Solar Battery in Cold temperatures

184 Posts


Hello, can anyone tell me if a Solar Battery installed in a cold garage has less stored energy in the winter than in the summer?
I had my Solaredge 10kWh (9.7kWh usable) battery installed recently in November and noticed I get approxtimately 6.5kWh- 7.5kWh of battery power after looking at some charts and numbers.
At a base discharge rate of around 260w-300w through the night I lose 1% every 15 minutes, which would mean about 6.5kWh - 7.5kWh in 375minutes @ 100%.
This seems to be a 30% loss from what is advertised.
Thank you
I had my Solaredge 10kWh (9.7kWh usable) battery installed recently in November and noticed I get approxtimately 6.5kWh- 7.5kWh of battery power after looking at some charts and numbers.
At a base discharge rate of around 260w-300w through the night I lose 1% every 15 minutes, which would mean about 6.5kWh - 7.5kWh in 375minutes @ 100%.
This seems to be a 30% loss from what is advertised.
Thank you
0
Latest MSE News and Guides
Replies
According to Octopus energy my consumption was 250-300watts per hour before solar/battery was installed.
I suppose with the additional inverter usage and losses it would add up to 9.7kWh battery capacity
This article seems to explain that:
'Most batteries are rated at 77°F (25°C), meaning their technical specs are based on how the battery's cells perform at 77 degrees. As a rule of thumb, batteries lose about 10% of their rated capacity for every 15-20 degrees below 80°F as measured in the cells.'
If I apply that to my Solaredge 10kWh battery in the garage which is currently 0c, but the internals of the battery reads about 3c due to discharging it would mean out of the 9.7kWh 'usable' energy I should be getting 7.7kWh which is close to what I charge from 0%>100%.
I seem to be the only one who has flagged this up, can't seem to see anyone else in UK that has their battery stored outside have this issue so uncertain.....
I'm puzzled by the idea that winter has an advantage - what advantage is that?
My first suspicion was when the battery couldn't take me through a whole day use when I averaged about 10kWh a day (19 hours) (5 hours off peak electricity). It kept falling short a few hours before off peak hours.
I then looked at my base usage at middle of night when noone is using power except fridge/freezer/boiler etc which turned out to be about 290watts/hr which it drained 1% every 15 minutes (4% every hour)
Doing the math that would mean 100% = 7.2kkWh
I also had a look at the Solarview app which showed me how much it charged up from 0% > 100%, beween last 'Lifetime charged' and next 'Lifetime charged'. That also showed about 7kWh charged added.
The app also told me I had about 8kWh capacity which seemed optimistic.