Serial%20vs.%20Parallel%20Connections

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Serial vs. Parallel Connections
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Serial Connections

• Serial connections are positive-to-negative in a
  chain

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Serial Connections PVs

• Current is the same through each device

• Voltages add
• Higher voltage and lower current reduce losses in
  wiring
• Can exceed voltage capacity of charge controller
• Reduces number of cables to combiner

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Serial Connections PVs
5 amps
An MPPT controller can take the 5 amps 48 volts
240 watts and charge a 24 volt battery with 10
amps (neglecting losses)
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Parallel Connections

• Parallel connections are positive-to-positive
  and negative-to-negative

12 v PV 5 A -
12 v PV 5 A -
10 A breaker
10 A breaker
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Parallel Connections PVs

• Current adds

• Voltage is the same across each panel
• Increases number of cables to combiner if
  multiple panel arrays are used
• An MPPT controller uses the actual array voltage
• A PWM controller sets PVs at battery voltage

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Parallel Connections
12 v PV 5 A -
12 v PV 5 A -
12 volts
10 A breaker
10 A breaker
10 amps
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Serial/Parallel Connections Batteries

• Batteries must be identical

Volts?
- 12 v 220 amp-hour
- 12 v 220 amp-hour
Serial or Parallel ?
Amp-hours?
Volts?
- 12 v 220 amp-hour
- 12 v 220 amp-hour
Amp-hours?
Serial or Parallel ?
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Serial/Parallel Connections Batteries

• Batteries must be identical

12 Volts
- 12 v 220 amp-hour
- 12 v 220 amp-hour
Parallel
440 Amp-hours
24 Volts
- 12 v 220 amp-hour
- 12 v 220 amp-hour
220 Amp-hours
Serial
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Serial Connections Loads

• Current is the same through all loads
• This is the current the source must provide
• Voltage drops between loads add
• Voltage available for the next load in series is
  reduced by the previous load
• Failure of any load results in failure of all

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Serial Connections Loads
Current is the same through each load. If the
total of all voltage requirements of all loads is
greater than the voltage supplied some will have
low voltage and may be damaged.
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Parallel Connections Loads

• Total current usage adds
• Same voltage is available at each load
• Failure of one load may not affect the others
• Loads with mixed current requirements are not
  affected (as long as the total current needed
  does not exceed system capacity).

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Parallel Connections Loads

• This configuration depicts multiple loads wired
  in parallel.
• Each load is rated for the battery voltage.
• The total current from the battery is the sum of
  the current through each load,
• even though each load pulls a different current

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?s