I knew that when we bought our travel trailer that it had a deep cycle battery. I did not think much about that until this past weekend.

So, first, a little technical information.

Both car batteries and deep cycle batteries are lead-acid batteries that use exactly the same chemistry for their operation. The difference is in the way that the batteries optimize their design.

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. Used in this way, a car battery can last a number of years. To achieve a large amount of current, a car battery uses thin plates in order to increase its surface area.

A deep cycle battery is designed to provide a steady amount of current over a long period of time. A deep cycle battery can provide a surge when needed, but nothing like the surge a car battery can. 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 thicker plates.

A car battery typically has two ratings:

  1.  CCA (Cold Cranking Amps) – The number of amps that the battery can produce at 32 degrees F (0 degrees C) for 30 seconds
  2.  RC (Reserve Capacity) – The number of minutes that the battery can deliver 25 amps while keeping its voltage above 10.5 volts

Typically, a deep cycle battery will have two or three times the RC of a car battery, but will deliver one-half or three-quarters the CCAs. In addition, a deep cycle battery can withstand several hundred total discharge/recharge cycles, while a car battery is not designed to be totally discharged.

Another thing to know is that deep cycle batteries can be “trickle charged.” Our travel trailer has a solar panel that is intended to trickle charge the battery and, up until recently, that was working just fine.

A couple of months ago, we got a covered spot in our community RV storage lot. I was worried that, because the spot was covered, the solar panel would not charge the battery. Lo and behold, when we went to move the trailer, the electronic jack did not work. So, I backed our truck up, plugged in the trailer to the truck, and after a few minutes everything worked. Afterward, we moved the trailer to an uncovered spot.

Problem solved, right?


We had to get the trailer inspected this month. When we hooked up the trailer, nothing worked. I tried plugging it in to the truck, but, again, nothing worked. The battery was dead. I had to crank up the jack by hand, something that is not necessarily very easy.

Like many, if not most, travel trailers, our Forest River Shockwave had an Interstate Deep-Cycle RV Batteries. Here is what Interstate has to say about their batteries: Our deep-cycle RV batteries offer strong, reliable power to bring the comforts of home, like cooking appliances and lights, to the great outdoors whether the RV motor is on or off.

Here is what Interstate does not say about the type of battery we have: it is a wet cell battery to which you occasionally have to add water.

What? The last time I had to add water to a battery was about 40 years ago.

Of course, our Forest River Shockwave user manual said nothing – ABSOLUTELY NOTHING – about battery care.

Our trailer also had a battery disconnect switch installed. We did not know what it was for and did not think much about it. Once again, our Forest River Shockwave user manual said nothing – ABSOLUTELY NOTHING – the disconnect switch.

So, what is a disconnect for? The disconnect should be turned off when you store your camper your battery discharges more slowly. Mind you, they’ll still discharge spontaneously over the course of several weeks, but with the switch off it’ll take longer. Keeping the battery off during storage helps prevents the battery from being completely discharged during storage from constant drains from such items as TV antenna amplifiers, Propane Detectors, etc.

The good news is that our solar panel is connected directly to the battery, so it will still get the trickle charge and will not discharge very quickly. We will still have to

Well, we eventually got the trailer hooked up and took it to an RV repair place. We discovered that not only was the battery dead, but the connections to the battery and solar panel were corroded. The repair guy fixed those for us as well.

I asked the repair place why wet cell batteries were used in travel trailers. The answer will shock you – they are cheaper than gel batteries. It is that simple.

So, if you have a battery disconnect switch, use it when storing your trailer, or simply disconnect the battery.

My guess is that most of you already knew this. We did not.