Ups or power pack. Duration?

[littlespark]

Customer has asked if I can source an ups or battery power pack to run their boiler if they have a powercut.

The powercut could last 3-5 days if previous ones are anything to go by!

Most advertise that they’re just suitable for 10 minutes- enough time to save documents and shut down the pcs in offices.
Most Amazon reviews are based on how long someone can continue to play a certain computer game.

They were looking at the Bluetti power packs… but I can only advise the bigger pack should last longer…. I can’t actually say how much longer.

Standard combi boiler with pump. They’ll set a timer so it’s only on a few hours a day, morning and evening.

 

[pc1966]

Are they planning any other top-up power like solar panels? If so battery / panels / inverter might hold up enough but middle of winter for most UK, and certainly Scotland, has very little average solar power. For example, near my home it is about 0.3kWh per kW of panels mid-winter:

Dundee Climate, Weather By Month, Average Temperature (United Kingdom) - Weather Spark

In Dundee, the summers are cool and partly cloudy and the winters are long, very cold, windy, and mostly cloudy. Over the course of the year, the temperature typically varies from 33°F to 65°F and is rarely below 24°F or above 72°F.

weatherspark.com

Actual boiler control will probably be trivial power, however, running the water pump might be 50-100W implying around 2kWh-ish per day so quite a big ~7kW solar panel set if it has to run mid-winter all the time!

 

[timhoward]

Check with a clamp meter, but AFAIK boiler pumps don't consume a lot of power, about 50-100W.

 

[littlespark]

No PV on the house as of yet.

I know the house, I worked on it for the previous owner.

Agree a boiler pump probably takes less power than a high end gaming pc….
I think they’re only wanting it for boiler…. But after that, they might want one for freezer, internet, a few lights…. The list goes on and on.


The Bluetti packs they’ve looked at already seem to be marketed as off-grid camping solutions… so I would expect them last a weekend or so on a few small appliances, and phone chargers.

 

[timhoward]

Of course, what the room thermostat is set at, what the weather conditions are, and whether they are at home during the day and when the heating is on all plays into sizing this! Going to bed 2 hours earlier during a power cut could save quite a lot of KVA!

 

[James]

something like this maybe?

Anker SOLIX C1000 1056Wh | 1800W

1,056Wh Long-lasting LFP Battery Expandable to 2,112Wh 1,800W Pure Sine Wave AC Output Run 2,400W Loads With SurgePad™ HyperFlash™ AC Input, 0-100% in 58 m

www.anker.com

you can add up to 600w of solar panels to it that will help extend the 1Kwh battery life.
it can recharge from a generator or similar in one hour (1300w)
so during the day, fully charge it from a noisy generator and have silent power for essentials overnight?

remember to test whatever you get, many boilers cant deal with a supply where the N is not referenced to earth because the flame detector is a single wire and relies on a return path through earth.

 

[littlespark]

That’s a good point about flame detectors. I better watch that.

I take it making up an extension lead with a bridged N and E is a no go???

 

[James]

a special supply lead would be a method of providing a N to E link.

one way i have done it in the past is to change the boiler from an fcu to a single (special) socket and put a plug (special) on the boiler
then next to the grid supplied socket for the boiler put another single socket marked generator supply.

you can make your link easily in the back of the new socket and put a trailing supply lead on it that goes to wherever your temporary supply is going to be.
sometimes this will be several meters to go out the window to a generator in the garden but it could be a short lead to a battery power bank.