(click pictures to enlarge)
I bought and installed the new batteries for Liberty yesterday. I will be writing about the where, what and why of the batteries in this post so I'll have a record of it in the years to come. For those not interested, now is the time to quit reading,,,:)
First let me qualify the things I'm about to say. I am not an electrical engineer and only have rudimentary understanding of electrical systems. Just enough understanding to
All RV's are a combination of AC current (like in your house) and DC current (like in your car). For example, in Liberty the air conditioners are AC and things like the water pump and lights are DC. The refrigerator and water heater are a little different in that they can run on either AC or propane, but when on propane, it needs about 1 amp of DC current every now and then. For the DC things in the RV to work while plugged in to shore power (AC), RV's come with a "converter/charger". It is used to convert AC power to DC power as well as to charge your batteries. So you see, if you always have electrical hookups, it is hard to tell what is AC and what is DC, because everything works without having to do anything special. In general, it is safe to say that the big power users like air conditioners, microwave, ceiling fan, electric water heater, etc need AC power while the smaller things use DC. So the next question is how do you use the electrical outlets, which are AC, to do very important tasks, like make coffee when boondocking (running on DC, batteries). That requires an "inverter", which is the opposite of the "converter" in that it changes DC current into AC current. Some RV's have large inverters installed so that everything runs in the RV when on batteries just the same as if it was connected to shore power. Liberty doesn't have an inverter so when I'm not plugged in to shore power, my AC things will not work. This means my coffee will have to be either, instant coffee using hot water heated on the stove using propane or an old fashioned "cowboy coffee pot". I used to have one of those many years ago when my family and I did a little, very little, tent camping. I do have a couple small, portable inverters that can be used to recharge my cell phone, laptop, etc.
Like I said, when I'm plugged into shore power, everything works in Liberty because the converter is doing its job. The next term to learn is "boondocking". It simply means to camp without using shore power. That can be in the desert, National Forests/Parks, driveways, walmart, etc. There hasn't been a lot of boondocking opportunities for me since I have mainly been traveling in the eastern half of the country. I have never purposely been without shore power, therefore the one battery that came with Liberty was enough for my needs. That is about to change since I'm now in the western part of the country. There are many more places to boondock. Although I may try it for a day or two, I don't plan to boondock for extended periods of time in the desert. There are places where you can just drive out into the desert and camp. Usually for a maximum of 14 days. I'm pretty sure that type of boondocking is not for me. But what I am planning to do is to camp in some of the National Parks and National Forests. Many of these places have campgrounds but without services at the campsite, like power, water or sewer. They are mainly parking spaces in some very pretty settings. When you camp in those places, you need to have your fresh water tank full, your waste tanks empty and your batteries fully charged.
The battery that came with Liberty is what I call a wet cell battery. It is the type that is usually found in your car, although this one was a little step above in that it was a marine battery. These type of batteries need to be checked on a regular basis and water added to them when needed. Of course, lazy ole me didn't do that because it didn't really matter to me at the time and by not doing so, the battery was probably on it's last legs. But now with some boondocking in my future, I needed a new battery. So, I did what every American does in a time like that; I Googled.
I was looking for what type and how many batteries I would need for my boondocking plans. My plans are to boondock for a few days then go to a campground with shore power to charge my batteries while exploring that area. This means I won't need a generator or solar panels. I know from past experience that I can easily go 5 to 7 days on one tank of fresh water and empty waste tanks. So, that gave me a goal on how much power I needed in the batteries. There are a lot of terms in dealing with electricity, like Watts, Amps, Volts etc. After reading everything I could find and asking a couple questions on some Forest River online forums, for me and my simple mind, it all boiled down to Amp*Hours. Each battery has a certain number of amp*hours that can be used before it is dead. For example, if you have an appliance that is drawing a 5 amp current hooked up to a 50 amp*hour battery, then theoretically you can run that appliance for 10 hours before the battery dies. But, (there's always a "but" isn't there) generally if you drain a battery more than roughly 50% of it's amp*hours, you will shorten it's life span and you will be buying a battery sooner. Without doing too much heavy duty figuring and generously rounding up, I guessed wildly that I would need about 10 amp*hours per day. That meant for 7 days of boondocking, I would need a battery bank of 70 amp*hours. But, knowing that I don't want to buy batteries too often, I will only drain my battery bank about 50% so that means I need a battery bank of at least 140 amp*hours.
Next is the type of battery to buy. Being lazy, I want a maintenance free battery so I don't have to mess with it unless it stops working. The best type of maintenance free battery is an AGM (Absorbed Glass Mat). It was designed so as to not have liquid inside. This works great for airplanes and boats so the liquid doesn't spill out when they move side to side. These type of batteries can be mounted on their sides if needed. They also charge faster, have a longer life span and don't expel toxic fumes while charging like the wet cells do. That means the compartment you mount them in doesn't have to be completely vented since the AGM's only expel a little hydrogen while charging. The only negative thing about them is their cost; more than twice the cost of wet cell batteries. Let me say here, that if you are of the type that will check and maintain your batteries in excellent condition, have plenty of time to recharge and don't mind replacing them more often, then by all means buy the wet cell batteries as they will work fine for you, especially if you only use your RV occasionally. I personally went with the lazy man's option.
So, I now know I need AGM batteries with at least 140 amp*hour capacity, but which brand, where can I buy them and can I install them myself? Again, after checking many sources, the brand most often mentioned as to the best in terms of reliability, design, long life and durability was Lifeline Batteries with Trojan Batteries coming in a close second. Lifeline has an excellent webpage with information on everything about batteries. Very good source of information. Their webpage also listed their distributors. That does not mean those distributors keep batteries in stock. They are expensive and they don't want the overhead, so some only order batteries for the customer which may take a week to get in. I found that out in Tucson. But Copperstate Battery in Phoenix is a hub for Lifeline and they have some in stock all the time. I planned to buy two-12-volt Lifeline GPL-27T batteries that would give me a total of 200 amp*hours. When I got to Copperstate, they had just sold their last 27's to a commercial customer but they offered me their 12 volt GPL-31T's for the same price as the 27's. The two 31's gives me a total of 210 amp*hours. Remember though, recharging at 50% gives me about 105 usable amp*hours. They also made up some cables on-site for me to connect the two batteries in parallel. From high school science class, batteries in parallel adds their amps but not their voltage while batteries in series adds their voltage but not their amps. I wonder if they still teach that in school today. I could have went with 6 volt batteries with two connected in series to give the required 12 volts, but I decided to stay with the individual 12 volt batteries.
Each GPL-31T battery weighs about 65 pounds. I decided to put them in the location where the original battery was placed. I toyed with the idea of moving them to a different location inside Liberty but decided against it. I turned the converter off at the breaker box, pushed the battery disconnect and removed the old wet cell battery. I checked the connections of all the wires and found one that was loose. Apparently it had been that way for a while. It looked as though whoever installed it had cross-treaded the nut and the connection was never able to be tightened. I didn't have one of those connections so I improvised and connected the wires directly. I think it will be ok, but time will tell. The lower part of the plastic box that the old battery was sitting in was bolted to the frame of the compartment with the bolt heads sticking up. I didn't like that set up because with the possible bouncing and moving around, those bolt heads could wear a hole in the plastic body of the batteries. I cut some 1X2 peices of wood and laid them in the bottom half of the old battery box to protect the new battery from the bolt heads. This set-up was very secure and would not move while I was traveling. I set the second battery next to the first and ran a strap around the old battery box and the second battery. I wired the batteries in parallel and turned everything back on. Nothing exploded or got hot after several hours so I guess I did the job good enough.
After a couple of hours of buying, installing and one bumped head, I was in business. I even found a portable volt meter so I can check the status of the batteries from inside of Liberty. This is where it gets a little more confusing. Although, with me, it is all about amp*hours, the easiest and cheapest way to check the charge on a battery is by checking its voltage. Using the information provided by Lifeline, I will need to recharge when the voltage gets to about 12.2 volts. This morning, the volt meter was reading 13.6 volts which is in the range of the "float charging" of my converter/charger so I figure I'm at full charge. I verified the portable volt meter with my multimeter tester and they are within one tenth of each other, so I think I'm good.
I don't have any plans to boondock yet, but I'm set up and ready if one comes along. The weather plays a big part in boondocking too. Without A/C, I don't want to boondock in very hot weather and without being able to use my ceramic heaters due to the power draw, I don't want to camp in freezing weather either. We will see how it all pans out in the future.
|The original wet cell. It's the best picture I could get with the battery still in place.|
|The old battery and battery box has been removed and the picture is of the wiring. The little connector in the middle is the one with the cross-threaded nut. The name on the side is a "short-stop". Hopefully, I won't need it.|
|The two batteries are installed and all wiring completed. I think it will work just fine.|
|The portable volt meter plugged into the cigarette lighter inside of Liberty. The 13.6 volts has been steady since last night.|
|A picture of the campsite. The batteries went inside the door beneath the king-pin overhang. That is where I bumped my head. It will heal up in a couple days, until then, I can wear a hat. :)|
Ya'll take care of each other. I'll Cya down the road.