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zorro
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# Posted: 6 Jan 2020 04:19pm
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Just looking for some thoughts, ideas or help………….as I am struggling badly
Ok
Brand new solar array/system, made up as follows;
· 3 x 340W panels
· 60A MPPT Charge Controller
· 1500W/24V Pure Sine Wave Inverter
· 8 x 6v/230ah Batteries
Cabin is literally 10 LED lights, some cell charger outlets and that is it – nothing else
The well (which is winterized) runs off the generator, but in any case, is not running
Now for the problems
The battereis are not fully charging (max – 62%), then dropping pretty fast over a 3 week period to 40%, even though I was not there and the Inverter was turned off
As a result, some of the battereis froze
So I have 8 totally new batteries (8 full replacements), but I don’t want to connect them until I try to figure out what is happening
I am also getting an audible warning from the Charge Controller;
BAT-UVW â€under-voltage warningâ€
Which essentially shut down the system one night, setting off audible alarms
So I am worried about setting up the replacement batteries as I have no idea what has caused these issues and don’t want to repeat it!
Any thoughts?
Thanks
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FishHog
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# Posted: 6 Jan 2020 04:31pm
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either something isn't wired properly or your charge controller is faulty and allowing the batteries to discharge back to the solar panels.
Perhaps a drawing of how you wired everything would help us narrow down your issues.
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Steve_S
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# Posted: 6 Jan 2020 06:47pm
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If I understand it right. You still have the old batteries attached to the inverter, the ones that froze and your getting an Under volt alarm. Those batteries are damaged and likely depleted so remove them. Be cautious to note any leaked, just in case. After checking each battery to make sure it's ok, with an electrolyte tester you can charge it.
As for lack of charge as you noted. It is winter and your not likely getting enough good hours to actually fully charge the batteries. But without an actual load on them (inverter off) they should have eventually topped up and when fully charged they would not have frozen. The SCC should have just gone into float in that situation.
The continued voltage drop is certainly a red flag. There are a few things that could do it, bad charge controller, a bad battery (but there would be other signs) a short of some sort. One sure fire way to freeze FLA batteries is low fluid and if the plates get exposed more issues follow quickly.
Disconnect the old batteries. Test the voltage off the panels @ the SCC. if the SCC has a display make sure it matches your readings. Work your way through your wiring and check the connections & terminals.
Wiring diagram, photo's etc would all be helpful.
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ICC
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# Posted: 6 Jan 2020 07:46pm
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Is this a remote, part-time use system?
Quoting: zorro The batteries are not fully charging (max – 62%), then dropping pretty fast over a 3 week period to 40%, even though I was not there and the Inverter was turned off
That sounds like the system was left idle, with the inverter off for a period of three weeks. Correct, or not?
If that was the case the batteries should have been okay if the charge controller was left on so the batteries would get a daily short bulk charge, then absorb for whatever time is set and finally spend the rest of the sunny hours on float.
Question... how are you determining the state of charge? A hydrometer is the best way with flooded lead-acid batteries. A hydrometer is accurate whereas voltage readings can be misleading.
Brand names, models of the equipment??
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zorro
Member
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# Posted: 6 Jan 2020 07:55pm
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Guys
thanks for the comments - really appreciate it
It is a remote cabin and i am not there at present so limited on what i can do
To summarise
When i was away for 3 weeks, the inverter was switched off but everything else left on - the batteries lost a 20% charge during that time
I actually tested all the batteries at the weekend with a hydrometer - no battery was better than "fair" and maybe 3 or 4 of the batteries had some cells in the red reading - these are brand new batteries (Deka)
I know for certain that most of them had started to freeze a couple of weeks back as the fluid was crystalised when i checked the levels
I spoke to the electrician who fitted it up - he is not sure
I spoke to the equipment supplier and he needs to get readings in terms of volts, amps, etc to try to determine where the issue is
I know the batteries are wired correctly as i sent a picture to the solar guy (supplier) today and he confirmed they were fine
I am identifying the battery charge levels from the CC and also a remote meter i have set up which shows the actual charge
I will see what pictures i have and try to post them - but will likely need to get others when i am back there around 3 weeks time
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zorro
Member
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# Posted: 6 Jan 2020 08:04pm
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cspot
Member
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# Posted: 6 Jan 2020 08:11pm
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Just a thought, but assuming you paid the electrician to wire this up, I would think he should be testing it to find the issue. If there is an issue then the equipment supplier replace. Just a little concerned that the electrician said he is not sure. Does he have much experience with solar setups?
Hope you get if figured out. Tough to figure things out and get it fixed on a recreational place.
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ICC
Member
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# Posted: 6 Jan 2020 08:18pm - Edited by: ICC
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The third image shows what appears to be 30.7 volts from the panels. Is that correct? The first image shows 26.5 volts.
In order to charge a 24 volt battery bank one needs 28.8 or a little more voltage going into the batteries. No way that will happen with image #1. And image #3 will be iffy when CC losses are taken into account or when a cloud drifts by.
My assumption is the solar panels you have are wired in parallel? INO, I believe you need one more panel and hook them up in a 2S2P configuration. Or maybe, depending on the specs of the CC you have, the three panels you have could be placed in series.
What panels do you have and what charge controller? For the panels we need to see the specs for the Vmp, Voc, Imp, Ioc in particular and for the CC what maximum input voltage it is rated for.
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zorro
Member
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# Posted: 6 Jan 2020 09:58pm
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I have 3 panels all linked together - not exactly sure how
Specs are;
Pmax - 340W
Vmp - 38.3v
Imp - 8.88a
Voc - 46.1v
Isc - 9.5a
Inverter - 1500W Samlex Pure Sine Wave
SRNE 60A MPPT CC (pretty sure it is this)
And all set up for 24V
Voltage from the panels seems to fluctuate from 20V to 120V..............again, dont understand that, if it is simply the lack of sunshine, cold, or an issue?
Problem is I am not there for another 2/3 weeks
Electrician is a good electrician but very limited in solar systems
The supplier is highly rated, but again 4 hours away
And i know very little about this at all and trying to learn
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ICC
Member
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# Posted: 7 Jan 2020 12:26am
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Quoting: zorro Voltage from the panels seems to fluctuate from 20V to 120V..............again, dont understand that, if it is simply the lack of sunshine, cold,
If you have seen the voltage from the panels at 120 volts then the three panels must be connected in series. (With panels or batteries in series you add the voltage of each one to get the total. The amps stay the same as one)
When the voltage falls lower that is due to low amounts of sunshine. Or some other intermittent problem. It can also be because of shading. There should be NO shading at all for best results.
Cold will increase the voltage output from panels. IF those three panels are in series that may be a problem with that charge controller. The panel Voc (voltage, open circuit) is the highest voltage the panels would normally produce; normal being at 75 degrees F.
The Voc = 46.1 volts. IF all three panels are in series, then 46.1 x 3 = 138.3 volts. The literature I see for that CC states the maximum input voltage is 145 to 150 volts, depending on the temperature. So, at 75 F the three series-connected panels, with bright sun on them, is very close to the maximum design voltage of the CC. Voc is reached as a short duration spike.
Just FYI, the Vmp is voltage, maximum power. That value is always lower than the Voc. Voc is usually a short peak value; like first thing in the morning as the sun pops up over the hills and strikes the panels. At that time the Voc can peak.
Vmp is the design voltage that would be reached under direct noontime, bright sun. Those panels are rated at 38.3 volts, again at maximum noon sun and 75 F degrees. So, 38.3 volts x 3 = 114.9 volts. That is a safe input voltage; at 75 F.
As the weather gets colder and colder that voltage will increase. The NEC has us use a 1.25 multiplier factor when designing a system to cover the increased voltage on cold days. If we round up, we have 115 volts x 1.25 = 144 volts. Again, very close to the CC maximum.
FYI, conversely, on a hot summer day the panel output voltage will fall.
My personal opinion is that those three panels, if all in series, are a poor match for the charge controller. Or vice versa, the CC is a poor match for those three panels in series.
Note that a well-designed charge controller will have circuitry that will disable the unit when the voltage hits the design maximium. We hope that it reacts fast enough to cut out and not damage the hardware. I don't know that CC at all, but my bet is that it is cycling off quite often when the voltage spikes too high. I don't have any idea if it quickly comes back online when the voltage drops or not. Chances are it times out for a while once a peak is hit to avoid rapid cycling and premature wear. You could ask the folks who sold that to you.
All that is working on the assumption the three panels are in series, which I think they must be if you have actually seen a reading of 120 volts from the panels.
FYI, altitude also has an effect on panel output. High altitudes can increase the amperage output by a solar panel. That is because at higher altitudes there is a less dense atmosphere and more sunlight will reach the panel surface. That is usually a good thing. This CC has plenty of amperage capacity so there is no downside if you have a high altitude location. It could be a problem if the CC amp capacity was marginal.
A fourth panel, so you could have a configuration of two sets of 2 panels per series string, with those 2S then connected in parallel (2S2P), could be advantageous in cold weather as that would hold down the peak voltages. The CC has plenty of ampacity for the parallel connection. That would still have sufficient voltage to operate well on a hot summer day.
The Samlex inverter is decent, better made than many. It might be a good idea to vacuum it once in a while. Dust gets inside through the vents slots and can cause heat to not be dissipated as readily. Heat kills electronics. Did they provide a circuit breaker or a fuse for the DC input to the inverter? I like breakers as they can be an excellent disconnect method. Better than just the on-off rocker switch built into the inverter.
I hope that helps you sort out what is happening.
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Brettny
Member
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# Posted: 7 Jan 2020 07:42am
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By the looks of the pic of your charge controller you either don't have enough sun light getting to the panels or a dead panel or two. You can disconnect each panel and measure voltage in the sun.
Either way bring a battery charger and generator to put some charge back in your battery. It's not good to leave them so dead. It's not good to bring them down that low also.
I suggest you do some solar diagnosis research, I'm sure your remote and you should be able to diagnose a simple system like this.
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NorthRick
Member
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# Posted: 7 Jan 2020 03:58pm
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I'd guess your charge controller is bad. As ICC suggested you could have exceeded the max input voltage, which may have damaged it, or it just failed. Before replacing it though, I'd check each panel individually to be sure one of those has not failed.
If you stick with those 3 panels and that model charge controller (a replacement), I'd rewire those panels to parallel. That would keep you within the CC limits on both voltage and current while still having high enough voltage to charge a 24v bank.
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zorro
Member
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# Posted: 7 Jan 2020 04:28pm
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Thanks for all of the info and advice
I need to read through it all and speak to my electrician and supplier
I have 8 new batteries on the way, so clearly I don’t want a repeat!!
I will update as I find out more likely in around 3 weeks when I can get back to the camp - assuming the weather holds out!
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cspot
Member
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# Posted: 7 Jan 2020 06:08pm
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Quoting: zorro Electrician is a good electrician but very limited in solar systems The supplier is highly rated, but again 4 hours away
I guess what I am trying to say is that a new system that you just bought from a supplier and paid someone to put in, you shouldn't have to be the one trouble shooting the system.
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zorro
Member
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# Posted: 7 Jan 2020 06:27pm
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Agreed - especially when I know very little about that troubleshooting and could do more harm than good - both to the system and myself!!
I did email the electrician and he is on vacation - but you are correct I need to get him back to help me run some tests - if nothing else to check and confirm the cables/wiring that he hooked up
I also intend putting in a charger so the generator can charge the batteries so he need to come back for that as well
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cspot
Member
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# Posted: 7 Jan 2020 07:05pm
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Quoting: zorro Agreed - especially when I know very little about that troubleshooting and could do more harm than good - both to the system and myself!! I did email the electrician and he is on vacation - but you are correct I need to get him back to help me run some tests - if nothing else to check and confirm the cables/wiring that he hooked up I also intend putting in a charger so the generator can charge the batteries so he need to come back for that as well
Sounds like a good plan. Good luck and let us know what they find wrong.
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