panels power rating

[h_1985]

hello

i have a question about panels power ratings in a project

is that necessary to use the same panels in one project or i can use different panels ratings (power , voltage, current, ....)??

[inetdog]

hello

i have a question about panels power ratings in a project

is that necessary to use the same panels in one project or i can use different panels ratings (power , voltage, current, ....)??

It really comes down to two key characteristics of the panels involved, Vmp and Imp.

If you are putting the new panels on a separate MPPT input (to either GTI or CC) then nothing matters except cost and physical size for installation.

If you will be putting new panels in series with old panels (or strings) the Imp numbers of the two panels should be within 5% of each other.
If you will be putting new panels in parallel with old panels (or strings) the Vmp numbers of the two panel types should be within 5% of each other.


Power rating by itself is never an issue. Always Vmp or Imp.

[h_1985]

It really comes down to two key characteristics of the panels involved, Vmp and Imp.

If you are putting the new panels on a separate MPPT input (to either GTI or CC) then nothing matters except cost and physical size for installation.

If you will be putting new panels in series with old panels (or strings) the Imp numbers of the two panels should be within 5% of each other.
If you will be putting new panels in parallel with old panels (or strings) the Vmp numbers of the two panel types should be within 5% of each other.


Power rating by itself is never an issue. Always Vmp or Imp.

Thanks for your reply

in other words if i have two panels from this

with one panel of this type

in a small pilot installation

can i use this mix ??

[inetdog]

The difference between 25V and 29V (Vmp/Umpp) is too high for parallel operation and the difference between 8.3 and 8.66 in Imp is a bit large for series operation.
But if you have the panels already, I would try them in series (if the sum of the voltages is withing the input range of your equipment!) and see what happens.
Depending on the MPPT algorithm used by your device, you may also be able to get away with putting them in parallel.

You did not say whether the panels would be feeding a GTI, or a PWM or MPPT CC.

[h_1985]

The difference between 25V and 29V (Vmp/Umpp) is too high for parallel operation and the difference between 8.3 and 8.66 in Imp is a bit large for series operation.
But if you have the panels already, I would try them in series (if the sum of the voltages is withing the input range of your equipment!) and see what happens.
Depending on the MPPT algorithm used by your device, you may also be able to get away with putting them in parallel.

You did not say whether the panels would be feeding a GTI, or a PWM or MPPT CC.

panels will feed MPPT CC

[inetdog]

panels will feed MPPT CC

OK. CCs generally take lower input voltages than GTIs, so make sure that your CC will accept an input of at least 90V (to leave a margin for low temperatures beyond the sum of the listed Voc values) before connecting the panels in parallel.