A reader asked about generators. But the topic is huge. There is so much to know. I won’t attempt to address anything but the most basic this time. If people want to know more, I’d be happy to elaborate in an e-mail.
There really is no such thing as the very best generator. Some, of course, are better than others but the definition of best has to include a lot of criteria such as price, noise, portability, voltage, fuel and purity of power, just to name a few that come readily to mind. Bottom line when it comes to generators: you need three of them.
Caveat – bear in mind that I live completely off-the-grid but I live a modern comfortable lifestyle. There is usually only my wife and me and we have pared our electrical requirements much leaner than we did before when we lived on the grid. We reduced our electrical requirements partially by revising our habits and partially by using propane appliances. The house is only 1200 square feet but I have several small outbuildings, a funicular and lots of tools. We are NOT the same as everyone else but, I think, we are reasonably ‘normal’ in our power needs.
Probably the most useful generator, for me, is the Honda EU2000. Yamaha has a comparable one and so do many others manufacturers from Subaru to weird Chinese brands but the Honda and Yamaha seem to have the best reputations around here.
The EU series produces ‘inverter’ power meaning – for the most part – that the power is ‘clean’ enough to use with computers. In reality, you are unlikely to fire up a generator to power something as small as a computer but a lot of products these days have computer chips (dishwashers, washing machines, etc.) and so having an inverter-series is safer for your appliances. But significantly more expensive. You can buy a generator twice the size (Honda EM5000) for the same money and, if you have a separate inverter for the house (which you should), that should do fine.
The main benefit of the Honda 2000 for me, though, is portability. I can carry the thing all over the property and take it to the work rather than taking the work to the shop. As soon as you are generating 3000 watts or more, the generator gets too heavy to carry easily. Especially on hilly terrain.
The second genset you need is one ‘sized’ right for the houseload. But do not make the mistake of adding up the power requirements of all your appliances (there should be a label on them giving the specs) and letting that determine the size of the genset. Doing that ‘addition’ thing is the usual advice from the experts and they are wrong! In reality no one has all their lights and appliances on at any one time – especially in an off-grid situation. Just think about what you might be using at the same time (and then add the water pump. It kicks on whenever it feels like it!).
Sally and I can – generally speaking – get away for weeks on end with running only the Honda EU2000 for a few hours a day to charge our batteries. But that is partly because we have solar panels and a wind generator to add juice to the battery bank. Which means the Honda and the battery bank together get us through the day. Without the battery bank or the alternative energy sources, a 1200 square foot house might need all of 5000 watts. To be on the safe side, I would recommend 7 – 10Kw with my inclination closer to the lower number.
The ‘house unit’ should be diesel or propane. And if the fuel can be delivered, so much the better. Fuel handling is an awful job. And fuel spilling is worse than spilling milk. Diesel models run longer, as a rule, and propane is cheaper and cleaner than gasoline. Most gensets run at 1800 rpm or 3600 rpm. And, to my mind, the 1800 rpm units are way better.
Always go liquid-cooled if you can (but you can’t in the small sizes). They are quieter and generally run better. In this category, you are looking at Yanmar first, maybe Kubota. There are lots of good small diesel generators but stay away from the cheap Chinese brands. They simply don’t last.
I have an Isuzu-powered 15Kw house generator and it is way too big. 15Kw is total overkill. But the Isuzu is a good engine. And I bought it second or third hand so it wasn’t very expensive.
If I was to buy a new house generator, it would likely be a Honda 5/6/7 Kw unit converted to propane. It would not, however, be the best unit. But it would be the least expensive-but-still-reliable unit burning petroleum products. And I think that any longer term planning has to consider that fuel will become more of an issue as the years go by. Put another way: I wouldn’t invest heavily in gas/diesel burning infrastructure. The ubiquitous ‘they’ will have something better soon. I hope.
Like many technologies, improvements in generating power are incremental. And the latest improvements include co-gen plants. Co-gen basically means ‘very efficient’ use of the energy used. Cogen plants make electricity and capture the heat for household hot water and such as well. Plus they are ‘inverter’ types that save a bit of fuel by adjusting for demand. Yanmar makes a 7 and a 10 kw co-gen plant that is ideal if you are starting from scratch. AND I am pretty sure it can run on propane.
But, as a retrofit, it is likely impractical.
Finally, you need a third one. A back-up. Any good, basic 5Kw genset will do. Even a good-running Coleman or a Generac will do in a short term pinch. Generators are machines and they break. But, when you are off the grid and your main genset breaks, you need to get back on to the e-grid at the very least if, for no other reason, than to find a way to fix it. Plus, you will find that water pumps and battery chargers are needy little users and they demand their juice. I don’t have a good third one, but it is on the list.
If you are a welder, you will need more power than 5Kw. If you are going to work at something in a shop all day long, you may need a different amount again. If you can’t get propane, then all your power needs will be greater than ours as we use propane for the fridge, hot water, cooking and the freezer. And, so it goes…………..different power needs for different folks.
Having said all that, the biggest tip for those who have yet to make the leap is to design the whole system from the very start so that all components are compatible with each other – and logical for where you plan to be – doing what you plan to do. There is no sense in having a huge battery bank with a small charger. There is no sense getting off the grid, in fact, if you don’t employ some solar panels (They are marvelous in the summer in our location with no need for the generator most days). And there is no sense at all in buying a propane generator just to find that you have to haul in the stuff in 20 pound tanks. That will become your hobby whether you want it to or not.
System design is not about brand name. It is about use. It is about fuel types and it is about reliability and flexibility. So – the teeny bit on generators? Start with the whole system design first. The genset is only a small part.