Frequently asked questions about batteries

What does deep cycle mean?
Deep cycle means using the battery in an application that will typically discharge 60% to 70% or more of the battery capacity. An automotive battery is an SLI (starting, lighting, ignition) battery. It’s plates are designed to deliver maximum power for a short duration. Starting a car typically discharges an SLI battery only 1% to 3%. When an SLI battery is used in a deep cycle application, or in a vehicle with heavy accessory loads, the battery life will be shortened proportionally to how deeply it is cycled on a regular basis.

When should I consider a deep cycle battery?
Any time you need the battery to supply all the operating power for a vehicle or other device. Additionally, deep cycle batteries should be used in vehicles that have heavy accessory loads where the alternator cannot maintain the battery in a fully charged condition. This is typical of large bow thrusters.

How do small batteries, such as the Optima & Odyssey produce high power?
This new range of engine start batteries have been specifically designed to provide extreme high current very quickly whilst maintaining a high stable voltage. This is only possible if internal resistance is very low. This is achieved by using pure lead for plate construction. Ordinary batteries use lead-calcium alloy plates with a higher resistance that limits power output in high rate applications. Usually very large and heavy batteries – generally in excess of 100Ah are specified to compensate for this limitation.
What are “dry” and what are “liquid” batteries?
The terms “dry battery” and “liquid battery” are restricted to primary systems and date from the early development of galvanic elements. At that time, a liquid cell consisted of an electrolyte-filled glass container into which electrochemically active electrodes were immersed. It was only later that unspillable cells which could be used in any position and had a completely different construction were introduced, these being similar to today’s primary batteries. These earlier cells were based on paste electrolytes. At that time they were known as dry batteries. In this sense today’s primary batteries are also dry batteries.

The term “liquid battery” is in principle still applicable to certain modern secondary batteries. For large stationary lead-acid or solar batteries, liquid sulfuric acid is preferred for the electrolyte. For mobile applications unspillable, maintenance-free lead-acid batteries are recommended and have been available for many years. Their sulfuric acid is immobilized by a gel (or a special microglass mat).

Are leak-proof semi-traction batteries available?
Yes, AGM and Gel batteries are readily available and becoming more popular due their ease of use and non-hazardous nature.

What type of charger should I buy?
An automatic charger offers the greatest convenience. Just plug the battery into the charger and the charger does the rest. Manual chargers, although equally effective at charging batteries, require a greater level of attention. Generally speaking, automatic chargers are priced higher than manual chargers.

Do you ever add acid to a battery?
Under normal operating conditions, you never need to add acid. Only distilled, deionized or approved water should be added to achieve the recommended level. When a battery is shipped in a dry state or accidental spillage occurs, electrolyte should be added to the battery. Once filled, a battery should only need periodic water addition.

What are common mistakes made by lead acid battery owners?
Undercharging: Generally caused by not allowing the charger to restore the battery to full state of charge after use. Continually operating the battery in a partial state of charge, or storing the battery in a discharged state, results in the formation of lead sulphate compounds on the plates. This condition is known as sulphation. Both of these conditions reduce the battery’s performance and may cause premature battery failure. Undercharging will also cause stratification.

Overcharging: Continuous charging causes accelerated corrosion of the positive plates, excessive water consumption, and in some cases, damaging temperatures within a lead acid battery. Deep cycle batteries should be charged after each discharge of more than 50% of the batteries rated capacity, and/or after prolonged storage of 30 days or more.