Solar Power (part 3) Wiring

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.

Let me know if you have specific questions.

 

Solar Power (part 2) Panels

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!

 RV SOLAR STORE

 

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.

How have you installed your panels?

Solar Power (part 1) Battery Bank

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

Appliance Wattage 15min 30min 1hr 3hrs
light 100   2 4 8 24
blender 300 6 12 . .
coffeemaker 1000 20 40 80 .
Refrigerator 750 . 21 42 126
microwave 1500 30 60 120 360
vacuum 1100 22 44 88 264

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

Batteries-Ratings & Size

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

  • Group 24: 10.75” x 6.82” x 9.4”
  • Group 27: 12.1” x 6.82” x 9.25”
  • Group 29: 13.2” x 6.75” x 9.2”
  • Group 30: 13.5” x 6.82” x 9.25”
  • Group 31: 13” x 6.82” x 9.44”
  • Group 34: 10.25” x 6.82” x 7.88”

Fifth Wheels

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.

Looking at Travel Trailer Floor Plans

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.