solar panels with diodes between each cell

pianotuna wrote:
The output is between 46 and 47 volts depending on the panel. That's a nice sweet spot for safe operation voltage.

thats the open circut voltage, which hopefully you never see except when your testing the pannel when you first buy it. thats a 24v pannel. the 325 is the exact same as what I have, just a different name.

Steve

The output is between 46 and 47 volts depending on the panel. That's a nice sweet spot for safe operation voltage.

2oldman wrote:
I can't find that about those panels either.
And the full specs are listed for only one type of panel.

I found some here:

https://www.qookka.com/en/solar-panels/901-solar-panel-ae-smart-hot-spot-free-60-cells-275-300w.html

StirCrazy

Read the whole thread. This has been covered already with a quote and a link farther into the discussion.

What panels do you have?

StirCrazy wrote:

where did you read about the Diodes, I cant find anything in the link you posted.

I can't find that about those panels either.
And the full specs are listed for only one type of panel.

pianotuna wrote:
Hi folks,

I stumbled across these panels today:

https://ae-solar.com/wp-content/uploads/2018/10/AE_P6-36_155W-175W.pdf

They apparently have diodes between each and every cell which gives them an advantage for series connection of the panels (i.e. shade tolerant)

Does anyone know of other panels that do this?

where did you read about the Diodes, I cant find anything in the link you posted. Most solare pannels have bypass and blocking diodes, which allows sections to be bypassed in shady conditions or what ever. the lower end only have 3 and higher end ones have more. the cost of adding the diodes is pretty substantial, so if some one is putting them on every cell that would be wild but I wonder how much of a difference it would be from say every second or every 3rd cell.

for me its a 12V pannel so I am not sure I would realy look at it for use, 24V pannels let you run smaller wire and such. but I also have a split cell pannel and they are touted for being more efficient in low light and partial shading situations so dues to the smaller cell design allowing them to have a slightly higher output per cell.

doing some more digging into this my split cell 24V pannel has a bypass diode for every cell, which is why thes pannels are so good in partial shading so I guess that must be becoming a pretty standard thing now.

Steve

CA Traveler wrote:
Bypass diodes for shading of parallel panels have limited advantage. Each shaded cell loses 0.5V + the diode loss. So that panel is under performing other non shaded parallel panels perhaps significantly.

It does not appear these panels are physically larger than ones that don't have this feature, and 300 watts is 300 watts no matter where it is coming from. There are a few you tube comparisons of output between this tech, and the more common 3 or 6 diode units.

What I can't find so far, is a price.

FWC wrote:

pianotuna wrote:
FWC,

I'm still waiting to hear about your power system.

I am not sure why this is relevant.

It is relevant because it would help others understand your approach to mobile power.

For example, I prefer a larger than usual battery bank that can be used at extreme temperatures. The OEM bank was about 375 amp-hours which I immediately raised to 875 amp-hours. I would certainly never consider a 200 amp-hour bank, but that might be lots for many other end users.

2oldman has jumped to a 48 volt battery bank--which means he may likely have a DC 48 to dc 12 device of some kind. He has gone from 12 to 24, to 48 volts. He is expert at winnowing out searches on RVnet

BFL13 prefers a minimal approach to solar and is willing (or once was) to tilt and twirl his panels. He even experimented with a fixed tilt tracker. Quite a creative thinker of the "out side the box" variety.

If one knows the context from where the other person is speaking it is easier to understand what they are trying to share.

Bypass diodes for shading of parallel panels have limited advantage. Each shaded cell loses 0.5V + the diode loss. So that panel is under performing other non shaded parallel panels perhaps significantly.

Definitely better performance with each cell having a bypass diode and a single panel or series panels.

The typical panel has 1 bypass diode for each string. A 4x9 panel has 2 strings 6x10 has 3 strings. And these diodes are external to the cells and in the wiring box which is close to the junction box. From the diagram above 2 more wires are routed to the junction box for the 3 diodes.

My 60 cell panels have 3 byass dioes or 1 for every 20 cells which is 10V. With 3 panels in series each string has 10V. I've previously posted a graph showing a rising sun with leafy shade on the panels. Charging starts at 20V and jumps by 10V increments as the shade moves off of the panels. My diodes have a 0.3V drop so very small effect.