In part 2 of this series I added a video that showed you how to wire photovoltaic cells together. In this post I will describe the best practice to connect the entire system together (batteries, regulator, panels).
Open space on your roof, and the number of panels you decide to install (typically 2) will determine where on your roof you can install solar panels. It is best to find the shortest wiring distance as possible from the panels to the battery bank.
8 gauge wire is the ideal size to use for your entire solar system. It will handle the fluctuating current best. Wires should be run inside flexible conduit to protect them from the sun’s UV rays. If you can run the wires through an existing vent such as the refrigerator it is better than drilling holes that could leak over time.
If installing more then one panel wire them in parallel. Solar panels do not provide consistent current, therefore a regulator is required to make sure batteries are not over charged. Panels are wired to the regulator, both positive and negative wires run into the regulator (a.k.a charge controller). A fuse or breaker should be installed on the positive wire between the regulator and the batteries. The fuse or breaker should be rated 5amps higher than the capacity of the panels, and then to the corresponding battery terminals. From the batteries the standard RV wiring is sufficient to have DC power that runs lights and some other appliances. From the batteries power runs into a inverter that powers larger appliances. Fuses or breakers should be placed between the batteries and the DC appliances and a fuse between the batteries and the inverter, if not already equipped.
Solar power is very attractive to many RV users. I have not installed a solar system yet, but plan to on my next RV. As I have been reading not all panels are created equal.
There are a lot of choices when it comes to selecting the components you’ll need for your RV Solar System. Some components are inexpensive and some cost an arm and a leg. Solar for RV’s is one of those things that you get what you pay for!
It is best to do some research to find out what panels will work best for your needs. Most solar experts suggest that 32-36 cell panels work best for RV use.
Things you will want to know for a RV installation is how durable are they, will they hold up when you drive on unpaved pothole filled roads? How well are they sealed, will they stay water tight in a heavy rain storm? Does the manufacture offer a warranty on the panel if it is installed on an RV? What are actual users of the panels saying about them?
As a DYI kinda guy I was intrigued by the idea of making my own panels. I found Green Power Science and appreciated their videos. I’m not convinced this is the best practice for a RV application, but it will give you a better understanding of solar panels.
Photovoltaic cells work at peak performance when they are faced directly into the sun. Unfortunately for RVers it is impractical to install a tracking system to keep the panels facing the sun, and the best location to install is the roof. The reality is that a panel will only be in the best location a couple hours a day, so keep this in mind when you are calculating the size of panel or panels you need.
The best way to mount the panels is to use Z brackets. This provides the necessary clearance between the roof and the panel. Use nuts and bolts between the Z brackets and the panels, so that they can be removed easily. RV REPAIR & MAINTENANCE MANUAL
Solar panel performance is affected by temperature this is a good reason to leave space, at least 2″ between the solar panel and the roof of your RV. You may want to install a wind deflector on the front of the panel so the panel isn’t lifted off the roof while driving.
My previous series was on understanding batteries and different ways to connect them. This series is a continuation, but moves into solar power set ups.
How do you know how much power you will need to generate and store for your RV needs? All appliances are rated in AC watts or amps. You can use the following formula to determine the DC amp hour draw for a 12 volt DC system:
(AC amps X 10) X 1.1 X hours of operation = DC amp-hours
(AC watts / 12) X 1.1 X hours of operation = DC amp-hours
This formula should be used to calculate the number of amp hours used between recharges for each appliance. Although a deep cycle can be discharged 80% without permanent damage it is best practice to allow for 50% cycling to improve battery longevity. Do this by calculating the amp hour usage between charging cycles and then use a battery bank twice that capacity.
Sample Power Consumption in 12 volt DC Amp hours
How many batteries do you have in your battery bank?
Some of the information contained in this post is from the Bob Livingston RV Repair & Maintenance Manual 1998
In my previous post I talked about the most common way RV batteries are wired when there are multiple batteries being used for electrical power in your RV. In this post I will describe series wiring. To wire two batteries in a series you connect the negative lead to the positive lead of the second battery. The open posts of each battery are connected to the load. Keep in mind each battery increases the voltage. In the example below two 6 volt batteries connected in a series create a 12 volt output.
Likewise if two 12 volt batteries were wired together in a series you would have a 24 volt output. Most autos, motor-homes, and travel trailers operate with 12 volts.
So why would you use two 6 volt batteries wired in a series to run a 12 volt system? I’ve heard competing opinions on this topic. There is one school of thought that says 6 volt golf cart batteries have higher reserve capacity and are constructed better for deep cycle discharges than a 12 volt deep cycle battery. There is another school of thought that says today’s 12 volt deep cycle batteries are constructed just as well as golf cart batteries.
There are two ways that batteries are typically wired, when there are multiple batteries being used for electrical power in your RV, that is either parallel or in a series. Parallel wiring is the most common. In this post I will describe parallel wiring. Parallel wiring does not increase the voltage, so when two 12 volt batteries are wired in this way it remains a 12 volt system. here is an example:
the effects can be seen when jump starting a car. The battery in the dead car remains 12-volts, and will still turn the starter, but only very slowly. Parallel wire a charged up 12-volt battery to the weak battery, and the dead car turns the starter at the required speed and the car starts immediately. Parallel wiring the charged battery to the weak battery did not alter the voltage – it remained a 12-volt system. The car’s system is 12-volt, and running greater voltages through that system would be destructive to it. To avoid increasing the voltage and damaging the vehicle, the batteries are simply parallel wired.
Two 12 volt batteries wired in parallel means that the positive post of each battery is connected to each other, and the negative posts are also connected together. Connecting the lead of the positive side of one battery to the load, and the lead of the other battery’s negative side to the load is the best practice. In parallel the voltage remains the same, but the amount of current available increases. Batteries connected in parallel should be the same brand, type, size, and age. Otherwise long-term capacity could be reduced. It is possible to connect more than two batteries together in parallel, but space is a major hindrance in a RV setting.
It is recommended that if you are going to wire more than two batteries together in a parallel system that they share a common positive connection, and a common negative connection. This will best allow each battery to be charged correctly. Again using the same brand, type, size, and age are important factors for the life of the batteries.
How many batteries do you use in your set-up (motor home, or travel trailer)? How long are you off the grid usually?
This is part two in my series on batteries. In part one I explored the different types of batteries used for RV’s. In this post I will do an overview of batteries-ratings and size.
Batteries are rated in one of two ways Amp Hours or Reserve Capacity. RC is the most common rating today.
Amp Hours (AH) .The amp hour rating is basically, how many amps the battery can deliver for how many hours before the battery is discharged. Amps times hours. 5 Amps X 20 Hours = 100Amp Hours or 20 Amps X 5 Hours = 100 Amp Hours.
Reserve Capacity (RC). Reserve Capacity rating is the number of minutes at 80 degrees F that the battery can deliver 25 amps until it drops below 10.5 volts. If you want to figure the amp hour rating you can multiply the RC rating by 60 percent. RC X 60 percent.
RC rating is established by the Battery Council International (BCI). Some manufacturers use a 15 or 22-amp discharge rate rather than 25-amp discharge. The lower discharge level allows a higher number of minutes to be displayed on the battery label which does not reflect the true RC minutes at a 25-amp discharge. According to interstate batteries
BATTERY CHART CHEAT SHEET The battery group size number listed for each battery in our chart represents the maximum dimensions of the battery and they are as follows: Maximum LENGTH x WIDTH x HEIGHT
I was talking with a friend about his RV set-up that allows him to go hunting and stay off the grid for weeks at a time. I thought this info might be helpful to RV’ers of all kinds so I’m going to do a series on batteries, which will lead into solar set-ups too. Just so you know I’ll be using references from the “RV Repair & Maintenance Manual” by Bob Livingston Trailer life books 1998.
The electrical system in your RV runs on two types of current; AC (alternating current) the same as your house, and DC (direct current) the same as your car. The stronger your DC system, the longer you can remain off the grid. The terms you need to understand are amps, watts, and volts. Most RV’s run on a 12 volt system, but did you know 2 – 6 volt batteries wired in a series will run your lights and appliances longer than 1 – 12 volt battery? Before you go and replace your batteries lets look at some basic information in this post, and the pros and cons along with the requirements of each set-up in posts to follow.
Batteries are not created equal
A car’s battery is designed to provide a very large amount of current for a short period of time. This surge of current is needed to turn the engine over during starting. Once the engine starts, the alternator provides all the power that the car needs, so a car battery may go through its entire life without ever being drained more than 20 percent of its total capacity.
A deep cycle battery is designed to provide a steady amount of current over a long period of time. A deep cycle battery is also designed to be deeply discharged over and over again, something that would ruin a car battery very quickly. To accomplish this, a deep cycle battery uses fewer, but thicker lead plates often coated with antimony or calcium, which increases the hardness of the plate.
Deep cycle batteries tend to cost more than the average car battery, but buying a regular car battery for your RV will only save you a few dollars on the short run. It will wear out quicker making it necessary to replace sooner.
We are preparing for a year long journey beginning next June (2012). We are currently looking at travel trailer floor plans just to figure out what will work well for us. Today we stopped by Curtis Trailer on Powell BLVD in Portland. As I mentioned in my previous post my family fell in love with a 5th wheel that is way out of our budget. In general I’m not a 5th wheel fan, but the space was amazing. Today we wanted to look more in our actual price range.
Honestly I wrote off 5th wheel trailers as an option because you lose pick-up bed space, and they tend to be harder to resell. I may-be changing my mind. I looked in several today and discovered they have more storage space than the typical travel trailer. That is a huge consideration for us with a family of 5 on a long journey. The salesman also mentioned that they tend to ride smoother, and are easier to connect/disconnect than hitch trailers. 5th wheels usually have a 12′ height compared to 10′ on a travel trailer. That 2′ makes a big difference in the size of exterior compartments and interior cabinet space.
The floor plan that we all liked was on a Keystone Outback, but either Keystone has discontinued the Outback 5th wheel or they have changed the name. I found the same floor plan on a Keystone Copper Canyon. This trailer is roughly 30K. That is more than we are going to spend. Unless we find an incredible deal, we expect to buy used. I love the brand new look and smell, but I don’t like losing value just by driving off the lot.
Next step is to find out what other models have that floor plan and when it was introduced into the market. Anyone know? I think I’m becoming a 5th wheel fan.
If you’ve been following us at all you know that in 9 months we plan to travel the US with our three boys for one year serving in different non-profit organizations along the way. We still have a lot to do to get ready. Things like sell existing vehicles, and purchase ones that will function best on a long journey. We also need to map out our travels. Keep following and you will see us reveal and put plans into place.
To involve our boys in the process we thought it would be fun to go look at some new travel trailers to see what floor plans we like and think would work to actually live in for a year. The reality is the majority of travel trailers are not intended to live in as a primary dwelling. There are some, but they are designed with the retired couple in mind. So we walked to B.Young RV, it’s not too far from where we live, and it was a nice day for a walk. Some of the features that are important to us are storage, room for individual space, and functional kitchen and bathroom.
The first trailer we looked at pushed the upper limits of our budget At 31 feet my wife said “I’m not sure this is big enough, I’ve seen trailer floor plans with more floor space in the bedroom.” Our two older boys were impressed that there was space for 2 TV’s and immediately commented how this would work great with the Xbox. They were ready to buy, not caring about how their belongings would fit, as long as the Xbox fit.
We toured several other models and floor plans, in fact we looked at every model they had available. We found one that that we all saw the potential. It met all the requirements we have in a year long road trip, except it is not even close to our budget. It was a 39 foot toy hauler starting at $90K.
This trailer has 4 queen size beds. Perfect for a family of 5. Because it’s a toy hauler there is lots of open space, well and it’s nearly 40 feet long.
Besides the fact that we would need to sell our house, which is not part of our plan, and purchase a semi-truck to pull it, it was perfect. I have to admit the the trim, the space, and the design were impressive.
The kitchen isn’t quite a full size, but it definitely rivals a apartment size kitchen. Yeah, this would work for a year.
The bedroom had lots of closet space compared to many travel trailers I’ve seen.
It’s tough to see the top of the line trailer, and then work your way down to reality.
Saving with credit sounds like a contradiction, and is but read on. Saving money usually requires us to stop using credit, but there is one way that using credit can save your money. We all want to save money, right? I do. Recently my wife and I were pleased to pay off all our credit cards. In our excitement to be debt free my wife was only using her debit card, no credit cards, for purchases both local and online. When I realized that she was using our debit card online, I suggested she not do that.
If your debit account is compromised and money is stolen your bank will work with you to identify the fraud and recover the loss, but the money is gone until the dispute is resolved. Small amounts may not impact your checking account much, but what about a significant loss of funds?
Well, just like I warned her (this isn’t a I told you so, but advice for others who are trying to live within their means) I got a text from my bank about a large purchase (that wasn’t mine). When I called to talk to the fraud department there were several purchases. Someone got our debit number and went on a shopping spree. Our account was emptied, but we still have bills to pay, and are responsible to make sure our account doesn’t overdraw.
If you want to save your money use a credit card for online purchases. If your account is compromised, the bank will work with you to identify the fraud and resolve the issue. The difference is that your credit limit is reduced until there is resolution, rather than funds from your checking account being depleted.
Have you had your debit card stolen from online activity? How long did it take for the dispute to be resolved?