We have a Multiplus II 48/5000 connected to 5 Pylontech US3000C batteries. These have been functioning as expected since installation (August 2022), but we are experiencing low charging power overnight at the moment - 2kw vs the 3.5kw we normally have. We are on a time of use tariff and want to fully charge the batteries during off peak rates (6 hours), however this isn't working with the lower charging power.
When we first noticed this the battery temperature was under 18c, since then we have added insulation around the battery and introduced a seed germination mat to help increase the temperature when necessary. Currently the battery temperature is 27c and we are still seeing reduced charging rates. Looking in the battery parameters the CCL and DCL are both 185A and none of the modules are blocking.
Could anyone suggest reasons for the lower charging rate? Thank you for your help.