Stand Alone Solar! Where does the Power Go?

[porgey]

I am planning on a stand alone solar system for a garden shed but as its not grid connected where does the electricity go when its not being used but still generated and the accumulators/batteries are full?

[Snoopy]

I believe it just turns the circuit off and the generated power goes nowhere! I’d read previously that it was burned up in heatsinks, but not according to my solar designer/installer.

I’m looking to put a small air conditioner in our place to use the otherwise wasted power creating cool air. Some folk hook up pumps to move water around their blocks, etc.

[Anonymous]

stand alone usually means nothing to do with any grid connection, with stand alone you sue storage batteries so you have power to use as you need it. most go the convenient way and buy new batteries at some expense others on tighter budgets source second hand 2v deep cycle second hand forklift batteries, or batteries from telstra’s bush exchanges. usually they are load tested to 80% and give good service, saving heaps of dough.

last price i was given was that chinese PV cells were falling in price then they were app’ $1.17AUD per watt. thought to help people with their research put a catalogue and price list (PDF) on my sustainability page:

http://www.lensgarden.com.au/sustainability_essay.htm

anyhow not a recommendation just a comparison.

len

[Bala]

When you have wind or hydro you need a heat sink to use the excess when the batteries or load do not require it, with solar the regulator simply stops the power from the panels whane it is not needed.. It is wasted if you are not set up to use it,that is one of the joys! of stand alone.

If you have grid connect why are you setting up stand alone??

[DB346]

the power doesn’t go anywhere, because the inverter is generally smart enough to know when batteries are full and turns the collecting off. The panels are charged, with heat/power but it stay there until the inverter lets it go to the batteries.

[Bala]

he power doesn’t go anywhere, because the inverter is generally smart enough to know when batteries are full and turns the collecting off. The panels are charged, with heat/power but it stay there until the inverter lets it go to the batteries.

Inverter turn dc power into ac power,

Regulators control battery charging

[Stuie]

hi porgey

on solar panels they can be simply disconnected form the batterys with out destroying the panles, however with wind and hydro you need a dump load as these loads cannot be disconnected or they will “run away” that is over speed and self destruct as these are designed to be under load all times,you can turn off the water to the hydro, but you cant simply turn off the wind.

a dump load simply turn power into heat this can be put in a heatsink to pervent it getting too hot or you may wish to put one into a hot water cylinder to heat water.

there are many people who try to minimise the wasteage by only running fridges/freezers when it is day, you need a well insulated fridge/freezer though for over night, or pump water form a storage tank to a header tank when the batterys are nearly full this eliminates a need for a pump to constantly supply water for the house all day and night. these are examples of using power most efficently.

smart regulators can switch these systems automatically.

hope this helps

[porgey]

Thank you all for your replies, most informative.

However, can you just disconnect the solar panels, where does the generated power go?

[Bala]

When the panel is disconnected there is no circuit so no power is being generated.

you should not disconnect panels when they are producing power, they will arc,

Can i ask why if you have grid power you are considering an off grid system?

[porgey]

Bala post=331657 wrote: When the panel is disconnected there is no circuit so no power is being generated.

you should not disconnect panels when they are producing power, they will arc,

Can i ask why if you have grid power you are considering an off grid system?

Right so no circuit no power, thanks for that.

I wont disconnect the panels when there producing power.

The off grid system is for a back shed. Although I can still shag like a banshee I dont have the grunt anymore to dig a 600+ mm trench to the spot and I want the whole food producing area which includes the shed to be completely self sufficient. I dont believe the xxxx will hit the fan big time in my lifetime but I still want to be as self reliant as I can.

All my back shed power tools & lights are/will be battery powered and charged during the day but the idea of dumping all excess solar panel output into a fridge/freezer does sound like a good idea.

[Bala]

You need to ensure you identify all your load requirements and size your panels and batteries to those requirements, and you will almost always need a generator for top up when needed. if you dont work it out properly you will destroy a lot of battereis.

A fridge or freezer is not what I would consider suitable for excess power, they run 24/7,i use excess power for pumping water . washing clothes etc

[Andre]

So how is it all going Porgey?

What did you decide to do…?

:whistle:

[Author]

Posts