You're Going To Build A What?

The saga of J building his tiny off-grid house

Archive for the ‘alternative energy’ tag

Braking news…

without comments

John came down for a couple of days and we worked on the trailer brakes. Pulled the hubs off and cleaned everything out as they were in quite a state, gunged up with dirt and grime to an almost unrecognisable degree. A can of suitable solvent and a roll of rags later and they looked much more reasonable. Almost no wear on the bearings so back in they went along with a large amount of high temperature grease.


In the process I discovered that one of the hubs didn’t even have brake shoes in it which, after some of the other things I’ve found as I’ve worked through the trailer renovation, doesn’t come as much of a surprise, and another set of shoes came apart in my hands as I removed them. I’m off to the trailer spares place tomorrow to get some new sets.


The other puzzle to the brakes is that the actuating rods seem to have been connected backwards, as I can’t find any way that they could work in the correct manner in their current state. I’m hoping to have a look at a trailer or two at the spares place and see if I can figure out the correct way to put it all together.

I also took the other 6 batteries over to where they’re currently living and swapped them onto the panel. The first 6 seem to have charged up to where I expect them to be after the past couple of week’s sunshine which bodes well. Another couple of week on the panel for the new set should put them in good shape too and then they can all be tied in together and left to stay topped up until such time as I can put them in place. Which reminds me, I should think about designing a folding stand for the panels to ensure they stay securely positioned.


I’m thinking I may just rent a welder for a couple of days and do the trailer welding myself after my holiday. Nick taught me the basics and I reckon that if I work on the side supports first, of which there are 14, then I should know whether I can safely tackle the main structural members after that. Otherwise it’s going to be winter before I’m getting anywhere and the delays are just driving me nuts. Besides, it gives me a chance to play with things that make fire and sparks and, after all, what could possibly go……… oh!

Peace, out.

Written by justin

September 14th, 2009 at 2:46 pm

Powering up.

with one comment

The bad news is that my welder is definitely knackered, so I’m looking at alternatives to get the trailer fixed and finished, probably I’ll just either hire a welder if my brother can make it down soon or I’ll just find a friendly welder to come over and do the welding for me.

In the meantime, I finally got half the power system up and running. The batteries have been in storage for a while, which isn’t the best thing for them, so the first 6 are now wired up and connected to one of the panels. It’s only temporary, which is why the cabling looks shoddy, but at least they’re under charge and being taken care of properly. In a week or so I’ll have the other 6 in place too. I can then monitor them to see what condition they are in as I have a couple of spares if any of them have been damaged by their storage time. All the cells were reading between 1.98 and 2.02v, which isn’t too bad, but we’ll leave them on charge for a week and then remeasure them when I take the next lot up.




One of my next jobs will be to design and build a decent support frame for both panels. They’re going to stay on a ground based frame so they can be moved when needed. If they were mounted on the roof and I had to park the house anywhere that I can’t get the best angle I’d lose a lot of power generating ability. The solar hot water panel will be on the roof as this is less susceptible to angle changes.

I’ve also managed to pick up a few days work this week and next, so that will pay for a short holiday I’m taking later this month and put a bit of money back in the coffers for continuing the build. However, it also means I won’t be doing much on the house for the next week or so.

Swings and roundabouts.

Written by justin

September 1st, 2009 at 11:34 am

That’s the hot water sorted then.

with 2 comments

I’ve been thinking about the best way to heat water for the tiny house this week, and have finally decided to go with gas. I had considered solar, which is in keeping with the green theme and off-grid nature of the house, but it would involve a lot of extra equipment and expense. To start with I’d need a water tank to store hot water in, and that takes up a fair amount of space, the panel would be large and, unless I built my own, quite expensive. I did think of building my own, that was my original way into green technology when I was about 14 and built solar water heaters that could provide hot water for washing up etc. But in such a small house it’s not really practical.

I then looked at a back boiler for the little woodburner I’ll be fitting for winter heating but again you need storage and additional plumbing. So I’m going to go with an instant gas water heater, which will be simple to install, cheap and efficient. Ideally I’d like one of the Bosch ones designed for off grid homes but you can’t buy them in this country and that makes it expensive to install.

Interestingly, there seems to be some confusion amongs manufacturers as to what you would need in a mobile environment and how to provide a suitable device. Ideally, you want a room sealed heater, ie one that takes it’s combustion air from outside and pipes it’s exhaust outside too. In fact, if you’re selling a device for motor homes, caravans etc, this is a requirement. It’s strange then, that the only one of these I can find requires mains electricity to run the igniter, whereas the heaters that aren’t room sealed (ie are for things like static caravans etc) are generally powered by a couple of batteries. Surely it should be the other way round.

In the end, I’ve decided that I’m going to go for a heater that isn’t room sealed, mainly because it will run for such a short time that there’s not going to need to be much air supply drawn from inside the house. It will only be one when I’m running hot water from the kitchen tap for washing up or when I’m in the shower, which won’t be for that long as I’ll be aiming to conserve water as much as I can. The heater I’ve found that looks a good buy is available direct from China on ebay

and details can found here

I’ve been working on designs for two water systems and the rainwater capture which I’ll post next time. Undecided on which one to go for right now, so more pondering to do.

Written by justin

April 27th, 2009 at 5:04 pm

I have my very own power station too!

without comments

One of my primary plans for the tiny house is to be completely off grid. I want to be able to park pretty much anywhere and not need to connect to anything or rely on another property for facilities. Ideally I’d like to be out in the country, away from everywhere and so to this end I’ve been designing the systems within the house to give me complete autonomy. I’ll cover the various systems and their designs one by one and today I’ll go over the power setup, as I have most of that already.

I picked up a couple of Kyocera photovoltaic panels from ebay. They’re 85w each. One of them is damaged, the glass is cracked and I need to fix this before I can use that panel outdoors. The glass is tempered, so when it breaks it’s like a car windscreen and just shatters. It’s also bonded to the cells underneath so not much comes out, just leaving it with a crazed appearance. However, this is enough to let air through to the cells and over time they’ll degrade because of it. Some online research suggests that automotive clearcoat, the stuff that’s sprayed over car paint to protect it, is good for sealing it, so I’ll need to get that done as soon as I can. I may be able to do that myself as I have a new compressor and spray gun to play with, amongst other air tools. More on that later.

Given that I effectively got the broken panel for free, I don’t mind if it doesn’t make quite as much power as the good one, anything extra is a bonus. A quick check with a meter when it arrived showed it to be putting out as many volts as the good panel but I’ll have to wait until there’s a proper load on it before I’ll know just how good it is. Fingers crossed.

Of course if you have panels you need batteries, and here I was lucky again as someone on an alternative energy forum I take part in was selling some. Most batteries that people use for small off-grid setups are either 12v deep cycle batteries or a number of 6v golf cart batteries. These are built to withstand repeated charging and discharging, which ‘normal’ car batteries aren’t. You’ll kill a car battery pretty quickly if you do that. Even these ‘deep cycle’ batteries have a limited lifespan, usually 2-5 years, depending on how heavily they’re used. For more serious battery backup setups, you want batteries that are designed for much longer life and much heavier discharge cycles. The problem with these is that they’re big, heavy and very expensive. Good options for second hand stuff is from fork lift trucks and large power backup systems in places such as telephone exchanges or power stations. I even know of people who’ve got hold of battery banks from decommissioned submarines, which have tens of years of life in them still. Not very practical for a tiny house that moves places.

What I’ve managed to get hold of is a set of second hand batteries from a power station backup. These are about 10 years old and absolutely immaculate, probably have a good 20 years left in them as long as they’re looked after properly. They’re about 25kg each, 2 volts per cell and 110ah. I have 14 of them which is enough to make up a 12v 220ah set with a couple of spares. Given that they weigh a little over quarter of a tonne, I’ll not be towing them in the house, they’ll have to go separately and, when parked, will live in a box on the back of the house with a bit of extra support under them. I’ll wire the house up using marine grade equipment which should ensure decent quality and levels of safety. I’ll cover the wiring setup in a later post when I’ve settled on exactly how I’m going to do that. I’ll get some photos up of the panels and batteries later.

Written by justin

March 24th, 2009 at 9:19 am