davidg wrote:What size bank do you have

800AH @ 26V, actually discharge mostly happens around 26.5V, so I call it 21kWh of energy storage in my DOD calculations.

what would the typical number of kWh per day used

A bit tricky to answer, as it varies so much! I have used over 24kWh DC (~21kWh AC) on a big day in summer when preserving fruit and generally using lots of power, and when trying to minimise power usage, that can be <6kWh AC. Typical use is around 8-10kWhAC, but 10-12kWh is also fairly common.

what is the number of no sun days you target or have acheived,

The

low sun days are generally no more than 4 in a row here- see the graphs I posted on the previous page of this thread (but winter is worse with the shorter possible total of sun hours), or below are 2 graphs from a week ago I prepared earlier today, these ones account for all loads (the earlier ones did not include some small DC loads), and the true charging efficiency works out to be just over 96%.

In the below graphs I had 4kW of PV operating, 1kW of which was fixed, pointing a bit E of N, the rest tracking the sun. The energy used was a bit above average, no efforts were made to limit consumption this time.

Gross Power and Energy Use

- click to de-fuzz

Net Power and SOC + Voltage

- click to de-fuzz

what would you consider to be the worst amount of energy you have derived from a no sun day and how many days in a row would that likely to be.

I think the worst day I've had was about 0.3kWh from a just under 2kW array, but I have had 2 days in a row with just over 1kWh from a 2.19kW array. At the moment I'm running 4kw of PV, so could probably go about 4 very gloomy days straight, without needing the generator if I conserved energy. I've never had 4 days of completely gloomy weather in a row though... but then, my comprehensive records only go back a few years. The high efficiency of the LiFePO4s mean you can climb out of a big DOD hole pretty quickly

Anyway, enough of this for now, its BBQ and beer time