Transcript Photovoltaic Batteries

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”).

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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 amphour capacity of the battery system.
 Both series and parallel can be
combined.
Manufactures
 http://www.dcbattery.com/solar.html
 Get
quote.
 Great opportunity to compare manufacture
quality and price.
Parallel
Series
Series &
Parallel
Questions