DC Battery Care, Maintenance & Charging


Electric powered scissor lifts are most often 24 volt DC systems using four 6 volt deep cycle batteries, connected in series to give us 24 volts. Batteries also act as part of the counterweight of the machine, so it is very important to install the correct battery. The minimum weight of these batteries is usually around 61 pounds per battery, but always check manufacturer’s parts and/or service manual for proper information. Because these are deep cycle batteries, they are made to be discharged to a rate of approximately 80% and then build back up. Optimum conditions include 8 hours usage time, 8 hours charging, and 8 hours cooling. Short charging, anything less than 3 hours on the charger, will shorten the life of the battery and just provide a surface charge.


There are three main types of batteries: Flooded, AGM, and Gel. All three types of batteries use an electrolyte solution to produce a chemical reaction to create electricity.


Flooded batteries are the most common and use a liquid electrolyte solution of sulphuric acid and water flooded around a network of interconnected lead-sponge plates in each cell of the battery. The larger the surface area of the lead sponge plate, the higher amp hour capacity (AHC) the battery will have.


Absorbent Glass Mat (AGM) batteries make use of a special glass mat made up of thin glass fibers. This is designed to absorb the electrolyte solution and prevent any leakage.


Gel batteries use a special type of silica gel that holds the electrolyte together. The thick consistency of the material allows electrons to flow freely from the plates.


There are some similarities between AGM and Gel batteries. The two batteries are classified as Valve Regulated Lead-Acid (VRLA) batteries. The oxygen produced on the positive plates of lead-acid batteries is absorbed by the negative plates. In turn, the negative plates produce water. This helps expel the heat from the chemical reaction produced by the electrolytes. Because of this, the user does not have to water these batteries, making them maintenance-free.


When it comes to comparing AGM and Gel batteries, there are a few things to consider. Gel batteries tend to lose power faster than AGM batteries, especially at lower temperatures. This is because of the gelled Thixotropic composition of the battery. AGM batteries work in extreme weather, making them suitable for power-hungry winter utilities such as snowmobiles. When it comes to Depth of Discharge (DoD), Gel batteries make use of acid better than AGM batteries. Acid protects the Gel batteries’ plates, enhancing their deep discharge applications. However, a Gel battery must be recharged correctly, or else it will suffer premature failure. A scar inside its jelly material can create packets that will corrode the plates.  AGM batteries are comparably less expensive than Gel batteries, but they present a longer life span and offer bigger bursts of amps when needed. These batteries work best in high-power usage. Flooded batteries are the least expensive of these batteries.


Each of these batteries have pros and cons, depending on their application. Proper maintenance and care will extend the life of each style of these batteries, extend the life of your equipment and reduce downtime. Clean, tight connections are a must. Do not, under any circumstances, use grease or petroleum jelly on battery connections. These will collect dirt and debris, which will also sweat themselves into the connections, causing poor connections and high resistance. There are products specifically designed to keep these areas clean and sealed and prevent corrosion.


When it comes to the charging process for each of these batteries, Flooded and AGM batteries use the same type of charger, while the Gel batteries require a different type of charger. C-Tech supplies new style high frequency battery chargers that can be set up for charging gel batteries. Failure to use the correct charger on gel batteries will significantly reduce the life of these batteries. When charging AGM batteries, just plug it into the charger, as these batteries are maintenance free and should not require the water be added. When charging flooded batteries, check to make sure that the tops of the plates have electrolyte solution over them. If not, add only enough water to cover the plates. Top off these batteries after charging is complete. The lead-sponge plates that are in flooded batteries suck up the electrolyte as the batteries are being discharged. When charging, it is like wringing out a sponge and the electrolyte level will increase. If you top off batteries before charging, you will cause boil over which will cause electrolyte solution to come out of the tops of the batteries and leak into the compartment and onto floor, causing numerous problems.


Battery types are a choice you have to make, depending on your application.


Battery care and maintenance is also a choice you have to make.

Need help selecting the correct batteries, battery chargers, or connectors? Contact the experts at C-Tech at 1-877-755-7311, email us at, or live chat with us on our website.