tying together sharp panels

Ralph Day

Hello
I have an array of 2x175 Sharp panels and want to add 2x180 Sharp panels to it. Problem being the leads on the 180's might be too short to connect to each other for wiring together. To avoid pulling the already mounted 175's off the sattelite dish mount, can i wire each existing 175 (24 volt) with one 180 (also 24 volts)? THis would make life easier.

Wanting to avoid ruining diodes on panels if this is verbotten. Of course, by the time the power gets to the MX-60 it doesn't care, it's all from the sun.

Thanks

ralph

edit:
Present config 175+175
proposed config 175+180 175+180

or must I 175+175 180+180

niel

Re: tying together sharp panels

you can run it 175 and 180 in series, but it'll just basically act like 2 175s in series. the 180 will sacrifice some current, but a slight rise in voltage from it will occur amounting to not enough to make up for the current lost. it's all irrelevant as it gets utilized efficiently in the mx60 through its mppt circuitry. i say go for it. running straight 175/175 and 180/180 would also suffer a small loss so this is a case of what's easier for you.
on the subject of diodes, most controllers these days don't allow the nightime backfeed of current, but during the times the 2 strings receive differing amounts of sun a small amount of current could be dumped into the string most shaded from the other sunnier string so you may wish to judge for yourself if blocking diodes are warranted. you may have been thinking to incorporate bypass diodes, but the pvs do contain builtin bypass diodes making that unnecessary.

Ralph Day

Re: tying together sharp panels

Thanks Neil

Problem figured out, just need the right number of arms...4. How far the panel's leads go, that will determine the final configuration.

thanks

ralph

crewzer

Re: tying together sharp panels

There's little real difference between the two modules' voltage and current specs, especially when you factor in production tolerances. I agree with niel... wiring up a 175 and a 180 in series will work just fine.

Regards,
Jim / crewzer

Ralph Day

Re: tying together sharp panels

Problem solved...the leads from the new panels reached the combiner box, didn't need to wire 175 with 180 panels at all. Thanks for your help.

ralph