Hello @AlanB. I've a similar situation to you, albeit my batteries are Puredrive. No space internally so they went on an outside wall. Obviously IP-rated for external but I'd failed to appreciate how cold temperature impacts them. Charging current drops to a few hundred Watts once temp is around 3°C and then stops completely once it gets to zero or below.

I'm about to have a small timber lean-to built around mine, with 50mm Kingspan surrounding the batteries. I contacted Puredrive and they told me it was fine for the insulation to be in close contact against the batteries as long as I left the controls at the top accessible. I've also bought an 80W tubular heater to sit underneath the batteries, within the enclosure. I'm sure this will keep them warm enough. The small power penalty is worth it to take advantage of Cosy time rates to fill the batteries.

@dunlorn Thanks for your reply. Please keep me posted on your shed and heater. I'll let you know if simply wrapping the batteries in insulation has any effect. The CYG Skyline batteries are supposed to have built in warmers. However, I can find no confirmation that they do and am awaiting on CYG reply from their UK arm, Cambridge Renewables.

We have a givenergy 9kWh battery and it recommends a rain-snow roof shelter. Discussion with other users says batteries don’t like the cold. One way to help all batteries keep themselves warm is to charge them overnight, adjusting your charging rate for all of your low price period to keep it steadily warm. 
Your new enclosure needs to have removable panels for summer since no battery likes it too warm either.

Hello @alanb.

Wee heated lean-to enclosure now built and in operation. I've a wireless thermometer that's telling me it's 2.1°C inside (it's about -1 outside) so it's starting to make a difference, although really I need it to stay above 5°C I reckon to have full charging capacity.  I need to get a few brush edging strips to seal the odd gap and time will tell whether 80watts worth of tubular heater is sufficient for the task! 

@dunlorn Is there any ‘loft insulation’ under that roof?😉 Seriously though, a background heat of 80 watts should keep the frosts out if the insulation is sufficient. Otherwise, do you have a dog? 😉. Regards and Respect, it looks very neat! Toodles.

Thankyou @toodles, I am feeling quite pleased with myself I must admit. 50mm Kingspan all round but they are still fixed to a cold stone wall sucking the heat out and 2m away from my heat pumps expelling freezing air 😱 so it has some work to do! 

I'm now thinking of what tools I need want to spend with the money I saved building it myself! 

@dunlorn Hi Simon. Hmm impressive enclosure. Fancy a trip to Bucks to fit on for us?? 

I have now fitted foil faced insulation to the 4 batteries and it's made a difference. Will now fully charge during our 2 x 3 hour cheap periods down to -1C. Any worse than that its around 50% max charge.

Our installers have accepted that they should have known about the cold issue and warned us. They were also told by CYG that the batteries have heaters built in, which they don't as it's an optional extra. They are taking up issue with CYG.

They have offered to pay for a lean to shed to be built ? Just got to get a quote from our local builder now...which may be a problem. We will need to have something bit larger than yours and with a tiled roof as its on a semi prominent part of the house.

Cheers Alan

What app are you using 

Hi @alanb can I ask how you're getting on with the Skyline? I think we might be the only two people running these in parallel! 

I have been advised to enclose my batteries for the same reason.  However, my DIY skills are unlikely to result in anything quite as good looking.

@ipeel Hello. Just got back from Canada. Once the guys from CYG got the software set up ( took a few weeks of back and forth ) , it's been pretty good. Had to do the odd reboot when things drop off the net.

Not sure the Solar Touch app records the solar power input correctly, but we have outputting to the grid a lot over the summer.

We are all electric including plug in hybrid, so we are high users 20k kmh/year

I have 20.8kWh of batteries and am on Octopus Cosy tariff as we have ASHPs. This seems to be working well as Octopus have 3 off peak periods totalling  8 hours a day when we can charge the  batteries at 11p/kwh.

System is outside, so have built an insulated shelter for the system to protect from weather and cold. Batteries don't charge well at or near zero. First winter with this installed coming up, so we'll see if it works.

Alan