I don’t think I’ll ever be in the situation where the panel(s) can produce more power than the battery/load requires but I thought that a MPPT controller got as much out of the panel as it could give and what the battery didn’t need was dissipated within the controller into the heatsink. But I know nothing Mr Mainwaring.
It’s right if the panels are producing zilch, the controller uses a small amount of power just sleeping.
That what I figured too.... well the panel is producing volts, that much I know; not much in the way of amps, not enough to register on the controller display which only reads to one decimal place. There’s something using a multimeter but I’m not bright enough with this stuff to know how much, depending on where the decimal place is (nothing on the 10A setting). Trouble is, nothing is leaving the controller and heading to the battery; in fact, as you say, the current is heading backwards from the battery to power the controller display. I’ve spoken to Photonic Universe who supplied it all and am awaiting an email from their engineer.
I can't remember your set up do you have the same controller (Ecoworthy). I got my rigid 100w panel from Photonic Universe but I bought the Ecoworthy controller on Ebay.
You could always call @MickJames Call and see you perhaps , I’m sure he would be more than happy Sent from my iPhone using Tapatalk
I've got a 100w flexible panel, and an EPever Tracer A controller (labelled up as a Photonic Universe one, but without a doubt it's all from the same factory in China!). To be honest, I'm sure there's not much of a difference between the controllers - Ecoworthy and EPever - but my big thing now (should I need a new one) would be to buy an Ecoworthy…. you all have them, and user knowledge and experience is worth so much! I'm not sure who else has one like mine apart from @1973daisey. The engineer from Photonic Universe emailed and asked if I could do a short circuit current test on the panel, check it over for any form of damage, cracks, blemishes etc, and also to take a photo so he could see how it was mounted on my roof - to eliminate a few panel issues initially. Fair enough. Needless to say by the time I have got home from work, the panel is shrouded in darkness and the controller is in sleep mode. Don't blame it! The battery does have the same 12.7v in it as when I left it this morning, so at least it's not all leaking away - it's just not topping up. Hey ho.
I found this page on the internet when I was checking it all earlier in the week: https://www.selectsolar.co.uk/cat/171/testing-your-solar-panel-regulator According to this, a short circuit current measure is taken in the same way as voltage, but obviously with the multi meter set differently. Positive panel to positive multimeter, negative panel to negative multimeter, with dial set to 10A. As opposed to operating current, when the multimeter is added in series between the panel positive and the controller positive. At least I think I've read it correctly. I definitely should've listened harder in school!
I thought that the panels provide the voltage and current all the time when illuminated by Sun, thus if the battery doesn't need/want it then it has to be dissipated as heat through a heat sink which is why the controllers usually have a heatsink in them, is this not how it happens?
The solar cell delivers no current if you open circuit it. It delivers a maximum current if you short circuit it. Example of a 100 watt panel in bright sun.. Open circuit : No current times 20 volts equals no power delivered. Short circuit : 5 amps times 0 volts equals no power delivered. Some where between these two is a loading of the solar cell where you draw current and its voltage drops a bit but not too much and you are getting maximum power. What the MPPT does is keep trying to find the optimum loading for Maximum Power. It does this with a switch mode power supply that draws energy from the panel at one voltage, through a low loss switch stores it in a magnetic field, and then dumps it through another low loss switch into the battery. . If it needs less current because the battery is charged it opens the first switch for less time and stores less energy. As a result the solar cell voltage goes up and the current from the panel drops. Less energy flows from the solar panel. The heat sinks on MPPT controllers are only there because the switches are not perfect. An MPPT controller managing 200 watts may only be wasting 10 watts in heat at full blast, and much less at lower load.
12.7 volts is Ok for a battery that has been charged and then left for a while. It would only be 13.8 while it is float charging. Yes the controller may well draw power all the time from the battery.
Following yesterday’s thrilling instalment todays episode involved more testing and disappointment. Weather: Virtually a clear blue sky with just a little very high-level haze. I took the bus out of the garage and put it up on the ramps again, opened the roof and checked the controller (still only one panel connected from yesterday), battery at 13.3v float charge at 0.45amp. Well, it would be as the battery has been on the smart charger all night. Disconnected the RH panel and measured the voltage of both panels. Open circuit LH is 19.57v, RH is 20.03v, that’s not too bad I thought, now the short circuit amps. LH 0.74amp, RH 1.23amp – bugger. It looks like both panels are shot with the RH one slightly less bad than the LH. I left the LH panel disconnected and reconnected the RH, the controller went to bulk charge at 0.8amps. I lowered the roof and the controller started snoozing. The bus is back in the garage. Now, I’m still not convinced the controller is doing what it should, but it might be. The panels are a real disappointment and I was hoping the problem was the controller because it’s easy to change and relatively cheap. The panels on the other hand will be difficult to remove and costly to replace and they’ve only been on few months. Why have they failed? It couldn’t be a faulty batch because although I bought them at the same time the date of manufacture is several months apart. Did they get too hot? The bus has certainly been left out in very hot sun this summer. Or are they very sensitive to the angle of the sun? It’s not much good if they only work at midday on mid summers day.
Dont envy you at all, given that you can't be certain what is causing the problem I think I'd either go down the route of new controller first being the easiest thing to replace. Alternatively just get one panel and try that with the existing controller, you wouldn't even need to stick it on your roof to do that.
I probably won’t bother until next year but I’m tempted with these to replace the Eco Worthy panels. https://www.amazon.co.uk/dp/B07FYW3...olid=3DX4MXB353TI4&psc=0&ref_=lv_ov_lig_dp_it Before I buy more panels, I’d like to understand why the Eco Worthy are so poor, I don’t think they even worked from day one but there has to be a reason. Plenty of others have unbelievable results from similar panels and controller but there are also quite a few whose panels produce next to nothing. And if I have to get a new controller it’ll be the Epever Triron 2210N or Tracer 2210AN.
Buy an under £10 PWM controller and see what happens. Cheap quick and easy to replace Y&H 20A PWM Intelligent Solar Charge Controller 12V/24V Battery Regulator Solar Panel Controller LCD Display with Dual USB Port https://www.amazon.co.uk/dp/B07GQVMJHV/ref=cm_sw_r_wa_apa_KrzWBbB0KG4CJ Although the panels don't sound too smart. If you do replace them, use one bead of sikaflex or tigerseal all the way around the edge, makes it much easy to remove using a cheese wire/fishing line. Mine have been in for 3 years at least and haven't overheated. I have them over the ridges in the westy roof so some air can get under the but I doubt it does much.
I’m tempted to simply connect both panels directly to the battery, they don’t produce enough power to do any harm. I’m trying to find out via Amazon if others have had Eco Worthy panels fail, so far only two have responded but including mine 6 panels have failed at around one year old. They’ve probably sold 10s of thousands of panels. The problem is I don’t really know what causes them to fail, I thought they gradually degraded but had a useful life of 20 years or so. Hot spots seem to be a potential problem but I don’t know how to spot a hot spot – visually my panels look exactly the same now as when I installed them 5 months ago.
