My system is ~3 months old and has been working well through our NZ summer, but, on cloudy days the battery voltage drops into the <50% SoC range. With winter coming up, I am trying to prioritise between adding battery capacity or adding panels. My sense is that it's 'now or never' for battery because I hear that new batteries adopt the 'age' of existing batteries.
My question is, what information produced by the system should lead me to decide on more batteries or more panels? Hoping someone can help...
My off grid system comprises:
- 6x 320 W Trina brand panels (roof mounted so point more east than optimal)
- 3 kW Victron EasySolar II GX (seems to consist of:
- SmartSolar MPPT 250/70 -Tr charge controller
- Multiplus-ll] 48/3000/35-32 inverter/charger
- connected to VRM about 1 month after install )
- BMV 700 battery monitor (no VE.Direct connection- should there be?)
- 4x 12V 260 Ah AGM batteries in series
Our power draw averages around 250 W 24x7 plus 30 W for the EasySolar II GX itself. VRM says over last 30 days, consumption has been 171 kWh and production 192 kWh. I haven't found anywhere that VRM (or the remote console) tells me "but production would be higher by X if you had more storage".
Hope someone with more experience can help.