OT/Ping Daryl? Solar panel question...

[Jeßus]

Just a quick question - if one wanted to add extra solar panels to a
shed roof which is about 30 metres away from the main array of panels,
how does one connect them up to the existing system? I'm thinking if
left as DC current then the voltage drop would be significant over
30m, so does this mean another inverter to convert to AC, and if so,
how would you connect that to the existing AC supply?

Thanks for any answers...

 

[D Walford]

On 23/08/2013 3:17 PM, Jeßus wrote:

Just a quick question - if one wanted to add extra solar panels to a
shed roof which is about 30 metres away from the main array of panels,
how does one connect them up to the existing system? I'm thinking if
left as DC current then the voltage drop would be significant over
30m, so does this mean another inverter to convert to AC, and if so,
how would you connect that to the existing AC supply?

I think that distance would be a problem, voltage drop will be a problem
plus the cost of running the cable underground back to the existing system.
If you already have power at the shed with a separate switchboard it
would be simpler and even possibly cheaper to add another complete
system to the shed.
I will ask my son if running DC cable 30mtrs would be feasible.



--
Daryl

 

[Jeßus]

On Fri, 23 Aug 2013 17:50:35 +1000, D Walford
<dwalford@internode.on.net> wrote:

On 23/08/2013 3:17 PM, Jeßus wrote:
Just a quick question - if one wanted to add extra solar panels to a
shed roof which is about 30 metres away from the main array of panels,
how does one connect them up to the existing system? I'm thinking if
left as DC current then the voltage drop would be significant over
30m, so does this mean another inverter to convert to AC, and if so,
how would you connect that to the existing AC supply?


I think that distance would be a problem, voltage drop will be a problem
plus the cost of running the cable underground back to the existing system.
If you already have power at the shed with a separate switchboard it
would be simpler and even possibly cheaper to add another complete
system to the shed.
I will ask my son if running DC cable 30mtrs would be feasible.

Thanks, for that, appreciated.
Somewhere along the line I'd heard that somebody has done this, but
can't recall who or where...

 

[Trevor Wilson]

On 23/08/2013 3:17 PM, Jeßus wrote:

Just a quick question - if one wanted to add extra solar panels to a
shed roof which is about 30 metres away from the main array of panels,
how does one connect them up to the existing system? I'm thinking if
left as DC current then the voltage drop would be significant over
30m, so does this mean another inverter to convert to AC, and if so,
how would you connect that to the existing AC supply?

Thanks for any answers...

**DC or AC is irrelevant. It is the Voltage that matters. Low Voltages
means high currents and thus, thick (expensive) conductors are required.
High Voltage means lower currents and thinner conductors (but more
(inexpensive) insulation is required.

There are several methods of connecting PV panels.

Series: This is the most common method and Voltages of around 300 Volts
DC are common in such arrangements.

Parallel: Panels are usually rated at 12 Volts or 24 Volts, so the total
Voltage will be either 12 Volts or 24 Volts depending on the panels
used. (In reality, the Voltages will be somewhat higher under no-load
conditions.

Series/parallel: Voltages can be anything convenient with such an
arrangement.

There are advantages and disadvantages to all systems. A series
arrangement is usually the cheapest and is, therefore, the most common
one employed by installers. It is also the dumbest system for several
reasons:

* Lethal Voltages are present on the system during daylight hours.
* If just one panel is obscured by shading, the whole system shuts down.

Personally, I prefer a straight 24 Volt system, as it uses reasonable
sized conductors, is relatively immune to partial shade and is safe to
work on.

Check with Solar installers (who REALLY know their stuff) before you
begin. 30 Metres of heavy duty cable is expensive, but not ridiculously so.

--
Trevor Wilson www.rageaudio.com.au

 

[keithr]

On 24/08/2013 6:59 AM, Trevor Wilson wrote:

On 23/08/2013 3:17 PM, Jeßus wrote:
Just a quick question - if one wanted to add extra solar panels to a
shed roof which is about 30 metres away from the main array of panels,
how does one connect them up to the existing system? I'm thinking if
left as DC current then the voltage drop would be significant over
30m, so does this mean another inverter to convert to AC, and if so,
how would you connect that to the existing AC supply?

Thanks for any answers...


**DC or AC is irrelevant. It is the Voltage that matters. Low Voltages
means high currents and thus, thick (expensive) conductors are required.
High Voltage means lower currents and thinner conductors (but more
(inexpensive) insulation is required.

There are several methods of connecting PV panels.

Series: This is the most common method and Voltages of around 300 Volts
DC are common in such arrangements.

Parallel: Panels are usually rated at 12 Volts or 24 Volts, so the total
Voltage will be either 12 Volts or 24 Volts depending on the panels
used. (In reality, the Voltages will be somewhat higher under no-load
conditions.

Series/parallel: Voltages can be anything convenient with such an
arrangement.

There are advantages and disadvantages to all systems. A series
arrangement is usually the cheapest and is, therefore, the most common
one employed by installers. It is also the dumbest system for several
reasons:

* Lethal Voltages are present on the system during daylight hours.
* If just one panel is obscured by shading, the whole system shuts down.

Personally, I prefer a straight 24 Volt system, as it uses reasonable
sized conductors, is relatively immune to partial shade and is safe to
work on.

Check with Solar installers (who REALLY know their stuff) before you
begin. 30 Metres of heavy duty cable is expensive, but not ridiculously so.

My panels are wired to give ~300 volts at the inverter (at least that is
what the inverter indicates).

 

[D Walford]

On 25/08/2013 12:30 AM, keithr wrote:

On 24/08/2013 6:59 AM, Trevor Wilson wrote:
On 23/08/2013 3:17 PM, Jeßus wrote:
Just a quick question - if one wanted to add extra solar panels to a
shed roof which is about 30 metres away from the main array of panels,
how does one connect them up to the existing system? I'm thinking if
left as DC current then the voltage drop would be significant over
30m, so does this mean another inverter to convert to AC, and if so,
how would you connect that to the existing AC supply?

Thanks for any answers...


**DC or AC is irrelevant. It is the Voltage that matters. Low Voltages
means high currents and thus, thick (expensive) conductors are required.
High Voltage means lower currents and thinner conductors (but more
(inexpensive) insulation is required.

There are several methods of connecting PV panels.

Series: This is the most common method and Voltages of around 300 Volts
DC are common in such arrangements.

Parallel: Panels are usually rated at 12 Volts or 24 Volts, so the total
Voltage will be either 12 Volts or 24 Volts depending on the panels
used. (In reality, the Voltages will be somewhat higher under no-load
conditions.

Series/parallel: Voltages can be anything convenient with such an
arrangement.

There are advantages and disadvantages to all systems. A series
arrangement is usually the cheapest and is, therefore, the most common
one employed by installers. It is also the dumbest system for several
reasons:

* Lethal Voltages are present on the system during daylight hours.
* If just one panel is obscured by shading, the whole system shuts down.

Personally, I prefer a straight 24 Volt system, as it uses reasonable
sized conductors, is relatively immune to partial shade and is safe to
work on.

Check with Solar installers (who REALLY know their stuff) before you
begin. 30 Metres of heavy duty cable is expensive, but not
ridiculously so.

My panels are wired to give ~300 volts at the inverter (at least that is
what the inverter indicates).

That's more normal than 24volts, I think mine (13 180w crystaline panels
in series is over 500volts.


--
Daryl

 

[Jeßus]

On Sat, 24 Aug 2013 06:59:34 +1000, Trevor Wilson
<trevor@SPAMBLOCKrageaudio.com.au> wrote:

On 23/08/2013 3:17 PM, Jeßus wrote:
Just a quick question - if one wanted to add extra solar panels to a
shed roof which is about 30 metres away from the main array of panels,
how does one connect them up to the existing system? I'm thinking if
left as DC current then the voltage drop would be significant over
30m, so does this mean another inverter to convert to AC, and if so,
how would you connect that to the existing AC supply?

Thanks for any answers...


**DC or AC is irrelevant. It is the Voltage that matters. Low Voltages
means high currents and thus, thick (expensive) conductors are required.
High Voltage means lower currents and thinner conductors (but more
(inexpensive) insulation is required.

There are several methods of connecting PV panels.

Series: This is the most common method and Voltages of around 300 Volts
DC are common in such arrangements.

Parallel: Panels are usually rated at 12 Volts or 24 Volts, so the total
Voltage will be either 12 Volts or 24 Volts depending on the panels
used. (In reality, the Voltages will be somewhat higher under no-load
conditions.

Series/parallel: Voltages can be anything convenient with such an
arrangement.

There are advantages and disadvantages to all systems. A series
arrangement is usually the cheapest and is, therefore, the most common
one employed by installers. It is also the dumbest system for several
reasons:

* Lethal Voltages are present on the system during daylight hours.
* If just one panel is obscured by shading, the whole system shuts down.

Personally, I prefer a straight 24 Volt system, as it uses reasonable
sized conductors, is relatively immune to partial shade and is safe to
work on.

Check with Solar installers (who REALLY know their stuff) before you
begin. 30 Metres of heavy duty cable is expensive, but not ridiculously so.

Thanks. I'm definitely not proceeding with this idea until if/when I
have it figured out... I also need to lay some network cables between
these buildings, so I have another excuse to dig a trench anyway.
All comes down to cost in the end...