Newb / Convincing the wife

blarby

First of all, hello !

My name is blarby.


I'm not new to electronics by any means, but its been awhile since highschool, for certain.

Anywhos.....

I would like to setup a demo solar sytem for the wife, to show her that solar can indeed work as part of our power solution for our new home. While likely never going to be competely off grid, I know the value of having an alternate renewable and non-grid power supply.

So.... With that in mind, I've decided to make a demo system that will power a small home computer.

I dont have unlimited funds- but I do have lots of free time to assemble cells, etc.

This is what I would like my simple system to contain :

2 deep cell batts ( so I can practice with equalization, etc... and for supply ! )

6 1amp / 15 w panels for a total of 90 watts

A solar charge controller

a 1000w inverter ( I have this already )


I have a few questions concerning charge controllers, but any advice on the setup listed would be helpful.

The most burning question comes to charge controller capacity ; as this system is only going to be 6 amps, as CC go its pretty small.... but I would like to buy a CC large enough for expansion when that happens ( positive thinking ! ) but I'm not sure if the CC i'm looking at will handle lower amperage, or only the amperage stated.

For example :

http://www.altestore.com/store/Charg...isplay/p10313/

I like the cost and features of this unit ( but hey, WTH do I know, right ? ) but do I need 30 amps of input, or will it handle my lowly 6 ? Do I need a cheap 6amp only unit, or am I going in the right direction thinking further down the road ?


I'm not set in stone for any components- so if you have suggestions on batteries, cells, controllers, or anything else- please lay it on !

ANY advice would be greatly appreciated !

vtmaps

Re: Newb / Convincing the wife

blarby wrote: »

I would like to setup a demo solar sytem for the wife, to show her that solar can indeed work as part of our power solution for our new home. While likely never going to be competely off grid, I know the value of having an alternate renewable and non-grid power supply.

Welcome to the forum,

When your wife figures out that a kilowatthour from your system costs at least 10 times as much as a kilowatthour from the grid, will she be convinced? Will you still be convinced? As you scale up your system (and they don't scale up very well) you will just increase your expenses relative to the grid.

Perhaps you should look into grid-tie systems. Those can make economic sense with enough tax credits and incentives.

--vtMaps

waynefromnscanada

Re: Newb / Convincing the wife

If you consider it a hobby of interest, a hobby in which you put in your time, and take pride and pleasure therein, and put your time, effort and money into that instead of drinking and smoking for instance, then it can make economic sense from a hobby point of view. It's a hobby that gives back positive things instead of the health problems of drinking and smoking. It can also be awesome when the grid goes down.
If you're thinking of this proposed project purely from an economic viewpoint, then go no further, stop now. If however you consider some things in life to be of more value than money, and if you have the money - - then go for it!
I missed my calling in life. Even as a kid I dreamed of working with power production and distribution, and now as a senior, with the system I've built up over the years, I derive great pleasure in having all the electricity I need, and that I did all the work myself. Moreover if the big ice storm predicted for tomorrow takes down the grid, I'll take even more pleasure in my system and ability supply all my electricity needs.
But it's most definitely NOT for everyone. It requires constant tending to and maintenance, just like if you kept rare animals for a hobby. You just can't purchase, then and turn your back expecting them to thrive. You've got to love them and love tending and working with them. Then you'll get positive results.

blarby

Re: Newb / Convincing the wife

vtmaps wrote: »

Welcome to the forum,

When your wife figures out that a kilowatthour from your system costs at least 10 times as much as a kilowatthour from the grid, will she be convinced? Will you still be convinced? As you scale up your system (and they don't scale up very well) you will just increase your expenses relative to the grid.

Perhaps you should look into grid-tie systems. Those can make economic sense with enough tax credits and incentives.

--vtMaps

Given how fragile the grid is where we're putting in our home- an alternate to a gas generator is not a bad option.

blarby

Re: Newb / Convincing the wife

Given that we've had rare pets for most of our lives, thats not a bad analogy.

Very few things are "set and forget", and I certainly didn't expect this to be one of them. Reloading your own ammunition, baking your own bread, and repairing our own vehicles are questionably cost effective at times- but I still do those, too ! A measure of independence is nice, but being able to actually do it is another bonus in and of itself.

BB.

Re: Newb / Convincing the wife

In general, an off grid power system will generate power (all in costs, installation, hardware, replacment batteries/electronics over 20 year life of system, etc.) of (very roughly) ~$1.00 to $2.00+ per kWH (well sized system used 9+ months of year). Some folks here have been able to get down towards $0.50 per kWH with careful design and shopping for components).

So--If your kWH cost ~5-10x as much as grid power--That usually will give you some ideas about how much conservation will buy you. That new 365 kWH per year fridge vs the old one that is 1,360 kWH per year fridge will save you ~1,000 kWH per year... At $0.10 per kWH, that is only a $100 savings. At $1.00 per kWH, that is a $1,000 per year savings (for off grid power).

Also, if you have heavy A/C usage, that is ~1,000 kWH per year that is not being dumped into your home.

Lighting is another issue... LED/CFL lighting can reduced upwards of 25% or so of the heat dumped into a home. In a cool region like mine, it is "free heat" (although natural gas heating is cheaper here). In hot climates, you have to pay to move that heat "outside" during the summer.

I also believe that conservation (new windows, more insulation, new heat pump system, etc.) will offer better returns (if you sell the home) vs installing an on grid/off grid solar power system. Some people are "afraid" of solar. Others just are not going to do the battery maintenance/load management if they have utility power to the property.

For you, it may be worth the "investment"--For others (if you ever sell), not so much.

-Bill

northerner

Re: Newb / Convincing the wife

I agree with waynefromnscanada in that if solar power interests you, then go for it with a small system. I have done this and find it plenty of fun building the system and operating it. Where I live power electric power from the utility is very expensive as well, close to $0.40 per kwh depending on usage, etc... If I just factor in the initial investment (doing it myself as well), I predict a payback in about 30 years. Of course there are battery replacements and other equipment maintenance that will add to that. The real downside to off grid usage is dealing with the batteries that are currently available. They have a limited life span and require constant attention. There is new battery technology that may be here soon that could change all that, but not quite available to date.

The real value with solar power I feel is that in many locations, you will be potentially displacing fossil fuel usage. On an individual basis it will make little difference, but if everyone began using renewable energy from one source or another, it could make a real difference to our planet as a whole. Good luck with your project and have fun!

SolInvictus

Re: Newb / Convincing the wife

BB wrote:

In general, an off grid power system will generate power (all in costs, installation, hardware, replacment batteries/electronics over 20 year life of system, etc.) of (very roughly) ~$1.00 to $2.00+ per kWH (well sized system used 9+ months of year). Some folks here have been able to get down towards $0.50 per kWH with careful design and shopping for components).

Over the last 23 years my PV system has cost me 70 cents/kWh, so far, calculating it as money spent divided by electrical energy generated despite 9 of my PV panels being purchased back when they cost $10 per rated watt. The cost continues to decrease. This is less than grid electricity would cost because I would have to pay more than I have spent on the PV system just to have it installed. In a grid connected house there is a hidden cost of electricity in the price of the house that few count.

blarby, one 220 W PV panel for grid-tie or one 140 W PV panel for off-grid would probably cost less than six 15 W PV panels and be more suitable for future expansion. You have a choice to make: an inexpensive PWM charge controller that works with expensive PV panels designed for off-grid systems, or an expensive MPPT charge controller that works with cheap PV panels that have incompatible voltages for batteries.

blarby wrote:

For example : http://www.altestore.com/store/Charg...isplay/p10313/

The Schneider Electric C35 PWM charge controller is less expensive but does not have the display. The Blue Sky limits your battery array to 12 V whereas the C35 allows it to be 12 V or 24 V. If you intend to expand in the future, then it would be best to pick a 24 V or 48 V battery array which would make the Blue Sky unusable. In 12 V mode the C35 can have four 140 W PV panels attached and in 24 V mode it can have eight (1,120 rated watts or 5 kWh/day under ideal conditions). You can combine PWM and MPPT charge controllers provided their battery voltages are compatible. Charge controllers operate with less than their maximum rated current otherwise they would not operate on cloudy days nor around sunrise and sunset when the power output of the PV panels is low.

Before you start sizing your equipment, determine the power consumption of the computer, its accessories and perhaps a lamp that you might use to illuminate it. The watts of power consumption for the equipment times the maximum hours per day that they will operate, gives you their power consumption in watt hours per day (Wh/day). A Kill-a-Watt meter could be useful in measuring actual power consumption of things around the house.

So you can determine the best battery voltage, you should look at your power consumption of your entire house recorded on your last 12 electric bills. If you consume a lot of power or use high powered appliances, pumps or tools, then a 48 V battery array may be the best option.

niel

Re: Newb / Convincing the wife

here's another angle. the battery and inverter works independently at supplying power and the solar just keeps it charged. this is over simplifying it as components should have some compatibility and suit your loads. with this simplification you can throw just about any little thing together for a demo involving a laptop.

expanding on a system is not so easy to accomplish and you may want to go with different components altogether.

now i'm gathering you want backup power and be able to sell to the grid? this is the best when you want battery backup as excess charging can then be used to lower your bill and is known as a hybrid system. do know what it is you intend on backing up and for how long. most times you start with what you'd need in a day and this involves knowing what the watt hours or kilowatt hours are to be in a day. a kilawatt meter is good for plugin items as it can measure that. you can interpolate if more or less than 24hrs of measuring. example:30hrs at 1.86kwh (1,860wh). this breaks down to 1860wh/30hrs=62w and over 24hrs would then be 62w x 24hrs or (1.488kwh) 1,488wh per day. once parameters are known some idea of equipment needed can be addressed.

if you opt for grid tie only this is cheapest to do, but then you lose power during outages as you have no backup.

if you opt for straight off grid then you lose offsetting your bill with the excess power produced after your batteries are charged.

niel

Re: Newb / Convincing the wife

wayne,
the way you put it my wife would get jealous and say no as you make it sound like a high priced woman. just suffice it to say you can't leave it unattended for long periods as it requires some maintenance and inspection at times.

westbranch

Re: Newb / Convincing the wife

If you are going to look at the BlueSea, I would recommend you look at the MidNite "KID" , new on the market and a LOT more CC than the BlueSea...and only a few dollars more.

http://www.midnitesolar.com/productPhoto.php?product_ID=530&productCatName=Charge%20Controllers%20-%20KID&productCat_ID=43&sortOrder=1&act=pc