Dappled sun issues?
- Thread starter Sutty
- Start date
sunshine_eggo
Happy Breffast!
LOL... "underloading"
I know, right! EPEVER have some funny terms, but I suppose someone just must have decided what can be the opposite of overloading?
I think the prior software app, Solar Station, just says normal. Yes, just launched that app, and it does.
Gone quite dark now.
Cheers
Sutty
I think the prior software app, Solar Station, just says normal. Yes, just launched that app, and it does.
Gone quite dark now.
Cheers
Sutty
I'm hoping for some further advice from those of you who may know EPEVER Tracer SCCs. I've been keeping my eye on what my EPEVER mppt charge controller has been up to, over the last few days, since the deployment of my new 500W panel, and today I noticed that it went into equalise mode, which I'd left enabled, but at the same voltage as bulk, so effectively it was just running an extra period of bulk, once per month. Seeing as it only runs on the 28th of any given month, I thought, why would it matter, especially as I'd set it to the same voltage as bulk, but today I decided, why even bother letting it do that, and I set the time limit down to zero. On doing so it immediately went into float, which was what I was expecting, and was happy to see.
What I didn't expect, was that not too much later, considering the weather today is sunshine and showers, not that uncommon for the UK, it had dropped back into bulk, which is set for two hours. Having earlier seen float, I thought it would float all day, despite the likely intermittent sun, based on the forecast. Checking the battery charge settings I noted that the bulk retrigger level was set to 27V. Considering that I have a constant load on the batteries, albeit low, almost as soon as the sun passes behind a cloud, I'm going to be dropping back down below 27V and triggering another cycle of bulk.
This strikes me, that on a fairly typical UK day, the system is going to be re-triggering bulk voltage charge levels repeatedly, and I will basically be holding the battery array at a level which is considerably higher than that of float, almost all of the time. Without having put any large loads on my system, just my usual, constant, low demand, what I would hope would happen, is that it would spend most of its time covering that small load, whilst also maintaining float.
On this basis I'm wondering if the bulk re-trigger voltage ought to be lowered, considerably, from 27V to something more like 26V. I mean, after all, that would still mean the individual batteries would be at 13V each, which seems to me is fully charged, especially under a small load, and it should be at float?
Considering I have a permanent small load, does this seem like a reasonable course of action, or does anyone have a better value to apply here? I mean, considering the small load, 26V must surely be comfortably fully charged still, and it should be at float?
I worry that having watched the behaviour, particularly today, I'm going to be holding the batteries at an unnecessarily high value? I gather lead acid is fairly tolerant of over charging, but this just seems to me to be pointlessly high, for what will likely be overly long.
As an aside, it would be good if this information could be logged, and maybe even graphed. Is there an android phone app that anyone has created which is able to do this?
What I didn't expect, was that not too much later, considering the weather today is sunshine and showers, not that uncommon for the UK, it had dropped back into bulk, which is set for two hours. Having earlier seen float, I thought it would float all day, despite the likely intermittent sun, based on the forecast. Checking the battery charge settings I noted that the bulk retrigger level was set to 27V. Considering that I have a constant load on the batteries, albeit low, almost as soon as the sun passes behind a cloud, I'm going to be dropping back down below 27V and triggering another cycle of bulk.
This strikes me, that on a fairly typical UK day, the system is going to be re-triggering bulk voltage charge levels repeatedly, and I will basically be holding the battery array at a level which is considerably higher than that of float, almost all of the time. Without having put any large loads on my system, just my usual, constant, low demand, what I would hope would happen, is that it would spend most of its time covering that small load, whilst also maintaining float.
On this basis I'm wondering if the bulk re-trigger voltage ought to be lowered, considerably, from 27V to something more like 26V. I mean, after all, that would still mean the individual batteries would be at 13V each, which seems to me is fully charged, especially under a small load, and it should be at float?
Considering I have a permanent small load, does this seem like a reasonable course of action, or does anyone have a better value to apply here? I mean, considering the small load, 26V must surely be comfortably fully charged still, and it should be at float?
I worry that having watched the behaviour, particularly today, I'm going to be holding the batteries at an unnecessarily high value? I gather lead acid is fairly tolerant of over charging, but this just seems to me to be pointlessly high, for what will likely be overly long.
As an aside, it would be good if this information could be logged, and maybe even graphed. Is there an android phone app that anyone has created which is able to do this?
sunshine_eggo
Happy Breffast!
Your suspicion is correct. Re-bulk was triggered.
A freshly charged AGM sitting (no load or charge at all) for 24 hours will settle to 25.8-26.0V.
Given the light load, I'd take the position that a re-bulk is never needed. I'd adjust down to 25.6V and accept the occasional re-bulk when not needed and occasionally not get a rebulk when needed.
Logging data only feeds OCD...
A freshly charged AGM sitting (no load or charge at all) for 24 hours will settle to 25.8-26.0V.
Given the light load, I'd take the position that a re-bulk is never needed. I'd adjust down to 25.6V and accept the occasional re-bulk when not needed and occasionally not get a rebulk when needed.
Logging data only feeds OCD...
That's great, thank you, that's what I shall do. I think I mentioned previously that I also have an inverter, which I use from time to time, weekly, or thereabout, during the fishing season, so if I use that it should still drop well below even the new lowered value, and ought to trigger bulk when really needed.
As for 'logging data only feeds OCD', I don't mind that, it suits me, lol. I've been checking in so often, I think I'd be better off being able to look at a log, weekly, or monthly, rather than 15 times per day.
As for 'logging data only feeds OCD', I don't mind that, it suits me, lol. I've been checking in so often, I think I'd be better off being able to look at a log, weekly, or monthly, rather than 15 times per day.
sunshine_eggo
Happy Breffast!
25.8V should be good for operation when you're off site, and with heavier on-site use, it will trigger re-bulk more often, which might be appropriate. The occasional re-bulk doesn't do any harm.
If you really want to nearly eliminate re-bulk, 24.8V should get you there.
If you really want to nearly eliminate re-bulk, 24.8V should get you there.
I'm not really wanting to eliminate it altogether, or even close to that. I'm fine with it doing it after I've used the inverter, probably the day after would be usual, because I normally use the power after dark. This would seem appropriate to me. I just didn't want it being retriggered repeatedly, on a normal, low load (3W), day, when the whole system is just sitting there doing it's own thing, running my security system. In my mind, if they're charged, they should be at float, and not going back into bulk, every time a cloud passes by. Bit of an exaggeration, but I know you take the point.
With that in mind, I'll go with the higher of the two suggested values, knowing that it should prevent many occurrences, but still be triggered each time I actually run a higher load, when on site, or, after having had many really bad sun days in a row. Again, that would seem appropriate to me.
Thanks again.
With that in mind, I'll go with the higher of the two suggested values, knowing that it should prevent many occurrences, but still be triggered each time I actually run a higher load, when on site, or, after having had many really bad sun days in a row. Again, that would seem appropriate to me.
Thanks again.
Early days, as you know, but as far as I can tell, everything is now just perfect. Bulk isn't now retriggered, even after the overnight discharge, at least whilst I have a topped off battery. I'm sure it will be, when I use high on-site loads, and every now and again in general day to day use, which is what I'd want, but right now, in my absence, it's doing just what I'd hope it would do, and is basically floating all day, or it has been every time I've looked so far today.
The panel voltage has risen to over 40V, fairly close to the rated Voc, so it must nearly be open circuit now, and despite it being nice and sunny, and nearly local noon, there's barely a trickle coming out.
Which, begs another question, even if I had logging, there must be no easy way to track potential available power, because I'm barely using any of it, so from now on, every time I look, I'm likely to have only a very low trickle, even if it's full sun, the height of summer, and noon. The only way to see what might be possible is to either use a high load, and watch it during top up, or maybe something crafty can be done with regard to panel voltage, I'm not sure, but I doubt it?
Top and bottom of it is, the generated stats, held in the charge controller, are all but irrelevant, because as long as you have a system which is in surplus, the generated energy is always going to be just that little bit more than the used energy. Naively, wrongly, I had for a while, been looking at those stats, thinking, I would see my daily used, and my daily generated would be hugely more, but of course that can never be. Stupid boy.
Anyway, I'm not bothered, the goal is achieved. The extra panel has got me back to where I want to be, and better, based on early observation, it can provide more energy than I need, even on a bad day. Of course, it remains to be seen what a really bad day can do, in the depths of winter, but I'd be surprised if the combination of the two systems can't provide me with enough energy to keep up. Even if they don't, with the battery capacity I have, it can last many many days, whilst waiting for a good day to come along and top it back up.
Thanks all, especially sunshine_eggo, for the very detailed replies. I'll be back in winter, to post the results on a bad day.
Cheers
Sutty
The panel voltage has risen to over 40V, fairly close to the rated Voc, so it must nearly be open circuit now, and despite it being nice and sunny, and nearly local noon, there's barely a trickle coming out.
Which, begs another question, even if I had logging, there must be no easy way to track potential available power, because I'm barely using any of it, so from now on, every time I look, I'm likely to have only a very low trickle, even if it's full sun, the height of summer, and noon. The only way to see what might be possible is to either use a high load, and watch it during top up, or maybe something crafty can be done with regard to panel voltage, I'm not sure, but I doubt it?
Top and bottom of it is, the generated stats, held in the charge controller, are all but irrelevant, because as long as you have a system which is in surplus, the generated energy is always going to be just that little bit more than the used energy. Naively, wrongly, I had for a while, been looking at those stats, thinking, I would see my daily used, and my daily generated would be hugely more, but of course that can never be. Stupid boy.
Anyway, I'm not bothered, the goal is achieved. The extra panel has got me back to where I want to be, and better, based on early observation, it can provide more energy than I need, even on a bad day. Of course, it remains to be seen what a really bad day can do, in the depths of winter, but I'd be surprised if the combination of the two systems can't provide me with enough energy to keep up. Even if they don't, with the battery capacity I have, it can last many many days, whilst waiting for a good day to come along and top it back up.
Thanks all, especially sunshine_eggo, for the very detailed replies. I'll be back in winter, to post the results on a bad day.
Cheers
Sutty
Just thought I'd pop back in with another update, and also to ask a question. All is still going well, in that now that it's the closed fishing season, and I'm not visiting at all, my batteries continue to be topped off again, every day, as long as there is a little sun, at some point, or even just a bright cloudy day. Where they fail is when it actually seems dark, as a result of proper rain clouds, and even with several hundred watts of power being available with peak power from the sun, I barely break even, and certainly don't catch up from the night before, despite only using around 3-4W continuously, and of course the nights are still to get longer, but I hope everything will continue to be okay.
So far, at least, my system has not turned off the load output, meaning that the batteries have been staying above the LVC setting that I was advised to use to protect the batteries, without being overly conservative, at 23.4V. That means it's been doing its job well for about 10 or 12 weeks now.
This is not to say I don't want to improve things, and the problem I have now is that my bigger, flat, 500W panel, is getting covered in leaves. The back two are currently doing the heavy lifting, so to speak, because of the sun angle, but also because of the leaves on the bigger panel, which you can see here on this shot from my panel cam.
I had a spare security camera, so I put it up a tree to keep an eye on the panels, whenever I wanted, and below you will see that I have no problem with the back ones. Clearly the leaves slide off, and you can also see that they are at a good angle for this more winter sun. Picture taken just before noon yesterday. The front panel though has far too many leaves. I still caught it putting out 79W, at the time of the shot below, whilst the batteries were still being topped off, but it would be much more effective without the leaves. I suppose it's a good job it's half perc cells, which I understand helps.
Anyway, tilting it is not an option, as discussed earlier in the thread, so I'm wondering if anyone has ever given any thought to a remote cleaning solution for small panel installations. I mean, I can drive up, but it's a bit of a long trip, which would take 3 hrs, all told, and about £20 in petrol, only to have the panel covered in leaves, once more, possibly before I got home, lol.
I've been thinking of either a linear windscreen wiper type solution, a blower fan type solution, or a water spray type solution, either of which could be triggered with a WiFi relay switch, that I already have at the cabin, and is currently powered up, for another purpose, and I don't really need that now, but it does mean I know it doesn't use a lot of power. Nor would the device itself, because despite perhaps having a powerful motor, it would only be on for a minute or two, perhaps weekly.
I ask, simply because there's no point reinventing the wheel, if it's already been done, successfully. I did search the forum, with no luck and I did try to search with Google, but again, I found nothing.
In the end they may well all blow away in a month, and if everything keeps going well until then, no need to worry about it, but if the batteries start dropping off, I may well have to do something about it, perhaps to be ready for the same period next year.
Cheers
Sutty
So far, at least, my system has not turned off the load output, meaning that the batteries have been staying above the LVC setting that I was advised to use to protect the batteries, without being overly conservative, at 23.4V. That means it's been doing its job well for about 10 or 12 weeks now.
This is not to say I don't want to improve things, and the problem I have now is that my bigger, flat, 500W panel, is getting covered in leaves. The back two are currently doing the heavy lifting, so to speak, because of the sun angle, but also because of the leaves on the bigger panel, which you can see here on this shot from my panel cam.
I had a spare security camera, so I put it up a tree to keep an eye on the panels, whenever I wanted, and below you will see that I have no problem with the back ones. Clearly the leaves slide off, and you can also see that they are at a good angle for this more winter sun. Picture taken just before noon yesterday. The front panel though has far too many leaves. I still caught it putting out 79W, at the time of the shot below, whilst the batteries were still being topped off, but it would be much more effective without the leaves. I suppose it's a good job it's half perc cells, which I understand helps.
Anyway, tilting it is not an option, as discussed earlier in the thread, so I'm wondering if anyone has ever given any thought to a remote cleaning solution for small panel installations. I mean, I can drive up, but it's a bit of a long trip, which would take 3 hrs, all told, and about £20 in petrol, only to have the panel covered in leaves, once more, possibly before I got home, lol.
I've been thinking of either a linear windscreen wiper type solution, a blower fan type solution, or a water spray type solution, either of which could be triggered with a WiFi relay switch, that I already have at the cabin, and is currently powered up, for another purpose, and I don't really need that now, but it does mean I know it doesn't use a lot of power. Nor would the device itself, because despite perhaps having a powerful motor, it would only be on for a minute or two, perhaps weekly.
I ask, simply because there's no point reinventing the wheel, if it's already been done, successfully. I did search the forum, with no luck and I did try to search with Google, but again, I found nothing.
In the end they may well all blow away in a month, and if everything keeps going well until then, no need to worry about it, but if the batteries start dropping off, I may well have to do something about it, perhaps to be ready for the same period next year.
Cheers
Sutty
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