Suggestions for a router & ONT UPS?

Many of the older systems use a landline to make to outside connection...

(also there are places with no mobile signal. Even in places were coverage is good, a longer power outage (days) can cause the mobile base stations to go down)

LOL!

Renewables are so cheap that the UK is now the most expensive electricity in the world.

And that f****it Milliband hasn't even started yet...

Mine is so low traffic I just let it crash. It never has a major issue

Well I'd be more likely to out in a whole house UPS to keep the fridges and the sewage plant operational. And the central heating and some lighting.

Probably a 10kW diesel generator

Which basically says to me that there is no one magic solution. Just a range of more or less desirable options depending on circumstance

That's what my father had, about 10 years ago, and presumably they had sorted the power-off operation of that type (I don't think we ever had a power cut while the alarm was there).

But nowadays, with fewer places having a pure copper landline, and that number rapidly reducing, presumably no-one is making that sort any more.

But I wonder how long a typical alarm button system stays in use? My father's was 2 or 3 years I think, ours will probably be less than a year. In my limited experience they help extend a period of living at home before the inevitable care home or hospital.

nib

Interesting HoC document on renewables here:

It starts with this:

And gets worse from there.

My guess would be that inside the box there are some 18650s. 15000mAh suggests 5-6 cells. To make the power conversion easier they might use buck converters only, so let's say it's a 5S 1P configuration (max voltage 20V).

If it's 3000mAh per cell in 1P then you're talking ~20A max discharge current, so about 100W peak - sounds about right.

There are probably 3 power converters (5V, 9V, 12V) rated at say 4A each.

But the cells only want to be charged at 1C (ie 3A), meaning the max charge power would be 60W. However that's with good cooling, which this doesn't have, so instead maybe they charge at 20W instead (0.33C).

What that means is that it can only actually power devices continuously at

All this makes it fine as a powerbank but limited as a UPS. Probably fine for the router + ONT situation but take the '114W' with a large pinch of salt.

Theo

One modern alternative might be a smart watch. Some of them can have their own phone number and make their own calls, using either wifi calling or the mobile network. There is also fall detection built in to some. I think there is also some support for emergency SMS via satellite on fancier models (although whether it would work lying at the bottom of the stairs is another question).

The downside is you have to remember to charge them (daily or weekly), but that might be ok if part of the user's routine and they aren't particularly forgetful.

Of course that doesn't help if you live alone and have nobody to call in an emergency, when the response service might come in handy.

Theo

But maybe you could still power it with something like a 140W input, so it could provide its stated output and charge the battery at 1C at the same time, like a UPS. It's just that the PSU that comes with it can't do that.

nib

The see-through 'shooped image shows eight, so cheapo sub-2000mAh cells?

To make the power conversion easier they might use buck

I'd misremembered, it only claims 114W not 140W

You could, but only if the internal power converter is sized for it. Given they ship it with a 25W PSU it probably isn't.

Theo

You could do 4S 2P, at low SOC that would be about 12.8V so probably enough headroom.

Theo

Many thanks to all who contributed to this very interesting thread.

The prime decision was whether to go for a mini UPS or a mains-powered version.

The calculations regarding the mini UPS suggested that for the expected 24W draw from the ONT and router, the supplied 25W wall wart would be quite marginal, although something like a 12V 3A one (which I have to hand) would cover that.

The alternative UPS would be a mains-powered one supplying at least two mains sockets for its output, for which there are many available, and some were suggested by contributors to the thread. After researching these and others, I decided to go with this form of UPS, settling on this one:

It’s by SKE, the 625VA/360W version, having two AC outputs. The spec says that it should provide 50W of power for 60 minutes, so my 24W draw might give as much as 2 hours of backup. It’s due for delivery later today, and when installed and fully charged, I’ll give it a test run to see how it performs.

The UPS duly arrived, was unpacked, and following the instructions was put on charge for six hours.

So this morning I gave it a test, by plugging in two loads to simulate the router and ONT; an 8W LED and a 20W halogen lamp, and pressing the On button for the required three seconds. The lamps lit straightaway, accompanied by a beep every few seconds to let me know it was running on battery backup. This can be silenced by a three-second push of the On button.

After 4h20m the unit beeped again, as it seemed to have reached 25% full level, and I terminated the test. This comfortably exceeds my requirement for 2hrs of backup.

Some points to note:

Both the Battery Level and Load Level indicators are of the four 25% per segment type.

With only 28W being drawn, no segments of the Load Level indicator were showing.

With a full battery, all four segments are on, but the instant a load is drawn, the 75-100% segment turns off, meaning that the remaining capacity is at an unknown level above the active segment.

The LCD screen needs to be viewed directly from the front otherwise meter segments appear to on when they are actually off.

The output voltage was showing as 235VAC, input when being charged was

The unit reached a lukewarm temperature during discharge on the top at some point towards the front.

It was completely quiet in operation apart from the beeps.

Some 90% of the instruction manual concerns the management software, which is only available for Windows. It isn’t necessary to run any software to use the device.

Plug the usually-supplied USB cable into a Mac, and it will detect it automatically as a UPS and provide basic information (such as battery level) in the Energy Saver pane of System Settings.

A UPS that will allow itself to be turned on without mains is handy.

That way you can turn it off when not needed - say after shutting down vulnerable systems, and then use it in short bursts later - giving say

Even my 3.2kW one proved to be plenty useful last time we had an unexpected few hours without power (normally when uk power networks ring to say there is a non planned power cut in your postcode etc). The UPSs held up the important stuff while waiting to see if it was going to be a quick one. Then when it looked like it was not, I fired it up. Flicked a few MCBs off on the CU for stuff I could do without, and flicked the transfer switch. I could carry on working, heating and refrigeration carried on as normal, and the only real concession was to swap to the lower powered kettle since the normal 3kW one does not leave much slack in the system!

For anyone that has not stumbled over it Network UPS Tools (NUT) is a handy cross platform bit of software for managing and talking to UPS devices.

(one of the limitations of many UPS monitoring systems is that they are USB based and can only connect to one machine. Often the supplied software can only do stuff on that machine. NUT lets you run a server on the connected machine and multiple other devices can then use that to query the UPS. They can have rules for what they need to do in response to a UPS event and/or the UPS reaching a certain threshold battery level)

Thanks to you and Tim Streater for that information.

JAAMOI the SKE unit has two Ethernet sockets on the rear panel.