Multiple strings vs Higher voltage single string

[binky]

Thanks guys, That's probably the best solution....now I just need an extra 4 foot of roof space

Think I'll live with it for now, maybe revisit once the batteries are installed.

alternatively you could buy a 3 kw inverter which start up at 90V rather than 120V, and I think you can use the existing inverter as an AC battery setup, not directly connected to the panels. The other option, apart from buiding an extension, is to look at the Tigo panel optimisers and connecting via a single string. I've never fitted the Tigos, so do please check the info about how they work and compatibility with our inverter.

 

[glenns]

alternatively you could buy a 3 kw inverter which start up at 90V rather than 120V, and I think you can use the existing inverter as an AC battery setup, not directly connected to the panels. The other option, apart from buiding an extension, is to look at the Tigo panel optimisers and connecting via a single string. I've never fitted the Tigos, so do please check the info about how they work and compatibility with our inverter.

Thanks again Binky, some decent ideas there. I'll check out the tigos but hopefully we'll get our extension up soon.

Now, finding a reasonably priced builder...that's a real challenge!

 

[binky]

Thanks again Binky, some decent ideas there. I'll check out the tigos but hopefully we'll get our extension up soon.

Now, finding a reasonably priced builder...that's a real challenge!

Builders tend to be Mr 10% types. It can be cheaper to organise different trades yourself sometimes.

 

[glenns]

Builders tend to be Mr 10% types. It can be cheaper to organise different trades yourself sometimes.

Definalty... and right now they seem to be making stacks while they can. I'm all for people making money but got quoted 10k for a 15m trench fill seems to be taking the pi$$

 

[binky]

Definalty... and right now they seem to be making stacks while they can. I'm all for people making money but got quoted 10k for a 15m trench fill seems to be taking the pi$$

it's fair to say materials have also shot up in price, but that does seem rather steep. Buiders also have a habot of overpricing work if they are busy. I never understood people doing that as it ruins your reputation for when things go quieter.

 

[stuboy]

If your panels are facing the same direction and there is no shading, simply "seriesing" them up will solve all your problems. It used to be even worse with the SMA Sunny Boys as they had a 175v startup but once alive it would run on a much lower voltage, I never really understood that?! Off the top of my head I think your threshold is 120v on the inverter you have? The on off fix is that when you take the panels off line they are not on any load so float up to whatever their no load voltage is, when you crank the switch back over it sees the higher voltage and says ok that's enough I'll switch on now. If this was installed by a "professional" they did a s*** job! They clearly need to go back to school and take a basic course in maths;-)
Hope you get it producing like it should
Cheers
Stuart

 

[binky]

If your panels are facing the same direction and there is no shading, simply "seriesing" them up will solve all your problems. It used to be even worse with the SMA Sunny Boys as they had a 175v startup but once alive it would run on a much lower voltage, I never really understood that?! Off the top of my head I think your threshold is 120v on the inverter you have? The on off fix is that when you take the panels off line they are not on any load so float up to whatever their no load voltage is, when you crank the switch back over it sees the higher voltage and says ok that's enough I'll switch on now. If this was installed by a "professional" they did a s*** job! They clearly need to go back to school and take a basic course in maths;-)
Hope you get it producing like it should
Cheers
Stuart

I chose a Power One for the lower start up voltage compared to SMA when I installed my own system 11years ago. Seen that run down to as low as 7watts before shutting down. Small differences, but they add up over the years.

 

[bladerunnerpv]

I stayed in a holiday property near Bude recently which had an Aurora power one, seemed to work nicely. I had a look to see if they were still available but ABB have now sold off their solar inverter business
https://new.abb.com/news/detail/577...tment-of-solar-inverter-business-to-fimer-spa

 

[bladerunnerpv]

HI, just curious, which batteries are you using with this system please?

 

[glenns]

HI, just curious, which batteries are you using with this system please?

2 x Pylontech 5000 from ITS Technologies ... they are working great

Currently using less than half kW of grid power each day, batteries only discharge to 65-70% from 19:00 to 08:00 the next day, full again by lunchtime from solar.

I'm on the Octopus Go tarrif and have the inverter set to charge from 00:30 to 04:30, but disabled for now.