Lux ac battery controller

chainreaction

What rate are you getting for your deemed export? Eon give 16.5p/kWh on their SEG if you are supplied by them.

orrery

chainreaction said:

What rate are you getting for your deemed export? Eon give 16.5p/kWh on their SEG if you are supplied by them.

5.07p, index linked of course.

chainreaction

orrery said:

chainreaction said:

What rate are you getting for your deemed export? Eon give 16.5p/kWh on their SEG if you are supplied by them.

5.07p, index linked of course.

So I jumped ship when I was getting 6.5p last summer and it is certainly worth it. Basically I start exporting at around 7 am until sun goes down at 16.5p/kWh.  Then top batteries overnight at 6.7. I still get the FIT generation payment. I reckon I make at least 3x the deemed export payment.

philologus

I currently have 16 x 300w panels on a 22 degree E/W facing roof in two arrays of 8.

My inverter is a Lux 3.6 hybrid.

These have been in operation since 10.05.2019 (6 years tomorrow.)

I have gradually built up to 19.2kWh of battery storage. (8x 2.4 Pylontechs.)

For about £1k I can now buy 16 x 440w panels. For not much more than that I can get 16 x 600w panels.

Is it worth doing a replacement? Would they be a direct replacement and therefore easy to fit?

Would I need to upgrade the inverter too? 

As always - all thoughts/suggestions welcome

chainreaction

philologus
Number of things to think about. 
Do you have FIT
Current set up what has been annual production. What is max achieved on each string currently, eg today if it was a sunny day, this will give you an idea of potential clipping with 600w panels (or even 440w)
What is your export rate payment? 
How much extra to buy the 600w panels. 
If you want to go for Max export you'll need a bigger inverter.

philologus

Best day of the year so far today

30.2 production

13.3 to Grid

8.4 Consumed

66% currently  in battery.

No FIT

Export rate payment is variable (Octopus Agile) but I can change tariff and get 15p

I've had a 10% off voucher offer from Solaren that woul mean that:

16 x 600w would be £1,760 

JA Solar Panel 600W Glass Bifacial N-Type Cells Monocrystalline

16 x 440 would be £1136

Renesola Bifacial Solar Panel 440Watt Front 90W back Half-Cut

QrizB

philologus said:

 Would they be a direct replacement and therefore easy to fit?

Check the dimensions, panels have got larger. It might not be a simple job to swap them.

I've got eleven 250-watt panels. They're the standard size for 2012, which was about 1600x1000mm. Hardly anyone makes domestic panels that small any more.

chainreaction

What was the peak power from today for your east or west strings?

Martyn1981

You'll need to check sizes carefully as QrizB mentions. Panels now are typically wider, and both of those you mention are 1.134m. Length of 'normal' panels these days tends to be longer too, at around 1.78m, and the smaller panels you list are 1.772m, the more powerful ones being 2.278m.

So I'd guess that you struggle to fit the same number of panels in, but doesn't mean you can't fit a few less, and still get a biggish bump in kWp.

Regarding the inverter, I'm not 100% sure what your exact model is, so you'll need to go on-line and check its datasheet. But the two 3.6kW hybrid models I looked at, both said they could handle upto 7,000Wp on the DC side. So 16 x 440Wp would just exceed this (the 600Wp would be way too much), but fitting one less panel (or more) would be OK.

Is your battery on the DC side? If so, then you could prevent clipping, so long as the inverter can put some of the generation to the DC batts and some through the AC side. Until that is, the batts are full, then gen will be clipped to the AC side max.

You could of course go for a larger inverter, but you'll need to get the installer to apply to the DNO for permission to exceed 3.68kW.


Just to say, I did something similar last year. My old 2011 system had 13 small 185Wp panels on the main roof, and 5x 235Wp panels on the lower roof. I added a groundmount of 4x 530Wp panels, and whilst at, took the opportunity to swop out the easy to get to lower 5 panels for 440Wp. The inverter (and permission) was already at 3.68kW, so I was able to swop in the newer hybrid model with 3.68kW AC, but 7.36kW DC (and batts) and avoid any need to change DNO permission limit.

The 440Wp panels were roughly 100mm wider, and 200mm longer, but there was just enough spare space for these to be installed, after the rails had been replaced with longer ones.

philologus

I've forgotten where to get the info about how much each string has produced today.

Current pamels are:

Length  1.640

Width 902

Depth 35

Weight 18.1Kg

The current inverter manual says it can handle up to 7000w

If I got 15 x 440's to replace the 16 x 300's I'd get an increase of 37.5% in production and the inverter could handle it.

On a day like yesterday (30 produced) that would increase to 41

On a day when I'd normally get 15 it would increase to 21.

That's significant, but I'll have to work out the costs now.to see how long payback would take.