mastervolt xs4300

[sime27]

Had a call today from a customer of ours saying his pv system was underpreforming.
Ok so i went round . System is 2xstrings 8 panels per string xs4300 inverter.
1st thing i did was check the dc voltage on the inverter it was displaying 105v dc 6.8amp and 800watts
So i thought somthings not right voltage should be way higher
So powered down unpluged mc4s and tested voltage at the mc4s for each string
I was getting 268v on both string
So i pluged it all back in and powered up this time i had my probes into
The loads side of 1 of the dc isolators which was still reading 268v
But as soon as the inverter kicked in it reduced to just over 100vdc both
On the inverter and the dc volt meter .
Anyone had anything like this before looks like a inverter fault to me
But want to be sure before i get a replacement unit

 

[Worcester]

Sorry I can't comment on the xs4300 inverter, Just bear in mind that this heat is causing a reduction in outputs see this thread: http://www.electriciansforums.co.uk...55-spring-versus-summer-system-results-2.html

 

[sime27]

Thats what i told the customer on the phone .
But after testing a voc 268 per string which then drops to 100vdc when systems running dont seen right

 

[Worcester]

Depends what the mppt voltage comes out at .... have you checked out the power curves on the panel data sheet..