3 Stage Charge Controllers for Solar Battery Charging

Batteries have many different behaviors when it comes to charging and recharging. Ignoring these behaviors will greatly affect the lifespan of a battery. Many industrial applications today call for the use of a Sealed Lead Acid (SLA) Battery. In order to ensure equipment longevity, Vorp Energy uses state of the art 3-Stage Charge Controllers with every Remote Solar Power Kit, UPS Battery Backup System, and Solar Surveillance Skid.

VE-MPPT 75 - 15 3 stage solar charge controller

What is a 3 Stage Battery Charge Controller?

 

A 3 Stage Battery Charge Controller relies on microprocessors to regulate battery charging VOLTAGE and CURRENT. As the name suggests there are 3 stages, or charge settings, that the Controller will use, based on information it receives from the battery: Bulk, Absorption, and Float. Each of these is important to maximizing SLA Battery life.

 

Bulk

 

The Bulk stage is where the battery receives the majority of its energy, making up about 80% of the recharge cycle. During this stage the Battery is given as much current as possible while keeping the battery temperature under 100° F.

 

Absorption

 

A 3 Stage Controller adds an Absorption phase (Sometimes called an “Equalization Stage”) that other “Smart Chargers” don’t include. During this stage the controller will maintain the target charging Voltage (Between 14.1VDC and 14.8VDC), while decreasing the charging Amperage. This helps retain the energy stored during the Bulk stage.

 

Float

 

Keeping a battery topped off once it is fully charged is a big part of getting the most out of SLA Batteries. The Float stage does exactly that by reducing the input Voltage to between 13VDC and 13.8VDC, and the Current to less than 1% of the Battery Capacity. This will keep a battery fully charged indefinitely.

3 stage charge controller graph

Over-Discharge

 

Sealed Lead Acid Batteries are not meant to be discharged by more than 50% of their Amp Hour Rating. Putting this extra strain on an SLA Battery will drastically reduce its effective lifespan. A quality charge controller will have a Low Voltage Disconnect feature. If the Voltage of the Battery drops to a level that would harm it, Low Voltage Disconnect will cut off power until there is an opportunity to recharge the battery to proper levels. Significant advances in battery technology are going to make the Sealed Lead Acid Battery obsolete. Click here to learn about cutting edge Lithium Iron Phosphate (not to be confused with Lithium Ion) batteries and how they stack up against the competition.

 

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