tell me about generators

[Baloo]

i better explain what i want i suppose, i have a field in the middle of nowhere there are 3 buildings there i spend a lot of time there in the summer not so much in the winter, i would like to convert one of the buildings to a workshop and spend more time thee now ive retired and youve guessed it no mains power i did get a quote from western power distribution a rather eye watering £44,000 just to get to the corner of the site and then on top of that more for poles to bring the power down to the buildings and then on top of that there will be a standing charge and on going bills, thats just not going to happen, several years ago i bought 4 cheap 100w solar panels off ebay and wanged them up on the roof cheap charge controller and a few car batteries and it was enough to run the cameras internet and led lights, this later escalated into 20 240w panels bought from a solar farm that was upgrading to 480w panels, followed by victron charge controller and inverter and 16 120A leisure batteries connected series/parallel to give me a 24v system for the batteries, now all the solar stuff works just fine for the moment its easy to produce enough to fill the batteries in the summer months the winter is a different story but as i wasent there much it dident really matter much, however times are changing and i want a workshop there with workshop tools,
so my needs are 2 fold and im guessing you are going to say i need 2 different generators, first i need to power the workshop but that only needs power when im actually using a machine be it car ramps or welder, grinder what ever and i assume i will only ever be using one tool at a time as im not clever enough to use the welder while pressing the up button on the car ramps, i can run led lights in the workshop from the solar system so some days i wont even need the generator probably several days a week it might not be needed, so the first question how big do i need some of you have generator power for workshops ? ive always belived in bigger is better but i guess i dont need to be running a perkins V8 diesel just to used the bench grinder
and the second requirement is charging the 24v battery system in the winter months for maybe an hour a day again i dont needs to be running a 6 cylinder diesel just to do that, i was thinking of a single cylinder lister or such like running a lorry 24v alternator just to top up the batteries as and when required, i have 2 spare shipping containers that i can utilize one can house the generators and the other a thousand gallons of diesel and i can be independent, ok that might add up to nearly ten grand but its only a quarter of what weston power wanted for me to be shackled to the grid for ever, actually it might be less that a fifth, i wonder how long a thousand gallons will last on an infrequent basis , there is a wood there to so log burner in the work shop me thinks, so how big a generator should i be shopping for ?

 

[hotponyshoes]

Does your inverter give you mains voltage out?

I'd look at a generator to feed in alongside the solar.
Feed mains around the workshop fed from the invertor plus 32a sockets fed from the generator (unless you have an inverter that can provide 20a+)

Then, you can turn up, work in peace using the battery power. Then have the generator auto-start when the batteries get low or fire it up manually to use a welder.

The majority of the time when using a grinder etc you won't actually be using it but you won't want to be turning the gennie on/off every few minutes either.

If you bought a 3ph generator (and maybe needed to also buy a new inverter) you'll make savings in buying welders/ramps/etc as 3ph kit is cheaper.
Put the savings into increasing battery bank capacity. And you can just add batteries as you like, no need for a big upfront investment.

Even in winter I'd expect you could get a lot of run time off battery if they have all week to charge from solar and you just pop up at a weekend

 

[Wildefalcon]

There's a 3 ph Jenny for sale in the for sale sake section. I'd get that and have done.

 

[8ob]

Before I bit the bullet and got the mains laid on this place was run off generators, difference between then and now is red diesell isnt 50p a gallon anymore. The big sets are into gallons per hour so it would pay to run a smaller single phase unit along side something that will run the machines.

Or go Lister powered flatbelt drive to all the machines

880 × 629

 

[voipio]

16 x 12V x 120Ah leisure batteries = 23kWh, or realistically 11.5kWh to 50% discharge.

20 x 240W solar panels, in winter, might typically give around 5% of the rated 4.8kW, if overcast*, for say 8 hours = 1.92kWh, so about 6 days to charge the batteries in winter, or a few hours in full summer sun.

A 2kW genny could charge the batteries in about 5-6 hours in darkness, if used with a properly rated charger, and lightly less time if there are overcast conditions, and even less still if it's sunny.

A large capacity inverter, or several 230V inverters, preferably sine wave for the machine motors, could then be used to run the machines off the batteries. The batteries could be charged from the genny and solar panels combined, and discharged via the inverters, which give a 230V supply. Ideally, the inverters would only be switched on as needed, to reduce the standby current drain. The inverters would be best placed close to the batteries, to minimise the runs of high current-carrying cables. It's not really much different from the situation of having a consumer unit, with several different circuits coming from it. The genny would only need to be run, if the demands made on the batteries were going to exceed their capacity.

(*overcast conditions typically result in about 2% of rated solar panel output, so the 5% figure assumes at least a bit of winter sun).

 

[frank horton]

cheap D genny's tend to be noisy......I have a single cyl Lister with a 240v and a 110 outlet.....it's great for and hours working outside BUT not for much longer.....
for quiet read a LPG converted petrol genny......not so many around.....I believe that the cost of red D and LPG work out similar.....BUT none of the caravan erks will nick the gas......
for a bit bigger n 3phase there are the ex hire silent models....but now were begining to spend big bucks....
I'm in the same boat as u but I get sunshine all year but for a few odd days......so were are going solar next year and then within another year fully OFF GRID.....
but I will still have my old lister and poss something newer and 3phase as well.....
When I was living in the UK I just wish I'd bought a weld generator....esp as most of my weld jobs are stick.....
need to know how big the machines u have or will buy.....it''s not the running of said machines thats the prob it's the start up draw that makes bigger gens nec....

 

[addjunkie]

Budget for the set up, and budget for daily running, are both big factors here…..are we talking 50k or 500 quid.

Then what type of load are you looking to run.

A friend of our has just done similar buying a set up, batteries, auto start genie from a farm. Its old but works, no big loads though.

 

[500e]

There is no Hobbs on the gen @8ob and appears not to have had one (no blank holes)
We think it weighs about 1.5 T. @Baloo Don't have a Merlo in yard with weighing capability at present, maybe next week

https://www.mig-welding.co.uk/forum/threads/generator.138716/#post-2474121

 

[Robotstar5]

An alternative would be wind power, where the stables are in Wythall there always seems to be wind and a couple of the stables have put up "windmills" to charge batteries.

 

[GRW]

When I was somewhat involved with the odd off-grid job, then the core element was an intelligent inverter-charger unit.
At 24v, we'd use something like an Outback VFX3024, which had a max output of 3kW 230vac, and a charger rated at 85A max.

They can issue a remote start (2-wire no-volt signal) to a genset with a remote start control panel - and you can configure the settings to suit your charging regimen for your batteries, the input rating of your genset and more.

On top of that, they can get set with a load start threshold.... meaning if you exceed the value of say 2kw for 60-seconds, then to save the batteries from getting hammered it'll start the genny, synch with it, ramp the load onto the genny seamlessly, and then use surplus generator capacity to charge the batteries at the same time.
If the batteries get to needing a full recharge cycle, it'll run a different programme where it'll auto start the genny (regardless of load), run on Bulk charge till the peak charge voltage is reached, then run a timed Absorption period to properly charge & maintain the cells, before shutting the genny down.
If you start the genny manually to run machinery or whatever - the inverter senses the availability of AC input, and will automatically put charge into the battery bank.

Genny. You need a proper 4-pole, 1500rpm, AVR controlled industrial generating set. To avoid the risk of harmonics from the inverter causing voltage and charging & functionality problems - the genset needs to be double the inverter-charger output rating, or larger (not likely to be an issue if you're fitting a biggish 3-phase set for machinery, but very pertinent if you also had a small 1ph set for the periods when you don't need the heavy kit. (You could have changeover switches or plugs to swap start signals and output supply from different Gens easily enough.

Get the setup based around sound principles and it'll work well and be pretty efficient.

Fuel consumption. A good rule of thumb is that every 4kva of load requires 1 Litre per hour (so a 40kva genset at max will drink about 10L/Hr). Of course if you run a 200kva set at 40kva - it's got its own mass to drive, so it'll use more than 10L/Hr... but its a good guideline.

Hope this helps. Cheers, G.

 

[8ob]

16 x 12V x 120Ah leisure batteries = 23kWh, or realistically 11.5kWh to 50% discharge.

20 x 240W solar panels, in winter, might typically give around 5% of the rated 4.8kW, if overcast*, for say 8 hours = 1.92kWh, so about 6 days to charge the batteries in winter, or a few hours in full summer sun.

A 2kW genny could charge the batteries in about 5-6 hours in darkness, if used with a properly rated charger, and lightly less time if there are overcast conditions, and even less still if it's sunny.

A large capacity inverter, or several 230V inverters, preferably sine wave for the machine motors, could then be used to run the machines off the batteries. The batteries could be charged from the genny and solar panels combined, and discharged via the inverters, which give a 230V supply. Ideally, the inverters would only be switched on as needed, to reduce the standby current drain. The inverters would be best placed close to the batteries, to minimise the runs of high current-carrying cables. It's not really much different from the situation of having a consumer unit, with several different circuits coming from it. The genny would only need to be run, if the demands made on the batteries were going to exceed their capacity.

(*overcast conditions typically result in about 2% of rated solar panel output, so the 5% figure assumes at least a bit of winter sun).

When I was somewhat involved with the odd off-grid job, then the core element was an intelligent inverter-charger unit.
At 24v, we'd use something like an Outback VFX3024, which had a max output of 3kW 230vac, and a charger rated at 85A max.

They can issue a remote start (2-wire no-volt signal) to a genset with a remote start control panel - and you can configure the settings to suit your charging regimen for your batteries, the input rating of your genset and more.

On top of that, they can get set with a load start threshold.... meaning if you exceed the value of say 2kw for 60-seconds, then to save the batteries from getting hammered it'll start the genny, synch with it, ramp the load onto the genny seamlessly, and then use surplus generator capacity to charge the batteries at the same time.
If the batteries get to needing a full recharge cycle, it'll run a different programme where it'll auto start the genny (regardless of load), run on Bulk charge till the peak charge voltage is reached, then run a timed Absorption period to properly charge & maintain the cells, before shutting the genny down.
If you start the genny manually to run machinery or whatever - the inverter senses the availability of AC input, and will automatically put charge into the battery bank.

Genny. You need a proper 4-pole, 1500rpm, AVR controlled industrial generating set. To avoid the risk of harmonics from the inverter causing voltage and charging & functionality problems - the genset needs to be double the inverter-charger output rating, or larger (not likely to be an issue if you're fitting a biggish 3-phase set for machinery, but very pertinent if you also had a small 1ph set for the periods when you don't need the heavy kit. (You could have changeover switches or plugs to swap start signals and output supply from different Gens easily enough.

Get the setup based around sound principles and it'll work well and be pretty efficient.

Fuel consumption. A good rule of thumb is that every 4kva of load requires 1 Litre per hour (so a 40kva genset at max will drink about 10L/Hr). Of course if you run a 200kva set at 40kva - it's got its own mass to drive, so it'll use more than 10L/Hr... but its a good guideline.

Hope this helps. Cheers, G.

Thanks chaps, there are some very useful numbers in there.

Bob