Depth of Discharge
Hi, we had a 6.5kW solar system with two 5.12kw Sunsync batteries. Obviously if DOD is only 20%, then we've paid for 10 and are only really getting 6kw/H of storage, which is frustrating. We pull from the grid at night, every night (and presumably will do so until the sun starts being a bit more powerful). On a good day we get around 20kw/H of solar so a) was wondering if that's any good for December. 2) more importantly, if anyone has gone below the 20% DOD level - we were advised not to re warranty - what have been your experiences? Have you noticed more or any battery degradation? I was thinking perhaps to 15% so we get another KwH in the evenings, but suppose if I'm saving only 27p a Kw (x365) - around £98.50 a year, x 10 years of life: £985 vs. damage such a level might do. As many have noted the DOD disparity between Sunsync saying DOD is 100%, but then installers saying 20%, is a huge issue. . Has anyone sought any legal advice on the matter, as surely if it's there in black and white on the one hand and then that's not quite true in practice, there's surely a case for a form of class action. Any solicitors on the forum that specialise in such law and have a bone to pick on this issue - could you please provide some thoughts? Basically £6k for 6kw/h of storage instead of 10 is patently a mis-sell, surely??
Battery life is affected by Voltage NOT DoD. But in reality [and to keep it simple] the DoD is an easy way to reflect the likely voltage lows and highs at low and high DoD charge states....... And to make it even simpler many articles will state 80% to 20%.
If you look at the voltages at high and low at various DoDs you will see where the voltage drops below or peaks above the average voltage and it is these larger variences of volatge that effect the battery life...... Have a look at what your battery does.
Aside from warranty requirements - you can set accordingly.
I have seen that voltage starts to ramp up above 95% night charge from grid and shows lower voltages below 14%. So thats what I set - 14% to 95%.