Economics of charging at 7p and exporting at 15p

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Stinsy
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Joined: Wed Jun 02, 2021 1:09 pm

Re: Economics of charging at 7p and exporting at 15p

#31

Post by Stinsy »

I'm not sure I subscribe to the idea of batteries having a limited number of cycles. Evidence points to temperature, calendar age, and deep discharging as being the key factors.

My stack is 5-years and probably a bit less than 2000 cycles old.
12x 340W JA Solar panels (4.08kWp)
3x 380W JA Solar panels (1.14kWp)
5x 2.4kWh Pylontech batteries (12kWh)
LuxPower inverter/charger

(Artist formally known as ******, well it should be obvious enough to those for whom such things are important.)
AE-NMidlands
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Joined: Wed Jun 02, 2021 6:10 pm

Re: Economics of charging at 7p and exporting at 15p

#32

Post by AE-NMidlands »

Stinsy wrote: Sun Dec 22, 2024 2:21 pm I'm not sure I subscribe to the idea of batteries having a limited number of cycles. Evidence points to temperature, calendar age, and deep discharging as being the key factors.
My stack is 5-years and probably a bit less than 2000 cycles old.
Which might be why Givenergy feel able to offer a 12-year unlimited cycle guarantee... (with a 4% floor. The next one claims to be 100% useable, but maybe they have just made it bigger and hidden the floor)
2.0 kW/4.62 MWh pa in Ripples, 4.5 kWp W-facing pv, 9.5 kWh batt
30 solar thermal tubes, 2MWh pa in Stockport, plus Congleton and Kinlochbervie Hydros,
Most travel by bike, walking or bus/train. Veg, fruit - and Bees!
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Stinsy
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Re: Economics of charging at 7p and exporting at 15p

#33

Post by Stinsy »

AE-NMidlands wrote: Sun Dec 22, 2024 2:41 pm
Stinsy wrote: Sun Dec 22, 2024 2:21 pm I'm not sure I subscribe to the idea of batteries having a limited number of cycles. Evidence points to temperature, calendar age, and deep discharging as being the key factors.
My stack is 5-years and probably a bit less than 2000 cycles old.
Which might be why Givenergy feel able to offer a 12-year unlimited cycle guarantee... (with a 4% floor. The next one claims to be 100% useable, but maybe they have just made it bigger and hidden the floor)
There are a few batteries that claim to be OK discharged to 0%. However in reality they just report “0%” when they are really at 5% (or whatever).
12x 340W JA Solar panels (4.08kWp)
3x 380W JA Solar panels (1.14kWp)
5x 2.4kWh Pylontech batteries (12kWh)
LuxPower inverter/charger

(Artist formally known as ******, well it should be obvious enough to those for whom such things are important.)
John_S
Posts: 378
Joined: Wed Jun 02, 2021 10:03 am
Location: West London

Re: Economics of charging at 7p and exporting at 15p

#34

Post by John_S »

wookey wrote: Sat Dec 21, 2024 4:18 pm
Doing Stinsy's sums for my kit I get:

Capacity 16kWh
Useable capacity 16kWh
(EVE tell us things are rated at 100% cycles and there is no point leaving a bit at the ends on LFP - let's take that at face value even though we dn;t really know if it's true)
Cost to fill £1.12(although they've not had much of a workout yet, it being December).
Received from selling at 15p £2.40
Profit per day £1.28
Profit per year £467.20
The above calculation assumes that the charge discharge process is 100% efficient. You will need to allow up to 10-15% round trip losses. Say 2kWh or 30 p per day.

Also, there will be some self consumption.
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