At the back end of last month we got our 4th battery back from the suppliers so these figures will be slightly different from the months before due to the extra 25% battery storage. This was only for around 9 days so this next month should reveal far more of what needs to happen next. I need to see the discharge number reduce as this is dumping the stored electricity making way for new generated electricity. The system is literally throwing away 30% of the power generated due to lack of storage and not being able to send back to the grid.
Just doing some quick sums tells me I need to purchase or invest in 2 more batteries which will cost in the region of R36K ($2K). This is not bad at all considering the nearly 300Kwh being thrown away is worth R1K monthly so this investment would be recouped within 3 years. Prices have risen this month so my figures may be slightly out which is good as that means the 3 year recouping the investment would be less time.
This is June so a South African winter period with shorter days with sunset at around 5pm and a sun rise at around 7am. I would like to see the system being more balanced this month with less imported power coming from the grid. We are mid winter so this is worse case scenario when it comes to sunlight hours and at the end of next month we should start seeing the daylight hours slowly increasing.
We are in a tricky spot right now as we know load shedding can happen at any time so keeping the batteries fully charged is more important than overall savings. The 527 Kwh imported last month as top ups is way too much, but there is little that can be done under these circumstances. Load shedding is definitely hindering what this system is capable of and running the batteries down to 20% is just too risky as I have no other back up if we have bad timing and 8 hours of no power supply. We had a power outage last week for the entire day which was fine as it was daylight hours and we were obviously not affected.
The only appliance I have currently directly linked to the grid is the stove and that will change when the kitchen gets redone and gas lines installed with a new gas oven. Until then realistically I am tied to the grid no matter what I do with the solar. This has to be done this year as I refuse to pay the R30K registration fee for having the solar installed. This is like a penalty for leaving the grid and not using the power company fully like everyone else.
The 988Kwh generated last month used by the home is the equivalent of R3.5K in saved expenses which equates to paying off this investment within 6 years. Less as we know the prices are rising this month and every year thereafter so some where between 4 and 5 years is what I am expecting to see the break even point. The home would be costing R5.5K monthly or $300 monthly without the solar so with that in mind within 40 months of paying electricity bills you may as well have invested in one of these units instead.