"pre wired for solar"... how much power will it carry? (1 Viewer)

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Sep 17, 2017
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My van was "pre wired for solar", which appears to mean there's a run of cable from the cupboard at the back of the van to the Elekroblock under the passenger seat. It's currently got a 175w panel and a 75-15 Victron SmartSolar attached to it.

If I were to add another 200w to it (because it's cheap and I can't help but modify)... what would I need to do?

I know I'll need another controller. And more holes in the roof.

I know the EBL input won't take more than about 15A, so I'll have to go straight to the battery, which is under the driver's seat. Which isn't an issue as I already have a busbar on the negative side and a midi fuse box with a spare slot on the positive.

But can I throw >30amps through the pre-wiring that goes to the front of the van? Or will I need to create a new cable run?
 

Tombola

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Nov 21, 2020
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Has the cable got mm2 stamped on it.

Is it 2 separate black cables or 2 thinner cables in one sheath
 
May 16, 2023
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But can I throw >30amps through the pre-wiring that goes to the front of the van? Or will I need to create a new cable run?
It may not be 30 amps. If yuo can get a MPPT that supports a wider voltage range (Victrons can usually accept up to 60V on the input), you could wire the panels in series, which doubles the voltage... (2 12V panels should be a 40-46V peak).

Meaning you can send double the wattage down the same cable. Ie, if it's good for 10A at 20V it'll also be good for 10A at 40V.
If you wired the panels in parallel so that it's 20V at 20A however you do need to check the cables diameter/construction to be sure it's good for that current.. You also need to chcek the cable is good for 40V, but in general most insulation good for 12V is okay for 40V.

(ie, you could consider wiring the solar down the same wire, and colocating the higher current 12V between the MPPT and the battery closer to ... the battery). Hope that makes sense, putting the MPPT close to the battery, so the solar is running at a higher voltage down the existing cable ... means you can potentially use existing wiring ... as it will be at a higher voltage if wired correctly thus getting more wattage from same current..
 
Sep 29, 2007
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If your existing panel/controller is using the existing wires, wouldn’t you run new wires all the way to the battery for the new panel/controller?

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May 16, 2023
1,125
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Funster No
95,993
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Bailey Alliance 66-2
It may not be 30 amps. If yuo can get a MPPT that supports a wider voltage range (Victrons can usually accept up to 60V on the input), you could wire the panels in series, which doubles the voltage... (2 12V panels should be a 40-46V peak).

Meaning you can send double the wattage down the same cable. Ie, if it's good for 10A at 20V it'll also be good for 10A at 40V.
If you wired the panels in parallel so that it's 20V at 20A however you do need to check the cables diameter/construction to be sure it's good for that current.. You also need to chcek the cable is good for 40V, but in general most insulation good for 12V is okay for 40V.

(ie, you could consider wiring the solar down the same wire, and colocating the higher current 12V between the MPPT and the battery closer to ... the battery). Hope that makes sense, putting the MPPT close to the battery, so the solar is running at a higher voltage down the existing cable ... means you can potentially use existing wiring ... as it will be at a higher voltage if wired correctly thus getting more wattage from same current..
Indeed, should point out if you double the voltage you'll need one controller handling it. So a 30A controller (as the amp rating is for the 12V side not the solar side) not 2 15A ones.

Simplicity is run another cable as Roger said for the second controller and panel.
 

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