Photovoltaic Batteries Battery Components Configuration Manufacturers

Storage Batteries In a photovoltaic system batteries store and deliver energy. In this system batteries are most affected by the size and usage of the energy load.

Charge Controller Batteries can easily be drained and damaged without regulation of energy loads. Systems must be sized to match within load range (“voltage set point window”). e.g. Battery with 14 volts charged,11 when fully discharged. If load will not operate below 12 volts. Voltage window does not match that of the load.

Amp-hour capacity Amp-hours: number amps of current can discharge x number of hrs it can deliver that current. This attribute is very important to designers to determine length of operation without sunlight. e.g. 200 amp-hr battery should be able to deliver 200 amps for 1 hr, 50 amps for 4 hrs, 4 amps for 50 hrs, or 1 amp for 200hrs.

Depth of discharge This describes how much of total amp- hr capacity of the battery is used during a charge and recharge cycle. Most “shallow cycle” batteries discharge from 10% to 25% of their capacity. Most photovoltaic batteries discharge up to 80% w/o damage.

Vented Lead Acid Lead & Sulfuric Acid combination. Vents allow hydrogen & oxygen to escape. The battery of choice for most solar and backup power systems. Discharges up to 80%.

Details Larger Plates, or more of them will increase amp hrs. Thicker plates will prolong life of batt.

AGM or Gel Lead Acid Batteries Never need watering. Cannot freeze or spill. Does require very accurate regulation to prevent overcharge and over discharge.

Nicad (Nickel Cadmium) Pros Low self-discharge. Can totally discharge w/no damage. No freezing. Low Maintenance. Cons Expensive to buy. Expensive to dispose of.(Cadmium is very Hazardous)

Future Battery Prospects Redox Battery- short for reduction-oxidation, which is a cycle of chemical reactions. The lithium-metal sulfide battery operates at a temp. of almost 850F. Requires a special container to maintain that temperature. A polymer battery is being developed,uses no liquid or dangerous materials, can be molded into any shape.

Batteries in Series & Parallel Like photovoltaic cells, batteries connected in series increase voltage. Connected in parallel to increase amp- hour capacity of the battery system. Both series and parallel can be combined.

Manufactures Get quote. Great opportunity to compare manufacture quality and price.

Parallel Series Series & Parallel

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