Solar PV battery options

i might try that at the next board meeting. To be fair the CFO is making great strides in using big ticket items after 11pm already and the electric shower is growing cobwebs.

Have an email sent to Puredrive so will wait for a response.

Looking at the video clip linked earlier it implies that all cables are included, will find out in due course I suppose. Hard to get a price for the battery, seems to be ranging from £1500-£2500.

I also wondered previously if there was an (ideal) ratio of battery size to panel Kwp. Assuming you size your panels correctly to match (needed) production that is, the figure I came to was about 50% greater. e.g. if you have 4Kwp in panels then you'd have 6Kwhr in storage.

Where did I get those figures? Guess work to be honest mostly. The reality is that there are so many variables that it's impossible to have a general figure. Some people are 100% south, others east/west with the same Kwp.....so consequentially they will generate and consume differently. So they will need different sized batteries to get to night time rates (if that's in fact one of the objectives). So it's hard/impossible to have a ratio for it.

One thing I've noticed is that 2.4Kwhr battery is waaay better than nothing, but really it's just too small for the average household in Ireland. Average household needs ~5Kwhr these days.

Not sure I agree with you there championc that it would be pointless. A 2.4Kwh has it's uses. If you were to graph "usefulness" verses "capacity" those first couple of Kwhr are the ones which are easily filled and used. So in some respect they have the highest utilitarian value. it also has the ability to help give you ability to turn on the kettle (2kw) and not draw from the grid when you might only be getting a solid 1.2Kw from the sun. Sort of trickle charging over time to fill up and then giving you "some" ability to turn on larger loads without importing when the sun is shining. Along with helping reduce your export of course.

But yeah, I think 5Kwhr for an average household is needed these days. 2.4Kwhr as you say doesn't tally with the loads we place on them.

Your right poker - it's a complex problem and there isn't really a magic answer that solves everyone's scenario.

If we're talking pure economics though, I struggle to see the argument for "no battery". The problem with solar is that by nature of our weather, it's not constant on a day by day basis, especially in Ireland. Monday can be blue skies and Tuesday a gale coming in off the Atlantic. Even during a day you can have it (like yesterday) snowing before lunch and blue skies in the afternoon, although to be fair that's an unusual case.......but (obviously) it does happen.

Virtually nothing up until 12:15 and then it cleared up a lot and in the afternoon from 1pm to 2:30pm was decent enough. Basically 6x times the production before noon! The reason why I bring that up, is that it's difficult to know when to put on the tumble dryer or the dishwasher to take advantage of your production.

You've paid for the panels and the inverter, so anything your not using your exporting to the grid. We're not there yet, but when they do bring in a FIT, they'll give us what 5-6 cent/unit? Yeah, I'll take it..... but had I put that same unit into a battery and used it an hour later I'd reap 22 cents (day rate with SSE) . so then it becomes a equation of how much capacity do I need to get me through the night (or at least stop me from having to use day rate).

Having a storage capacity helps you increase your self-consumption. It's smooths over the sun behind the cloud for 20 mins. I think that's an easy argument for a battery, it's the size of one to get which is tricky. That's more down to your consumption. If your average (4000/year) I'd say 5Kwhr is about right....

Go back to about page 40-45 in this very thread.

Us3000 sand us2000 can be mixed easily but you have to have the 3000 as the master battery so basically it is the top battery with the can cable in it. Wiring instructions can be found online or in the booklet with the battery. Plug and play really as you just click the positive and negative terminals on to one and to the correct polarity on the next one and away you go. Obviously the positive cable from inverter goes to the top master battery and the negative to inverter on the bottom battery

This is probably a better shot of the situation (as the slope of the roof infront of the "v" matters)

You'd definitely be fine to put 8-9 panels in there above the velux window. You might get poor production in the dead of winter as the roof in front might block the extremely low sun to the south (mid december it only gets to 15 degrees or so above the horizon), but other than that, you should be fine. They'll have to "build a tower" to gain access to the roof though. it's out of a ladders reach

Note: Probably not the best folder for this - which is about "battery options"

Have you decided it's a no-no for panels on the front roof ? If so, I'd be rethinking that. Who gives a fook what's up there, and if that is the house, it's three stories up and not two, so not that visible from the street. Besides, black panels in black frames are really not that noticable and are quite flat to the roof.

Take the discussion over to a more appropriate thread