Powering and Lighting Outdoor Shed With DC Battery+Inverter

IT Loser

Hello all,

I am considering throwing up a smallish garden shed, and I want to power it independently of the mains.

It is currently impractical to use a generator {housing estate, noise and fume issues etc}- and the power being drawn from the house is leaving the house via a 20A cooker circuit to feed an adjacent garage. A feed off this is unfortunately not an option.

I have been turned in the direction of using DC power via an Inverter- I do not know much about this but the idea appeals to me.

Principally, the shed will require mains 220-240AC to run a laptop, or at the very least a laptop charger, and to run a 60W lightbulb, desk lamp, and sundry battery chargers {for AA and AAA cells}

I would be grateful for any advice or tips. I have a budget of around €150. Thanks:cool:

2011

As I am sure you know an invertor will give you AC from a DC supply. Where do you intend to get your DC supply from?

[Edit] Sorry I see from your title that you intend to use a battery!

IT Loser

2011 wrote: »

As I am sure you know an invertor will give you AC from a DC supply. Where do you intend to get your DC supply from?

[Edit] Sorry I see from your title that you intend to use a battery!

Yes! I was hoping to use a battery- I have a range of batteries at my disposal- 20Ah 48v Lithium to old 12v car batteries. What could I expect to achieve with such a set up?

I also see that certain inverters are rated to 1500w or 3000w etc. Is there a happy medium I should seek?

Thanks.

2011

To be honest this is not a good way to go! First of all when your battery goes flat you will have to recharge it. You will find that the battery is only good for so many charges. Also you will be carrying a battery back and forth all the time and then replacing it frequently.

The other thing is that the 3 things you intend to power (laptop, light and battery charger) can all be powered by DC, so why bother with an invertor at all?


The total load you require is quite small, so unless your shed is very far from your house a small supply cable would be suitable. Why not run a supply cable from the house?

I think you would find that it is not only cheaper, but a far better job in the long run. This is whhat most people do.

IT Loser

2011 wrote: »

To be honest this is not a good way to go! First of all when your battery goes flat you will have to recharge it. You will find that the battery is only good for so many charges. Also you will be carrying a battery back and forth all the time and then replacing it frequently.

The other thing is that the 3 things you intend to power (laptop, light and battery charger) can all be powered by DC, so why bother with an invertor at all?


The total load you require is quite small, so unless your shed is very far from your house a small supply cable would be suitable. Why not run a supply cable from the house?

I think you would find that it is not only cheaper, but a far better job in the long run. This is whhat most people do.

Running a cable is not an option due to aesthetics, and the practicalities of it also- the garden is already a mire in this weather and I dont want to be hanging cables etc. Its something I wrote off in the preliminary stages of the plan. Of course, 220 mains would be best. Just not an option however. Besides, I want the shed to be self contained.

The shed will not always be lit up.

Principally, I will be in there for around 3 or 4 hours per day, maximum.

Its basically a self-contained command centre, so to speak. I go in, power up, get some work done, and clear out.

Its not like I will have the battery draining and charging almost constantly- but you are correct about the practical limitations of that aspect.

2011

I have a range of batteries at my disposal- 20Ah 48v Lithium to old 12v car batteries

Lithium batteries are expensive and would be of high quality. If these batteries are rated at 48 volts needless to say your invertor must be designed to have an input of 48 volts DC. This may be hard to find! Even lithium batteries would only be good for a number of charges.

Old car battreies are not much good!

What could I expect to achieve with such a set up?

I think you would end up spending money on something that may perform to a medicore level for a short time at best!

I also see that certain inverters are rated to 1500w or 3000w etc. Is there a happy medium I should seek?

You should size your invertor according to your load. Work out how many watts your load is in total.

Think of it this way: What is a UPS system??? Basically it is a load of batteries and an invertor. What does it cost?? Lots!! With no mains supply how long can it provide mains power?? Often in the region of 10 minutes.

IT Loser

So why do they sell inverters if they achieve fack all?

2011

Running a cable is not an option due to aesthetics, and the practicalities of it also- the garden is already a mire in this weather and I dont want to be hanging cables etc.

I understand, but let me just "bounce" a few ideas off you as it may inspire you!!

1) You may be able to run a in a 20 or 25mm steel conduit down the garden wall.

2) Run an armoured cable (SWA) along the ground (out of the way) and bury it when the weather gets better.

Its something I wrote off in the preliminary stages of the plan. Of course, 220 mains would be best.

Just not an option however. Besides, I want the shed to be self contained.

What about simply charging the laptop in the house and using a battery powered LED light?? The LED lights use very little power.

It would be very inefficient to use a battery powered invertor (fed by a battery) to supply a charger to charge other batteries. Why not charge these in the house???

Principally, I will be in there for around 3 or 4 hours per day, maximum.

A modern laptop should be able to power itself from its own battery for that lenght of time.

Its not like I will have the battery draining and charging almost constantly- but you are correct about the practical limitations of that aspect.

Dont count on it! Initially the batteries will last best. After each charge thier capacity will reduce.

2011

So why do they sell inverters if they achieve fack all?

Lots of reasons. For example:

1) If you plugged an invertor intor your car it would give you out 230 volts AC for as long as the engine is running. The Car engine "trickle charges" the car battery. The car battery in turn supplies the invertor with a nice staedy 12 volts. On the other hand if the car engine is turned off the battery starts to drain. I am sure you have run a car battery flat trying to start a car at some stage in your life?? It did not take long did it?? Batteries are great, but they have thier limitations.

2) Also in industry invertors are often used just to seamlessly fill the gap between mains failure and the back up generators coming on line.

3) Othertimes they are just used to provide enough time to shut down a computer safley

IT Loser

2011 wrote: »

Lots of reasons. For example:

1) If you plugged an invertor intor your car it would give you out 230 volts AC for as long as the engine is running. The Car engine "trickle charges" the car battery. The car battery in turn supplies the invertor with a nice staedy 12 volts. On the other hand if the car engine is turned off the battery starts to drain. I am sure you have run a car battery flat trying to start a car at some stage in your life?? It did not take long did it?? Batteries are great, but they have thier limitations.

2) Also in industry invertors are often used just to seamlessly fill the gap between mains failure and the back up generators coming on line.

3) Othertimes they are just used to provide enough time to shut down a computer safley

Okay, thanks for all the suggestions and info- your feedback has been most helpful. Cheers.;):cool: It appears I have overrated the usefulness of Inverters! Ta!

2011

Sorry for pi55ing on your parade!

I can see that you were just trying to think outside the box

I have overrated the usefulness of Inverters!

They are useful, they just have limitations!

Someone else might come on here and totally disagree with me!

IT Loser

2011 wrote: »

Sorry for pi55ing on your parade!

I can see that you were just trying to think outside the box


They are useful, they just have limitations!

Someone else might come on here and totally disagree with me!

No problem...I am all for debate and opinions. LED's and AAA's might yet be the best bet. Thanks.

clinchy

candles?

Stoner

there are kits available with 12V DC 9W CFL lamp, you get the switch the lamps and holder inc solar panel for about £70 from www.cpc.co.uk all you need to add is the battery.

i.e. you wont need an inverter



http://www.boards.ie/vbulletin/showthread.php?t=2055709329&highlight=solar

ray78

If you decide to go down the battery route you could charge the battery with a solar panel or/and wind generator,