As I have said before, I know a little bit about a lot of stuff, if I need to know something I do the research for more detailed info. The following are just a few basic tips I have picked up along the way and hopefully will help someone avoid an avoidable problem or extend your time in the bush when not connected to power. I have included links to some great resources for a much more in depth study than I will attempt here. This subject can be quite technical and I am intentionally making this very brief, the links provide a lot more. Also remember some of this technology is changing rapidly.
I welcome any comments and/or corrections to anything that follows. Please do feel free to join the discussion.
Gel and AGM batteries do not require you to maintain water levels, they are virtually maintenance free. Lead acid batteries do require you to maintain water levels along with other issues that need to be considered. We choose gel cells but would make a different choice today. Battery technology is getting better all the time and who knows what will ultimately be available for the storage and use of electrical power.
Our battery configuration consists of four 6 volt gel cell batteries which are only three years old – there are better choices available today. These six volt batteries are making 12 volts, here is how: two wired in series + two wired in series makes two 12 volt batteries from four six volt batteries. Then you wire those two 12 volt banks to each other in parallel. The schematic below shows how. Wiring in series will double voltage and amperage stays the same, parallel leaves voltage and doubles amperage, so… What you have then is a 12 volt battery bank with about 440 amp hours but of the 440 amp hours only about 88 amp hours should be used before fully charging the batteries. Gel batteries don’t do well with deep discharge cycles.
12 volt battery bank
I’ll say it again, unfortunately it is not good to use more than 20% of that 440 amp hour charge without risking damage to those gel batteries. It is very important to keep them charged. Solar is an answer but we have backed off for now on that upgrade. We just do not spend THAT much time in the bush YET. Our Yamaha 2400 inverter generator keeps the batteries charged when we do.
It is also very important for the life of your 12 volt ‘stuff’ (motors etc.) to be operating them from a FULLY CHARGED battery bank. In fact we do not run slides unless we are connected to power, the converter sends a charge to the batteries. So we are either connected to the pigtail on the truck, the pedestal at the camp site or our Yamaha generator BEFORE we run the slides out or operate the leveling jacks. Call it extreme but I like to do the little things that avoid bigger problems later.
In our 5er we re-purposed the battery compartment and now use it for the inverter and any future additional inverters will go there also. The battery bank is inside a vented plastic container in the front basement utility compartment.
If your batteries are conventional ‘wet’ batteries, be sure to keep them filled with distilled water. Charging and the heat of summer can result in the need for frequent top offs for ‘wet’ batteries.
In a nutshell here is how solar works: Solar panels charge your batteries, your batteries provide 12 volt DC and some of that power goes to an inverter which converts DC to AC. The larger the inverter the more power you have available. There is a bunch more to it than that but be clear, solar panels do nothing but charge batteries. To have a sufficient system you need to know how much power YOU will need. That will tell you how many batteries, how many solar panels and what size inverter you need.
For a great overview of Solar there are some really good resources available. Here is a very in depth overview. It is a very technical subject and this is a long read so book mark it and dig in. When you are finished reading you will be all charged up!! (sorry, just could not resist!!)
Here are a couple more references that are very current and trusted sources, the first is Handy Bob, the second is the folks over at Technomadia. These are two more of many resources out there. They are two that I personally have high confidence in and in a market segment that is rapidly changing they both, at this time are very current.
Here is a guideline of power usage by device.
Air Conditioner 12.5 amps
Converter (with nothing in use) 1.5 amps
Electric Water Heater (6 Gals.) 12.5 amps
Electric Refrigerator 4.0 amps
Microwave Oven 12.5 amps
Electric Coffee Pot 9.0 amps
Toaster 10.0 amps
Hair Dryer 10.0 amps
TV 2.0 amps
Dirt Devil Hand Vacuum 2.0 amps
Electric Fry Pan 10.0 amps
Iron 10.0 amps
Food Processor 6.0 amps
Crock Pot 1.5 amps
Space Heater 12.5 amps
And remember for using your generator, watts / volts = amps
so my 2400 watt generator = 20 amps
* Watts / Volts = Amps
* Amps x Volts = Watts
Electrical capacity is expressed in Amp Hours. If you use a 2 amp appliance for 5 hours that’s 10 Amp Hours. Remember my batteries with 440 amp hours of which I should only use 20% before needing to fully charging them? That is 88 amp hours that I can safely use with that battery configuration. That is not really all that much usage. Use the list above to see the rate that various appliances will consume power and you can quickly see it is prudent to be conservative. Since we have LEDs in strategic locations and switch to propane for the fridge and hot water, take our cooking outside to the grill or use high demand appliances like the microwave or coffee pot when we are running the generator to charge the batteries, this works for us. We don’t use or need to use that much electricity when we are boon docking. See this link for determining your own energy needs with an energy audit.
This looks like a mess of wires but the orange one drops through a vent from below and plugs into the pedestal or the small inverter shown here if we are ever in a COLD environment, the other end is connected to a 40 watt light bulb near the water pump. That is just enough heat to keep the water pump and lines from freezing when temps are down to less than 30 overnight. (we don’t hang out where it is very cold very long…) That yellow cord goes up to an outlet in the stateroom above for my CPAP machine and plugs into the inverter when needed.
That little inverter is a 350 watt pure sine inverter. Very small and mostly for the use of my CPAP machine when we are not hooked up to a pedestal. We do also use the inverter to charge computers, phones etc. when we are in the bush. We only run the generator when we are charging the house batteries. There will likely be a day when we will go forward with a solar system, maybe in the next 12 to 18 months. Our desire to be out in the boonies continues to grow. That would then include a much larger inverter but make no mistake, you still do not get to run your Air Conditioner and other high power electrical devices, (heaters) like you were hooked to the power pedestal. However check out what is going on with the solar set up Chris and Cherie over at Technomadia have. They are blazing the trails with cutting edge stuff. Keep in mind they do have an EXTREME and LEADING EDGE solar set up with a very cutting edge lithium battery bank. Even still they will need to be mindful of their electrical consumption.
Another example of the rapid evolution of technology is lighting. Fact is as a category of product it is about time, the basic light bulb has not changed in a hundred years. The incandescent lamp is a heater that makes light. LEDs for use in RVs are really great but still bleeding edge technology. The unfortunate thing is there are folks who have made mistakes or have been ‘burned’ by the purchase of an inferior product and now condemn LEDs. It’s a shame. Why and how is that? Well there are a lot of cheap products being pawned as quality, be careful what you buy and do a bit of research before you do buy.
Miss-use is also a factor in LEDs getting a bad rap, same as with motors LEDs will not tolerate wide fluctuations in voltage. In other words keep your batteries charged. I did see a listing of a brand of LED targeting the RV market. They are supposedly designed to be more tolerant of a range of voltages, I can’t however find the brand I saw that listed that feature, it’s been a while.
Color temp is another issue, an incandescent lamp will be about 3500 kelvin, meaning it is on the warmer (red) end of the color spectrum. Many (not all) LEDs are a lot bluer (6500 kelvin) than that. Be sure to select the correct LED for your application. Also, do NOT use LEDs on a dimmable circuit if they are not SPECIFICALLY rated for dimming.
Why are LEDs so great? Well if you have found the right ones for the application, you are saving a huge amount of power. You do not need to run the generator as long to charge those batteries. You can have much more power available for other stuff. How much power do LEDs save? About ten to one. In other words if you have ten LEDs operating for one hour it is generally the same as having one incandescent lamp burning for the same hour. I’d say that is very… enlightening (get it, could not resist again, sorry!) LOL.
Like I said LEDs are changing and improving very fast. I have not purchased any in over two years and I am sure there are better sources than what I found at the time I purchased mine. I see a lot of folks with great reviews on LEDs they found on Amazon.com and that today would be where I would start a search.
This is a subject that books could be and are being written about. I have not even scratched the surface and intentionally kept this brief. Please do comment on what is important to you. If I don’t have the answer, I assure you I can get the answer.
That’s the readers digest version of 12Volt systems in your RV.
Stay tuned, and remember, TurnWhenTheRoadDoes.com
Keep your ‘wet’ batteries filled with water the EASY way.