Thread: RAPS for a shed

Originally Posted by Oldneweng

I have seriously thought about converting all my house and shed to LED lights running off a small solar backup system. If I use 12v I can do it myself legally except for disconnecting the existing light circuits.

Dean

My thoughts as well, it won't be long before pretty much all lighting will be LED anyway, but my main motivation is to get better lighting in the workshop as well as save a quid on the power bill. LED's have reached the point where they can do a better job.

The only thing I'd suggest to check out carefully is the colour, the ones I'm using are called "warm white" (2700-3500) I'd hate to have to work under that horrible bluish white light that some of them have.

Simon, there have been a lot of changes in solar in the last few years, panels for $1 per watt were pretty much unheard of just a few years back, and lots of pretty good controllers have come onto the market. I think solar for lighting is a no brainer, but for powering machines I'm not so sure. There are people who make 3 phase inverters that run on solar, maybe you could get 3 phase 415 out of the deal?

Regards
Ray

PS.. Forgot to mention that yes I did get that remote monitor for the mppt charger.

Originally Posted by RayG

My thoughts as well, it won't be long before pretty much all lighting will be LED anyway, but my main motivation is to get better lighting in the workshop as well as save a quid on the power bill. LED's have reached the point where they can do a better job.

The only thing I'd suggest to check out carefully is the colour, the ones I'm using are called "warm white" (2700-3500) I'd hate to have to work under that horrible bluish white light that some of them have.

Simon, there have been a lot of changes in solar in the last few years, panels for $1 per watt were pretty much unheard of just a few years back, and lots of pretty good controllers have come onto the market. I think solar for lighting is a no brainer, but for powering machines I'm not so sure. There are people who make 3 phase inverters that run on solar, maybe you could get 3 phase 415 out of the deal?

Regards
Ray

PS.. Forgot to mention that yes I did get that remote monitor for the mppt charger.

I have been following your thread Ray and taking note. Lighting colour is a matter of personal preference so I will test fire before I decide. I have some pretty good LED driving lights on my car (only 1 at the moment tho) They are "white" light. Best for car lights in my opinion and I have had some experience. They are not long range but that is not what I want. All the roos I have trouble with are in close. Only 2.5 A per light. That is the best part. For shed work a warmer colour would probably be better.

Simon.

Sorry but I have no romantic suggestions to make. I find it is often the way on this forum. Your expectations outweigh the reality. Sad but true. To balance that there are often revelations that really are helpful and impressive. That is probably not likely to console you tho.

Dean

Hi Simonl,

Just to add my 2cents worth...

As several other posters have pointed out, motor starting is going to be your biggest problem. Single phase motors are usually worse than three phase. I don't know enough about Variable Frequency Drives (VFD) to know how much one of these could help you.

If you go with the mains power, I would suggest that while you may be able to do your own wiring, you get a sparky to design it, check it over, make the actual connections and test it before it's turned on. The trade off in doing your own work is the risk of fire or electric shock versus a few dollars saved. Only you can decide on how much your life or workshop is worth to you! I would suggest that after your sparky has told you what size cable to run to the shed, you have a chat with him about how much load that size cable will allow. Then consider going one size larger! A shed with insufficient power may become a major pain if, at some future time, you buy bigger equipment. The extra cost of running heavier cable now is nothing compared to digging it all back up later.

I have thought of installing LED lights in my shed (the shed is not up to that stage yet) and my preliminary research suggests I'm probably best off buying a conventional flouro fitting and converting it to run a LED tube when the first tube dies. The conventional wisdom is that lighting use accounts for 10% of power use in an average house.

There is something wild about generating your own power. My romance with our mains connected solar system is still all good. Keeping the lights on when the mains goes off, with a RAPS or the like, would be wonderful. I still have room for another 8kW of panels on the roof. One day, one day.

Cheers

The Beryl Bloke

Hi Simon i was speaking about your conundrum with my sparkie mate today. He was under the impression that $2500 was probably over the top for what you are talking about getting done.

May i suggest you give him a call and have a chat about your requirements. He will likely need to see the place to give an accurate quote but he needed more information than i could provide to even give an estimate. He did say that if you were to do the grunt work, like digging the trenches etc it would bring the bill down substantially.

Ian - ElecRight - 0418 887 058

I can vouch for his work, top quality. The slogan for Elecright is "Do it once, do it right!" and he works by that ethic.


I also dont think RAPS/solar would be a good way to go. I cant think of anything worse than having to be stingy with the power in my shed....
Ian has done plenty of big solar installs so should be able to give you some insight on that side too.

Originally Posted by Theberylbloke

Hi Simonl,

If you go with the mains power, I would suggest that while you may be able to do your own wiring, you get a sparky to design it, check it over, make the actual connections and test it before it's turned on. The trade off in doing your own work is the risk of fire or electric shock versus a few dollars saved. Only you can decide on how much your life or workshop is worth to you! I would suggest that after your sparky has told you what size cable to run to the shed, you have a chat with him about how much load that size cable will allow. Then consider going one size larger! A shed with insufficient power may become a major pain if, at some future time, you buy bigger equipment. The extra cost of running heavier cable now is nothing compared to digging it all back up later.

Pretty much what I did except I oversized the cables and downsized the breakers ie for a 20m run in 6mm^2 cable I installed a 32A breaker. This ensures the breaker will trip long before the cable gets hot. Got to keep in mind that the breakers are there to protect the cables from overheating & starting a fire etc, not to protect anything attached to them.

I did all the physical installation of my systems & had it checked by a licensed electrician, who did the final terminations in the sub-boards. We were all happy with that arrangement as the person I'd used had done a lot of work for me in a professional setting where I was basically his slave (even though I was paying him) so he was confident that I would not cut corners.

FWIW I have 90A per phase on my 3 phase system. If I ever max that out I am going to have serious power bill problems that a roof covered in PV panels is not going to alleviate much. OTOH I have no problems starting a 25 HP air compressor, so it all depends on your level of need (want).

I'm with Ray, though. I never really thought I'd see $1/watt panel prices. I think I'm going to build another shed just so I can install a big PV array. The current shed doesn't face the right way. At least that's my excuse & I'm sticking to it....

PDW

Thanks guys. While i would love to have a go at wiring my own shed with mains, It's never going to happen, I always envisaged a sparky to do that. Two reasons, safety AND insurance purposes. I was at the Melbourne Show yesterday with the missus and the kids, I saw that Energy Safe Vic had a marque. Being topic of conversation on here, I thought I would ask them about the legalities of wiring up my own RAPS system in the shed given that I am not a sparky. "Oh, good question, give me your details and I will get someone to call you back" the answer was! I am still waiting..........

Anyway, the RAPS system is all but dead and buried given the advice from here. It's great to be able to bounce ideas of people BEFORE you shell out much effort and CASH to find out it was maybe never going to work.

I still like Rays idea with the lighting. Being a low/moderate draw system with efficient LED's it really lends itself to solar. WRT cable size, I have spoken to a sparky in the past about my shed and at the time he suggested that 10mm sq cable would be a good size given the distance from the house and envisaged use. Not sure but I think that was to cater for a 48A circuit from house to shed. On the surface, that sounds like plenty for me.

Thanks Andrew for the contact details. I will keep that in mind when I'm ready to take the plunge.

I looked into a grid interactive system for the house a few months ago. But with a buyback rate (at the time) of 8c/Kwh it seemed senseless. Buyback rates used to be 25 - 35 and even 65c/Kwh some time back. This meant that selling back to the grid was well worth the cost and effort. Now it's 8c/Kwh which is a game changer. Its means that you may as well use what you make while you make it. So instead of setting your washing machine, dishwasher etc in traditional off peak periods when the power is cheaper, you would have to wash your clothes, iron, do the dishes when the sun is shinning because it's not worth selling it to the power company and then buy it back!

Seems stupid to me that solar power is worth less than mains coal fired power! I have recently seen an ad for a buyback rate of 25c/Kwh so maybe things are on the way up again?

Cheers,

Simon

Hi Ray,

I just spent a bit of time having a closer look at your LED's. A luminous efficacy of 90 lumens/watt is better than fluoros (from memory) even the quad phosphor ones. This is quite impressive!

It's a shame that I have pretty much made my bed when it comes to lighting. A couple of years ago I bought about a dozen twin fluoro. The trough ones with the reflectors, they were a good deal at about $12 each with tubes, starters and plugs. They will be fine for general lighting but I will still need some specific task lighting over my benches etc. I was thinking of just using "normal" LED downlights but they are nowhere near the efficiency of the ones you are using.

Cheers,

Simon

Originally Posted by simonl

Seems stupid to me that solar power is worth less than mains coal fired power!

Hi simon

the issue is you can't readily store the solar generated at midday to use in the evening when you get home and want to cook dinner. And while you and your neighbours' dinky little solar systems are cranking out power between 9 and 3, the coal fired power station is merrily burning coal, super-heating steam and running it's generators, as if your systems didn't exist. So there's really no system-wide saving -- it just takes far too long to slow a coal fired plant down and then bring it back on line.

IIRCC
hydro power generators take about 15 minutes to get up to speed and about 10 to shut down
gas turbines take about 30 minutes to fire up and about the same to shut down
coal plants take about 36 hours to get up to speed and around 24 hours to shut down -- so once started you leave them running until they need to be shut down for major maintenance

Originally Posted by simonl

Seems stupid to me that solar power is worth less than mains coal fired power!

Why? Economies of scale are all against you. I suspect it's nuisance value to the grid authorities. Also there's a limit on just how much current you can back-feed into the grid before things start getting interesting. It was never designed for a large number of small generating sources. All adds costs therefore reduces value of power...

Now, for a truly stunning waste of money combined with a ton of 'feelgood' try wind generated electricity. Approx 30% delivery on installed theoretical capacity and zero guarantee of timeliness of delivery or amount delivered, combined with a premium price.

Fossil fuelled power plants run at ~85% of theoretical capacity with downtimes scheduled (friend of mine is working on a shutdown ATM) and nuclear fuelled power plants better than 90%. PV isn't great but is a lot more reliable and with the continual drop in panel prices, becoming a better alternative for small scale stuff all the time.

Now we need a similar breakthrough in batteries. As I said, currently LiFePO4 batteries cost approx 4X the price of lead-acids of equivalent theoretical capacity, though when you consider the amount of capacity you can actually use, the price is closer to 2X to maybe 2.5X. I'm putting off buying my 400 AH battery bank for my boat until the last minute in the hope prices fall further (and I do better than a guesstimate on just how big a bank I need).

PDW

Originally Posted by simonl

Just out of interest, the new Toyota Land cruiser 200 series run twin batteries. They are in parallel, one each side of the engine bay just to give enough CCA for their monster V8 diesel.

yeah but it does not have dedicated 12v outlet at the back to allow one to keep the gods nectar cold
one needs to split them so that can happen

a big genny?.....can find some cheap at auctions now and then?

Originally Posted by eskimo

yeah but it does not have dedicated 12v outlet at the back to allow one to keep the gods nectar cold
one needs to split them so that can happen

? why. if they are parrallel, its a 12V system

Stuart

Originally Posted by Stustoys

? why. if they are parrallel, its a 12V system

Stuart

the 12v outlets go dead when the ignition is turned off...meaning that brown stuff gets warm and becomes unusable

Originally Posted by eskimo

yeah but it does not have dedicated 12v outlet at the back to allow one to keep the gods nectar cold
one needs to split them so that can happen

The batteries are paralleled and so still 12V. I assume they did it because it was either easier or better weight distribution to have 2 "smaller" batteries on each side rather than one "larger" one with all the weight on one side. I say "smaller" because they are still quite big!

In terms of dual battery systems used in 4x4 etc for running accessories like fridges etc. this is not a dual battery system, it's a twin battery system. You really need a dual battery system to cope with running fridges etc. So, you would need to fit a third battery which is isolated from the other two batteries and is charged/discharged independently.

From memory, there is not much room left under the bonnet so it would most likely have to be put in the rear but I'm not rich enough to be a Land cruiser 200 series owner so I'm not up with how the 200 series fraternity have gone about it. Chances are if you can afford the 200 series and all the aftermarket gear needed, then you can probably afford a few solar panels and a Honda Eu generator too problem solved!

My second (dual) battery is an AGM 105Ah and is the biggest I can fit under the bonnet of my prado. I used to run my 50L fridge for about 3-4 days in mild (under 30 deg) weather. Now that I have a 150W solar panel and charging system, the 105Ah battery is probably bigger than needed. I will probably downsize it when it gets replaced and rely more heavily on the solar charging. Mind you, with monocrystalline panels it only take a tiny amount of shade or some cloud to reduce your potential charging capabilities by about 90%. Apparently this is where amorphous panels are more suited but there is a price to pay for that too. They are both more expensive and much larger for the same wattage rating.

Slightly off topic but hey, it's my thread and I'll cry if I want to, cry if I want to. You would cry too if it happened to you.......

Simon