Victron BlueSolar charge controller

[tanglewood]

These shading test videos are really showing the behavior of a particular MPPT charge controller as much as the behavior of shading. The video by the two kids is really a bit of a joke because you need to let the MPPT control relocate the new MPP after shading occurs. Some controller do it quickly, and some do it slower. The Outback controller that they use is actually one of the slow one. What they really need to do is shade the panels, then wait for the controller to rescan and find the new MPP.

[socaldmax]

What two kids are you referring to?

[Hickers]

Originally Posted by john61ct

I haven't heard of any controller that has a "stop charging" option.

People either set float at 13.2V, or have an external monitor like BMV-702 or a BMS cut off charging via relay.

Best setting for absorb in normal usage cycling IMO is 3.45Vpc, or 13.8V for 4S.

Yes you can select any max charge rate you want from zero to the maximum the controller is rated for.

[OceanPlanet]

Originally Posted by socaldmax

My testing with partially shaded panels indicated a huge drop in current and a smaller drop in voltage. Just from memory, the voltage dropped from 37v down to about 30v, the current dropped from about 12A down to less than 2A. This was a single panel on an MPPT controller.

Here's a video where they do some testing with partial shading of identical panels, which is what most people have connected together. This video shows slightly more power out in parallel mode with no shade (might have been more sun at that time) and significantly more power in parallel with partial shading.

I thought everyone already knew this (go parallel in shading, ideally with separate controllers). Going back to 2012...see testing done together with Nigel Calser (attached)

[john61ct]

Originally Posted by Hickers

Yes you can select any max charge rate you want from zero to the maximum the controller is rated for.

I wasn't talking about max charge rate.

But now you have me curious, could you outline the rationale for what you're referring to?

[socaldmax]

Originally Posted by OceanPlanet

I thought everyone already knew this (go parallel in shading, ideally with separate controllers). Going back to 2012...see testing done together with Nigel Calser (attached)

Read back a couple of pages and you'll see that some people still don't think so.

[OceanPlanet]

Originally Posted by socaldmax

Read back a couple of pages and you'll see that some people still don't think so.

Yeah, I know...

[foggysail]

I viewed the test video done with similar panels. What I expected to see when the test person shielded one of the panel's cells was a 50% loss in output power. There are many variables when something such as a solar panel is subjected to testing and many difficult for a viewer to explain.

Look back at the schematic shown by the tester and note that there are two parallel strings of series cells in the panel. So I expect a complete shutdown in 1/2 of that panel under test. Not so! The shielded cell still produced power. My guess is the shielded cells still received irradiance from reflection and refraction in the glass covering the cells allowing them to produce electrons.

Make no mistake about those panels however. DotDun was correct when he stated there were no bypass diodes in the panels. The presented schematic did not show bypass diodes and I certainly believe the tester would have mentioned their presence if the panels were so equipped. Bypass diodes are employed for a purpose, to allow upwards to 2/3 of the panel's output to get processed.

There are advantages to wiring panels in series especially when using today's modern panels with everything from bypass diodes to PERC which helps reflect light that passes through the cells and then back to the cells to generate more electrons.

And keep in mind that unless your panels face unmovable objects such as a chimney, shade is not permanent. And the claim about a mast constantly shading is moot! I owned a sailboat for years. Nothing was stationary when the boat was under sail. But inadequate wiring is there forever so those who prefer wiring panels in parallel must contend with wire losses which indeed affect the power delivered by a panel.

So do as you wish with your solar installation. One thing for sure, whether your installation configuration is series or parallel, you certainly will benefit from solar!!!

[Hickers]

Originally Posted by john61ct

I wasn't talking about max charge rate.

But now you have me curious, could you outline the rationale for what you're referring to?

Given your panels can deliver the required voltage you can vary the maximum amps being fed into the battery from, on our 50 amp controller, from 50 to 0 amps. I've no idea where they all go but it works!

[foggysail]

Originally Posted by Hickers

Given your panels can deliver the required voltage you can vary the maximum amps being fed into the battery from, on our 50 amp controller, from 50 to 0 amps. I've no idea where they all go but it works!

[DotDun]

Originally Posted by foggysail

I viewed the test video done with similar panels. What I expected to see when the test person shielded one of the panel's cells was a 50% loss in output power. There are many variables when something such as a solar panel is subjected to testing and many difficult for a viewer to explain.

Look back at the schematic shown by the tester and note that there are two parallel strings of series cells in the panel. So I expect a complete shutdown in 1/2 of that panel under test. Not so! The shielded cell still produced power. My guess is the shielded cells still received irradiance from reflection and refraction in the glass covering the cells allowing them to produce electrons.

Make no mistake about those panels however. DotDun was correct when he stated there were no bypass diodes in the panels. The presented schematic did not show bypass diodes and I certainly believe the tester would have mentioned their presence if the panels were so equipped. Bypass diodes are employed for a purpose, to allow upwards to 2/3 of the panel's output to get processed.

There are advantages to wiring panels in series especially when using today's modern panels with everything from bypass diodes to PERC which helps reflect light that passes through the cells and then back to the cells to generate more electrons.

And keep in mind that unless your panels face unmovable objects such as a chimney, shade is not permanent. And the claim about a mast constantly shading is moot! I owned a sailboat for years. Nothing was stationary when the boat was under sail. But inadequate wiring is there forever so those who prefer wiring panels in parallel must contend with wire losses which indeed affect the power delivered by a panel.

So do as you wish with your solar installation. One thing for sure, whether your installation configuration is series or parallel, you certainly will benefit from solar!!!

Exactly!

It amazes me how insecure some are with their solar installation such that they have to disparage those that implement solar differently. They fail to accept that a good implementation needs to meet a set of requirements which may be different than their own.

I have no shading issues, my panels are mounted aft of the boom at about the same height. I require 800+ watts and require the wiring to fit inside 1" id tubing. I used 10awg wire to ensure little voltage drop. Hence no multiple wire runs will fit. My (3) 275w panels, wire, 2-pole disconnect, and Victron 150/70 controller cost <$1100 USD. My implementation is best for my set of requirements.

YMMV

[BigAl.NZ]

I have been reading this thread with interest.

We have 4 Siemens 75w panels with 4 x Genasun controllers.

Can someone please explain the implications of this shading effect on 1 controller vs 1 per panel?

Thanks

Al

[john61ct]

Especially with MPPT and high-voltage panels, 1:1 ratio is best for handling partial shading.

[BigAl.NZ]

Originally Posted by john61ct

Especially with MPPT and high-voltage panels, 1:1 ratio is best for handling partial shading.

Ok, but why? What happens if you have one controller, 4 panels and one panel goes in the shade?

[noelex 77]

Originally Posted by foggysail

Make no mistake about those panels however. DotDun was correct when he stated there were no bypass diodes in the panels. The presented schematic did not show bypass diodes and I certainly believe the tester would have mentioned their presence if the panels were so equipped. Bypass diodes are employed for a purpose, to allow upwards to 2/3 of the panel's output to get processed.

I would be very surprised if this was the case. Bypass diodes are needed to prevent the cells overheating and it very rare to see modern panels without these fitted. The lifespan would be short.

The only 50w panels sold by the AltE store have two bypass diodes:
https://www.altestore.com/store/sola...-j-box-p11889/