Feasibility of Battery Backup/Generator for Boiler/CH/Hot Water etc

motorman99

Further to my previous posts, I bought an inverter that gives a pure sine wave (some SAY pure sine wave but are actually modified sine wave) from eBay with a 1kw output and 2kw max surge. 

I ran it off the car battery with the car running and am delighted to say it runs the sky box, tv and boiler perfectly. 

So if we get a power cut we will have telly and heat until the power comes back on 
the inverter was £90
sorted 
bob

Arfa__

Apodemus said:

I had suggested using a UPS as a line conditioner on the output of a generator or on the output side of a low-quality inverter if a pure sine wave one was not available.

Of course, be aware of the difference between an online and an offline UPS. The former's outputs permanently come from the batteries, and the latter simply switches (extremely fast) to batteries only when the power is out. So, although an offline UPS may kick in during a power cut and protect against spikes etc, do your research before assuming it will clean up a rough power supply. For just smoothing a rough power supply, there may well be better-suited devices, e.g. something with just a big bank of capacitors.

As for the 20min runtime on a UPS, yeah, I don't think that is fixed. But I've certainly had UPS devices in the past with a USB socket to hook up to your computer. This would then notify the computer when the power is out and allow it to schedule a clean shutdown if the mains power is not restored after a few minutes.

Geoff123

ansaryon said:

FWIW, I tested using a bog-standard APC UPS (capable of providing 800W peak) with my old Glowworm boiler system a couple of years ago.

The good news is that it only drew 70W at most, including the pump running upstairs, meaning it could, in theory, run for at least an hour. 
The bad news is that the boiler wouldn't ignite, it went "click, click, click" but no flame was produced. It then had to be reset, only to fail again. Plugging it back into the mains - it fired up the second time (before the experiment it fired up first time, every time). From then on, it usually took two goes to fire up... could be coincidental, maybe not.

Searching online didn't give a definitive answer. Some mentioned that a pure sine wave UPS would be better (although TBH the boiler's fan and pump upstairs sounded fine), others said it's something to do with ground/earthing being out of spec when running from a UPS.

I wonder if anyone's actually managed it...

Hello

It took me some time to find out why I could not run my combi off the inverter or the generator. I almost gave up .

The reason they will not power the ignition on many combi`s is because the inverters and generators have whats called "floating earths" Even if their bodies are earthed with a rod they often will not power the ignition system properly.

I had a three pin plug fitted to my boiler instead of it being directly wired to the mains .

You need to use a short extention lead from the boiler to the power source , ( inverter or generator) but the Neutral and Earth of the lead need to be bonded (connected) .This then fools the clever ingition electronics into recognising a true earth and will fire up properly.

This is legal and proper as long as it is only used for the intended purpose .

Remember never to use this modified extention lead connected to the mains circuit. Label it in someway . N&E BONDED

I wanted mine done properly so I had a registered electrician supply the short bonded lead . He said he had not come across a request like it but thought it a cool idea and totally safe .

I now have two alternative power sources that will run the electrics of my combi in case of a power cut .