DC UPS (Battery Backup) for ONT, Router and Raspberry Pi4b

[naylor2006]

Thought I would post about a positive experience trying to find a UPS for my internet devices incase anyone else comes across the same.

Lately we've been having a few extra power cuts, not for a huge period of time but a few minutes, sometimes when the power comes back on it dies straight away before then coming back up permanently, which isnt ideal, although devices are more than capable of handling that I did want to mitigate it in case it caused a stale session or something.

Devices I wanted to power:

• Nokia ONT (12v 0.5A) <- Fibre Modem
• ER-X (12v 0.5A) <- Router
• Raspberry Pi 4b (5v USB 'Ok with' 2A) <- this is my DNS server
• 2.5Gb Switch (12v 2A) <- My main switch

Turns out the Pi, even though it's genuine adapter is 3A, the Pi itself will never use more than 1.8A unless profiteroles are connected, of which there are none.

Keeping these things online will really smooth out powercuts and allow the overall infra at home to come back gracefully.

I found the following:  SKE Mini UPS 10400mAh

It has 3 DC outputs (2x 12V 2A and 1x 9V 2A) along with one USB-A (5V 2A), shipped with the unit is two DC barrel type cables, one is a Y cable (5.5mm 2.1mm) which means you can run two devices from the same UPS output, so long as the current doesnt exceed the 2A. You also get another cable which is also a Y piece but has 1x 5.5mm jack and a the smaller one, which I forget the sizing of.

Connected my ONT and ER-X up to one output using the supplied Y cable (5.5mm 2.1mm) as they both are under 2A and have the same barrel connector type, located a USB-A to C cable and used that to power my Pi4b and got myself another male to male 5.5 DC jack to connect to my main switch. All works great, pulled the power on it and after an hour or so I still have 50% battery, way more than long enough.

Cant speak for the longevity as ive only had it a few days but definitely seems like an option for anyone who wants to keep this stuff powered through power cuts. Pretty sure ONT's used to come with some sort of battery backup years ago.

[iniltous]

years ago Huawei ONT did have a BBU but it was for the short lived FVA , fibre voice access, where there was a phone port on the ONT ( not like DV where it’s the router that has the port ) , and it was necessary to keep the phone service available during a power outage, initially Openreach we’re going to be involved in providing telephony , but decided it wasn’t desirable to do that , so dropped it , that’s why later ONT don’t have BBU and phone ports .

[naylor2006]

In which case I probably just read it somewhere.

Thanks though, your explanations are always so concise and accurate, same as over on Thinkbroadband, assume thats you too.

[chrisjp]

This looks to be a useful unit. However, one of the reviews on Amazon says it can't be used with the BT SH2. Does anyone know if this is true?

[naylor2006]

Isnt that because of the jack being slightly different.

Finding replacement adapters for the BT Wholehome WIFI was a pain, although they look like the typical 5.5mm 2.1mm I think they are a 5.5mm 2.5mm....although I was able to ram the smaller jack into the slot if I pushed really hard and it did work.

So for the SH2 you'd just need to get a 5.5mm 2.1mm Male to 5.5mm 2.5mm Male to solve the issue with this supporting the hub. 

Something like this:

DRUT 1pcs. 5.5mm x 2.1mm Female Socket to 2.5mm Male Plug DC Power Adapter Cable Converter (Black): ...

[chrisjp]

Thanks for this.
Can you confirm that the BT SH2 and the BT Wholehome units both have 5.5mm 2.1mm sockets on them, rather than 5.5mm 2.5mm ones?
The Amazon offer for the SKE Mini UPS states that is comes with 2 Y cables:
Cable 1 is 5.5mm 2.5mm male to 2 off 5.5mm 2.5mm male
Cable 2 is 5.5mm 2.5mm male to 5.5mm 2.1mm male and 3.5mm 1.35mm male.
This seems as though they've changed the cables they supply with the unit, but it looks like only Cable 2 would support the SH2, and I also want to power my first Wholehome unit

[naylor2006]

I dont have any Wholehome stuff any more nor do I use the SH2, but I can get the SH2 out of its box later and check for you.

I didnt even realise that the other Y cable was a 2.1mm, in my case I have used 5.5mm 2.5mm all round then, into my ONT, my Router and my Switch. I guess the tolerance is fine enough, ill have to check!

One of the reviews on Amazon shows someone powering an Plusnet Hub, it looks identical to the BT one just white, so I expect that the 2.5mm cable is fine for that. 

[WSH]

The SH2 plug is 5.5 x 3.0 x 11mm long.  (The old HH5 type A was the same).

Presumably this UPS is going to be tucked away somewhere in a cupboard with the SH2?  Speaking as someone who was originally trained as an industrial chemist, before I went into IT, I would be very dubious about a lithium based solution.  That tech's far from well behaved yet and when it goes wrong you've got a fire most people wouldn't believe possible.

Mind you, I also keep an eye on the science press, as well IT, and they are already talking about sodium batteries.  They'll make lithium look tame.

[naylor2006]

I used to work for the police, I have dismantled 1000’s of phones, indeed the odd accident occurred, I know what can happen with a lithium battery.

I remain sceptical about many of these imported products but I still use them….at the moment I’m still here to tell the tail.

Mine is stored with all my internet equipment which definitely isn’t away in a cupboard but I do take the point and I’m starting to feel a little bad for ‘recommending’ the product if folks are having concerns.

The BT SH2 has a 3mm internal pin?

Ill get it out in a bit and check the different cables and post back.

[WSH]

Yes, I’ve only measured the plug with a drill bit, (not the most accurate thing, of course), but 3.0mm was the best fit.

What would bother me is that a UPS is on charge continuously.  At least with most items you can keep an eye on them while they’re on charge.  You can’t stand a watch a UPS all the time.

My advice would be as soon as you notice something is not quite right about it, heat build-up, swelling, funny noises etc. take it straight out the back garden.

The damn stuff’s so reactive it will even rip the oxygen out of CO2 and use it to flare up.  Alkali metal fires need a specialist dry powder* extinguisher and are extremely difficult to put out even then.

*They'll decompose the cheap ammonium carbonate ones.