some data from the Domestic system:
here is the charge plot from the Pylontech battery BMS`s for the last 14days.
the RED is the current, above the 0 line is charging,
below the o line is discharging.
the BLUE is the voltage, the battery's are 48v nominal,
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as the sun is starting to fade away for the summer, I'm using the cheaper night-time electric rate to charge the battery bank. . .
Agile Portal
agile.octopushome.net
in this example i charged between midnight and 3am . . . at the lower price of 11.65p/kWh
once the battery is charged, that will see me through till the following night . . meaning that ill skip the peak rates from 4-7pm of 37.8p/kwh
happy days !!!
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looking at how we do this. . . we set the battery timer to charge from midnight to 3am. ( on the Sunsynk inverter)
at full power - 8kw
at a SOC of 90% ( which leaves some headroom, incase the sun pops out the following day)
then,
from 3am . . . all day and night to midnight the following day,
its set to discharge as needed, up to full power, down to a battery minimum of 12% Soc.
..
in practice, this is what that looked like last night. . .
the yello is full power charge to the battery,
from the grid in blue,
till 215am, at which point the battery was 90% charged.
then we use the grid for the next 45mins.
at which point, the battery takes over and starts powering the whole house.
.....
here is yesterdays full plot. with next to no sun all day . . .
.
versus a good sunny day in July . . . where there is enough sun to keep the battery bank fully charged by mid afternoon,
then still be at 80% soc by mignight,
meaning that we only needed 15mins to to top it up over night.
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during summer i tweek the charge settings to that it charges from the mains to 70% soc at mignight, - leaving a larger 30% soc overhead for the sun the following day.
but what normaly happens is the battery will have a small topup chgarge over night,
then drop some soc during the day,
which is then topped up again by mid afternoon,
which will drop down through the rest of the day. .
until the cycle repeats. . .
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what about export?
well for me i try to keep all the power i generate.
im a power user at home, as well as in the van.
so on a very sunny day ill just about break even on gerneration vs usage.
so there is none left for export - which suits me fine.
if i wanted to export. . . id need to add more panels to get more solar. ( that means panels fitting on the house roof proper)
or reduce my daily usage.m ( wheres the fun in that?)
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This means that even in the dead of winter with no sun, I've halfed my electric bill by charging at the cheap rate over night and using that power throughout the day.
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