Matching existing solar panels

[boondox]

Hi All,

An off grid pal of mine is finally upgrading his system. We installed a new inverter and batteries a couple weeks ago. Now he wants to add some more solar panels. Naturally, since the system is 6-8 years old the same panels are not available. My understanding is that as long as we get new panels with as close a VMPP as we can find the rest of the specs don't matter too much. True or false?

Thanks!

 

[JoeHam]

Hi All,

An off grid pal of mine is finally upgrading his system. We installed a new inverter and batteries a couple weeks ago. Now he wants to add some more solar panels. Naturally, since the system is 6-8 years old the same panels are not available. My understanding is that as long as we get new panels with as close a VMPP as we can find the rest of the specs don't matter too much. True or false?

Thanks!

For series panels you want matched Voc.

For parallel panels you want matched Isc.

 

[Forbisher]

An off grid pal of mine is finally upgrading his system. We installed a new inverter and batteries a couple weeks ago. Now he wants to add some more solar panels. Naturally, since the system is 6-8 years old the same panels are not available. My understanding is that as long as we get new panels with as close a VMPP as we can find the rest of the specs don't matter too much. True or false?

Is the existing Solar Charge Controller maxed out with panels now or are you replacing the SCC?
If you buy a new Solar Charge Controller for just the new panels you wont have to match the old panels.

 

[boondox]

Thanks for the help gents. As always, I should have provided more details.

Current set up is two strings of three in series. 3S2P. We want to add two more strings. Charge controller is a Midnite Classic 150, so plenty of room left on that.

If the VMPP is not matched, we will lose some of the value of an MPPT, no? The existing panels are Solarworld SW 275's.

 

[JoeHam]

Not that simple and I stand by what I said earlier.

Read this to understand better, it’s how I learned about it!

Mixing solar panels – Dos and Don’ts • SOLAR POWER SECRETS

Mixing Solar Panels: Discover Now Dos and Dont's of Mixing the Same Types or Different Types of Solar Panels. Act Now to Save Your Money!

solarpanelsvenue.com

Hope that helps.