Cold batteries

[Stinsy]

It is displayed on the sems portal (goodwe) in the one level down maintenance info. Can you maybe run rs232 and see data on hyperterminal?

My inverter doesn't expose that data (so far as I am aware).

[martinW]

I have been wondering on the cold side too here in sunny wales.

I am looking to use a Victron multiplus 2 5kW inverter which has a charge rate of 70 amps @48v (3.360kW) so I'd really like to keep my batteries at full charge rate as I can only shoehorn in 5 or 6 batteries. Initial set up will be 3 batteries. I only have a 5 hour cheap rate time

The battery location will be a steel bicycle shed (not a lot of options for alternative locations). I am considering installing them in a sort of insulated box / area of the bike shed.

The bike shed will have full summer sun from around midday. Most of the charge time will be after 1 am so I should be cooler in the summer. I am wondering if I put in insulated box, I can just install a manual summer mode vent which I open to keep them relatively cool.


IIRC 25°C is the magic temperature that the Batteries like for charging / discharging.

I am sure the insulated box would be fine for winter, but what about over heating for summer?

[Stinsy]

My batteries are in a very cold attic. A few days a year they report a maximum charge rate of 5A per battery (25A / 1200W for my stack). However, once they’ve been charging for 30mins or so at that rate they warm themselves up and allow full power (25A per battery) charging.

[martinW]

Thanks for that Stinsy, its good to know that the reduced charge rate in cold would not be for very long... I assume once they start discharging, they will also warm up in winter.

Maybe I'll just stick some insulation on the inside of the roof to stop condensation drips and on the back panel as I won't be able to access it once the batteries are installed.

[Stinsy]

The max charge rate of my inverter is 3.6kW so the charge-rate reduction isn’t as dramatic as it could be. More batteries would mean a faster charge rate when “coldgating”.

Both charging and discharging warms up the batteries. However, in winter, my stack has usually been sat depleted for several hours by the time the cheap period kicks in.