Electric where there's no mains supply?

[Stu3y]

Not sure if this is the right forum or if any of you could put some ideas across, I have an allotment which has no power what so ever, a few people have a car battery and a little solar panel to recharge it. I'm basically wanting a way to power some lights (led prob use the least energy?) ideally I want to be able to set them up on a timer to come on at say 6pm and switch off at 10pm I was thinking along the lines of a solar panel and a large leisure battery to power some 12v led strip lights, but not sure how I could use a timer on these? Unless there's a 12v timer or something? another garden further along has a large panel on his roof, along with a TV aerial and 3 cctv cameras that are permenatly on and recording, I dont speak to the guy or even know who is is but would love to know how he's powering a tv, a dvr and 3 cameras... Any one got any ideas or suggestions?

 

[333rocky333]

12volt timers do exist, ive seen them on burglar alarm systems, though a lot dearer than normal ones

 

[HERTS P&D]

One of these that you can take home with you:

http://www.ebay.co.uk/itm/DIGITAL-P...183?pt=LH_DefaultDomain_3&hash=item487bbbc397

Andy

 

[333rocky333]

Im quessing he wants the lights on when hes not there, hence the timer.

 

[JohnW2]

12volt timers do exist, ive seen them on burglar alarm systems, though a lot dearer than normal ones

There are a lot out there (just Google - or , if you dare, search on eBay).

This one (click here) on eBay seems far too cheap - although I suppose it's only 12V and even if it caught fire in an allotment that probably wouldn't be the end of the world - but there is a whole spectrum available from that all the way up to the very expensive ones.

[ I presume that the (electrical and mechanical) life figures of "107 times" is meant to be '10 to the power 7' (aka 10 million) operations! ]

Kind Regards, John

 

[big-all]

Not sure if this is the right forum or if any of you could put some ideas across, I have an allotment which has no power what so ever, a few people have a car battery and a little solar panel to recharge it. I'm basically wanting a way to power some lights (led prob use the least energy?) ideally I want to be able to set them up on a timer to come on at say 6pm and switch off at 10pm I was thinking along the lines of a solar panel and a large leisure battery to power some 12v led strip lights, but not sure how I could use a timer on these? Unless there's a 12v timer or something? another garden further along has a large panel on his roof, along with a TV aerial and 3 cctv cameras that are permenatly on and recording, I dont speak to the guy or even know who is is but would love to know how he's powering a tv, a dvr and 3 cameras... Any one got any ideas or suggestions?

i suspect they will be dummies
if not remember 12.5w at 12v is around 1 amp so solar power alone wont provide more than a small part off the power
if you have say a 50 ah battery and say a 35w draw it will last about 12-15 hours allowing for losses or around 1-2 days the solar may provide another few hours so taking a battery or 2 home every other day or twice a week to charge may be the solution

 

[ericmark]

The solar panel and price tags is the real stumbling block.

If you simply use a solar panel and diode it will charge a battery and if the panel is small and battery large this works OK I use it to keep caravan battery topped up.

As the panel size increases then one has to include a regulator the simple regulator converts excess into heat but the panel is not very efficient using this method.

So as the panel size increases more then one uses a special controller which runs the panel and varying voltages to extract the maximum out of the panel then converts the power to voltage required to charge the battery and temporary stores the power sending pulses of power to battery and measuring the battery voltage between pulses to work out the maximum safe power it can put into the battery without damaging the battery.

PWM regulation is expensive this one at £134 is not the cheapest and a MPPT regulator can cost more and it is the regulator which decides how much power you get from the panel.

There are some Cheap Ebay MPPT regulators which are designed to do exactly what you want with an output which auto turns on lights as the panel stops charging how good the cheap controllers are is another question.

The balance between battery, controller, and panel sizes is not easy to work out. A traction battery should last around 7 years but ask any narrow boat user and they well tell you your lucky to get 2 years. It is because often the batteries never get an equalising charge in fact lucky if ever fully charged.

So in other words it's a can of worms and be it solar or wind it's still a bit hit and miss. A bike front wheel with a hub dynamo (not really a dynamo they are alternators) with the rim replaced with a wide band and insulation tape around the spokes just placed to get prevailing wind will work and light the garden in poor weather but my attempts to store the power failed as rarely got the voltage high enough.

Wind chargers all use permanent magnets so use the same controller as solar panels in fact Rutford make regulators designed for both inputs I am told by boat owners the combination of wind and solar works far better than either alone.

I would suggest you take a walk along the local cut and ask canal boat owners as they use both solar and wind a lot and will likely give you a lot of first hand advice. In the main they are a friendly lot.

 

[JohnD]

Unless you have an excessive amount of money that you want to get rid of, get some battery-operated lights.

I have a few LED lanterns in my outbuilding, and one wind-up lantern in case I forget to change the batteries.

 

[westie101]

Posted elsewhere

Well according to the met office we are now officially in spring.



We now have completed winter without having to rely on the national grid or generators.



Our solar setup performed so well we even topped up a few other vanners batteries during the season.



sorry to be boring but we just wanted to say that we have a very modest setup, which consists of;



2 * 80 Watt panels and a 60 Watt panel on the vans roof and a 100 Watt panel that we move to best get the sun, this is all parallel connected to our controller.



We also have a 3KW inverter but that was only used once a week during the winter and even then was only for a 10 minute quick hoover.



We have a 260AH battery bank and our battery SOC has not gone below 60%



Sorry to bore but we are so pleased with our setup, no more paying for hookup