Adding solar, need Blocking diodes?

[LandKKnight]

We are installing a 190 watt Go Power flex panel to add to our factory 2 100 watts panels. I asked the FB group if there was anything I needed to set or change on our setting for the solar controller or the inverter. We have 3 1 yr old AGMs. I still would like an answer to that question but the only answer I got so far from the FB group told us we need to install one way blocking diodes on each of the positive ends coming out of the panels. I went on the Go Power site and I see "In line reverse blocking diodes" but I cannot find anything called that anywhere. The person who answered me said to search for 20 amp In line Diode Connector Photovoltaic Solar Panel Fuse adapter. I found those, but they are fuse adapters, not blocking diodes. Are they the same thing? We got one of these diodes that came with the new 190 watt solar panel, do we need 3? One for each of the panels? When we spoke to Go Power they never mentioned it even though we told them we were adding the 190 watt to the existing 100 watt panels. There are 10, 15, 20 amp fuse adapters. I think we need the 20 amp for the 190 watt panel, which do we need for the 100 watt panels? Thanks for the help!!

[Sandiegodoug]

I was going to add 3 x100 panels. I was going to unplug current 2 panels, install a splitter, reconnect the 2 panels to one side and my new panels to the other side . I added a solar system to my previous solera mb, didn’t add any diodes. It was plug and play. Never had any issues of panels discharging batteries at night.

[LandKKnight]

Originally Posted by Sandiegodoug

I was going to add 3 x100 panels. I was going to unplug current 2 panels, install a splitter, reconnect the 2 panels to one side and my new panels to the other side . I added a solar system to my previous solera mb, didn’t add any diodes. It was plug and play. Never had any issues of panels discharging batteries at night.

My understanding is that you only need the diodes if the panels are of different wattage. We will have 2 100 watt and 1 190 watt. The diodes are supposed to keep the current from back flowing between the unequal panels.

[twp5253]

Originally Posted by LandKKnight

My understanding is that you only need the diodes if the panels are of different wattage. We will have 2 100 watt and 1 190 watt. The diodes are supposed to keep the current from back flowing between the unequal panels.

I have been researching solar for my towed trailer. My recommendation would be to scrap the two flex panels you have and install as many of the hard panels as will fit. Next question is to run them in parallel or in series. The four 190 W Hard panels I have are about 20 Volts. Factory installed 4 and ran two in parallel to the each of the 100V x 30A Victron controllers. Series means less wiring thickness as the volts will be higher. If I add a couple panels to the XL roof, I will probably change them over to series and have 3 panels or 60+V running to each of the Victron charge controllers.

[Flybob]

Many panels ( all of mine) have blocking diodes built in. If you open the connection box on the back of the panel, you should see them. I had to replace a set of diodes on one of mine. The other thing you need to check is the current rating of your controller. It is unusual that OEM systems come with controllers with 100% margin.

[TitanMike]

Originally Posted by Flybob

Many panels ( all of mine) have blocking diodes built in. If you open the connection box on the back of the panel, you should see them. I had to replace a set of diodes on one of mine. The other thing you need to check is the current rating of your controller. It is unusual that OEM systems come with controllers with 100% margin.

Actually, the diodes you refer to are bypass diodes and wired in parallel with the PV cells.

A blocking diode is wired in series at the combiner box for multiple panel arrays.

Both are diodes that allow only one-way current flow but have different purposes.

Today's solar charge controllers provide the function of a blocking diode and prevent reverse current through panels. Blocking diodes are only required if a battery is connected directly to solar panels. Not a general practice with RV applications.

[KRedburn]

Originally Posted by twp5253

I have been researching solar for my towed trailer. My recommendation would be to scrap the two flex panels you have and install as many of the hard panels as will fit. Next question is to run them in parallel or in series. The four 190 W Hard panels I have are about 20 Volts. Factory installed 4 and ran two in parallel to the each of the 100V x 30A Victron controllers. Series means less wiring thickness as the volts will be higher. If I add a couple panels to the XL roof, I will probably change them over to series and have 3 panels or 60+V running to each of the Victron charge controllers.

You might want to check your charge controller specifications, may or may not be able to handle your 60v plan.

[twp5253]

Originally Posted by KRedburn

You might want to check your charge controller specifications, may or may not be able to handle your 60v plan.

Charge controllers from Victron have all the information right there in big print.

I have two units that say 100 30 So they can take up to 100volts and up to 30Amps.

I can go either way with three of the 190 watt units to each controller. It is also worth noting the panels very rarely if ever produce their max number.