Generator - how do I go about getting an assessment of my requirements and generator location?

[Rollerball]

I"m still pondering whether to get a generator (for emergency use only) but I'd like to get an expert (not some glorified sales person) to visit my property and so get some good, unbiased advice and recommendations as to the type that's suitable for me and where to place it. I have an old, very open (and hence well ventilated) outbuilding which might be a suitable location for example, that building is also where the power comes into my property so it has the meter, fuses, etc.

Is this a case of finding a good electrician or regularly installs generators or should I be looking at a reputable company which sells and maybe also installs them?

As mentioned, this is to be used in the event of a prolonged power cut (I seem to get one a two a year) and its main use will be powering my oil-fired boiler, the chest freezer and the fridge.

 

[ericmark]

As mentioned, this is to be used in the event of a prolonged power cut (I seem to get one a two a year) and its main use will be powering my oil-fired boiler, the chest freezer and the fridge.

This is what my system runs, no lights, just on FCU that powers the oil boiler, and 4 sockets (3 used) that powers my fridge and freezers, and I am using a 5 kW inverter, connected to a 6.4 kWh battery, and 6 kW solar panel array, the software is set to retain 10% of the battery for emergency use, as to if big enough, it would depend on time of year and day, as to how much actually in the batteries when the power fails.

In my case, it is all automatic, there is no need for me to start a generator so if a power cut when away, the freezers would still work.

Clearly, mine is part of a larger project, the main thing was fitting of solar panels and battery, the UPS (uninterruptible power supply) was just part of the project, and I had to decide how much to cover with the UPS. Too much and the battery may not last long enough.

I had looked at things like this

at 1000 watt, it would keep a freezer running for around 8 hours, it can have solar

so I would think it can also be charged off a small generator, or maybe your car. I have not fully looked into them, as now I have battery back-up, however if you look at the cost of auto change over equipment, the idea of an UPS of some sort has a lot of plus points.

My first look into this, was when my son had a narrow boat, and it was a Heath Robinson affair, a charger class II, so no need for an earth charged three (fourth one was engine start only) 140 Ah lead acid batteries, and a 3 kW (6 kW peak) inverter fed the boat, it was not a success, as the inverter was rather cheap and failed, but the idea was sound.

The problem with a generator is you need to do the change over, unless you pay a fortune, but with an UPS, this is built into the inverter, and also no worry about old petrol, will the generator start with petrol which has sat in the tank for 6 months or more?

Wait and see what others say, but I would favour the battery, and it also means it can be used elsewhere, and no fumes.

 

[Robin0577]

i would imagine that an expert on domestic scale backup generators will be hard to find. Most of the experts in dealing with back up generators are going to be used to working on a much bigger scale.. hospitals, telephone exchanges, data centres, TV/radio studios, etc.
Most household solutions involve manually unplugging and replugging things as needed, although there's no reason why you couldn't have a proper automatic transfer system installed.
Household battery systems, however, are becoming quite popular and it may be much easier to find an expert in that field.

 

[Murdochcat]

Why do you think you need a generator?

 

[ericmark]

Why do you think you need a generator?

As mentioned, this is to be used in the event of a prolonged power cut (I seem to get one a two a year) and its main use will be powering my oil-fired boiler, the chest freezer and the fridge.

What ever method is used, it will need some wiring, could be as simple as a commando plug and socket, and cables to the items so they can be unplugged from grid supply and plugged into a generator.

A chest freezer can go for some time with no supply, an upright freezer it is often luck, as to where it was on the freeze/defrost cycle, if on the defrost cycle when you get a power cut, then items at the top can start to defrost within ½ hour, but otherwise can do nearly a day.

So we, that includes me, tend to take a chance, for me the worst time would be 1:30 am, battery today was down to 40%, but during the day 80% was the lowest it went to, so oil boiler around 150 watt, freezer average 30 watt, so 7:20 pm to 9 am so around this time of year 12.5 hours that the battery needs to bridge, so would need around 2.4 kWh of battery back-up to bridge when no solar in summer, less as the central heating not running, winter would use ½ my batteries' capacity if fully charged when power cut happened, December would likely be a problem, and if it snows, as panels covered. But most of the time, I could continue for months without grid power. I have 6.4 kWh of battery back-up.

Using a 2 kW generator I would not be worried about state of charge of the battery, as long as I have petrol it will run, but it would not auto start, the cost for that system would be huge, I would need to manually unplug from grid supply and plug into generator supply, no automation.

My inverter can be configured for grid or generator, but not both, the ideal system would be an inverter/battery/generator system, so the battery takes over, but you can start the generator to recharge them, but at what cost?

For me, if worried, I would ensure the oil boiler plugged in, not a fused connection unit, and rely on extension leads etc, during the power cut, with a 2 kW inverter generator, for the times we are without power, not really worth hard-wiring in, and could take generator with me for camping/caravaning holidays etc.

The farmer I knew who used a generator, had a kill button in the house, but had to go out to start it, as that way also checked oil and water before starting.

 

[Harry Bloomfield]

As mentioned, this is to be used in the event of a prolonged power cut (I seem to get one a two a year) and its main use will be powering my oil-fired boiler, the chest freezer and the fridge.

Likely the simplest way, is to add a separate consumer unit, to include all of your what you consider to be 'essential items'. Then feed that new CU, via a 13amp plug. You then add a 13amp socket to your original CU, which is how they would be powered when you have the mains supply available.

You would then have a second 13amp socket, powered from the generator, over to which you can transfer when necessary.

You could add further 13amp sockets, in strategic locations, into which you could plug lights etc..

Much depends on how far you want to take it.

 

[ericmark]

Then feed that new CU, via a 13amp plug.

I would have used a 16 amp commando type, as used with caravans, but what you describe does seem a sensible approach, even allows for hiring a generator if one's own has a problem. But remember at least 3 minutes from unplugging from one supply, to plugging into another, this allows the pressure to drop in the refrigeration plants before it tries to restart.

Also remember an old refrigeration plant has an in rush, so a freezer which normally has a load of ½ amp, may take 5 amps to start, so it more than one, then start one at a time, not all together. The new refrigeration plant uses inverter drives, and has nothing like the start amps of the old refrigeration plant, the highest load is when it goes into defrost and mine use around 160 watts for defrost. (75 watt normal running)

 

[Harry Bloomfield]

Also remember an old refrigeration plant has an in rush, so a freezer which normally has a load of ½ amp, may take 5 amps to start, so it more than one, then start one at a time, not all together. The new refrigeration plant uses inverter drives, and has nothing like the start amps of the old refrigeration plant, the highest load is when it goes into defrost and mine use around 160 watts for defrost. (75 watt normal running)

Mine seem to include several minutes of delay, after power up, to attempting to restart anyway.

 

[plugwash]

Afaict generators on a domestic scale aren't great. Small generators often have trouble handling load surges and/or produce poor quality power. Larger generators have less of those problems but suffer from significant fuel consumption when idle.

I think if I was looking to improve my power resiliance I'd be looking to solar/battery first and maybe generator later. IIRC there is at least one solar/battery system that is designed with a port that can be used for a generator.

 

[Scally-Ho]

Go for a decent ex MOD genny and opt for one that will power your whole house during a mains failure. With the correct changeover contactor, you will have genny power running in seconds and on-line providing power. At the rear of my workshop, you'll find my Lister Pitter 25KVA next to mains intake unit all ready to go. It burns the same oil as fires the oil boiler, so both are connected to the same gas oil tank.

 

[morqthana]

Old Lister engines will run on virtually anything.....

But 25kVA? How often do you need that?

 

[Scally-Ho]

Old Lister engines will run on virtually anything.....

But 25kVA? How often do you need that?

The full 25KVA? Never, but I obtained what I could from what was readily available. Bought a lot of other redundant plant too and the profit made from selling that more than covered my genny and its convoluted connection. I enjoy the hustle & bustle of buying and selling, or rather I did until my wife became suddenly disabled. Now I seldom leave her out of communication range.

 

[morqthana]

Hadn't thought about looking for MOD/military surplus - might do that.

I did do one quick search, https://www.modsurplus.com/index.ph...by=&Itemid=178&task=&search=generator&x=0&y=0 - not quite what I'm looking for, but 87 generators in the 45-550kVA range, all new and unused.

Shocking, really.

 

[Scally-Ho]

Oh yes, many MOD items are sold as unused bought as seen and at a mere fraction of the new price. My genny when it arrived on the low loader had only 15 running hours clocked, so was not even run in. I would have preferred something along the lines of say 10 to 15KVA, but the one I did buy was almost stolen as I paid so little for it. My pillar lift was the same and so was my single vehicle trailer .. gifts the lot of them

 

[morqthana]

You owe me a tax rebate