More panels or more battery

irishchris · 16-01-2022 2:05pm #1

Looking for people's advice as to which they think would be better investment. I'm currently in two minds at to whether to do an extra 2.5kw self install array or DIY battery.

Currently have

1) 2.5 inverter with 2.88 panels

2) 6kw inverter with 4.3kwp panels.

3) 9.6kw pylontech batteries

Was thinking of adding an extra 2.5kwp panels to the 6kw inverter whilst understanding in peak months will have max 6kw set for export. Was going this route to ensure on more cloudy days in spring and autumn to get max production and also to aid winter dire months.

Could go the route of getting 10kw battery from aliexpress. Money at the minute though would restrict this to 10kw until sell the pylons and would get another 10kw to add. Again not sure how easy to sell pylons would be.

Daily usage here is generally 10-16kw depending on season with no ev in immediate plan but should either of our cars pack it in then ev would be next motor.

Siding towards more panels but thought would ask here on others opinions first

bullit_dodger · 16-01-2022 2:35pm

What's the orientation on 2) the 4.3Kpw panels? Are they all in one string? Or split into two. Asking as if they are split, you may not hit that 6Kw limit.

Like you Chris I'd be inclined to go with the panels. My logic is that I don't think you'll be able to cycle more than 10Kwhr every day with that usage - bearing in mind that for 9 hrs of the day you have night rate costs anyway, so the battery's main earner would be covering for day rate. So of that 10-16Kwhr you using, how much is in the day?

My daily consumption is 32-35kwhr, pretty stable

I reckon any more than 13-14Kwhr would be a bit of a waste for me. I couldn't "cycle it" daily. Now, that said, there are some other reasons to get a bigger battery, for example if you had a HUGE battery, you could fill that mother up on a sunny day and if the next day was cloudy you could "ride through" until the next day.

Still though, panels are the whole engine here. If you're thinking (like me) that EV will be in the mix in 1-2 years......I think you know the answer. :-)

graememk · 16-01-2022 4:03pm

as you already have 9.6 of pylontechs, going aliexpress, Would mean selling the pylontechs and you'll be getting the same, Would only go DIY pack if going 20kwh. And did the 9.6kwh cover to night rate in the summer?

With the 6kwh inverter, you could put the 4.3 all on one string, (From memory it looked like you had the longi panels).

If you had the space, you could go for another string of 4.3 (12 panels) and set them at a steeper angle to catch the low sun in the poorer months.

And as always, your hitting a diminishing returns on it being worthwhile.

irishchris · 16-01-2022 4:09pm

https://www.boards.ie/discussion/comment/118484274#Comment_118484274

The orientation is south and was split into 2x6 panels. New setup would be 12 on one array at south and new array of 6/7 panels at SW.

On average 10-12 KW of the usage would be from morning to around 10pm and only about 2kw for test of night

I'm starting to think that correct answer here alright is panels

irishchris · 16-01-2022 4:09pm

https://www.boards.ie/discussion/comment/118484791#Comment_118484791

Yes idea would be to sell the pylons to eventually purchase 20kw. To be honest the 2.4kw battery I originally had last summer covered me nearly through the full night so 9.6 will definitely cover me for late spring/summer and early autumn. In winter though with night charging it covers me through most of the day/night but on particularly bad days I struggle and was also hoping to be able to charge it up through summer and cover bad cloudy days but may be better value in panels the more I think about it

slave1 · 16-01-2022 5:36pm

Both, selling the Pylontechs will all but pay for a 20kWh DIY battery install

More panels or more battery

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