Solar Battery in Cold temperatures

1961Nick

The DOD for Pylontechs was 90% but that was increased to 95% for the 'C' version. If that's what the battery manufacturer states then that's what I'll stick to. If anything goes wrong, they can interrogate the battery & void the warranty if those parameters have been breached.

blueskyaboveme

The thing is nobody tells you, before they sell you one of these things, that cold weather materially affects a solar battery's capacity to charge in particular (less so the discharge apparently). I've got a Duracell Dur5 battery installed and, at temperatures nudging towards freezing, it's been barely charging via the Octopus cheap rate in the early hours and not a lot during the day from our PV array. Apparently, this is normal for lithium batteries in cold conditions I discover after doing a web search (I guess if you have an EV - I don't - you know this).  As far as I can tell, not one of the battery manufacturers tells you up front that, when you need it most, an unheated, uninsulated solar battery isn't going to serve you too well in winter when the days are short and its cold.  Duracell's promotional material on its web site is misleading, it clearly implies that it will work just fine down to -10 deg. C across the board for charging and discharging - which it won't.  Maybe the scarily expensive Tesla batteries with their heaters will work fine but my unheated thing won't unless its warmish (above 7 deg. C) and the sun shines a lot.

The installers aren't interested and Duracell hasn't responded to my communications so far, I wonder why? I feel I've been mis-sold something.

QrizB

blueskyaboveme said:

As far as I can tell, not one of the battery manufacturers tells you up front that, when you need it most, an unheated, uninsulated solar battery isn't going to serve you too well in winter when the days are short and its cold.

Duracell might be an exception, but most of the LFP battery suppliers are quite up-front that they can only be charged in temperatures above freezing and discharged down to -5 to -10 C.

One quick and relatively easy option might be to drape an old duvet or blanket over your battery. They all self-heat a little bit (it's where the losses go) and keeping that heat in could make all the difference.

Consider adding a heat pad (something like this) if there's not enough self-heating.

Or have it installed indoors.

Netexporter

I am surprised that a company like Duracell, with a reputation to protect, would make a battery designed to go outside would not include heating. Could it be that it has not been enabled?

Fogstar, who make some of the best value batteries on the market include automatic heating that comes on when the temperature falls to plus 10 degrees.

Screwdriva

vienly said:

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?

This varies across batteries but the SolarEdge battery does seem to be affected disproportionately more by colder temperatures (i.e. when the battery is installed outside or in a garage). 

The Tesla PW3 performs best from what I have seen.  

QrizB

Netexporter said:

I am surprised that a company like Duracell, with a reputation to protect, would make a battery designed to go outside would not include heating.

Duracell's solar batteries are a bit "meh" to be honest. It's as though they've sold their brand name to a middle-of-the-road box-shifter.

Edit: per the start of this video Duracell originally licensed their brand to Social Energy and Project Solar (two names from past threads!) but the licence is now held by Puredrive. The Dura5 is probably a Puredrive product, potentially a re-badged PureStorage II (link, datasheet).

Netexporter said:

Fogstar, who make some of the best value batteries on the market include automatic heating that comes on when the temperature falls to plus 10 degrees.

Some Fogstar batteries included heating, others don't.

JKenH

FWIW my PW3 typically charges at around 4.9kW. On 6th Jan when outside temperatures fell to -9C the PW3 inside the garage charged at 3.9W.

debitcardmayhem

My Givenergy has winter conditioning set on at the moment and mine charges fine , even hen it was minus 8 putside (battery outside) 

NedS

Screwdriva said:

vienly said:

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?

This varies across batteries but the SolarEdge battery does seem to be affected disproportionately more by colder temperatures (i.e. when the battery is installed outside or in a garage). 

The Tesla PW3 performs best from what I have seen.  

As we only had suitable locations that were outside, thermal management was a large factor in our decision to purchase a Tesla Powerwall 3. I have seen no degradation in performance in winter. The battery still charges at a peak rate of 5kW/h so is more than capable of fully recharging within a 3h window, and can discharge at 11kW/h.

Not much point having a battery that won't charge in the cheap rate slots  in winter when you have a heat pump to run.

Magnitio

Huawei Luna batteries also have built in heaters, though mine is installed in the garage against a house wall so doesn't get too cold.