Empyreal Solar - Batteries

Deep Cycle Batteries

Deep cycle batteries are the heart of any mobile power system and provide electrical storage for you to use any time you need it. There are various types of deep cycle batteries that will cater to your specific needs.

Lead Acid Deep Cycle

A lead acid deep cycle battery consists primarily of lead plates and acid mixed together in a series of cells which create a galvanic effect. This mixture creates an electrochemical reaction which can produce an electric current. This is what we typically call a lead acid Battery and are the most common batteries used in RVs. They come in 6 and 12 volt varieties that vary in size and reserve capacity, and must be ventilated to the outside air.

Gel Cells and AGM (Absorbed Glass Mat)

Other types of deep cycle batteries used in RVs and boats are Absorbed Glass Mat (AGM), and Gel-Cells. These types are more expensive than regular lead-acid batteries because they are sealed, which means they cannot spill battery acid when tipped over allowing the user to mount them horizonally, vertically, or even upside down! AGM and Gel batteries are ideal for situations where the batteries do not have adequate ventilation to the outside air.

Many RVers prefer the use of AGM and Gel due to their rugged sustainability in harsh conditions. AGM and Gel batteries are very heavy, and can handle extreme temperatures and vibration which is why they are a good choice for mobile applications.

Lithium Iron Phosphate (LiFePo4)

A new battery technology that is taking the RV world by storm are Lithium Iron Phosphate batteries, also referred to as LiFePO4. These batteries offer incredible reserve capacity and sustainability when compared to traditional lead-acid or Gel. They also offer a huge gain in performance when supplying large amounts of amperage draw, and will not suffer from voltage drop as much as the traditional types of batteries. While these batteries have proven to be very good power storage, they are very expensive. A 100 Amp Hour Lithium battery can cost up to $1200 Canadian dollars! While lithium technology is quickly gaining popularity among RV owners, not all solar controllers are compatible with them. Be sure to consider this when choosing a solar system to keep them charged.

27 Series 12v Battery

AGM 27 Series 6 volt Golf Cart Battery LiFePO4

Are my current RV batteries good enough to run an inverter?

In most cases, yes. However the age, strength, capacity, and design of your batteries will vary in performance. Typically, two 6 volt batteries tied in series will perform better than one 12 volt battery for a large inverter. The lead plates inside a lead acid battery will determine the performance available for the application.

For example, lead acid batteries tend to have much thicker plates than standard "starting" batteries, and will be able to deliver greater amounts of power for a longer duration. Starting batteries have thinner plates which are ideal for quick bursts of current to start a large motor, and not as effective for long periods of continuous draw.

Deep cycle batteries are the best choice for battery storage because they have the ability to handle more cycles and last longer overall. Additionally, physical size and "Reserve Capacity" or "Amp Hours" are defining factors of what makes a battery acceptable for your application. The higher the Ah or RC rating, the longer the battery will last. The number of batteries you have connected will also increase the amount of time you will get out of your batteries.

Reserve Capacity Explained

Reserve Capacity is a term used to measure the amount of time you can get out of a battery at a 25 Amp draw.

25 Amps is actually quite a substantial drain on a battery when put into perspective. An easy way to visualize this amount of draw would be to imagine 16 small incandescent lights burning at the same time. Each of these lights draws a little over 1.5 Amps. If your battery has a reserve capacity of 160 minutes, your battery would be drained in a little over 160 minutes. (16 lights x 1.5 Amps = 24 Amps.

Series and Parallel

If you are wondering what these terms mean in the battery world, here is an easy way to understand what they mean, and how they apply to any situation.

Note: This is only recommended with batteries that are identical in voltage, reserve capacity, amp hours, and physical size for long periods of time. Do not mix batteries of different size or voltage. Only in instances where the connection is brief (such as jumping a car battery from another in parallel) will different battery size hookups be acceptable. Long term connections will cause problems.

Series Battery Hookup

When you hook two batteries together in series, you are essentially doubling the voltage.
Example: Two 6 volt golf cart batteries with 445 minutes reserve capacity (each) tied in series.
It would look like this: (6v @ 445min + 6v @ 445min = 12v @ 445 minutes reserve capacity)

Series Battery Hookup

Parallel Battery Hookup

When you hook two batteries together in parallel, you are essentially doubling the reserve capacity.
Example: Two 12 volt deep cycle batteries with 160 minutes reserve capacity (each) tied in parallel.
It would look like this: (12v @ 160min + 12v @ 160min = 12v @ 320 minutes reserve capacity)

Parallel Battery Hookup