@77 Westy , today is about as good as it gets in the East Grimlands so I thought I'd do a little experiment for you. Mrs Monkey turned the fridge off last night so there has been no draw on the battery since 7pm Tuesday and the van hasn't been run for 4 or 5 days. At 10.45am this morning, this was the state of the battery....13.5v, float charge putting 0.97ah into the battery to maintain float. I then turned on the fridge and ran the air compressor to see what effect it had. Normally I wouldn't run the compressor without starting the engine as its a high volume 160psi jobbie which has a 45amp current draw but in the interests of the experiment.... So what you can see is the immediate effect on terminal voltage which understandably dives to 11.8v. The charge controller went into bulk mode and the display shows 2.59ah going into the battery. Everything off... And we can see terminal voltage back to normal full charge reading but the controller is allowing the panel to put 2.44ah back into the slightly discharged battery. Sooooo....what we are seeing on the display is not panel output but battery requirement. All this took place within 5 minutes or so, the time it took me to plug/disconnect things and take pics. Its glorious here today without a cloud in the sky so panel output is constantly constant. Maybe, just maybe, there is nothing wrong with your system and your low figures indicate a healthy charge? I don't recall if you have mentioned terminal voltage relative to controller amp display and charge state...?
So, to conclude... 2.5 hours and one Renault mot failure later , this is what's happened. The controller shows float charge, 13.5 on the terminals being maintained by a current flow of 0.82ah. The panel has fully recharged the battery. The above is all you see as the display toggles between that screen and the cumulative watt/hours and state of charge screen. However, look what happens when you activate the screen that shows the mppt algorithm working... That shows the panel producing 2.4amps pwm with the controller making that up to 2.80ah mppt via the tricksy electrickery. This tells me that 2.8amps are available from the controller if required but in this case we don't need them as only 0.82 are required to maintain float. So a smidge under 2amps of heat energy is being dumped through the controller body because the battery doesn't need it. (2.80mppt amps minus the .82 being used to maintain float). Hope that helps show how these controllers display their sun beam counting
I think the ecoworthy controller is definitely much better at showing what’s going on! With the van having sat in the sun all morning (so let’s say 4 hours after the mist cleared) my controller still says 0.0A off the panel and battery voltage has dropped to 12.7v. Humph.
Haha, that's not to say there aren't some broke ones out there though. It's a bit of a lottery with most things quality wise these days. I have worked directly with a Chinese manufacturer of plastic push fit components. They blatantly copy the Euro regs and state full product conformity to the various Iso standards required by the industry. We know damn well they don't adequately test but that's part of the game it seems. Global customers are satisfied re conformity coz we ensure locally that products pass the environmental tests. Its all about scale. Sell enough cheaply and to hell with the few that dont work!!
Thanks for that @theBusmonkey, it’s so different to mine it could be a different controller. My Eco Worthy seems to have three modes – sleeping, snoozing and bulk, I have never seen it float, although it’s tempting to see if it will. Unfortunately, I can’t do any testing today as the weather has gone a bit Isle of Wight – dull, overcast and damp. That’s more like mine on a good day.
Which is why I'll not be buying a cheapo Chinese cab heater although I will be fitting solar over the winter. Great thread with good advice - many thanks Sent from my SM-A320FL using Tapatalk
Indeed, we love our Propex and take comfort in the support of a local contact. It's never going to be Eberspacher or Webasto hot but then its half the cost. I'm dubious of halving that cost again to potentially be kept warm by the inferno of a burning bus whilst awaiting the fire brigade
Sticking the multimeter in series from the regulator to the battery gives a negative reading. Surely that means the current is running from the battery to the controller? That can’t be right can it? I must be doing something wrong surely?
I've got my computer back up and running so another photo of my controller this one was at 10.45 on 6 August. We were in France and the cool box was running, the forecast according to my diary was 33C.
It’s obvious that mine is not doing what it is supposed to do and I’m hoping it is a faulty controller as that is the easiest and cheapest thing to replace. The weather is not good enough at the moment to do any further tests but something I have noticed is that with the bus in the garage and more or less in the dark there is 10v from (or to) the panels – seems odd to me. The battery is on a smart charger and is fully charged in float mode.
Where are you measuring that 10v? Charge controller should show terminal voltage regardless of any input from the panel. If that reading is on the screen, and a multimeter on the battery confirms full charge then clearly the controller has suffered from either sh1te construction or a short when installing.
The voltage was measured with a multimeter at the controller solar panel terminals. 10v at the panel terminals and 12.9 at the battery terminals. However, I’ve just checked it again now it’s properly dark, 7.8v but when the garage light went off the voltage dropped to 0.6. The panels are producing volts with very little light.
Does the controller 'see' 12.9 on the display and at the terminals on the unit that run up/down to/from the battery?
Why is the word DEMO on that screen ? In normal electronics kit, that is the kind of display you enable in the shop when it is not wired up properly . And no, the MPPT controller does not "know "it can get more current that it needs from the solar cell. All it knows is the actual voltages and actual currents. All it does is find a solution on the solar cell voltage and current curve that applies at that exact instant, which represents the power it needs to deliver the current it wants to deliver to the battery. In this case 0.9 amps at 13.5 volts is completely reasonable. The controller just does not load the solar cell if it does not want the power, it does not dump energy anywhere. There certainly was a time when a solar controller might have dumped energy in an analog circuit but the MPPT controllers are more like a changing ratio in a CVT gearbox than putting on a brake to slow down.
I guess it says demo because it was made to confuse! There is no suggestion that the controller 'knows' more current is available. The current is what it is. All the mppt function does is to maximise the delivery of that current relative to battery soc. Which I think is what you are saying? I guess the designers of the controllers panel were trying to 'demonstrate' the uplift in efficiency by the application of mppt vs pwm. I guess that's their own way as a manufacturer of having a go at the competition? My post was to ty and show what these figures and screens represent because the set up instructions can be a bit confusing. Typical translation issues Smoke and mirrors maybe Mike but the fact remains that these relatively simple controllers, with no remote or iPhone interaction, are generally reliable and robust.
In today’s thrilling instalment: the sun comes out, I put the bus on ramps, play with some light bulbs and disconnect one panel. I raised the front of the bus and the roof to get the panels as near as possible facing the sun, there were a few clouds about but I waited for a clear sky before carrying out any testing. The leisure battery has been connected to a smart charger for a few days and is fully charged. The panels are clean. And I’ve made up a couple of test lamps; one with two 5w bulbs in series and one with a 21w in series with a 24w. First look at the controller – battery volts 12.9, bulk charging at 0.79amps, so more or less the same as usual. Both panels disconnected and tested with the lamps, the RH panel lights the 21w + 24w quite brightly but not as bright as directly across the 12v battery. However, the LH panel not much more than a glow from the 21w + 24w and still dim with even the 5w bulbs. I reconnected the RH panel to the controller and waited and watched, after a few minutes the battery voltage had increased to 13.5 bulk charging at 1.12amps then the charge went to float at 0.77amps – the first time it’s floated. Then I switched the fridge on, the battery voltage dropped to 12.5 and the controller went back to bulk charging at 0.85amps. My conclusions: One panel is better than the other but neither are producing what I was expecting and even the best panel couldn’t keep up with the fridge. The controller might be sucking all it can from the ‘best’ panel, I’ll give it the benefit of the doubt. The battery volts dropped much faster than I expected with the fridge on and I’m reasonable sure its past it’s best. I have a battery tester that Mike recommenced being delivered to Scotland and I’ll test the battery when I’m there next week. And I’ll buy a new battery, it’s cheaper in the UK. Now I’m going to have to think about removing one and probably both panels to replace them, or I could buy a three-way fridge and forget about the solar altogether.
