We are fulltime RVers and boondock a lot in our motorhome. Boondocking is living normally with no hookups. My tracking indicates we have averaged 12 nights-per-month for the last three years. Therefore, we depend on our batteries to allow us to live normally and be comfortable. I used standard lead-acid battery in my previous coach but only used AGM batteries in my current coach.
We don’t deprive ourselves of anything, i.e., we don’t “rough it.” Roughing it (to us) means living uncomfortably. We fully expect the furnace to keep us toasty warm when needed and the wine to be perfectly chilled. This is our home—our only home. I expect the same level of comfort from our coach as I did when we lived in our house. When you mix our “comfort” and daily living requirements with boondocking, batteries become a critical factor in our lives. We can’t live our normal lifestyle without them.
How Does it Work?
There are both chassis batteries and coach batteries in a motorhome. Chassis batteries have a single function… cranking the vehicle’s engine or generator to start it. Chassis batteries are designed to deliver a lot of current for a short time. Coach (also called “house”) batteries are not part of the starting system. They provide current (DC) directly to things like the lights, and, DC current that is converted to 110V AC (normal “household” current) through an “inverter” (device commonly found in motorhomes). This conversion allows you to plug in and run normal “household” appliances such as a TV, cell phone charger, computer, or refrigerator to name a few. Ideally, coach batteries deliver a level of current over some period of time but any usage continually drains them. It take ten DC amps to make one AC amp.
The more power (current) an appliance requires to operate normally, the faster it will drain a battery. When the batteries are drained, they must be recharged to, again, be usable. Batteries can be recharged a fixed number of times before they are worn out.
The amount of current any appliance requires to operate normally is measured in “amps” (Amperes). Some appliances are considered “high-amp-draw.” This means they need more current to operate normally. One rule of thumb is any appliance that creates heat (e.g., microwave oven, hair dryer, coffee pot) is among the highest amp-draw group. Others, like a large, digital TV, are not considered high-amp-draw but require more amps than smaller appliances. Even lights need some level of current. Touching a hot halogen light is not recommended. It has a higher amp-draw than a fluorescent light (warm) which is a higher amp-draw than an LED bulb.
The RVer’s Boondocking Challenge
While boondocking, you are not hooked up to any utilities. Unless you continuously run your generator, you function with the power stored in the coach batteries until they reach some level of discharge. It is common for a motorhome to have an Automatic Generator Start (AGS) built in to the inverter. When the coach batteries reach some preset level of discharge, the generator automatically starts and begins to recharge the batteries. The AGS is also set to shut-off automatically when the batteries reach a preset level of recharge. Your inverter (with AGS) monitors this operation and when the generator stops, automatically switches the coach back to operating from the freshly recharged batteries. In theory and with plenty of fuel, you could boondock a long time (weeks) alternating between power from the coach batteries and the generator.
To add to this mix, don’t forget solar. Lots of RVers have a few solar panels mounted on top of their motorhome. These are supplemental and their purpose is to help keep the batteries from discharging rapidly, i.e., their discharge rate is slower because they are receiving some supplemental charge from the solar panels.
My RV Battery History
We ordered our 2007 Dynasty with AGM batteries instead of lead-acid. The AGMs were longer-lasting and had more charge/recharge cycles—important features for us since we boondock a lot. We took delivery of our coach December 2006.
AGM batteries require no maintenance. They are sealed units. You cannot add water or even check the level. The only possible thing to do is keep them clean. I kept mine clean and regularly checked the terminals for any corrosion.
In September 2009, I was in for RV service and one of the problems was my generator seemed to be starting frequently on AGS. I thought maybe I was drawing some “extra” phantom amps from somewhere and these were running my batteries down. Phantom amps are those little “power-draws” in every coach that continuously run behind the scenes. If you have a digital appliance (like a TV) that is “instant on,” it continues using power even though you turned it off and went to bed. Another example is the clock in your microwave—it runs all the time. We don’t think about these but, collectively, they draw power (current) from the batteries.
The service center called my battery manufacturer and it happened that a battery sales rep was in the area. He came out, tested my AGM coach batteries, and declared them to be nearly worn out. This was September 2009 (33 months of use). The manufacturer gave me a prorated price and I replaced my four, 12V AGM coach batteries, with new ones. The replacement cost was $958.80. That, friends, is a prorated cost of $29.00/month or about $1.00/day to use my coach batteries.
I had been noticing the same problem again during Spring 2011. I have now experienced boondocking only about 1.5–2 hours on battery before my AGS kicks on. This means my generator is running 2.5 hours (my setting) every 1.5–2 hours—more than 5 times in 24 hours—running a bit over half the time (12.5 hrs in 24). At a generator fuel usage of .25 gal/per hour, I am using a bit over three gallons of fuel to boondock 24 hours. That’s too much. I just filled with diesel at $3.89/gal, that is about $12.00/day for fuel cost to maintain these batteries.
So, I Was Sitting in a Seminar…
It was simply coincidence that I sat in on a lithium ion battery seminar. They got my attention and especially when they invited my wife up to the front and handed her the RV battery! She took it from the guy like it was a pillow. Actually, it weighed about 10 lbs.
After the Seminar
We met with the presenter—the marketing manager for Lithionics Battery. Their office is in Clearwater, Florida.
We talked and determined both our schedules allowed us to visit the company about a week later. It was agreed that we would bring our coach, park in their big, empty parking lot, they would take some measurements from our coach, and build a lithium ion battery specifically for our needs.
We finally arrived, parked as suggested (boondocking), and met and talked extensively with Steven Tartaglia, President. Steve has several patents pending on lithium ion batteries and also has a background in RVing. Steve explained the technical details of why these batteries are significantly better and longer lasting than lead-acid or AGMs.
[Author Note… Be sure and read the next section to learn about the actual build and installation in our coach. For questions, contact me directly at…