Power Optimizers w/ a Charge Controller as opposed to an Inverter?

[DrLoLCat]

Hi,

 

Can power optimizers (MPPT) be used along with a Charge Controller and a battery bank? 

 

I am considering doing string based power optimization by having a power optimizer on each string of my solar array (4 strings). The outputs of the 4 optimized strings would then be wired to a combiner box and to a central charge controller which may or may not have its own MPPT.

 

Are there any technical issues associated with :

PV Panel -> Power Optimizers -> Charge Controller -> Battery?

 

I have been unable to find a single mention about the use of power optimizers with charge controllers. The only configurations described are PV Panel -> Power Optimzer -> Inverter.

 

 

 

 

 

 

[Wetkit]

Never heard of these "power Optimizers".

Could you perhaps post some details?

[DrLoLCat]

Hi Wetkit,

 

Thank you for posting the details surrounding the evolution of your Solar system, it has been very interesting to read. I found this forum because of your DIY roof mounting installation thread. I will likely be copying exactly what you did since I was specifically looking to save on the cost of ordering a mounting system from a Solar supplier.

 

Here are two examples of Power Optimizers:

 

http://www.solaredge.com/groups/powerbox-power-optimizer

http://www.tigoenergy.com/sites/default/files/attachments/mm-2es_data_sheet_1.12.2015.pdf

 

Here is a video of well-known Capetonian, Martin Lorton, in which he provides some explanation of Power Optimizers:

http://www.youtube.com/watch?v=Ma6TN0PkohI

[Wetkit]

Ok, so if I understand this correctly, the Power Optimizer is actually a per panel MPPT?

Personally I do not believe it will give you much gains. Where is will help though is when you run large serie strings with shaded area's.

If a single panel on a large string is pulled down due to shading, the complte string will go down.

Looks like this optimizer will help to prevent this.

 

With our small systems I think the cost will be far too high, like with string invertors. It is a brilliant idea, but the cost is just

 

If you running 4 strings, why not just have a single but smaller MPPT controller for each individual string?

The output of all the MPPT's is then combined onto your battery bank without any further combiners.

This actually makes more sence to me, especially if the strings face diffrent directions or diffrent PV panels is used between strings.