Hi everyone

Is it best to insulate my 2 x 5.2 GE batteries.
I am being told that they lose charge up my loft.
If so hows best to carry it out safely.
Cheers

I have a gen1 5 hybrid inverter and a 8.2 battery in the loft for the last two years and not had to insulate them. My main problem is keeping them cool in summer. Not noticed any issue with the battery over the last two winters.

Zaz
Thank you
Do you find your battery dicharges quicker when it is cold from the frost outside, and having loft insulation
which prevents any heat from the house getting in the loft.
This is my first winter with solor and to be honest i do not know what to expect.
People are telling me that my batteries will drain quicker in the winter without insulation.
thank you again
john

My loft got down to about 5-6degC at times over winter but I don't really know if that made a difference. The battery was dropping to around 15degC with dips below 10. Over the winter there is less sun so you use the battery up quicker than in the summer so I didn't notice anything. Please add insulation when the batteries are outside but that is even colder and risk of frost.
I might do some experimentation this winter. :-)

Maz I'm not sure that the batteries actually lose charge, but I think they are less efficient in winter. (Possibly manifests as increased internal resistance ?) That's certainly true of EV batteries (though they are often NMC rather than LFP).

There is one detail worth knowing: if it gets below a certain temperature, it won't charge (though it can still discharge). I don't remember details. Possibly 0 degrees ? But it's possibly kinder to the batteries to limit the charging rate at low temperatures. (I think discharging is more tolerant.)

See
https://community.givenergy.cloud/d/3725-winter-battery-charging-discharging
https://community.givenergy.cloud/d/3734-outdoor-installation-minimum-temperature-battery-spec

One way to keep the battery warm is to use it : if you're on a tariff with cheap overnight rates, simply charging overnight will help - possibly at a low charge rate so that it's charging for the entire cheap rate.

Some insulation probably does no harm - my battery is in the garage, and I fitted some cardboard loosely around it. No idea if it did any good or not. But high temperatures are also bad for batteries, so don't forget to remove any insulation in spring !

DD Rough rule of thumb on lithium ion batteries is don't attempt to charge if the ambient temperature is at or below 0C; reduced charge rate below 10C.

Maz Just one thought. All houses no matter how much insulation you have up there will leak an amount of heat into the loft. It's not a perfect system, same with the walls and windows they all let some heat through and the house without heating input will lose temperature over time some of which goes into the loft.

Unless you live in a very cold place (and stays very cold for many days) I would not worry your loft is not likely to get anywhere zero deg, colder than the rooms below for sure but not as cold as outside.

Mine is in the garage, keeps the car warm too. I have a battery monitor in my car on its battery. I can keep an eye on the temperatures in the car not charging. It will give me an idea of temperature in the garage too.

Might be an idea for me to pop a blanket over it when temps below 5 degrees.

I'm in the south, and my battery is outside, so I think it will be subject to lower temps than your loft. It went down to minus 5 or 6 last year and it kept working fine because the battery temp is usually a bit higher than the surrounding air. Just to be on the safe side I made a 3-sided box of 5cm polystyrene (from Wickes) that I push around it in the winter to insulate it a bit - not sure how much difference it actually makes!. DD is right - using the battery will keep it warm - a long slow charge overnight will keep it operating at a reasonable temp. Using it to discharge to the house during the day will also keep it warm. My battery (an 8.2) can be 8-10 degrees warmer when it is charging. If you use the portal rather than the app - open the inverter icon and select battery data. You can see the battery operating temp there and you can see what a difference charging can make. If you choose to use an insulated box, I would make it go right down to the floor and then remove the insulation under it - just like you would do for a water tank. That way you will optimise the amount of heat rising up from the house and trap it under the battery. Even when outside temp was at minus 5, my battery temp never dropped below+5 even when not charging. No need to panic.