Legality of combining off-grid with current PV Installation

[danesol]

Just been looking at SunnyBoy Backup and MultiCluster Boxes..... I was thinking if I connected another array ( totally off grid ) to an existing PV Installation - does that still count as an increase in the PV installation given that the off-grid would only supply the DC energy created to backup batteries which later could be either channelled through the Inverter at night or to be used within the home ?

 

[nowty]

I had thought of a similar thing a few months ago. To have an off grid system charging a bank of batteries and then drip feed them with a current limiting circuit through an inverter (either existing one or a new one depending upon the legalities) overnight to give an AC output of 1 or 2 amps to offset my background house load.

If through the existing inverter it would not alter the DNC or TIC of the system (at least some of us on this forum would think that). Of course your FIT supplier would have difficulty in understanding it even if it was legal.

 

[methley]

If you use your existing inverter then your total generation meter would also clock up your night-time usage! I'm sure your FIT provider would notice soon enough that your system was out-performing its targets by a considerable margin...

 

[nowty]

Absolutely but would it be against any known rules ?

 

[danesol]

Absolutely but would it be against any known rules ?

My point exactly and if not how can installers possibly fit SunnyBoy Backup units in the first place ??

 

[methley]

The Sunny Backup product incorporates its own inverter, hence nothing is piped through your generation meter when in "backup" mode.

http://files.sma.de/dl/2485/SBUPSYSEM-KEN112718W.pdf

If you suffer a grid outage during daylight hours, then your Solar PV array will compliment the output from the backup system and you'll be abe to take advantage of both. In this case the total generation meter registers as it would normally if the grid hadn't failed. The whole system will be disconnected from the grid in this scenario.

Have a look at the posts from Joey in the linked thread who explains all this in simple terms...

http://forums.energymatters.com.au/solar-wind-news/topic1011.html

 

[MorganPVI]

Sunny Backup or G59 relay seems to be the only way.

Biggest problem is sizing the DC side of the PV generator for winter months, a 1.5kwp array gives you about 1kwh of usable power in the winter per day. Decent batteries will set you back anything from 2.5-3.5K for the pukca 2v wet acid.

Sunny backup seems a great idea, but the cost of replacing/buying the batteries wipes out any electric savings, it's a marginal call to save anthing once the cost of installation etc is taken into condsideration. Of course if electricity rises in price it could be viable.

I really like the idea of off grid power so have invested in a system for research purposes!

 

[finchy]

Good on you MorganPVI (become a real innovator) ! There really is a growing demand for this, as energy prices increase & technology change the viability of such battery systems will certainly be part of a standard Solar PV install.

However much the governments discouragement or lack of commitment to solar energy its up to us to innovate it and drive the technolgy forward. The government will have to re-think its support for Carbon solutions as the public realise who's running the DECC. Power to the people !!

 

[LightGEN]

We took a good look at SunnyBackup and came to the same conclusion. A mains gas operated generator makes more sense if all you want is a backup solution.

 

[LightGEN]

Sunny Backup or G59 relay seems to be the only way.

Biggest problem is sizing the DC side of the PV generator for winter months, a 1.5kwp array gives you about 1kwh of usable power in the winter per day. Decent batteries will set you back anything from 2.5-3.5K for the pukca 2v wet acid.

Sunny backup seems a great idea, but the cost of replacing/buying the batteries wipes out any electric savings, it's a marginal call to save anthing once the cost of installation etc is taken into condsideration. Of course if electricity rises in price it could be viable.

I really like the idea of off grid power so have invested in a system for research purposes!

We took a good look at SunnyBackup and came to the same conclusion. A mains gas operated generator makes more sense if all you want is a backup solution.


....I'd have deleted posting number 9 if I could have found a way to do so!

 

[danesol]

We took a good look at SunnyBackup and came to the same conclusion. A mains gas operated generator makes more sense if all you want is a backup solution.


....I'd have deleted posting number 9 if I could have found a way to do so!

Yes, that may be true but I was more interested in feeding the Inverter at night with all the saved energy in the batteries, so as to get even more tariff at 43.3p/kwhr