DIY Solar Panels

[91cavgt]

Off the grid solar basics will be covered tomorrow. It's too late and I'm too tired to do it tonight. That sponge bath I had earlier took a lot out of me.

[91cavgt]

Off the grid. What does that mean? It means you are not connected to the power/information grid that our lives revolve around. Like when we go hunting, a lot of us prefer to leave the comforts of technology back at home. But there are some comforts that are very nice to have and could be very beneficial.

So, let's talk about off the grid power setups. Most of us know that there is a trade off for being off the grid. If you want power for off the grid, unless you are going to shell out a small fortune, you will not have all the creature comforts that the grid provides. However, lights, fans, short term refrigeration, charging of wireless items, and other small conveniences of home can be attained.

There are 2 trains of thought when it comes to off the grid setups when trying to size one for you. Either go as big as you can comfortably afford and just deal with not having a few creature comforts, or go really big and have your off the grid setup run everything in your daily life. Most of the hard working average Joe types prefer the first route. So, where do you start?

The back bone to your off the grid setup is a battery bank. If you choose poorly with wrong batteries or the wrong number of batteries then you could end up with nothing else working quit right. So a battery is a battery is a battery, right? Nope, not at all. For example, old used car batteries would be VERY bad for solar use as they are designed to give out a LOT of power over a short period of time and will not last long at all in a setup where a moderate amount of power is asked from them for any length of time. Not only that, but you would also have to constantly monitor water levels in the batteries to prevent deadly hydrogen gas buildup.

So what batteries are best? That's kind of like asking what caliber round is best for deer hunting. There's a whole lot of opinions out there. Some are right, some are wrong, but here is some info on batteries so you can make your own judgement.

Flooded lead acid batteries are common in golf carts, and in solar setups. They produce a lot of power over a long period of time and have a decent lifespan if treated right. You do always have to make sure the water levels are full in the cells though. These also can not be mounted inside a building because they do out-gas. If you do use these in a building then they need to be well vented to the outside.

Deep cycle batteries are very similar to flooded lead acid batteries. Deep cycle batteries are often smaller than the flooded lead acid counterparts and can be found for cheaper, only because they are smaller and do not put out as much power as flooded lead acid batteries. For example, Academy has a special right now on a 100 amp/hr(more on this rating soon) deep cycle battery for $80. That is a pretty good price! Just like the flooded lead acid batteries though, these need to be vented to the outside as well.

Sealed, AbsorbedGlassMat(AGM), or gell cell batteries are similar in characteristics to the deep cycle batteries as these are typically a smaller battery but you do not have to monitor these batteries as they are completely sealed. Because they are completely sealed, they can be mounted and used in any physical orientation, and they are safe to use indoors without outside ventilation. If properly maintained, these types of batteries have about the longest life span. For example, I have a pair of Hawker brand, 50 amp/hr batteries that have a build date of the year 2000. I have one of these and my brother currently has the other one and both of them are still working great, even with being 14 years old!!

So what battery is best for you? Well, if you intend to have your off grid setup attached to your RV then it makes sense to go with a couple of the deep cycle wet cell batteries. Different setups will yield one of the different types of batteries to work best for you. I for one have a 400 amp/hr battery bank of AGM batteries because I needed them to be mounted inside a building.

[91cavgt]

So what is this amp/hr deal that I keep hearing about? It is kind of like the horse power rating of a battery. A batteries amp rating is rated over a period of 20 hours. So, we'll use a 100 amp/hr rating battery as an example. A 100 amp/hr battery can supply 5 amps of current, continuously for 20 hours (100 divided by 20 = 5). After that 20 hours, the battery is going to need to be recharged fully in order to prevent long term battery damage. So, it is always best to have slightly more battery than what you think you might need.

So how much power am I going to use? Well, only you knows what that will be. Here is a chart of common 12 volt items found on a boat, and what it's corresponding amp draw is;

12-VOLT ITEM
Bilge Pump (500 gph) ——— 2.0 AMP Draw
Bilge Pump (1000 gph) ——– 2.9 AMP Draw
Bilge Pump (1500 gph) ——– 4.9 AMP Draw
Bilge Pump (2000 gph) ——– 8.4 AMP Draw

Navigation Lights (3 mile) — 1.5 AMP Draw
Live Well Pump ————— 7.0 AMP Draw
Fresh Water Pump————– 4.0 AMP Draw
Refrigerator (12v) ———— 6.0 AMP Draw
Ice Maker——————— 6.0 AMP Draw
Head (Macerator) ————- 9.0 AMP Draw
Anchor Windlass (900lb) ——- 75 AMP Draw
12v. Housing Lighting——— 15 per 10 Watts AMP Draw
Spot Lights (100k cp) ——— 8.0 AMP Draw
Spreader Lights (3k cp)——- 3.0 AMP Draw
Radar (24 mile) ————– 5.0 AMP Draw
GPS ————————— 0.80 AMP Draw
LORAN————————- 0.70 AMP Draw
VHF Radio - transmit———- 6.0 AMP Draw
VHF Radio - receive———– 0.50 AMP Draw
Depth Sounder (LCD)———– 1.0 AMP Draw
Depth Sounder (Color)——— 3.0 AMP Draw
SSB - Transmit—————- 3.0 AMP Draw

INVERTERS*
SSB receive——————- 2.5 AMP Draw
Autopilot——————— 5.0 AMP Draw
Stereo (50 watt) ————– 0.50 AMP Draw
Fan————————— 1.0 AMP Draw

TROLLING MOTORS (12VOLT)
24lb Thrust——————- 27 AMP Draw
30lb Thrust——————- 30 AMP Draw
36lb Thrust——————- 36 AMP Draw
42lb Thrust——————- 40 AMP Draw
55lb Thrust——————- 55 AMP Draw




Now you know how much power you need, so now you can go buy the batteries, right? Not so fast. We need to make sure you can afford enough solar panels to keep these batteries charged up good.

[Axe Man]

Thanks for the info. I am interested in being able to power an RV if it doesn't break the bank. Lots to learn.

[91cavgt]

So solar panels. Which ones do I need to buy? That is a very hard question, about like trying to find out what battery type and size you need. For most affordable systems, the over all area that you have to mount the panes dictates which ones you can go with.

When I first got into solar, I went with a bunch of small, 15 watt 12 volt solar panels. I figured that by having a bunch of small panels, it would decrease the chance of a hail strike decreasing the over all electrical output compared to if I only had a couple of larger panels.

As time went on, I found that most all solar panels are rated for at least a 1/2" hail strike traveling at terminal velocity. Also, when mounting the panels, if you mount them perfectly horizontal then any hail strikes will have a direct hit on them. However, if you mount the panels at an angle, preferably aimed toward the sun, then the hail strikes will be more of a glancing blow as opposed to a direct strike.


Panels range greatly in price, size, and type. As stated earlier in this thread;

There are also several different kinds of solar panels. Amorphous, Monocrystalline, and Polycrystalline. Confused yet? Don't worry as it's really quit easy. Amorphous solar panels are typically the cheapest, however they only have about a 5 year life span. Monocrystalline panels are about the best you can buy as they are the most efficient with Polycrystalline panels being the second most efficient. Both Polycrystalline and Monocrystalline panels both typically have a 25 year warranty for power output and are the best for the long term setups.

The 45 watt kit from Harbor Freight is good for entry level systems as it comes with most things you need (just add a battery). The solar panels in the Hardor Freight kit are amorphic 15 watt panels. You can get this entry level kit for about $150 with a coupon. This 45 watt kit will give you a realistic 2.5 amps of current in direct sunlight which is barely good enough to trickle charge a single battery.

However, for the same $150, you can go online on Ebay and find these solar panels; http://www.ebay.com/itm/Solar-Panel-...item3f298e4e6c
This setup gives 100 watts of power, quit a bit more and a little more useable 5 amps of current to recharge the battery(s). This panel also comes with a charge controller.


Wait a minute, we haven't talked about charge controllers. Well, hold on to your horses, we'll get to it in a bit. There is more information to talk about regarding solar panels first.

[91cavgt]

So there are a LOT of places to buy solar panels from, but you just have to keep in mind that typically, shipping will be extra. Ebay, Amazon, sometimes you can find solar panels on Craigslist, a place called solarblvd.com is another good place to buy solar panels. Just be careful if you buy panels off of Craigslist to make sure the panels are NOT damaged! I am finding more frequently broken panels being sold on Craigslist.

So when you start looking more into solar panels, you will see that the most common ones come in 12 volt models or 24 volt models. The benefit in going with the higher voltage models is that you don't have to run as large of a cable from the panels to the charge controller.

For example, let's say that you have 200 watts of panels at 12 volts and your buddy down the street also has 200 watts of panels, but at 24 volts. Both of your charge controllers are mounted 30 feet away from the charge controller. Using this calculator for wire size;

http://www.freesunpower.com/wire_calc.php

We find that your 200 watt 12 volt system will need at least 10 gauge wire for an allowable 5% drop in power over the 30' run.

However, your friend's same 200 watt setup, but at 24 volts will only need 14 gauge wire for only a 4% drop in power over the same 30' run.

So, in the long run, having higher voltage solar panels will make it so that you don't need to run nearly as large of wires from the solar panels to the charge controller. This typically frees up a little extra money in some people's budget to go with the higher voltage panels instead. All else fails, you can always buy the 12 volt panels, then wire 2 of them in series to get 24 volts. If you have any questions on wiring up of series or parellel then just let me know.

[91cavgt]

Charge controllers are VERY important for a solar panel setup. A charge controller controls the solar panel output and then sends it on to the battery(s). If you do not run a charge controller then there is no way to automatically disconnect the solar panels when the battery bank is charged. So, if you overcharge your battery bank, you will severely decrease it's lifespan and overall amount of power it is able to give you.

There are 2 primary types of charge controllers for off the grid solar setups;

Pulse Width Modulated(PWM) and Maximum Power Point Tracking (MPPT). PWM charge controllers are typically the cheaper models, and they will require that your solar panels be the same voltage rating as your battery bank. So, with a PWM charge controller, a 12 volt solar panel must be connected to a 12 volt battery bank. Once the battery bank gets up to charge, the charge controller will change from charger to maintainer.

With a MPPT charge controller, you can connect a 24 volt solar panel up to a 12 volt battery bank! This increases the options you have with wiring (higher voltage means lower amperage thus, smaller wire). I just purchased an MPPT controller that can take in up to 100 volt on the solar panel, and can work with either 12 volt or 24 volt battery banks. So the MPPT charge controllers are more versatile, but as a consequence, they are also more expensive.

For example;

Here is a PWM charge controller that is rated for 20 amps for $30.
http://www.ebay.com/itm/Instapark-PR...item2327b0387f

Here is an MPPT charge controller that is also rated at 20 amps, for right at $100!!

http://www.ebay.com/itm/141024539209...84.m1497.l2649

[horns07]

Following.

[pure lefty]

I am sure glad you posted this thread.

[91cavgt]

Tomorrow I'll try to cover wiring and power inverters in a little more detail.

[one2bowhunt]

Thanks! Following

[91cavgt]

Wire. Wire plays a HUGE part in a well designed solar setup. What size wire do I need for my setup is a VERY common question. You can't just use lamp wire for everything. In wiring, the smaller the gauge of the wire the larger the number. 16 gauge wire is actually smaller in size than 12 gauge wire. 16 gauge wire is about equal to lamp cord wire. 10 gauge wire is equal to the REALLY cheap jump start cables that you can buy. 4 gauge wire is pretty common for welding wire. Take this chart for example;



This chart shows that typical lamp cord (which is around 18-16 gauge) is only rated to handle a maximum of 5 amps, and for only 15 feet max. Small wire in the range of about 12-16 gauge is acceptable for connecting solar panels to the charge controller for short distances, as long as the length of the cable and the amperage going through it is on the chart then you're ok.

For going from the charge controller to the battery bank, I prefer to use a larger gauge wire, depending on your particular system needs of course. With my systems in the past, I have used 12 to 10 gauge wire for this. When connecting your charge controller to the battery bank, if you only have 1 battery then just wire it up to the + and - sides on the battery. If you are running multiple batteries then how you connected up your charge controller really depends on how you have the batteries wired. The most common way of running multiple batteries is in parallel though. This is where the + from one battery is connected to the + of the other battery, and on the - side, the - of one battery is connected to the - on the other battery. You can continue this for as many batteries as you want in a battery bank and you will end up with the exact same voltage for the group of batteries as a whole as you would with just one battery. For this kind of setup, you only have to connect the charge controller to 1 battery and all of the batteries will end up with an equal charge. When wiring batteries in series, it is a lot more confusing so I won't go into detail about it here. You can PM me and I can try to explain.

Now when it comes to the wiring from the battery bank to high power consuming devices like a power inverter, you need some HEFTY wiring AND PROPER wire ends. With a small, 800 watt continuous power square wave inverter, I ran 4 gauge wire for it. For my 1,000 watt pure sine wave inverter though, I went over kill and went with 00 gauge wire! When it comes to connecting items that have large power requirements, you can't use wire nuts and be ok! You need the proper, large gauge terminals that crimp on to the wire.

Now, you can't just connect everything up and expect every single component to work for it's entire lifespan and never short out. So, we need to add in some protection for your electrical devices and for the wiring. This means fuses for low powered devices and either really large fuses or circuit breakers for the larger items. I ran a 250 amp circuit breaker on my 1,000 watt power inverter for example. I had each one of my batteries in the battery bank with a 50 amp circuit breaker, and then I bought a small distribution block so I could have everything else fused that is powered off of the battery bank.

It is possible to run a system for years with no fuses or circuit breakers and never have a problem. However, if anything ever shorts out, having to replace the broken device and a blown fuse is a LOT better than having to replace your entire system, AND whatever else is around it because it all caught on fire. Circuit protection is no joke.

[Etxbuckman]

Subscribed. This is great stuff.

[91cavgt]

Power inverters. Once again, there are a LOT of power inverters out there, and there is a lot to know about power inverters. There are everything from power inverters that will fit in your truck cup holder to ones that need multiple, large gauge power wires connected to it and a WHOLE LOT in between. So, let's chat about the different types of power inverters.

The ONLY difference between these different types of power inverters is how clean the power is that the inverter produces. Square wave inverters, modified sine wave inverters, and pure sine wave inverters are the 3 different types of power inverters.

So what is the difference between those 3 different types of power inverters?

Square wave inverters are typically the cheapest first off. Square wave inverters are going to have the dirtiest power out of all of them. Ok, so what does that mean in the real life? It means that items that need clean power will either not run off of a square wave inverter, or if they do run then the power inverter could do damage to the sensitive electronics. Take any item that charges a lithium battery for example. Most lithium battery chargers will not work at all on square wave inverters. So what will work on a square wave inverter? Lights, fans, and most power tools will run just fine. The really bad thing about square wave inverters is that you have to look in the specifications of the inverter to find out if it is a square wave inverter.


Modified sine wave inverters are getting to be very common and are pretty affordable. They will run some sensitive electronic devices as the power is cleaner than a square wave inverter, but not as clean as a pure sine wave inverter. You can run devices like TVs, microwave ovens, most computers, and a majority of other devices off of these. They are by far the most popular power inverters to use because of the lower price but yet still some decent power.


Pure sine wave inverters on the other hand will produce power that is identical to your home electrical outlet (it may in fact be more stable). You can run pretty much any device you want to off of these pure sine wave inverters and you don't have to worry about damaging sensitive electronics, and lithium battery chargers will work on pure sine wave inverters. The down fall is that they will cost more.


No matter what power inverter you go to buy, look at the specifications to find out what type of power inverter it is. Also, plan ahead when buying a power inverter. You might not need a pure sine wave inverter now, but down the road you might need one. At bare minimum I would buy a modified sine wave inverter.


Keep in mind too that there are some things that you just don't want to plug into a power inverter. Items that produce heat are one thing that are HUGE power hogs! Most power inverter can not run a toaster, no matter what the power inverter's power rating. Toaster ovens, blow dryers, electric clothes dryers, electric heaters, all of those are items that VERY few power inverters can handle. Those that can handle it will use a consume a LOT of power to power them.

[91cavgt]

So, is there anything that I posted that you didn't quit catch or that you would like for me to go over again? Is there anything that I did not cover that y'all would like to hear about? Just post up and ask me!


Now my foot is telling me that it is time to take a pain pill and log off for a bit.