Step 3: Smart Ways to Increase Your Battery Storage Capacity
Before purchasing or upgrading battery storage you should have read and implement the suggestions in the first two sections of our Solar guides.
The next step to off-grid Scamping and/or going with a solar installation is to analyze your battery type/capacity and increase your storage capabilities.
We'll cover battery basics here and the coverage will expand as contributions and new technology comes on scene. In the meantime, for more in-depth understanding of 12v systems and batteries we recommend reading The 12v Side of Life Part 1 and 12v side of life Part 2
If you need help with battery questions or selection on your Scamp - Molded Fiberglass Travel Trailer, post your questions in our solar forum and lot's of experienced SOI Members will be happy to assist you.
Most RVs come from the factory with a single 12 volt Deep Cycle battery, usually Group size 24 or 27. In most cases, these batteries won’t be true Deep Cycle, but what is known as Hybrids. This provides enough storage capacity to operate the 12v systems for a few hours without being plugged into the Tow Vehicle or "Shore" power. While these batteries are adequate for many campers they are not going to supply enough power storage for extended boondocking or full time living situations where you would be using most of your 12v systems on a daily basis, for example: if you are camping in colder weather and you need to operate your furnace, you may find yourself wakening at 3:00 am, very cold and with a dead battery (ask me how I know this).
In order to monitor and analyze your power consumption there are a couple of simple options to monitor your battery voltage.
- Installing a top-end solution like the highly touted Victron BMV-712 Bluetooth Battery Monitor.
- Add a RV 12v cigarette lighter type plug.
At this stage, if you’ve determined your camping lifestyle is dictating a complete solar installation, I’d recommend the first step for serious boondockers. If you are doing light boondocking the second step will suffice because you’ll be installing a charge controller with your solar panels that will help monitor battery and usage. More on that in the next section.
Monitoring your battery is important because it lets you know the condition of your battery and it will let you know when your battery is out of power. 12v batteries should not be discharged below 50% because irreversible battery damage can occur. By-the-way, a 12 volt battery is 50% discharged when the voltage is at 12.2 volts (not at 6 volts as logic might suggest), by comparison, a fully charged battery is 12.7 volts. Never discharge your battery below 11.5 volts (80% discharge) because most batteries will not hold a charge after being drained so low due to internal cell damage.
Before we discuss ways to increase your power storage capacity we need to discuss battery types and ratings. First, you want to use a "Deep Cycle" or "Marine/Deep Cycle" battery in your Scamp or RV, these Deep Cycle batteries are built using heavier duty lead plates internally than a regular car or truck battery and have been designed especially for long, slow, discharge cycles.
Next, you need to know about the types of batteries, there are "Lead Acid" batteries, AGM batteries and Lithium Ion batteries. Lead Acid (aka wet cell) batteries are the most common type of battery, they can be maintenance free or they can require you to periodically check and maintain water levels inside the battery, they are the least expensive battery choice. AGM batteries (Absorptive Glass Mat) are usually more expensive but, they do offer some advantages over the Lead Acid/Wet Cell battery. AGM batteries will hold their charge longer in storage than a wet cell battery and they will often last longer. Lithium Ion batteries are a more expensive option, however, they do offer several advantages, specifically, they are much lighter and more energy dense than Lead Acid or AGM batteries, also, they can be discharged deeper (80%) and are designed for more discharge/charge cycles, consequently, they last longer than other deep cycle battery types.
There are several ways to increase your power storage capacity. First, let's talk about Amp Hours (abbreviated as Ah), this is the common rating for Deep Cycle batteries. Amp Hours are usually stated as: some number @ 20 hours. For example, 105 amps @ 20 hours means the battery has a 105 ah rating.
If your camper came with a "Group Size" 24 battery you have 70 to 85 Ah storage capacity if, your camper came with a group size 27 battery you have 85 to 105 Ah capacity. To increase your power storage you could upgrade to a larger group size battery. If you are conservative with the power you use (see "Solar Conversion", Step 1, regarding ways to reduce your power usage) this would probably translate into an extra day or two of boondocking without a battery recharge.
While upgrading your battery to a larger group size will offer some increased storage capacity, upgrading to a pair of 6 volt Golf Car(t) batteries (two 6v Batteries wired together = 12 volts) will more than double your power storage capacity and will allow you a deeper discharge on the batteries (70%) without ruining them. A pair of 6 volt Golf Cart batteries would be rated between 180 and 225 Ah, quite a significant increase in storage capacity compared to 12 volt batteries.
Special Note: Trojan Battery Corp now has a 330 Ah 6 volt battery.
Realistically, if you had a pair of 330 Ah batteries you could probably camp for a week to ten days without recharging your batteries. With this configuration you might not need to add Solar panels to your Scamp/RV.
The above discussion refers to Lead Acid (wet cell) and AGM (dry cell) batteries only. If you want to use Lithium Ion batteries to save weight you will need an upgraded power converter capable of charging your batteries at the voltages recommended by your battery manufacturer.
Before adding Solar panels to your Scamp/RV I would recommend upgrading your on-board storage with a pair of 6 volt batteries to take advantage of their increased storage capacity.
I would also suggest something I call "Boondocking with full hookups" !! Basically you go camping and don't hook up to the power at the campsite. Camp like you would if you were boondocking and monitor your power consumption. By Boondocking like this you will be able to determine how long you and your family could boondock without Solar panels. This practical exercise will allow you to evaluate how long you could boondock on battery power alone. Worst case; you are awakened at 3:00 am, cold and with a dead battery, but, you have the ability to simply plug into shore power and go back to sleep.
Contributed by SOI Lifetime Member ManWithAVan