little more detail i just built a solar panel and im running it to a grid tie converter should i put diodes in if i add another panel or are they only for battery systems?
do i need blocking or bypassing and how do i tell the diff?

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Answer by Scott
I’m assuming you are speaking about the blocking diode and not the bypass diodes. Positive side.

Answer by NL123
the blocking diode goes on the positive side

Answer by roderick_young
Bypass diodes would be in parallel with groups of solar cells in a panel. For example, if a module has 72 cells, maybe each 8 cells, there will be a bypass diode. A bypass diode does nothing except salvage some of the energy from the panel if some of the cells are shaded, and others are not. Or, if you have multiple panels in a series string, the bypass diodes grant the other panels in a string to continue to contribute energy when one panel is shaded. Unless you are forced to put the panel(s) where there will be shade during the day, the bypass diode does not matter. Commercial panels all include bypass diodes.

Blocking diodes are generally NOT included on commercial panels. If you are going to a grid-tied inverter, you probably do not need one. There are stringent regulations on how panels must be grounded, and whichever side of the panel is grounded should not have a blocking diode. NEC regulations call for a continuous ground to earth. For example, if you have negative ground on your system, the blocking diodes, if any, should go on the positive terminal of the panel.

By the way, if you are in the US or Canada, do comprehend that a home-built panel will not be legal to connect to a grid-tied system. And a grid-tied inverter that plugs into the wall will also be illegal. I am only saying this because I do not want you to get hurt, or your home to burn down. Line power is nothing to be trifled with.

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50w Solar Panel/2m Cable/Clamps Battery Charger Kit Package Includes One 50 watt Monocrystalline Solar Panel, One Blocking Diode Cable and One 2-Meter Long Charging Cable with Clamps. This solar panel generates free electricity by charging under sunlight during daytime for use with house, RV, boat, yacht, car, camping, as well as many electronics such as laptop, stereo, television, radio, fan, outdoor lighting. The solar panel and the cables included construct a com… More >>

Tektrum 50 watt Solar Panel/Blocking Diode Cable/2m long Cable and Clamps Battery Charger Kit for RV, Home, Boat, Pool

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Product Description
30w Solar Panel/2m Cable/Clamps Battery Charger Kit Package Includes One 30 watt Monocrystalline Solar Panel, One Blocking Diode Cable and One 2-Meter Long Charging Cable with Clamps. This solar panel generates free electricity by charging under sunlight during daytime for use with house, RV, boat, yacht, car, camping, as well as many electronics such as laptop, stereo, television, radio, fan, outdoor lighting. The solar panel and the cables included construct a com… More >>

Tektrum 30w Solar Panel/Blocking Diode Cable/2m long Cable and Clamps Battery Charger Kit for RV, Home, Boat, Pool