diy solar

diy solar

New panels for my RV solar project

Lisas RV Experience

New Member
Joined
Nov 9, 2019
Messages
3
Greetings,
I've purchased my batteries (battle borne), charge controller/inverter and monitor. I haven't purchased my panels because () I need to get on the roof and measure, and (2) I'm nervous about buying panels. I know I want noncrystalline panels and I'm going for about 1,200 watts but I've been using Arizona Wind and Sun and I get confused with the panels they have They show these REC N-PEAK 325 Watt Monocrystalline Solar Panel for $211. That sounds great but then I wonder what happens if the panel cracks and I can't find these again? Here are the specs from the webpage:

The REC N-Peak Series are premium n-type mono solar panels using REC’s proven half-cut cell technology. The panel features the innovative REC ‘Twin’ cell layout design, where the panel is split into two twin sections, also enabling continued energy production, even when partially shaded. The REC N-Peak Series has extra support bars across the rear of the panel, greatly boosting its strength and durability, and allowing loads of up to 7000 Pa.

N-PEAK 325 Specifications:

  • Nominal power: 325 Watts
  • Number of cells: 120 half-cut
  • Power tolerance: +5 / -0 Watts
  • Vmp: 34.4 Volts
  • Voc: 40.7 Volts
  • Imp: 9.46 Amps
  • Isc: 10.28 Amps
  • Module efficiency: 19.5%
  • Dimensions (inches): 65.9" x 39.25" x 1.1"
  • Dimensions (mm): 1675 x 997 x 30
  • Weight: 39.7 lbs (18 kg)
Warranty: 20 year product warranty, 25 year linear power output warranty.

My questions are:
1. are there better options with similar guarantees and price?
2. should I go with smaller panels?
3. Anyone have experience with these particular panels?

Thanks!

Lisa
 
Don't be too concerned replacing damaged panels, you just need to pay attention to the specs based on how your panels are configured.

If your panels are in parallel you need to keep the Vmp rating of the new panel within +10% or so. A MPPT controller will pull the voltage down while searching for the array's Vmp. The new higher voltage panel will have its power production reduced a bit, but it won't be a big reduction. It's important that you don't go the other way into lower voltages though as if the MPPT controller detects the existing panels are producing more power at their higher voltage than when it pulls them down to the voltage of the new panel, the new panel will not contribute at all. There is also the possibility that the older panels will end up being pulled down to the lower panel if the controller settles there, and that will lower their output.

If your panels are in series you need to keep the current rating of the new panel within +10% or so. The current at any point in a simple circuit is the same so if we have panels that produce 10 amps peak, and connect up a panel that can only produce 5 amps peak, the whole array drops to 5 amps, and you drop a heck of a lot of capacity. If your new panel is 15 amps and the old panels are 10 amps, you throw away 1/3 of the new panel's capacity.

The size of panels for mobile use has been covered in this thread, and this one, but I'm sure there are others and the search will turn them up.
 
Thanks for the quick reply, I'm getting 4 of the exact same panels to start with. Let's hope I don't break one! I'll check the other threads.

Lisa
 
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