January 26, 20197 yr Hi all the gurus out there I installed a solar PV system about 3 years ago. A brief description; a 3x phase setup with each phase connected to a 5Kw Mecer inverter and 8x 300w PV panels. 24x Trojan 6v batteries connected in banks of 8x in series and then parallel. My system has worked really well with my kW units reduced from around 60/day to an average of 15/day, winter and summer. Untill my batteries ran dry, (my ignorance and stupidity, and lack of info from my installer). I was able to resurrect them with the help of Battery Centre and although they work they do not hold any charge. This means that during the day my inverters are able to work requiring no grid input but at night I am using far more Kw/hrs than I should, 18 units iso of around 5 units... I intend to limp along like this untill I am convinced as to which replacement is best, lithium or supercaps. Please excuse any incorrect tech details, I am no electrician! What I wanted to know is whether there was any way to set the inverters to auto switch over to grid when the sun sets and rises. thanks.
January 27, 20197 yr 8 hours ago, Globe said: I intend to limp along like this untill I am convinced as to which replacement is best, lithium or supercaps. You won't be wanting supercaps, but do the research and convince yourself. 8 hours ago, Globe said: What I wanted to know is whether there was any way to set the inverters to auto switch over to grid when the sun sets and rises. Actually, there is, but till recently the received wisdom on this was wrong. The SOL output source priority (setting 1) does exactly what you describe: Battery mode daytime (when possible) and Utility mode when the PV input stops. See the correction in this post.
January 27, 20197 yr Author Thanks for the feedback Coulomb. You say I won't be wanting Supercaps, can you say what I should be looking at? The lifespan of the normal lead acid or gel battery is disappointing with lithium not much better, or is this not the case. I know Supercaps is new on the market and maybe still needs to prove itself but on the face of it the idea sounds fantastic...but expensive! i will certainly try the SOL setting and see what it does.
January 27, 20197 yr The lifetime of lithium batteries, particularly LFP, is much higher than that of most lead acid, with a few exceptions. I've heard of lead acid cells with 10 year warranty, that still failed well before the expected lifetime. Trojan lead acid seems to be long lived, but there is the hassle of maintenance. Super capacitors just don't have the energy density of batteries. Some that claim to be super capacitors with million cycle lifespans are clearly not what they claim to be, for example the Arvio.
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