DC UPS for Raspberry Pi 4 to run PiHole during power outage

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johno1234

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#3362271 9-Apr-2025 12:09

timmmay:

I think I might go with a HAT, like this one or this one. That way it's sitting right there on the pi, though somewhat unprotected. The Jaycar option is ok, but those things go for $5 on AliExpress which makes me doubt the quality.

How would you keep the 12V battery charged?

timmmay

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#3362273 9-Apr-2025 12:11

The constant vigil sentry light already does that.

johno1234

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#3362276 9-Apr-2025 12:23

This looks tidy - I wonder how long it can stay up for in a power cut?

https://thepihut.com/products/uninterruptible-power-supply-ups-hat-b-for-raspberry-pi?srsltid=AfmBOoqsSxViubMfcsb155TzAuWyzXiMzNPBpKpuErhqHSK3YN31-3d6

timmmay

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#3362281 9-Apr-2025 12:35

They are quite a few things like that around. That one has UK plug which would need an adaptor or replacing.

richms

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#3362283 9-Apr-2025 12:37

The fact that it comes with an 8.4v adapter makes me think that its not got a proper charger onboard and may need looking into more about how protected it really is, as this is just 2x the 4.2v CV part of the lithium charge curve. makes it a nightmare to replace the power adapter and without a DC to DC on the charging part of the board, its at the mercy of the accuracy of the supplied adapter.

Richard rich.ms

timmmay

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#3365754 19-Apr-2025 21:08

Talentcell have an interesting range of DC US, here. They come with Lithium batteries, and depending on the model have USB and 9 / 12 / 15 / 19 / 24V outputs. Ubuy has a few different ones, this one is $190 plus $20 shipping. Looks like a nice product, but it's fairly expensive.

BatteryMaster have a few options:

BFL11 12V 2.1A to USB cable for $50
Enecharger QC2-ACDC4 12V to 4xUSB 3A converter for $89 - in stock, details here. Supports AC and DC input, automatically switches to DC if the AC is unavailable

If I could get the Talentcell in NZ for a reasonable price I think I'd do that, as it could potentially power the R.Pi and if I could get the cables the router and such, but I'm not sure it's worth $210. The Enecharger QC2 looks like a good option, taking in AC or DC and only using DC when required. The Constant Vigil Sentry Lite can keep the 12V battery charged fine, especially given the Pi would run from AC except during a power cut.

timmmay

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#3370376 4-May-2025 16:24

To close this off... I had decided on the Enecharger 12V to USB when my sentry lite failed, so I bought an Eaton 3S 850 mains UPS, plugged everything in, and it works. Expected runtime 2-3h. Not useful in a disaster but good enough for basic protection for networking equipment for short outages.

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