Solar PV battery options

unkel · 05-04-2022 09:38AM

Basing a decision to buy hardware that will last 40 years on your use case of today is short sighted. As we move away from fossil fuels, we will all use a lot more electricity going forward. The install of a few extra panels costs peanuts if you are having PV installed (either by an installer or DIY). No matter what your use case, it makes sense to maximise the number of panels on your roof for the overwhelming majority of households. Remember a significantly big install can also handle a lot of your hot water needs and there will be a feed in tariff at some stage that will easily pay off for the extra panels on its own, over the lifespan of the panels. Perhaps it will get so warm that we will need air conditioning in houses in summer. PV is a perfect fit for that

It is also unavoidable that gas / oil will become increasingly expensive as we have to phase fossil fuels out over the next few decades. Even now heating your water with immersion at night rate is already pretty much on a par cost wise with using gas / oil in an efficient boiler. And doing it with clean wind energy at night (or indeed from your solar PV panels during the day) is far more environmentally friendly

Think forward, folks!

harderthanf · 05-04-2022 11:33AM

Sorry if this has been asked, I see in the thread some people have their batteries and AC inverter in a garage or some sort of out-house or cabinet. Is anyone using the EPS port in this configuration?

I really need a solution to power the house when the grid drops (it is so common where I am). I am looking at the Sofar and a changeover switch to allow power from the EPS back to the array (to start generation) while switching off the main grid connection.

I'd like to move this to my garage but I think I will need an extra run back to the consumer unit and main invertered, located in the house. That is, if it is even possible at such distance.

mp3guy · 05-04-2022 01:53PM

Yes I do this, we installed an extra run of cables back from the outbuilding to the house for the EPS supply. What's the distance? You're probably fine.

harderthanf · 05-04-2022 02:25PM

Thanks!

It's about 30 meters. I already have a some 2.5mmsq going out, connected to the consumer unit in the house. Might be a little light on size for 3-3.5kw at that distance. So, I would likely need to up the existing cable to 4mmsq and then another another 4mmsq for the EPS connection back to the critical load side.

SD_DRACULA · 05-04-2022 02:30PM

I would definitely go bigger, at least 6mm2, maybe even 10mm2, you never know down the line.

mp3guy · 05-04-2022 02:32PM

30 meters is no problem, I'm pretty much double that. I have 16mm2 for my PV supply (11kWp) and 10mm2 for the EPS (5kWp). Future proof, but even for the PV supply I notice a voltage difference of 5V between the inverter and the house due to resistance, which caused me problems when exporting >3kW.

irishchris · 05-04-2022 03:01PM

https://www.boards.ie/discussion/comment/118884223#Comment_118884223

Yes mine is exactly 30m from inverter to consumer unit in house. No problems whatsoever but went with 6mm SWA. If I was doing it again I would go 10/12mm cable as expanded and am getting close to it's limits soon

harderthanf · 05-04-2022 03:05PM

Cheers lads. Plenty to think of!

graememk · 05-04-2022 03:31PM

https://www.boards.ie/discussion/comment/118884383#Comment_118884383

Yeah and just to chip in my main solar inverter is almost 100m away from the house, It is run on 16mm2 cable though.

mp3guy · 05-04-2022 03:55PM

https://www.boards.ie/discussion/comment/118884496#Comment_118884496

Out of curiosity I'd love to know the voltage your inverter measures versus what you measure in your house when it's exporting full whack.

graememk · 05-04-2022 04:31PM

https://www.boards.ie/discussion/comment/118884620#Comment_118884620

Hmm, Looking back on saturday, exporting about 4.5kw, its about 3-4V above what my emontx is measuring and my sofar me3000 is measuring.

Its close to the cutout but not quite there.

Baoithin66 · 05-04-2022 07:22PM

https://www.boards.ie/discussion/comment/118884249#Comment_118884249

Is installing panels on your garage depending on having a duct into the house to connect not the main fuse board?

SD_DRACULA · 06-04-2022 05:42PM

Me after 20kwh delivery today

And no it didn't come like this, that's a photo of the aftermath 😂

graememk · 06-04-2022 06:00PM

https://www.boards.ie/discussion/comment/118890450#Comment_118890450

what cells did you get?

John mac · 06-04-2022 06:03PM

need an unboxing video .. :)

SD_DRACULA · 06-04-2022 06:04PM

Not cells, dyness rack mount 5.12s

Could have been about 80 cells if I went DIY.

unkel · 06-04-2022 08:11PM

How much were they and any link to where you ordered them from? Reason you didn't go CALBS is you not comfortable to do the DIY build (with BMS)?

randombar · 07-04-2022 02:43PM

Hi All,

So batteries are en route. Exciting stuff.

Is there any guide someone can point me to in relation to my configuration.

I've come across bits and pieces here and there but I was wondering if anyone had a start to finish guide?

Nice one!

shanemc30 · 07-04-2022 06:04PM

https://www.boards.ie/discussion/comment/118890450#Comment_118890450

How much were these batterie system. Did delivery take long

Big Lar · 10-04-2022 12:13PM

Can anyone see any issues with stacking the batteries on the flat in rows of 4 as the pic ?

I could pull them out from the wall a bit to allow airflow

bullit_dodger · 10-04-2022 12:35PM

I didn't know, but I did find...

Lifepo4 on its side ?? | DIY Solar Power Forum (diysolarforum.com)

Which might be of interest (short answer is "no" it doesn't appear to be an issue). However, they do expand/contract a little, so I'd make sur that you have some clearance like you have in the photo at the top.

championc · 10-04-2022 02:14PM

https://www.boards.ie/discussion/comment/118906338#Comment_118906338

I'd stack horizontally like the vertical stack on the right side - so batteries lined up, on their edges, with their connections outwards

Big Lar · 10-04-2022 02:23PM

https://www.boards.ie/discussion/comment/118906402#Comment_118906402

On the side so 🙂, will report back any issues.

puntypower · 10-04-2022 03:21PM

Has anyone built a case for the lifepo4 batteries? Saw a video on YouTube that you build a case while they are at a low state of charge and have them tight in the case so that when they get charged and expand slightly it doesn't put pressure on the terminals and gives a longer lifespan?

Also what do people use to top balance the batteries?