Location: Charging Cycle Definitions

What are battery charging cycles? How do charging cycles work?

Battery chargers flip through a series of charging regimen as they juice up the battery. We explain how the battery charges back up. Charge cycles defined:

Battery Desulfation - Before a select few advanced battery chargers go into start phase of charging, they pulse in a charge, and remove the power quickly. This "pulse" style technology literally forces the rapid breakdown and removal of sulfation (sulfur crystals) from the electrolyte solution in the battery. A prolonged desulphation cycle may be necessary if crystals have formed on the lead grid plates. The desulphation process is a preliminary charging process given to the battery so it has the ability to receive its charge faster and more efficiently. This would technically be the first phase in a charge cycle. However, many battery chargers do not have this cycle. Desulfation can be both positive and negative voltages, varying explicitly by manufacturer.

Battery Equalization - As an advanced mode on a select few advanced battery chargers resides the equalize functions. The "Equalize" regimen is run to remove deep sulphation from a battery, or to deep charge flooded batteries. A prolonged desulphation cycle may be necessary if crystals have formed on the lead grid plates, and as such, most equalize cycles are in excess of 12 hours. The equalization process is also a complete charging process so when your batteries make it through, they are ready to go. You don't have to charge them again. *AGM batteries and GEL batteries don't need or like this type of charge as it boils off Electrolyte, which shortens their lifespan. However, if an AGM battery is left alone too long in a shed, and would be dead anyway, an equalize charge may "SAVE" it for a while. Equalization voltages are usually 15.3 - 15.9 volts for a 12 volt battery bank, MAKE SURE YOU CHECK WITH THE MANUFACTURER OF YOUR BATTERIES.

Start Phase - plain and simple, this is the starting process of actually charging the battery. Before a battery can be charged, it must be tested by the charging device.
- Some battery chargers measure internal resistance to current.
- Some chargers measure current the battery will accept at varying voltages.
- Some chargers measure voltages very accurately.
The science behind each may be different, but the result is the battery charger environment test. Is there a battery? Is it hooked up right? Does it accept a charge or short circuit? If the battery passes these tests, it is onto the charging phases of the regimen. Voltages vary, but are intermittent.

Bulk Charging a Battery - bulk battery charging is the main process of charging a battery. While the battery charger is in bulk mode, it will output as close to it's rated label amperage as the battery will allow. Figure an 40 amp charger will output 40 amps in bulk mode, until the battery starts to fill up with power. During the bulk phase a battery is filled from 0% to roughly 80% of full. The bulk charge therefore is the most used charging cycle, and the workhorse of the group. Only an eqalize charge cycle can be completed without it. Bulk voltages are usually 14.1 - 14.6 volts for a 12 volt battery bank.

Absorption Charging a Battery - An absorption charge is the last and final stage of "charging" a battery in a 3 stage charger. The charger starts up, charges in bulk mode to 80%, and then flips into absorption mode. The absorbtion mode then "Finishes" the battery by bringing it to 100% charge at The battery charger will send a constant current of voltage until the current has This phase of charging will take the battery to a 100% charge. Absorbtion voltages are the same as the bulk voltages, 14.1 - 14.6 volts for a 12 volt battery bank, but the amperage goes from the rating to zero. Voltage stays constant as the battery reaches 100% charged, but the amperage through the charger goes from 40 amps to 0 amps.

Float Charging a Battery - Once a battery is charged, it should either be removed from the charge cycles above to avoid over charging. However, a battery begins to decay as soon as it is removed from the charger with a phenomenon call self discharge. Due to self discharge of batteries, they are always losing a certain percentage of power as they decay, just sitting there. A float charge won't overcharge the battery, but keeps it from decaying as it sits there too. Thing of float charging as being similar to equalized water pressure in two pipes. Both pipes are at the same PSI, pushing water against one another. Should one leak, the other pushes water in it's place. Well, we know our batteries leak, and so we leave the water on to fill the leaks. AGM Batteries are the most efficient, followed by GEL batteries, and then FLOODED batteries round out the group. The less efficient and stable the battery, the more you NEED the float charge.

Pulse Charging a Battery - Significant research has been done in the last 2 decades regarding pulse charging lead acid batteries. Leading government test laboratories have agreed that a pulse charge regimen breaks down sulfation better than a constant charge. Do purchase these higher technology chargers to see the difference in your batteries, and their lifespan.

Battery Charger Warnings:
Always read and follow the manufacturer's battery charging instructions prior to connecting your battery, or trying to charge a battery bank. Do not attempt to charge batteries in a confined environment. Explosive and hazardous gases are an inherent byproduct of battery charging, do think ahead. Batteries contain sulphuric acid, and lead, both of which are hazardous material if removed from the battery, or disposed of improperly, do take care to be environmentally responsible. Batteries are useful, just be safe.

Electrical How To Guides:
Electrical Breakers
DC Fuses and AC Fuses
Wire Sizes & AWG
Solar Charge Controller Guide
Battery Charger Information

AGM Battery Chargers

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