Solar panels and battery - any real world reccomendations?

rodders said:
Where do you locate it, what's your house insurance say about it?
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I have mine set up in the workshop in the garden, self built lifepo4 8S pack, running the house off it at this moment. (Just connected to the ring main from the house in there)
Another shipment of 8X280Ah OTW from China, be here next month so another 7KW will be added.
 
Cracking day to have solar, rest of the week looks good too. I'm investigating getting another battery sooner rather than later, given the current global situation while stocks are quite easy to get.
 
Tempted to buy a single Tesla powerwall and get it installed. We've had solar since 2012 so get paid a pretty penny for generation but it'd be nice to run off battery power in the evenings to cut the energy bills.

My main incoming supply splits:
  • 1 leg to a consumer unit in the house that's linked to a 4kW solar system
  • 1 leg to a consumer unit outside the house that's purely for shed lights and EV charging (2x chargers)
I made the decision to keep the install simple (it would have involved digging and having wires chased in to and tacked on the house) hence why I chose to split the supply. I looked at 3-phase but after speaking to Western Power I found that the transformer at the end of the estate wouldn't cope with the supply and I'd be personally responsible for the upgrade (circa £14k). No thanks!

In a way I think it'll work for me having a split supply as I don't particularly want the EV chargers to drain the powerwall every night - having 2x EVs draining the battery every night would surely ruin it and I can't afford 2 powerwalls :D

Am I mad? My goal is to use the battery to take the house "off grid" when the solar isn't generating and take advantage of the cheap off-peak cost for charging.
 
EVH said:
Western Power I found that the transformer at the end of the estate wouldn't cope with the supply and I'd be personally responsible for the upgrade (circa £14k). No thanks!
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I had this lovely conversation with them also.

EVH said:
single Tesla powerwall
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A powerwall is only 13KWH when I last looked and the price was double going for something like Pylontech.
 
Journey said:
Can you fit a secondary solar system on another inverter/meter, as well as getting a battery?
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No, my entire roof is one big solar array. Unless you meant something else?

kindai said:
I had this lovely conversation with them also.

A powerwall is only 13KWH when I last looked and the price was double going for something like Pylontech.
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I'm a noob when it comes to batteries. I liked the look of the Tesla unit but if there are others out there, I'll take a look!

Just prefer to have something that will look good on the side of the house and not like someone's electronics GCSE project :D
 
jpaul said:
so they are about £200 each ? https://offgridvan.life/shop/eve-280ah-32v-lifepo4-battery-cells

what is the timescale for LFP battery availibility, so, like for solar pv panel's aren't battery prices going to drop dramatically such that waiting to engage maybe prudent ?
(if we remain in good contact with china)
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I just paid £670 minus £31 topcashback for 8X280Ah including shipping and Tax......just under £640 all in for the 8 cells

They take 2 months to arrive from China.


PEkxsomh.jpg
 
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Troop said:
I just paid £670 minus £31 topcashback for 8X280Ah including shipping and Tax......just under £640 all in for the 8 cells
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wow - so all in with an invertor you could have 7KWhr for £1K .... and if you used 7 units a day and saved 20p/unit grid charging overnight - it would have paid for itself in 2 years.
 
^^^ you would need a BMS and a grid tie inverter to go with the Cells.

WARNING!! you need to be very careful with what you're doing as the energy they hold and discharge is huge if shorted.
 
Yea I'd be really careful about DIY batteries, you need to really know what your doing, I also suspect if you did it, and didn't get the appropriate sign offs, it would almost certainly invalidate your insurance if your house were to go up.

Ive seen what a 2 cell LIPO for a remote control car can do when it goes up, let alone a several KW equivalent.....
 
Just had the leccy bill, all electric house in use 24/7 with 2 people, electric hot water.
One medium storage heater on @ 50% (bottle gas for cooking/wood multifuel for most of our heating 3 bed house).

This is what can be done with 3 solar panels and a battery, panels ground mounted in the garden
Octopus go rate making as much use as possible of the cheap rate 12.30-4.30AM.

Feb13 to March 12 cost.

m6pCEIlh.jpg
 
Troop said:
Feb13 to March 12 cost.
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(initially I thought you were showing bill for a year) - so how much have you generated ?
e: ... and how much have you time shifted.

BUDFORCE said:
Yea I'd be really careful about DIY batteries
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Of course - the question is what is the price per Kwhr for your own batteries, how much that is declining too,
Musk was talking about sub $100/Kwhr in cars as a target; their seems to be some controversy how they will warranty batteries with car where feed into home grid is permitted, but witht the ev6, you could charge is at 4p/unit and use some of that during peak evening hours.
 
Troop said:
Just had the leccy bill, all electric house in use 24/7 with 2 people, electric hot water.
One medium storage heater on @ 50% (bottle gas for cooking/wood multifuel for most of our heating 3 bed house).

This is what can be done with 3 solar panels and a battery, panels ground mounted in the garden
Octopus go rate making as much use as possible of the cheap rate 12.30-4.30AM.

Feb13 to March 12 cost.

m6pCEIlh.jpg
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That is low usage though. Most on here are 500kwh per month+
We live in a detached 5 bed and our usage is around 700kwh per month.
 
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