Chris McLeod

Hi Jim,

That is possibly true, but what makes you believe that I would not install stainless steel mesh filters on the inlets to those water tanks?

The other thing is that culturally some countries are more attuned to consuming ground water from wells than others. In Australia we have a preference for rain water tanks because of the salt levels in the ground. Wells can often bring salts back to the surface and that is not good. In many countries wells are also contaminated by other minerals leeching out of the surrounding rocks, and I believe India has some areas where the ground water from deep wells is contaminated with arsenic for example. And fracking in the US is not problem free for ground water tables from my understanding.

Plus, the other thing to consider with wells is the availability of energy and pumps to lift the water from deep aquifers. Lifting water is not a cheap process (I am not connected to the electricity grid and rely 100% on solar power). I'm not actually sure how deep your wells are and that can make a difference, but here I know people who have water bores (what you call wells) and they can drop as far as 330+ feet. I'd be interested to hear about that aspect of your wells as it is such a different experience to here.

Chris

Hi there!

I wouldn't worry too much about evaporation and algae. If you are at all concerned, you may be surprised to know that your plastic down pipes will be already full of algae (green algae), they are part of the natural flora - as long as it is not blue-green algae which produces toxins and that seems unlikely in a water tank system.

I have about 105,000 Litres of water storage in tanks and that is my primary (and only) water source and I've been drinking the stuff for about a decade with no health issues.

You have to remember that in water catchments there are plenty of animals doing their business in and around the water supply. We're much hardier creatures than you may guess.

As to heat, you'll find that with a black tank, the air above the water inside the tank will be quite warm - even over winter.

The water itself won't heat up too much unless you get a few days in a row past 40'C.

Chris

Great thread.

It is also worthwhile mentioning that for stick (arc) welding at least, some of the older units (if mildly well cared for) will last longer far longer than the newer units.

Years ago I lived opposite a bloke who earned a living as a sculptor - he was quite well known, although I had no idea who he was and just enjoyed the use of his workshop and the occasional talk fest. He had a beast of an old stick welder which he reckons was from the 50's and he told me about the older welders being of remarkably good quality.

I run a beast of an old stick welder which looks like it was locally made in the 70's. It's heavy and it runs perfectly on the off grid solar power system too. The interesting thing about that is that at start up the unit draws quite a bit of electricity, but once the arc is underway, they're quite economical on electricity.

Mind you, I'm considering getting a MIG welder as well.  

And yes, I'd put in a vote for women being better welders than men too. I'd put it down to care and attention to detail. My welds can be a bit agricultural, but they do the job.

Cheers

Chris

I just read some of the other replies.

It is probably not a good idea to put too much material against the side of the water tank - if you bury it for example. The sides are flexible and if the water tank is not full...

Chris

Hey! I'm down under and have many water tanks. The largest is just shy of 10,000 gallon. It's big.

We use a layer of rock crusher dust underneath water tanks and that stuff compacts amazingly. It is like a really finely ground granite. If you can't get your hands on that, then a layer of sand will do the trick nicely.

When full, they weigh so much that they settle the ground.

The only other trick to remember is do not dig a trench running parallel and close to one side of the water tank. The trench will compact and the water tank can tilt. It happens.

Instead, dig any trench immediately away from the water tank as if you are trying to get away from the water tank as fast as possible (or like the spoke on a bike wheel). Then when you are a short distance away from the water tank then you can change direction.

Chris

M. A. Carey wrote:The box is insulated with 1-1/2" styrofoam on all sides, bottom with thin plastic above the styrofoam (with small slant and drain for runoff from cleaning during maintenance), and the top is insulated, and shingled on the outside, which is slanted like a house roof. This top/lid, comes off to maintain and check the batteries.  We have siding on the outside of the box on all sides other than the shingled roof. The battery box is right next to our cabin, on the south side, where it is close to have all the wiring coming into the cabin and also close to the solar panels that are on frames and can be tilted

Thanks for the reply and I have no particular problems with batteries being stored in a well ventilated box.

The thing to consider in these arrangements is that the battery charge controller possibly should have a temperature probe attached to the side of the batteries. The reason for this is that:
- In summer when the batteries are warm to hot, and yours are facing south so that the box they are in may receive direct sunlight as well as warm air temperatures. The batteries should be charged at a lower voltage than at colder temperatures. You run the risk of the batteries venting hydrogen and oxygen if you do not compensate for battery temperatures. Summers here can get over 100'F so perhaps this is more of a concern for down here.
- In winter when the batteries are cool to cold, they need to be charged at higher voltages because the chemical reaction is more sluggish. The alternative is that the batteries are undercharging during this time, and there is the inevitable risk of draining the batteries.

Most charge controllers have temperature probes attached to the sides of the controller - and that controller may sit inside a warm cabin rather than outside with the batteries.

As another consideration, styrofoam is a very flammable product - although as you correctly note - it is an excellent insulator. I believe this material was the possible culprit in the recent fire at the Grenfell Tower in London where I believe 58 people died (and maybe more). I'd suggest instead using mineral wool or fire check plaster, fibro cement as a possible alternatives.

Hey Dustin,

I've been off grid for about 8 years now and rely on 100% solar. My place is in down under and we are about the same latitude (I'm 37.5'S and you are about 35'N).

Firstly, you have to slow down and go right back to basics. The reply from Isa above is one of the best replies so far to your questions.

Mate, I'm sorry to tell you this, but your batteries are not a fuel tank and do not work like a fuel tank. I can't put it any simpler than that.

They are instead a chemical reactor. And chemical reactions change depending on how hot or cold it gets.

Mate, you were writing something strange about putting your batteries in a box which may be subject to the weather. This is not a good idea.

The batteries should be kept at best at a more or less reasonable temperature.

Also if something goes wrong in the system and for some strange reason the batteries (I'm assuming that they are lead acid chemistry) get too much charge they will vent hydrogen and oxygen. You may recall the Hindenburg airship. That mix of gases didn't work so well for them.

If on the other hand you are using lithium ion batteries (which is a possibility) if you over charge them, they can be subject to thermal runaway and catch fire.

Neither option is good.

So I suggest you go back to basics and figure where you are going to place the batteries so that they don't get subject to massive swings in temperature.

Then from there, the inverter as you rightly put it, needs to be located close to the batteries.

When you figure that out, the next step is placing the charge controller nearby all that stuff.

Give us a yell. Or drop by my blog as I was upgrading my off grid solar a few weeks ago and there are plenty of photos.

Cheers

Chris

Hi Dan,

A 500L water tank when full will weigh in at 500kg (for the water) + the weight of the tank itself. Make sure that tank support is strong enough to handle the weight when full - and remember that timber in your location will possibly break down unless sufficient air and sun can get to it so as to keep it more dry than it would otherwise be. I've been on tank water for many years being in the much drier country of Australia. Although I have 105,000L stored in the water tanks! With your roof space of 25 sq metres, you may be interested to know that for every square metre of roofspace you will harvest 1L of rainfall for every 1mm of rain - assuming you can catch all of that wet stuff which falls from the sky. The water should exit your tank at about 10L per minute using gravity alone. Hope that helps. One inch pipes (25mm) produce a good flow of water, but then 3/4 inch (20mm) pipes are pretty good too.

I'm also on off grid solar power and have been for many years. You are in the northern hemisphere at 8 degrees latitude, so you want to angle your solar panels at about that same latitude but facing south. The sun doesn't change its location in the sky by much from season to season and will be much higher overhead on average than down here. I'm at a latitude of 37.5 degrees south and my panels face north at about that angle. During summer the sun is high overhead, but during the winter months the sun is closer to the horizon during the day. The angle is really a compromise of sorts between maximising winter sun and summer sun. The solar panels have to face the sun in order to produce the best output, but near enough is good enough. Incidentally, ignore all advice about trackers for solar panels which follow the sun during the day because I have seen many installations of these devices and every one of them was broken. They sound great in theory and they will increase your solar output, but... Manual solar trackers are great, if you can remember to move the solar panels several times per day, every single day of the year without fail.

Good luck with the building!

Chris

Hi Greg,

Yes, not all inverters are the same in that regard and many of them have very high standby current draws. I've been off grid for about eight years now and I use a locally (Australian) made Latronics inverter 24V / 3000W which has only a 0.6Ah draw (24V x 0.6Ah = 14.4Wh).

There is no easy way to resolve your issue other than:
- Replace the inverter;
- Add more panels to compensate for the high standby current draw; or
- Switch the inverter off say at night when it may not be as essential.

Mind you, I leave mine running 24/7.

Incidentally, if you are hearing a lot of buzzing noises from your inverter, the capacitors may be on the way out, so try not to let the unit get too hot as that dries out the inverters capacitors. Also a huge amount of radio interference also means that the unit may pack it in in soon-ish.

Sorry mate!

Chris
Fernglade Farm

Hey,

The tyre retaining walls sound interesting.

As a suggested alternative, if you have access to free local rocks, have you considered rock gabion retaining walls? I make them here being on a steep site and they withstand very heavy rain - but I also have lots of free rocks so that makes them very cheap and very local.

Cheers

Chris