Diesel Generator

[Peasgood]

13 hours ago, openspaceman said:

I live in suburbia where power cuts seldom happen, so no recent remote experience but I would be looking at a hybrid inverter and 10kWh battery for about £3k. The thing is this can power a house and cope with varying loads you can add a cheap generator that can then charge the battery at constant power for a long outage, switching off when the battery is full.

This is the setup I am planning to fit but it was to be using the Petter generator on auto start/stop to charge the batteries. This will be to run my sheds for now but ultimately for a house I hope, with some adaptations that I figure out to be needed on the way.

[openspaceman]

1 hour ago, Peasgood said:

This is the setup I am planning to fit but it was to be using the Petter generator on auto start/stop to charge the batteries. This will be to run my sheds for now but ultimately for a house I hope, with some adaptations that I figure out to be needed on the way.

Yes you could sense the battery voltage to estimate the State of Charge switch the generator on at say 30% SoC and off at 90%. You can do siimilar to heat an immersion, I do this April to October.

 

With the way solar pv has brought down the cost of hybrid inverters and standing charges have increased if I were planning a new build I wouldn't bother with a grid connection.

 

Have a look at this screenshot of my system output (5.8kW PV and 6.5kWh battery)

The blue is what I draw from the grid, the yellow is what I produce and use and the red is what I export.

 

You will see I only need to buy from about now till mid March and I could generate that from 4x47kg propane bottles and have the heat for free.

 

The recent uptick in power from grid is because I swapped out the AC coupled battery 2 weeks ago for a 3.6kW hybrid inverter and  bigger (10.4kWh) battery and have not reconnected 1.8kW of PV because of a bit of bad planning, I should sort it today. I intend to add 2.4 kW before summer and get the income from exports to cover my standing charges.

 

Once you have the inverter and battery then it is very cheap to add PV panels, ground mounted if you have the space, about £55 per 0.4kW currently. Get it installed professionally and you save 20% VAT.

 

My previous system was entirely adequate but I was ill advised to have an AC coupled battery and inverter in the house, I have removed that and put the new stuff in the conservatory.

[Peasgood]

An interesting graph. I would hope to achieve similar but the blue would be fuel use in my generator and of course no red as it is off-grid.

A grid connection would be approx £25k based on a 5 year old quote which I just can't make sense of, solar is so cheap you can have masses of it if you want. Mine will be on shed roof as I just know I would break them on a ground mount with stones from mower etc. I also believe ground mount should have planning permission but roof mount not so. May not be correct but I would ask forgiveness rather than permission in either case.

 

Can I ask the reason for the constant blue line on your graph? I think it indicates a 1kw daily draw from the grid throughout the year, is that to run the system as it is grid tied?

[openspaceman]

2 hours ago, Peasgood said:

Can I ask the reason for the constant blue line on your graph? I think it indicates a 1kw daily draw from the grid throughout the year, is that to run the system as it is grid tied?

Yes, for off grid purposes you can ignore the fairly constant draw of 1/3kWh/day from the grid because in this case it is an ephemera of the inverters constantly trying to balance load  with solar power and diverting excess to the battery. It is because the system was not well integrated plus some times if the load exceeds 3kW the balance comes from grid,

 

With an off grid installation this would not happen and the inverters would need to  be matched to the load.

 

Note sometimes it may be better to parallel two (or more) inverters than have a larger one and my inverter will run a peak load for a while double its rating, great for start up surge but power factor has to be better than 0.8.

[openspaceman]

2 hours ago, Peasgood said:

I also believe ground mount should have planning permission but roof mount not so.

I prefer mounting on buildings (mine are) but many commercial sheds will not have been designed for the extra weight. Also a vertical south facing  panel here would produce 80% of an ideally tilted one, E-W can do better in summer. Off grid you are better of tilting at about 60 degrees to maximise winter sun, between the equinoxes you will always have excess.

[gensetsteve]

The two best engines Perkins 3152 and any kubota water cooled a close third would be lister flat top and air cooled.

 

to avoid at all cost anything Chinese 

don’t bother with old ruggerini or lombardini

dont bother with the lister alpha engines 

if your going petrol Honda industrial engines are great Briggs and Stratton are not 

 

if you need pallets of kindling let me know because I hate working on generators 🤣

 

Steve Beale

loggywood.co.uk