Deep Cycle Batteries Facts

For optimum battery performance only use deep-cycle batteries in an RV that has a Solar and/or Inverter system installed.

 Deep-cycle batteries fall into three categories:

• Wet cell (Lead Acid)
• Gel cell
• AGM Batteries (Absorbed Glass Mat)

High quality deep-cycle batteries are usually rated in Amp-hours (Ah) as opposed to cold cranking amps (CCA).

Wet Cell Batteries

Deep-cycle wet cell batteries have thick lead plates that are alloyed with antimony, and are flooded with an electrolyte and water mix. Wet cell batteries will give off gas as a natural result of charging, therefore the battery compartment should have some sort of ventilation. Wet cell batteries should never be installed in in living areas. Through daily recharges, over time water loss will occur. Your deep-cycle batteries water level should be checked monthly and topped off with distilled water. High quality deep-cycle wet cell batteries will offer good performance and are available in many dimensional sizes and Ah capacities.

Ah or amp hour is a unit of measure for a batteries storage capacity obtained by the amount of amps a battery can be discharged multiplied by the amount of hours at 80 degrees fahrenheit. For example a 100ah rated RV battery means that 5 amps can be discharged for 20 hours before the battery will fall below 10 volts.

Wet Cell Battery State of Charge Rates
100% charged = 12.6 volts
75% charged = 12.4 volts
50% charged = 12.2 volts
25% charged = 12 volts
0% charged = <11.8 volts

Hybrid Deep-cycle/Cranking type batteries are suitable for both engine starting and deep-cycle applications. Although not recommended, this type of battery will work as a coach storage battery, but will have a reduced life span if deeply discharged, which means that the batteries will have to be replaced sooner than a deep-cycle battery that is rated in Amp-hours. This hybrid type of battery is usually rated in cold cranking amps (CCA).

Gel Cell Batteries

Deep-cycle gel cell batteries are lead-acid batteries, but different in construction and chemistry than wet cell batteries. They offer unique features like: no maintenance, low self-discharge rate, and low internal resistance.

Gel cell batteries are sealed but the battery compartment still needs to be ventilated. These batteries will have slightly shorter life span than wet cell batteries. Gel cell batteries dimensional sizes and Ah capacities are more limited than wet cell.

Gel Cell Battery State of Charge Rates
100% charged = 12.95 volts
75% charged = 12.65 volts
50% charged = 12.35 volts
25% charged = 12 volts
0% charged = <11.8 volts

AGM Batteries (Absorbed Glass Mat)

Deep-cycle AGM batteries are maintenance free lead-acid batteries. They are similar to gel cell batteries and have the performance and charge rate of
wet cell batteries, although they are much higher in cost than wet cell batteries. Like Gel Cell batteries, AGM batteries are sealed but still need to be ventilated. AGM batteries are available in limited dimensional sizes and capacities.

Due not confuse AGM or Gel Cell batteries with standard maintenance-free batteries. Maintenance-free batteries have calcium plates alloyed with lead and will not hold up to repeated discharging.

AGM Battery State of Charge Rates
100% charged = 12.9 volts
75% charged = 12.6 volts
50% charged = 12.3 volts
25% charged = 12 volts
0% charged = <11.8 volts

Charging Deep-cycle Batteries

Because of the charging characteristics of deep-cycle batteries, a vehicles charging system will only charge most deep-cycle batteries 80% to 85% of their maximum capacity. Depending on your daily use, a solar system installed by RV Solar Connection will charge most deep-cycle batteries to 100% full charge before the day is out during spring and summer months.

For longest battery life it is recommended that deep-cycle batteries be charged when the batteries capacity has reached 50%. A solar battery charging system from RV Solar Connection will automatically take care of this for you 365 days a year.

Deep-cycle batteries can be discharged to about 80% of capacity before damage may occur.

For a free quote on installing a battery charging system in your RV visit Contact Us and give Randy or Jim a call.