solar generators

amharp
By amharp on Fri, Apr 19, 2013 - 8:59am

Hi all. I have some questions about solar generators and am hoping someone can help me, or at least head me in the right direction smiley.

 

I would like to soend my tax refund on a solar generator. I do not have a lot of money, so need to make the best purchase possible. In order of priority, I would like to run the following off it: water pump, refrigerator and freezer, then any extras such as stove and lights. I do not need to have all these on all the time. I am extremely ebergy efficient already. Also, I have an apartment over a garage and would like to run the same things there.

My questions:

1. How do I tell if the generator I am looking at has enough capacity?

2. The apartment and the house are on 2 different systems. Can I tie them together on one generator?

3. How far from the house does the generator have to be for me to get the maximum benefit?

Thanks for any insights. And you know of other things I need to consider, please enlighten me laugh.

Ann Margaret

5 Comments

treebeard's picture
treebeard
Status: Platinum Member (Offline)
Joined: Apr 18 2010
Posts: 590
Putting a system on my house now

I am in the process of having a system put on my own house now.  By solar generator, I assume you mean panels that generate electricity?  The least expensive systems sell any excess power that you generate back to the grid.  In power outage situations you have no power even if you have panels.  To use solar panels for backup power you need to install a dual inverter and storage batteries.  That system is very expensive.

I would talk to local companies that install solar systems to get a feel for the costs and what is involved.  They can size the system for you based on the items that you want to run, your budget, you typical utility bill, and your solar exposure. 

Oliveoilguy's picture
Oliveoilguy
Status: Platinum Member (Offline)
Joined: Jun 29 2012
Posts: 578
Solar System

Hi Ann,

Sounds like you want a backup system because you have prioritized essential items.

The 1st thing to do is a load calculation. Look on the pump for the amount of amps it uses and then determine if it is 120v or 240v. Multimply amps x volts and get watts.

Next look at the Fridge. They usually have an yearly Kwh use.  My new fridge is 520 kwh/ year. Calculate backwards to get daily usage.

Same on the freezer.

Then look at your lights. If you have 5 lights at 60 watt bulb size, you can calculate usage from there.

Your stove is going to draw too much for a small PV system.

The simple answer is that you add up all your loads, then determine how many hours per day you use each item and then calculate an average daily usage. But then you have to build in surge requirements into the design. For example a fridge uses more electricity to start it's motor and your system might be asked to cover that high surge if things are all running. Usually a factor of 3.

Then you have to factor in inefficiencies in the equipment cause the batteries are 80% efficient, the charge controller is 96%, and the inverter mighht be 90%. So with lots of math you can design your system.

If you want to post the specifics, I'll help you at least determine you load design.

 

 

 

amharp's picture
amharp
Status: Member (Offline)
Joined: Dec 9 2011
Posts: 4
Thanks. This is exactly what

Thanks. This is exactly what I was looking for. I will start to take inventory this weekend and get back to you. Thanks again, Ann Margaret

amharp's picture
amharp
Status: Member (Offline)
Joined: Dec 9 2011
Posts: 4
Treebeard, I actually did

Treebeard, I actually did have a firm design a system. Mine was off the grid and modular, so I could add as I had the money. They designed one like the one you describe, which, as you say, is expensive and no help when the grid goes down if you don't have battery back up.

 

What I was looking for is actual generator. Someone answered below, so I will use that information as a start. Thank you for taking the time to help me.

 

Ann Margaret

Oliveoilguy's picture
Oliveoilguy
Status: Platinum Member (Offline)
Joined: Jun 29 2012
Posts: 578
Load Inventory of Solar System
amharp wrote:

Thanks. This is exactly what I was looking for. I will start to take inventory this weekend and get back to you. Thanks again, Ann Margaret

Good luck....Glad to help

Mark

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