Advice on shed PV

Apiarist

Hi,

I am in the very beginning of my photovoltaics adventure, so I would appreciate your advice.

I want to have up to 250W of power available at an AC socket with probably total usage of 500 Watt-hours drawn during one day a week. The location is a small shed with a south-facing sloped roof.

The idea is to have a solar panel connected to a solar controller charging a car battery, with an inverter connected to the battery. The usual setup.



Questions:
- what size of a battery I need and where to buy it?
- what controller would you recommend? I want one that can at least show the battery charge remaining and probably current in/out. Also one that would not burn my shed down.
- can I buy a kit (panel/controller/inverter) in Ireland that is not outrageously overpriced?
- best way to fix a solar panel to a metal corrugated roof?

This is a PV education project for me, so an advice to charge a battery at home would be redundant. Money is not a problem for a reliable system.

Apiarist

So here are the things that I have bought:
* Renogy 100 Watt 12 Volt Monocrystalline Solar Panel (part# RNG-100D-SS-FBA, £80 from Amazon)
* Photonic Universe 10A 12V/24V solar charge controller (£34 from Amazon)
* Three Meter (10 FT) 10 AWG Solar Extension Cable (£20 from Amazon)
* Bestek 500W Car Vehicle Power Inverter (£43 from Amazon)

I have honestly tried to find the parts in Ireland, but it seems that first several pages in Google are taken over solar installer firms that want to "quote" me a multi-thousand euro installations. I have various connectors from previous projects, though I may need more high-Amp wiring. I also need to find a lead acid battery, I'll probably go and buy it from Halfords.

unkel

victor8600 wrote: »

I have honestly tried to find the parts in Ireland

Most of that stuff can be had on adverts, but I guess you wanted to buy new?

The parts you bought are fine, but quite expensive for what you got. Not too late to start saving a bit of money on your project, if you have an old car battery sitting about, I'd use that. Will be fine for very light / occasional use but do not discharge it too deeply or it will die on you quickly.

kanuseeme

I am no expert.

When I bought an inverter to run off my car battery, I bought a pure sine wave inverter, more expensive than modified sine wave, but from information I read that it would cause less problems with certain appliances etc.

I could be wrong, maybe some one could verify.

Hope it helps.

unkel

Yep you could do damage to certain appliances if you run a modified sine wave inverter. I have a pure sine inverter in my car too. For just some lights in a shed it makes no difference though.

kanuseeme

There is a light and a computer in his diagram, why need an inverter just for a light?

unkel

A PC mainly runs on 12V too

I wouldn't touch a mollified square waiver for any amount of money.

Apiarist

Sir Liamalot wrote: »

I wouldn't touch a mollified square waiver for any amount of money.

Looks quite horrific indeed. Any recommendations on a ~400-500 W range pure sine inverter?

Apiarist

kanuseeme wrote: »

There is a light and a computer in his diagram, why need an inverter just for a light?

Thinking about it, I would not actually need an inverter all that often. Only if I need to re-charge power tool batteries or my laptop's battery, but those can be charged from mains at home and last for quite a few hours.

Mostly I will be using USB ports on the solar power controller to charge my phone and the portable torchlight. The largest power drain is going to be the 12V electric blanket (85W). Lights are going to use only 10W or so.

unkel

If you are going to charge lithium ion batteries, a pure sine wave inverter is a must!

If all you do is use the USB ports and use 12V appliances, you don't need any inverter at all

victor8600

victor8600 wrote: »

Looks quite horrific indeed. Any recommendations on a ~400-500 W range pure sine inverter?

MorningStar SureSine is very good.





Schlicktron scrapes a pass if yer on a budget and don't need it to last as long.







Yellow Xantrex is quite affordable.


Studer are the best.






You can use a car laptop charger, they're way more efficient but the plug's guaranteed to melt inside of 6 months.


Inverters are very lossy. If you can avoid one I would.

unkel wrote: »

If you are going to charge lithium ion batteries, a pure sine wave inverter is a must!

Why?

unkel

Sir Liamalot wrote: »

Yellow Xantrex is quite affordable.

I was wondering about those, have come across them on the likes of eBay alright and their prices seem reasonable. These yellow ones all pure sine wave?

Sir Liamalot wrote: »

Why?

When I looked into that, it seemed that was the general advice. Fridges, TVs, microwaves (?) and lithium-ion chargers. From what I remember that's nought to do with the batteries, but the lithium-ion chargers don't like modified sinewave apparently. Transformer?

unkel

unkel wrote: »

I was wondering about those, have come across them on the likes of eBay alright and their prices seem reasonable. These yellow ones all pure sine wave?

Endorsed by the NHS. The only high frequency jobber on th market I would use.

unkel wrote: »

When I looked into that, it seemed that was the general advice.

Ha! Most of the advice on tinternet is old wives tales. If you can't prove it yourself then don't believe it

unkel wrote: »

Fridges, TVs, microwaves (?) and lithium-ion chargers. From what I remember that's nought to do with the batteries, but the lithium-ion chargers don't like modified sinewave apparently. Transformer?

You can't charge a battery from itself. Besides they're DC.

...oh you mean little devices and tools. Er yeah battery chargers hate MSW.
I thought you were talking about the main solar battery.

unkel

Sir Liamalot wrote: »

...oh you mean little devices and tools. Er yeah battery chargers hate MSW.
I thought you were talking about the main solar battery.

Well the OP did say:

victor8600 wrote: »

I need to re-charge power tool batteries or my laptop's battery

So how much would you pay for a yellow Xantrex 1000W like this

Linky

unkel

unkel wrote: »

Well the OP did say:

DC-DC (<98% efficient) is always a better option than AC-DC (<80% efficient, usually)
DC-AC-DC is even worse.

unkel wrote: »

So how much would you pay for a yellow Xantrex 1000W like this
Linky

That much.


Unless you can find a broken one..usually they just need a replacement relay.