UPS solution for ONT and SH2

[philip42h]

I appreciate that the topic has been raised before and I am grateful to those who have already posted (including on the Digital Voice FAQs) - I know more now than when I started out! But I would like to clarify my understanding in this space so do please let me know where I have "got it wrong".

I have been on FTTP for the past five years and have recently been moved from Fibre Voice Access (FVA) (supplied via the extension wiring) to Digital Voice (supplied via DECT on the SH2 (and the 'phone socket on the back)). Previously the ONT was supported by a BT supplied Battery Backup Unit (BBU) which upon checking yesterday provided an uptime of around 3 seconds (yes, I know, I could simply change the batteries).

BT advise that in the event of a power cut the Digital Voice service will cease and that subscribers use use a mobile 'phone instead. As with many in rural locations this does not really work for us - we have little to no mobile signal and rely on Wi-Fi calling to use our mobiles at home. No power means no Wi-Fi; no Wi-Fi means no mobile communications. I can, of course, overcome this problem by jumping in the car and driving to somewhere with a strong mobile signal and recharge the 'phone along the way - so that's plan B sorted.

Plan A is to provide a UPS solution that will maintain the ONT and SH2 for the first few hours of a power-cut - I'd like 'days' but doubt that I can afford that; 'minutes' just won't do.

The BT solution appears to be provided by a pair of Cyberpower Back-up for BT Digital Voice service units - one for the ONT and one for the SH2 and, to be honest, this appears to be the best, if not cheapest solution currently available. Each is supplied with a 12V 7Ah lead acid battery. According to the specs of their respective power supply units the ONT requires up to 1.0A (at 12V) while the SH2 requires up to 1.5A (also at 12V)  so this solution would be capable of maintaining the ONT for up to 7 hours and the SH2 for up to 4.5 hours. The calculation is likely to be a little more complex than "simple division" but it should, at least, give me an uptime in 'hours'.

Any solution involving a standard UPS - i.e. one providing power via 230V A/C - is likely to provide a much reduced uptime due to inversion and rectification losses along the way. On the face of it the power supplies for the ONT and SH2 appear to be 10% to 26% efficient - by simply dividing the output power by the input power. Again, the that calculation is unlikely to be quite correct but the losses at that stage will still be significant. And that doesn't yet take into account the efficiency of the UPS unit itself. So, I strongly suspect that to get a comparable uptime from a standard UPS I will need a much more capable and expensive unit. Or have I got this wrong?

Is there a better UPS solution for ONT and SH2 to give an uptime measured in hours?

[jac_95]

Hi philip42h,

Thanks for the post and welcome to the Community.

This is an automated response as I can see you have a question about BT’s Digital Voice service. Rather than waiting for a response from the Community, you may find an answer to your question by using the search bar on the Community homepage. We also have a thread that contains a wealth of info related to BT’s Digital Voice, click this link to take a look, Digital Voice FAQs.

If you have already looked for the answer to your question and have not found anything that can help, then please ignore this message. One of our Community members will be along shortly to help you further.

[yorkspark]

Why do you constantly put these yellow box statements on nearly every thread? They provide little guidance and in this case is totally irrelevant to the questions asked.

[imjolly]

They are automatic when there is mention of digital voice they try and cover the normal questions which are asked about DV and it was getting monotonous replying to the same questions over and over so the FAQ was was composed .  I agree it does not cover some of the questions but it does provide basic information for new  customers to DV

[Les-Gibson]

As I'm sure you know, FVA is a legacy product, the ONT battery backup is therefore now redundant as it was only there to support telephony (as opposed to full operation of the ONT), you can therefore do as I have done; disconnect it and plug the DC jack from the mains adapter directly into the  ONT.

As for the UPS, have you seen this? Cyberpower Back-up for BT Digital Voice service (FTTP) (097284)

[philip42h]

@Les-Gibson 

I am aware of the Cyberpower backup units - and refer to them in my original post.

As for the ONT BBU, you should be aware that it provides backup power to maintain the functionality of the ONT rather than just the now legacy FVA. It is only 'redundant if you not longer want a backup capability or have replaced it with something else ... 😉

[gg30340]

There are any number of UPS units on the market.

If you do an Internet search you will no doubt find some that will meet your needs however because you are looking for one that supplies hours of power rather than just minutes you will find that they are relatively expensive.

You obviously know the length of time that you may suffer from power outages better than I do but getting a UPS that lasts for many hours or days may be a bit excessive and it may be a better option to consider getting a "suitcase" generator. Depending on how much you are prepared to spend a generator will be able to power your ONT and hub with ease and will have additional power for other electrical devices if required. 

[spile]

I have the Cyberpower BR700ELCD and I use the six outlets to for my ONT, Router and NAS. I have my PC and monitors connected but of course that reduces the uptime before I have to shut down. It’s less than £100 and has proved reliable.

[philip42h]

@gg30340 

I have been doing my Internet research, and still am, and my head hurts! 😀

We live in rural Wales. Power (and broadband) comes via overhead cables. We regularly get power cuts when the wind brings down trees etc. and this seems to be getting worse in recent years. In last years storms folk not so far away were without power for several days - we only got cut-off for several hours towards the end of the repair cycle. Next time we might not be 'so lucky'.

I'm really not too bothered about brown-outs and short outages. The sensitive devices are on surge protected sockets and I'm not concerned about any consequent minor data loss - this isn't a mission critical / data sensitive environment here.

When a power cut has gone on beyond five minutes or so I want to ensure that the power company has registered the fact that they have an issue and be able to track its resolution. And in the 21st century that is most easily accomplished via the Internet. So, my target is to have Internet and phone line access for as long as I sensibly can under these circumstances - hence 'hours' rather than minutes though I pretty much accept that I cannot sensibly afford 'days'.

The "suitcase generator" idea certainly warrants investigation as an approach to longer outages and I've been thinking, but not quite doing, anything about it for some time as that would allow me to keep the boiler running, run some emergency lights and recharge 'phones and laptops. But that is, perhaps, a slightly different question to the one posed here ... there must be a "survivalist" forum somewhere for that! 😉

[philip42h]

@spile 

Thanks for that - the Cyberpower BRIC systems and APC equivalent seem useful and reliable. Having 230V A/C outlets allows users to simply plug in existing power leads / supplies and maintain a number of devices. They appear mostly aimed at enabling the graceful shutdown of the protected systems after a period of five to ten minutes avoiding equipment damage and loss of data. In this way they can fully protect against cuts of a couple of minutes or so but not that much longer.

Do you know how much uptime your system provides for you? With PC and monitors connected, and with just ONT, router and NAS?