combining mono & poly c solar panels through the same regulator

Hi to all out there would like to know if possible to wire mono & poly c solar panels together and then connect through the same PWM regulator {20 amps} I have 2 x 80 watt BP polyc. and 120 watt monoc panelsTar for anyanswers forthcoming Mick b
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Reply By: Member - Ups and Downs - Sunday, Sep 29, 2013 at 14:08

Sunday, Sep 29, 2013 at 14:08

Connecting the different panels is quite OK. I have had 2 x 64 polys and a 120 mono for a couple of years, no problem.

I don't know about the number of amps out of those panels though, compared to the controller's 20 amps.

AnswerID: 518899

Reply By: The Bantam - Sunday, Sep 29, 2013 at 21:47

Sunday, Sep 29, 2013 at 21:47
I have no doubt that there are people out there with mixtures of different solar pannels running on the same regulator and it may be working.

The question is," how efficiently?"

The whole point of a Maximum Power Point Tracking Regulator is to optimise the relationship between the battery and the solar panel.

For this to work at best efficiency panels with a similar behaviour are required.
otherwise the panel with the higher voltage will be will be doing more work than the lower voltage panel.

Apart from the fact you have a 20 amp regulator and in theory about 24 amps of panels.

If the regulator has some sort of current limiting you will get less than full output from your panels, If the regulator has no means of protecting its self, it may well be overloaded.

AnswerID: 518917

Reply By: Member - Boobook - Monday, Sep 30, 2013 at 06:17

Monday, Sep 30, 2013 at 06:17
It will work fine. The whole Poly vs Mono thing is overplayed these days. You may lose a few percent of efficiency with different maximum power voltages but nothing to worry about.

With a PWM controller you will only get about 140W out of your 200W anyway. Change over to a MPPT and you will probably get another 15% average output current to more than make up for any losses. You can get 25% more in the mornings when the panels are cold, and you need it most.

Make sure you put blocking diodes in series with each of the panels to stop reverse current flow when you have panel shading, but you should do that with any combination of panels in parallel anyway. You will need 10A schottky diodes, available on ebay cheap.
AnswerID: 518924

Reply By: Member - John and Val - Monday, Sep 30, 2013 at 09:35

Monday, Sep 30, 2013 at 09:35

Panels are best thought of as sources of current, rather than voltage. You can connect poly and mono in parallel, and your PWM controller will pass the sum of their currents (ie up to about 16 amps).

An MPPT controller would increase the current reaching the batteries, as already suggested.



J and V
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AnswerID: 518931

Reply By: Garry S3 - Monday, Sep 30, 2013 at 13:29

Monday, Sep 30, 2013 at 13:29
you will be fine with mixing them on a PWM charger, not gonna change anything. Can consider MPPT if you like, but I think its not worth it if you are not on a big system
AnswerID: 518954

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