Greg74

Hi Coulomb, Its been a while but I finally managed to do the swap out test at around 11am in the morning. I took my 5kva mecer and installed it at my Dads place. We noted the wattage coming from the solar array on my Dads inverter before disconnecting it and it was sitting at around 1000w. We then disconnected it and installed mine straight away. It immediately had around 2200w coming in from the solar array, sometimes even a bit more, up to 2400w at one stage. So it must be the MPPT right? Just strange how its almost producing exactly half the full amount?

Thanks Coulomb.

Thanks Coulomb, I'm going to give it a go when I get a chance. One more thing, you mentioned previously that I could be getting higher voltages than my 98v - 100v in the early morning? How would this be possible?

I guess I could take my inverter which is the same type, size and model and install it in the place of the "faulty" one and test like that. These are hybrid inverters with the built in MPPT and I have never removed an MPPT, so not even sure it is possible? Can the MPPT be removed and replaced?

Morning Coulomb and Sidewinder, Sorry, just a thought I had last night. Before I go hunting for a loose/bad connection, please remember the following tests I did at midday, peak sun. I have 3 series panels in 3 parallel strings - (9 panels) I separated all three series strings and did the short circuit test and load test with the following results. 1. Short circuit test (with Coulombs more accurate calc of 95% of 7.5 A per string), I should have 7.125 A at 98v = 698W per each series string. 2. Then when I connected each string back separately to the inverter, the inverter gave me the same reading on the screen of only around 430W at 98v and 8amps for each of the three strings. Why would each string behave exactly the same? at 430W when each should be around 698W? Surely this shows a common problem? More related perhaps to the inverter and the MPPT itself rather than a loose or bad connection in the wiring?

Hi Coulomb and Sidewinder, That's the thought I have resigned myself to - I have a bad/loose connection somewhere maybe. I will keep digging down those lines when I can and will be sure to let you know my findings. Thank you both for your advice.

Sorry, this system is installed at a residence. I oddly have the same system at home but with only less panels. I only have 4 x 310w panels. so around 1200w installed - before any losses derates etc. If I test mine, the system runs normally during the day with around 410w from the solar array and batteries pretty full. If I put the small 1kW kettle on for example, the solar kW immediately increases to 1001w to take as much of the additional load as they are capable of.

Hi Coulomb, thanks for your response and thanks for the welcome. This test was all done at around mid day, peak sun. I might be able to short the whole string, I'll look at that. I thought I'd lost a string because that would match the numbers so I tested each of the strings separately and got 430w, 8amps and 98v on each of the three strings whilst online, again shown on the inverter display. The batteries are new, only a few months old, bulk charge 58.4v, float charge 56.4v. We have increased the float charge to 58.4v for a while to. How would the inverter restrict the kW's? So that's my issue, I can't understand why when a load is applied and increases to above even 2kW why doesn't the inverter respond and allow more from the solar array? It used to so what else could have changed? Hi Bobster, the panels are cleaned every couple of weeks and were cleaned before we did the tests.

Good day, I am a new reader and have read a number of your threads and there is loads of knowledge here that perhaps someone could help me. My sincere apologies if this has been answered before but I couldn't find an answer that answered my issue. I have the old model 5kVA Mecer Hybrid Inverter(with the heat sink on top, SOL-I-AX-5M). It is connected to 9 x 310w solar panels(3 parallel strings of 3 in series) and 4 x new 230amphr silver calcium batteries. My problem is that the solar panels appear not to be able to deliver more than about 1300W any longer. After all derates and efficiency losses I was guessing to get around 2200W from the array, which I did in the beginning. Now, a couple of years later, if I apply a load of even 2500W the inverter does not deliver more than the 1300W. Almost as though the inverter is restricting or governing the solar capacity? Is this possible? Here is some stuff I have done/tested. -Setting 31 - SBE - (this was my first thought) -Total Current from the panels at the inverter is 23amps DC -Total online voltage is 98-100v DC (So this already tells me I should be getting 2200W = 23A x 98v) -Inverter total charging current I have maxed out at 120amps. -DC short circuit current test on each string was 7,5amps. So I should get 725w per string at 98v = 2205w total. -The display panel however doesn't ever show more than about 1300W Any advice would be greatly appreciated. Thanks. Greg.