Solar Panel makes- & grid-tie vs off-grid panels

lazza
lazza Solar Expert Posts: 336 ✭✭✭
in General Solar Power Topics #1
HI forum

We have been offered a very good deal for some solar panels, but they are makes that I am not familiar with (until now we have only been working with Kyocera)

They are yuraku (china) and bauer solarenergie (germany).

My questions are:
  1. Does anyone know these makes and will the panels be reliable?
  2. One is for grid (bauer) and the other (yuraku) off-grid. I dont understand the difference, surely as long as you use MPPT in the off-grid installation you can use grid-tie panels, cant you??

Thanks very much for any pointers

Larry
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Comments

  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #2
    Re: Solar Panel makes- & grid-tie vs off-grid panels

    I've never seen any reliability comparison studies for ANY panels, if there are some out there I'd love to see them.

    And you can use an MPPT to make on grid panels usefull for off grid, but why bother if you don't have to.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #3
    Re: Solar Panel makes- & grid-tie vs off-grid panels

    The two major differences between GT and Battery system panels are:
    1. NRTL approvals (Nationally Recognized Testing Laboratories)--These are the ULs, CSAs, ETLs, TUV, etc. of the world. In North America, solar panels need to have NRTL approvals for building and fire code compliance.
    2. Output Voltage--Typically, for the less expensive PWM type charge controllers, the Vmp of the solar panels are Vmp~17.5 volts for 12 volt battery banks (or ~35 volts for 24 volt battery banks, etc.). This allows for the most efficient use of solar panel output power (on average). With modern MPPT type charge controllers, Grid tie panels Vmp which is usually >>17.5 volts is less important these days. And large Grid Tied designed panels are usually cheaper per watt than the (typically) smaller wattage panels designed originally for battery systems.
    As always, the devil is in the details. Make sure you understand all the various pieces of equipment and how they connect together before laying out cash for the hardware.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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