Solar replacement

[Deleted member 2546]

Hi, I have 3 small 40 watt panels on the van roof, can I swap these out for 120 watt panels on the old wiring?
Or do I need different wiring?

 

[wildebus]

Hi, I have 3 small 40 watt panels on the van roof, can I swap these out for 120 watt panels on the old wiring?
Or do I need different wiring?

do you mean swap out 3 x 40W panel for a single 120W Panel? or swap out the 3 x 40W panels for 3 x 120W Panels?
For 1 120W Panel
Assuming the existing panels are wired in parallel, they will be just the same as a single 120W panel as far as the controller is concerned. Just connect the +ve and -ve of the new 120W panel to the +ve and -ve of the cables going to the controller
If they are in series (unlikely but possible), the new 120W panel will be a 1/3rd of the voltage but 3 x the current. Could be important if your cabling is REALLY thin, but unlikely given the current from a 120W panel is well under 10A

For 3 x 120W Panel
Similar to above. If you just used the exact same wiring, you would be increasing the current by a factor of 3 - this could be a potential issue if your cabling is thin, but again unlikely.
If current cabling is in Parallel, but your controller supports a higher voltage, you could change from 3 x 40W in Parallel to 3 x 120W in Series. This will make the current into the controller the same so cable gauge doesn't matter.
The cable from Controller to Battery might need an upgrade though?
Also, does your controller support 360W of PV?

 

[Deleted member 2546]

Thanks for advice. I have zero knowledge about the solar and battery and struggling to find a workman too

 

[Molly 3]

Thanks for advice. I have zero knowledge about the solar and battery and struggling to find a workman too

Try waving a blank cheque ,that might help

 

[Deleted member 2546]

Canned it for now, will sort over winter