OT/Ping Daryl? Solar panel question...

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...

Reply to
Jeßus
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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.

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Daryl
Reply to
D Walford

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

Reply to
Jeßus

**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.

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Trevor Wilson www.rageaudio.com.au
Reply to
Trevor Wilson

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

Reply to
keithr

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

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Daryl
Reply to
D Walford

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...

Reply to
Jeßus

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