New System and Newbie Operator

Studiojedi

Hello,
Ive been wanting to dive in deeper into solar and I guess am making the next step. I have used a lousy Harbor Freight 45watt system for my RV batteries in the past. Currently for now making some solar panels from cells( a gluton for punishment I know but Im not opposed to abandoning a bad project if that doesnt work out). My over all goal is to have my shop eventually go solar on my regular loads, but in stages. I am a computer/studio guy by trade and have a few servers, alarm system, and various routers/switches constantly running. Probably around 1000-1200 watts. My first stage to get my feet wet here is looking to do a 300-400 watt system for the routers, switches, and alarm system (which will be more than enough). I live in Central Oregon and we get 275+ days of sun a year. Cost of course is a consideration and I am looking at a 30amp MPPT charge controller, 500-600 watts of panels and 2-3 Walmart 29dc 12v 125ah deep cycle batteries. If for some reason there is too much a load I can reduce components to get to a point of equalibrium. I will be looking into a 500-750 watt pure sine wave inveter. I realize that solar setups can be a very subjective point of view but any real red flags with this approach/learning experience?

Cariboocoot

Re: New System and Newbie Operator

Welcome to the forum.

Any red flags? Why yes; there's cheaper ways to get an education!

Otherwise, you need to have an accurate measurement of how much power you are trying to provide. Get a Kill-A-Watt meter. Even if you don't do solar you should have one. It's a real eye-opener.

Now let's look at what happens with some of your numbers. "300-400 Watt system". What exactly does that mean? If the total load is 400 Watts and you run it for 24 hours: 9600 Watt hours. That's three times the power used to run my whole cabin! You won't do that on some department store batteries and a handful of homemade panels. A continuous load of 1000 to 1200 Watts would be a killer.

What would you get out of three 125 Amp hour 12 Volt batteries? About 2kW hours AC. Do you see the problem?

Are you really willing to spend your time, effort, and money to build 580 Watts worth of panels to recharge them? Homemade panels cost about 3X what you can buy them for now, instead of the other way around.

This is why the initial question we ask is "Why do you want to go solar?" In your case it's because you want to learn about it. Well that's lesson #1: it's expensive.

You would probably be better off reworking the solar on your RV so that it gives you some functional value.

ggunn

Re: New System and Newbie Operator

Studiojedi wrote: »

Hello,
Ive been wanting to dive in deeper into solar and I guess am making the next step. I have used a lousy Harbor Freight 45watt system for my RV batteries in the past. Currently for now making some solar panels from cells( a gluton for punishment I know but Im not opposed to abandoning a bad project if that doesnt work out). My over all goal is to have my shop eventually go solar on my regular loads, but in stages. I am a computer/studio guy by trade and have a few servers, alarm system, and various routers/switches constantly running. Probably around 1000-1200 watts. My first stage to get my feet wet here is looking to do a 300-400 watt system for the routers, switches, and alarm system (which will be more than enough). I live in Central Oregon and we get 275+ days of sun a year. Cost of course is a consideration and I am looking at a 30amp MPPT charge controller, 500-600 watts of panels and 2-3 Walmart 29dc 12v 125ah deep cycle batteries. If for some reason there is too much a load I can reduce components to get to a point of equalibrium. I will be looking into a 500-750 watt pure sine wave inveter. I realize that solar setups can be a very subjective point of view but any real red flags with this approach/learning experience?

What do you mean by "go solar"? Do you mean that you want to get your shop totally off grid power, or do you want to install enough grid tied solar that your shop is net zero? If it's the former and you have dependable grid power available, you'll want to take a good hard look at what it's going to cost and whether or not it's worth it to you. Amortized over 20 years, off grid power is going to cost you about ten times what grid power would. Grid tied solar in this type of situation is a far better investment. In a word, the difference is batteries. I hope that I don't insult you by telling you this, but since it's your first post I won't assume that you already know it - you cannot power anything* off grid without batteries, and the amount of batteries you'll need is a critical and usually expensive design consideration.

*with the exception of things like DC water pumps which run only when the sun shines.

Studiojedi

Re: New System and Newbie Operator

Well like I said in my first post I would like my regular loads to be as grid independant as possible. I my computer repair workstations, monitors, ac, shop equipment are far beyond what I am wanting to do. But I can break up my regular loads into managable "wattage pieces"(ie 12watts for wifi, 37watts for this firewall, 240watts for that switch etc). My interest, hope, and goal is as solar continues to get more efficient and cost effective I will attain experience if and when it becomes feasable to power larger endeavors. As I said my only real experience comes with my RV trailer. And after upgrading my battery bank and changing out my amp guzzling halogen intertior lights to LED, along with more efficient TV, DVD, and coffee maker, etc I have been able to greatly improve run times. My panels are horribly lacking and that along with a MPPT charger will get me where I need there. But I also want to take on this project with my constant shop loads as well. I knew I would get crap about those walmart deep cycle batteries but so far they are performing very well for me. And from a cost standpoint unless I am missing some big discount store and cant find any 125ah rated batteries even close to the price. I do understand you get what you pay for but if they end up sucing Im only out $250 for 3 and that is kind of a drop in the bucket when it comes to solar endeavors.

inetdog

Re: New System and Newbie Operator

Studiojedi wrote: »

I knew I would get crap about those walmart deep cycle batteries but so far they are performing very well for me. And from a cost standpoint unless I am missing some big discount store and cant find any 125ah rated batteries even close to the price. I do understand you get what you pay for but if they end up sucing Im only out $250 for 3 and that is kind of a drop in the bucket when it comes to solar endeavors.

You will also hear the advice from some regulars to make your first battery set a cheap one, because the odds are that you will ruin it anyway, even if it is an expensive one! Make all of your mistakes early and then move on. :-)
The trick is to avoid expensive mistakes.

Studiojedi

Re: New System and Newbie Operator

I figured I could build mine with tempered glass, aluminum frame, and encapsulant for roughly a bit less....if they are really 3x cheaper where is a good place to get them and what brand? As far as my regular loads I am limited to what I have and they consume, but I can break it down into smaller chunks of wattage used. Like I said this is a starting point to get my feet wet and get some working knowledge of numbers and gear. Other than a stint in the Air Force my education for pc builds, repairs, networking, audio-studio engineering etc has been done with books, ideas, and help from guys like you. I kinda like it that way.

Studiojedi

Re: New System and Newbie Operator

Thats kinda what I thought too.

Cariboocoot

Re: New System and Newbie Operator

It's not a bad price for batteries. We frequently recommend people start out with "warehouse golf cart batteries if they can get them: lots of Amp hours for a little price.

The problems are: three parallel batteries gets to be problematic in keeping current even; 375 Amp hours @ 12 Volts doesn't run much.

An ordinary golf cart battery is about 220 Amp hours @ 6 Volts. Buy four, and you get two parallel strings of 220 for 440 Amp hours @ 12 Volts, even current sharing, and for not much money (sometimes you can get these for about $80, Sam's being one of the potential sources).

If you're interested in learning about this stuff with some eye towards the practical, consider what would be your lowest power essential loads. For instance keeping the lights on in case of a power outage so you don't trip and fall into that rack of expensive computers sending wires scattering everywhere in broken pieces.

Cariboocoot

Re: New System and Newbie Operator

Problems with homemade panels:

1). The individual cells you buy off e-bay or wherever are ones that have been rejected by manufacturers for not meeting specifications. This doesn't mean they don't work. It does mean they aren't all the same in spec. To be successful with the panel you need to use all cells with the same Voltage, current, and shunt resistance. You'd have to check and sort each one, just the way the companies do. Then remember the first sentence in this paragraph. Panels made from mismatched cells will work, but they will not work optimally.

2). Soldering tabs. Be prepared to toss a few cells in the trash when you can't get the heat right and the tabs fall off the cells. Sometimes you get lucky.

3). Low iron glass. You won't have it, which means whatever you put in front of your cells will drop the efficiency. Kyocera recently altered their glass on the 135 Watt panels and now they are 140 Watts.

4). Encapsulation. Somewhere on the forum is a thread where member rollandelliot researched these materials in depth. Even with the right goop, keeping all the contaminants out and getting a really weather-proof seal is a trick. Do it wrong and the panel fails.

5). Failed panels. You've just spent how long putting one together and it doesn't work. Worse, it bursts into flames (no joke). There is no warranty, the insurance will not cover any damage from non-listed panels or even if the panel is not at fault. Where are you then?

To build a small, experimental panel is okay. But when you need (or want) hundreds of Watts for a system it is not practical. Here is our host's listing of >100 Watt panels: http://www.solar-electric.com/hiposopa.html They are not always the cheapest. Sometimes you can find deals on close-out or blemished panels if you search the 'Net. Be very informed as to what you are buying and from whom.