Battery hasn't charged for Saving Session

I set it to charge up ready for today's saving session and nothing has happened, it is currently 0 degrees C in the battery data, is this the reason? Also it's been at 0% for quite a while, usually sits at 4%.

Is the 0 degrees C likely to be correct? If it is then that is most likely the cause.
My battery (4%) is in an unheated detached garage and the battery shows at 3 Deg. C and the outside temp. was -4 Deg. C, I was wondering whether there was an 'auto charge' routine that would warm it up, but obviously not. I might experiment with timed charge to see the effect.

TRBob it's very possible, the BMS will protect the battery and 0 degrees is the minimum charging temperature so it's likely not charged because of this.

TRBob someone mentioned before that minimum 0 degrees for charging and -10 degrees for discharging.

SilverArt Yes, it's in the loft above 300mm of insulation, so very little heat escapes from the house up to there. I'm considering expanding my battery storage, so may have to site them inside the house if I do.

Thank you all for the replies.

TRBob

Just roll back some of the insulation directly under the battery, as you would do for a loft water tank. That'd allow some heat to seep up to keep the battery warm?

Zakalwe The batteries (2 x 2.6kWh) are sat on a reinforced wooden platform next to the new hot water tank for the heat pump, I should be able to get in there, I guess if I created a void underneath, it wouldn't be a massive heat leak area and result in a cold patch on the ceiling below? The hot water tank is super insulated already, it's ambient temperature when you touch the outside of it and seems to keep the water inside warm, I'm not sure whether that would benefit greatly from the same?

TRBob
Reading 0C and 0%. That sound like either the BMS has disconnected the batteries due to cold, or a breaker has tripped. What's the voltage reading?

If the battery is already at 0C, the only way to warm it is to discharge power, if flat. You are in a tricky predicament, as self discharge will also slowly drop the residual power down over a few days/weeks if left.
As soon as they can, get some power in them, set cutoff a bit higher maybe, to give you more headroom, if you plan to just let them sit

TRBob Perhaps a winter cover is needed with a suitably protected 60w incandescent light bulb to keep the cold at bay.

SilverArt That's a good shout. Something like a low wattage (ie electric, not naked flame) greenhouse heater under the battery within the battery insulation cover? Maybe the battery will recover enough to be able to be charged? Where can you buy a 60W incandescent these days?

Or a 40 Watt Dimplex ECOT1FT tubular heater with built-in thermostat may suit better.

Available from Screwfix, Toolstation and others for around £15.

TheDragon (GivEnergy) The voltage is between 6.1 and 6.2V.

When it gets warmer at the weekend I'll try a bit of a charge.

They haven't been used much recently as what little PV generation we receive gets used up by the house, I'd like to move to Eco7, but my Gen1 smart meter is not compatible, so waiting to hear from Octopus when that can be changed. During this cold snap, with only 5.2 kWh of storage I think that I'd be worse off on an Eco7 as the heat pump is on most of the time, so the usage in the day would outweigh any savings gained overnight.

What do you mean by set the cutoff a bit higher please?

Are there any bespoke battery covers available, or do people have recommendations of what to make one from?

TRBob
In the portal, go to your inverter settings, and set the cut-Off value to higher than 4%, so natural self discharge keeps the power in the battery at a safe level.
6.1v is way too low and may have already shut itself off into deep sleep. Engineer assistance needed to revive it, i suspect a force charge wont work

TheDragon (GivEnergy) Thank you, I'll see what happens when it gets warmer in a few days.

TRBob

TRBob The batteries (2 x 2.6kWh) are sat on a reinforced wooden platform next to the new hot water tank for the heat pump, I should be able to get in there, I guess if I created a void underneath, it wouldn't be a massive heat leak area and result in a cold patch on the ceiling below? The hot water tank is super insulated already, it's ambient temperature when you touch the outside of it and seems to keep the water inside warm, I'm not sure whether that would benefit greatly from the same?

In vented CH systems there is normally a cold water tank in the loft. Normally there's be no insulation under the tank and the loft insulation would be pulled up the sides of the tank. This allows a small amount of heat to warm the tank slightly to prevent heating.
The hot water tank is a different kettle of fish..it's insulated to keep the heat in as much as possible.