-A-Watt meter which is useful.
We have heard from Kevin who has some success using NUT with a portable
power bank. Anyone else??
==========
Bill Gee
On 9/8/26 12:01 PM, Bruce Pleat wrote:
> I have the following discharge tests:
> + Power-measuring plugs (I use P316M or KP115 mostly)
> + set of fans with known max wattages
> + Edison bulbs (I use 300W ones, and never exceed more than half their
> stated life before replacing) (only when not too hot outside)
> ~ set of fan heaters (must NOT be oil - those heat up. But then pause
> power use when the oil is hot )with known max wattages (only in winter,
> hahaha)
> - no air conditioners or dehumidifiers or anything else where parts go
> on and off like compressors, that alters the load.
>
> The keys are using steady power rated-usage devices and measuring that
> they actually consumed it, compared to what the UPS might say.
>
> Outlet (which is also power-measuring, but I haven't used that aspect
> yet) <~> UPS <~> Power-monitoring plug/strip <~> rated-power device
>
> When I use a power-measuring strip, I can use multiple power-consuming
> devices up to the strip and UPS capacity.
> Since most UPS support multiple output plugs, I might have multiple
> plugs/strips. (Plugs usually need short extension chords, like 8 in,
> because the plugs can't fit side by side in the UPS usually).
>
> I had one where I plugged 10 strips in, had 60 light bulbs and fans and
> heaters, nearly to the maximum 1800 watts per strip, just to see if the
> UPS could handle it. Yes, also stood at circuit breaker, goggles,
> electrical fire extinguisher in hand but fortunately not needed, hahaha.
>
> Apologies in advance if everybody knew all this, but I wasn't trying to
> be testy, hahaha..
>
> On Tue, Sep 8, 2026, 07:56 Bill Gee <bgee at campercaver.net
> <mailto:bgee at campercaver.net>> wrote:
>
> I don't have a way to do a controlled discharge at 25 amps. The best I
> can do on my test jig is about 6 amps. This is mainly due to a
> limit on
> the relay contacts which have a max rating of 10 amps DC.
>
> When I bought the current batteries back in February, I ran them
> through
> my test jig using a 4 ohm load resistor and 11.0 volt cutoff. With
> that
> they ran for a bit over 9 hours and delivered around 31 amp-hours. I
> figured with a rating of 35ah that they were at least in the ball park.
> Those ratings are not an exact science ...
>
> How do I change the shutdown to trigger at 22volts? That has to be a
> NUT setting. The display on the UPS says it has 15 minutes of runtime.
> A query from NUT shows variable runtime numbers in the range of about
> 950 to 1100 seconds. Here is a partial dump from NUT:
>
> battery.charge: 100
> battery.charge.low: 10
> battery.charge.warning: 50
> battery.date: 2001/09/25
> battery.mfr.date: 2026/02/13
> battery.runtime: 1107
> battery.runtime.low: 120
> battery.type: PbAc
> battery.voltage: 26.9
> battery.voltage.nominal: 24.0
> ups.beeper.status: disabled
> ups.delay.shutdown: 20
> ups.firmware: 865.L5 .D
> ups.firmware.aux: L5
> ups.load: 37
> ups.mfr: American Power Conversion
> ups.mfr.date: 2015/06/18
> ups.model: Back-UPS RS 1500G
> ups.productid: 0002
> ups.realpower.nominal: 865
> ups.serial: 3B1525X12484
> ups.status: OL
> ups.test.result: No test initiated
> ups.timer.reboot: 0
> ups.timer.shutdown: -1
> ups.vendorid: 051d
>
> Even if I can figure out a way to get these batteries to really run,
> the
> runtime will still only be in the range of 45 minutes. An
> improvement, but nothing like what a 2kwh power bank might offer. My
> calculation shows that two 35ah 12 volt lead-acid batteries will store
> around 400 watt-hours of energy, and might deliver only a bit more than
> half of that.
>
> Your point about BlueTooth Disease is well taken! I agree completely.
> I have an Android tablet but not a smartphone, so running that app
> might
> not work for me anyway. Another person commented that his EcoFlow
> works
> with recent versions of usbhid.
>
> ==========
> Bill Gee
>
> On 9/8/26 8:13 AM, Greg Troxel wrote:
> > Bill Gee <bgee at campercaver.net <mailto:bgee at campercaver.net>> writes:
> >
> >> I have been getting very frustrated by the short runtime of my main
> >> UPS. It is an APC BR1500G. I have a pair of 35ah batteries on it,
> >> but even so it runs for only 10 minutes. The batteries are good
> >> (independent testing) and the load is only 350 watts. I think
> the UPS
> >> runtime calibration just does not work.
> >
> > Did the testing do a controlled discharge at 25A and measure the
> > capacity to 10.5V?
> >
> > Change your shutdown to trigger at 22V, instead of remaining
> lifetime.
> > I suggest logging battery voltage and claimed remaining runtime, and
> > doing a test with a simulated failure, graphing that, and posting
> it for
> > comment.
> >
> >> Recently I noticed that some models of Bluetti power bank, such as
> >> AC200L and Fridge, have a "UPS" feature. They boast of
> switching time
> >> under 10ms in event of a power failure on the AC mains. The energy
> >> capacity is around 2kwh which should run my load for three to four
> >> hours. Expansion batteries can be added. And the price is not much
> >> different from a brand new 1500 VA traditional UPS.
> >
> > That's interesting. The first thing I checked was the battery
> > technology. Units like this used to have Lithium ion and that would
> > seem dangerous. This says it is LiFePO4. It claims listing to
> UL2743.
> >
> >> Has anyone used one of these as a computer UPS?
> >
> > not me :-)
> >
> >> Is there a way to have NUT monitor it?
> >
> > It looks like bluetooth/app, the modern disease. I would suggest
> > contacting bluetti, exlaining NUT, and asking for protocol details.
> > I suspect if you asked a lot the manufacturers of UL listed LiFePO4
> > power banks, one of them might end up being reasonable.
>
>
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