Homepage › Forums › Technical Discussion › Small Off-Grid Instalation – without batteries
- This topic has 2 replies, 3 voices, and was last updated 11 years, 2 months ago by s.mihai.
December 28, 2011 at 12:00 am #63005s.mihaiMember
I want to setup a small off-grid house without batteries, just the PV-panels + charger + inverter (230v). I want this for my office.
How will the system behave like this ?
1. if there is no consumtion at a given time
2. if there is too much consumtion (by mistake someone plugs in something)
what is your best technical advice ?December 28, 2011 at 12:00 am #65851retired profile of WrethaOffGridSpectator
Why not use batteries? You are going to be putting money toward the rest of the system…
Here is what I see, think of it like this, an analogy:
You have a semi-steady drip of water, this water only flows during certain hours during the day and some days it doesn’t flow at all, you wish to use this water from time to time, so you can either stand there with your mouth under the water drip and wait to get the amount of water you want, or you can put a bucket or other container under the drip to collect it as it drips.
If you don’t use a bucket, depending on how steady and fast this drip happens will determine how much you can use at any one time, to have enough to use for larger uses you will need a lot of water coming through, there is no guarantee that you will have water dripping at the time you need it.
If you use a bucket to collect the water, you can use a smaller drip
and you don’t have to worry about how much is coming through at any
one time. You will have water there when you want to use it.
My point here is if you aren’t using batteries, you will have to have larger and/or more solar panels, you will be forced to have the number or size of panels that you need at any one time for use right then. If you have a cloudy day, or want to use your system at night, you are out of luck (and power).
Why not add some batteries? Then you can use fewer or smaller solar panels, then you can use your system anytime you want, day or night, sunny or cloudy.
WrethaDecember 28, 2011 at 12:00 am #65854elnavMember
Good explanation Wretha. However the original poster is overlooking one basic requirement in any system. A battery acts as a stabilizeing load. Grid ties systems rely on the grid to stabilize things. A regular charger will not deliver the proper voltage without a battery to feed.
A PV system without any storage capacity is going to drop out if a cloud obscures the sun.What them? In an office this could mean a copier or phone stops at the wrong moment. Bad idea!
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