12v wiring bamboozlement

[BlueStringPudding]

9 minutes ago, TheBiscuits said:

 

Again from the manual:

 

12V battery and mono- or polycristalline panels

● Minimum number of cells in series: 36 (12V panel).

● Recommended number of cells for highest controller efficiency: 72 (2x 12V panel in series or 1x 24V panel).

● Maximum: 144 cells (4x 12V or 2x 24V panel in series).

 

So if you have three panels in series your controller will prefer it, be more efficient and your PV voltage will be around 60V so you won't be getting this "is 19V exactly 5V above 14V" nonsense.

 

I'm not going to suggest that you put two panels in parallel and the third in series to give boosted current at the ideal voltage because that would be heresy ...

 

Do the blanket-over-Sunni's-panels test first if you haven't already, so we can rule out any bad connections on the new PV cables to Blue Vicky.

Thanks. 

Why would combining series and parallel be heresy? Would not a higher current be a good thing? (I think that's why I've got them all in parallel at the moment, to increase current). 

 

Blanket thing we will do later once the hard working Monkey has had a cuppa and his dinner and a bit of a rest. 

[TheBiscuits]

4 minutes ago, BlueStringPudding said:

Why would combining series and parallel be heresy? Would not a higher current be a good thing? (I think that's why I've got them all in parallel at the moment, to increase current). 

 

I didn't say I wouldn't do it, I just said I wasn't going to suggest it on here. The purists will get cross. 

 

It would be ideal with 4 panels in a 2s-2p configuration, but it will still work with three.  Just make sure you very clearly label the connections if you choose to do this or some idiot will break your solar at some point in the future by "helping".

 

You probably want the shortest cable run to be from the highest current producing panels (the nearest 2 to the controller wired in parallel) then the furthest one away to be in series with the pair.  Unless it's easier to wire another way with your existing wires obviously, but we are talking theory here.

 

There is a regular argument about the pros and cons of parallel vs series on here, but the setup you have now is providing zero current.  All 3 in series would have been chucking sunshine into your batteries all day and shouldn't need any extra cable, just a replug of what you have installed.

 

Higher current is indeed a good thing, but that's on the output of the controller to the batteries.  If you go all series, you will (theoretically, peak power @ 800W/m²) get 48V (3 * 16V) at 6.3A  from the panels and your controller will convert this to 14.4 V at 21 A to feed into your batteries. 

 

That's why you are using an MPPT controller.  If it's a bit less sunny you might see the controller adjust the panel voltage and current up and down to get the most power possible given the conditions.

 

 

 

[Note to anyone else reading this in the future: This is valid advice for this particular solar controller and these 3 specific panels.  If you have just blown up your own other type of controller by plugging 3 big ass panels into it then I hope it didn't set fire to your boat.]

[BlueStringPudding]

Okay, thanks. I'm pretty sure my 400W SunSaver array which is made up of four panels is half series half parallel. But my dad rigged up the cabling for that a few years ago so I wouldn't want to begin to try to get my head round using the same principle to an odd number of panels even though your explanation makes sense. Thanks for explaining it to me - I'll stick with series for the 390W Victron array. 

 

Another question: can the 390W parallel array be unplugged at the MC4 connectors and reconfigured safely to series format, during bright sunshine? (Detaching the plugs that lead to the Victron controller first and then re-attaching those two again last) With 8 plugs to uncouple underneath the panels, it's going to be nigh on impossible to do while balancing blankets on the panels. 

[TheBiscuits]

4 minutes ago, BlueStringPudding said:

Okay, thanks. I'm pretty sure my 400W SunSaver array which is made up of four panels is half series half parallel. But my dad rigged up the cabling for that a few years ago so I wouldn't want to begin to try to get my head round using the same principle to an odd number of panels even though your explanation makes sense. Thanks for explaining it to me - I'll stick with series for the 390W Victron array. 

 

The easy way to think of it is that you first plug 2 panels together in parallel to make 1 bigger panel, then you connect the "big" panel and the other "little" panel in series.

 

Series is much simpler though.  Post a pic of your current plugs & wires and we'll see if there is an easy way to rewire what you have got at the moment.  Not a circuit diagram, a photo so we can see cable lengths and positions.

 

It might even be worth making a couple of patch leads with MC4 connectors and a short bit of solar cable if you have any spares.

 

10 minutes ago, BlueStringPudding said:

Another question: can the 390W parallel array be unplugged at the MC4 connectors and reconfigured safely to series format, during bright sunshine? (Detaching the plugs that lead to the Victron controller first and then re-attaching those two again last) With 8 plugs to uncouple underneath the panels, it's going to be nigh on impossible to do while balancing blankets on the panels. 

Not really.  Do it after dark, or at least twilight - or wait for a very grey day.

 

You might get away with it, but a 60V kick from the three panels is enough to dump you (or somebody ) in the water twitching and gasping so a really bad idea.

 

[WotEver]

1 hour ago, TheBiscuits said:

You probably want the shortest cable run to be from the highest current producing panels (the nearest 2 to the controller wired in parallel) then the furthest one away to be in series with the pair

At which point you are limiting the maximum current to that of a single panel. So you might as well have them all in series. 
 

Or parallel. 
 

Your choice. 

Two in parallel with one in series with them is the worst of all worlds. You don’t get the high voltage of having them in series and you don’t get the high current from having them all in parallel. 

[BlueStringPudding]

Results of the blanket experiment:

 

Monkey covered tin 400W SunSaver solar array with blankets and towels and whatever else we could find. 

This should have made the SunSaver think it's night time. It didn't. We added more towels. It still didn't think it was night time.

 

The SunSaver STATUS LED remained solid green with heart beat, which indicates charging. Had it thought it was night this bulb would have gone out. (Could it be interpreting the Victron input into the batteries, or this...?)

...The voltage at the SunSaver PV terminals was 13-point-something.  I would have expected this to be low or even zero. 

The voltage at its battery terminals was also high thirteens or low fourteens (sorry, didn't write it down)

The SunSaver BATTERY SOC LED was slow flashing green indicating float charge, load on (fridge was on)

 

The Victron controller STATUS LED continued to flash 3s blue in the Bulk indicator, showing "not enough power" as described in earlier posts. So the Victron controller didn't change.

The Victron PV terminals still showed 19-point-something volts.

 

I'm summary, by covering the 400W SunSaver array we achieved no voltage change and no controller-indicator-light at all on either controllers! Monkey is as baffled as I am. We peered under the blankets and towels and it was pretty dark under there. Presumably either not dark enough or somehow the output of one array is being fed into both controllers...? At different voltages...? By magical means because each controller has separate PV input cables...? 

Fecked if I understand it. 

 

After dark tonight shall I just detach the SunSaver PV cables again so that in the morning, the Victron is the only solar controller in the set up? And see what it does?

 

[Image shows the four solar panels totally covered... that really should have knocked the output back by a lot if not totally. But it did nowt.]

38 minutes ago, WotEver said:

At which point you are limiting the maximum current to that of a single panel. So you might as well have them all in series. 
 

Or parallel. 
 

Your choice. 

Two in parallel with one in series with them is the worst of all worlds. You don’t get the high voltage of having them in series and you don’t get the high current from having them all in parallel. 

Thanks. I understand that. 

 

Are you also saying that there is no benefit from changing the parallel set up to a series set up, even with regards to increasing the voltage difference between the battery and the PV input? It's a very physically demanding job for me and practically difficult, so I only want to change it if, as discussed in earlier posts, it's likely to improve how the two controllers work together.

[WotEver]

23 minutes ago, BlueStringPudding said:

Are you also saying that there is no benefit from changing the parallel set up to a series set up, even with regards to increasing the voltage difference between the battery and the PV input? It's a very physically demanding job for me and practically difficult, so I only want to change it if, as discussed in earlier posts, it's likely to improve how the two controllers work together.

Let's see what happens with the SunSkySaver disconnected first.

24 minutes ago, BlueStringPudding said:

The Victron controller STATUS LED continued to flash 3s blue in the Bulk indicator, showing "not enough power" as described in earlier posts. So the Victron controller didn't change.

The Victron PV terminals still showed 19-point-something volts.

I wonder if it thinks it's connected to a 24V bank.  As above, let's see what happens tomorrow.

[BlueStringPudding]

1 minute ago, WotEver said:

Let's see what happens with the SunSkySaver disconnected first.

So that's a yes to disconnecting the SunSaver PV array tonight.

 

What should I be expecting the Victron to do tomorrow, in that case? I need to know what I'm looking for, what ought to change, what measurements should be different to today's? 

The blanket experiment has added a whole extra layer of bamboozlement  

[WotEver]

17 minutes ago, BlueStringPudding said:

What should I be expecting the Victron to do tomorrow, in that case?

Work

 

Hope that helps...

[bizzard]

Blanketing is very easy you know, just the same as covering your pet bugerigars cage when the sun goes down, so he-she can get to sleep. Or like some folk that cover up mirrors when thunders about.

[TheBiscuits]

9 minutes ago, WotEver said:

At which point you are limiting the maximum current to that of a single panel. So you might as well have them all in series. 
 

Or parallel. 
 

Your choice. 

Two in parallel with one in series with them is the worst of all worlds. You don’t get the high voltage of having them in series and you don’t get the high current from having them all in parallel. 

 

See, I knew I didn't want to suggest it.

 

Are you saying it would effectively end up as 2 in series but with extra wires and a spare panel even if it was connected?  There's something been bugging me about it since I did not suggest it and that might be it. 

 

I only mentioned it because the manual says that the controller needs at least one of these panels(!), works best at 2 panels in series, and can handle 4 panels in series (80V continuous, 100V peak)

 

3 panels isn't mentioned, but in this case 1 panel doesn't work, and 3 in series should be somewhere between ideal and the rated maximum so will be fine.

 

 

[WotEver]

2 minutes ago, TheBiscuits said:

Are you saying it would effectively end up as 2 in series but with extra wires and a spare panel even if it was connected?

Yup. It would be no different to two panels in series. 

[TheBiscuits]

1 hour ago, BlueStringPudding said:

After dark tonight shall I just detach the SunSaver PV cables again so that in the morning, the Victron is the only solar controller in the set up? And see what it does?

 

[Image shows the four solar panels totally covered... that really should have knocked the output back by a lot if not totally. But it did nowt.]

 

Well that's not the predicted results of the experiment!

 

I'm going to blame @cheshire~rose for this awkward challenge failing.  

 

I agree that unplugging the panels from the DiLithiumCrystalSunCatcher (Sunni, as we know it) is a good test for tomorrow, and doing it when it's dark is good.

 

If we get the expected results (Vicky works, charges, is happy) then I'll stick with my first advice: the three Victron panels in series.  Like Tony says, let's see what happens tomorrow.

[BlueStringPudding]

Thanks all. I shall report back tomorrow.

[BlueStringPudding]

Weirdness. Or brokeness. That is my report summary.

 

VOLTAGE MEASURING FRIDAY MORNING (I'm writing this one first because it's what we've talked about yesterday, but I also took some readings last night which I'll tell you about later)

 

It's an overcast day today, unlike yesterday, but still reasonably bright. The PV input to the SunSaver controller is NOT connected. Everything else in the solar system (!) is connected.

 

Voltage measurements as follows:

SunSaver PV terminals: 0v (as expected)

SunSaver Batt terminals: 12.50v (as expected but only if no solar charge coming from Victron)

Victron PV terminals: 19.91v but it jumps suddenly to 1• (Literally a one and a dot, not one point zero.  I think 1• must be Uni-t multimeter code for something but I've yet to look for it in the manual.)  As a note, it is very hard to get the multimeter prongs into the Victron terminals, so the jump may be my not making perfect contact with them. But I tried it four times from different angles and it either did the jump from 19.91v to 1•, or it only showed 1•. It has not done the jump to 1• before today though)

Victron Batt terminals 12.50v (as expected but only if no solar charge coming from Victron)

Busbars 12.50v (again as expected if no solar charge coming from Victron)

 

And yes, the annoying blue light is still flashing as it did all night too, indicating that there isn't enough power going to the Victron for it to start charging. (Incidentally, if that blue light is going to flash every time the sun goes down even after the PV wiring is set correctly, that's a shoddy bit of design just to let me know there's not enough power, coz it's a bright light and ruddy irritating! Hopefully it'll go away when all this is fixed)

 

So wise ones, please advise what do I do next, given the above Victron readings and the continuing flashing indicator light? (Other than unscrew the bulb ? )

 

-----

 

And because I was curious,  I took these measurements last night which I would also like to understand better:

 

VOLTAGE MEASURING THURSDAY NIGHT:

After dark last night (9.45pm or so), the status LED on the SunSaver was off indicating there was no solar charging anymore. All good so far. Out of curiosity, before I detached the SunSaver PV cables, I took some night time readings:

 

SunSaver PV terminals (cables still attached): 6.91v (why? Tiny amount of light outside maybe that the controller couldn't use for charging but I could detect with a multimeter...? Any wiring explanation I ought to be worried about?)

SunSaver Batt terminals: 12.54v (as expected)

Victron PV terminals: 3-point-something volts (again, why? Same reasons as above maybe?)

Busbars: 12.54v (as expected)

 

Then I disconnected the SunSaver PV cables (not the Victron ones) and took the measurements again. 

 

SunSaver PV terminals (cables disconnected) 0v (as expected)

SunSaver Batt terminals: 12.53v (as expected)

Victron PV terminals: 0v (as expected but different to before I detached the SunSaver cables - maybe it was a bit darker by now hence the drop off of the 3v that lurked earlier? Or is there another explanation?)

Busbars: 12.53v (as expected)

 

Would love your thoughts again, please, just to satisfy my curiosity on that. Thanks

 

Edited May 22, 2020 by BlueStringPudding

[WotEver]

Two possibilities. 
 

1. Victron MPPT is broken. 
2. Victron MPPT thinks it’s connected to a 24V battery bank. 
 

2. Is possibly the most likely and you’ll need to read the manual carefully to ensure it’s set to 12V. 

[BlueStringPudding]

The very first bullet point in the manual says " the controller will automatically adjust to 12v or 24v nominal battery voltage" ?

I don't think that bodes well.

 

It doesn't bode well. It later says that the controller will automatically recognise  a 12v or 24v system once only and if it needs changing again it has to be done manually via a Bluetooth app. But this controller doesn't appear to have Bluetooth. Which means buying additional equipment for it. I would rather not spend money on it only to find out the controller was broken anyway. Is there any other way I can work this out? Or are there any other possible problems with the set up that I can rule in or out first before forking out for a £45 dongle that I don't want? 

 

Maybe the original owner of the controller reads this and can tell us whether it was last used on a 24v or 12v system?

Edited May 22, 2020 by BlueStringPudding

[Tony Brooks]

No help to your question but it seems Victron MPPT controllers setting themselves to 24 volts and when set back to 12V resetting themselves is becoming more common than it should be for a quality brand. Its not the first time we have heard about this on here. If it were mine I suspect I would be replacing it rather than buying a gizmo to reset it and risking it becoming a regular task.

[WotEver]

Maybe phone Onboard Energy and ask Kevin's advice?

[TheBiscuits]

Again, from the manual:

 

The controller can be reset by short circuiting the output and applying a voltage exceeding 7 V on the input (for example with a small power supply, or a solar panel) during a few seconds. After a reset, the controller will automatically adjust itself to a 12V system, or a 24V system (when connecting a 24 V battery with at least 17,5 V).

 

Just don't try this while the outputs are connected to the batteries!  

 

I'd disconnect one of the input wires - they are not under load so it's OK to do this in daylight.  Then disconnect both the battery connections, and insulate them so they don't short out.

 

Connect the battery terminals on Vicky together with a spare bit of wire, then poke the previously disconnected panel wire into it's connector for a few seconds (5? 10? it will probably flash some lights)

 

Remove the panel wire and reconnect the contoller to the batteries.  This should in theory have reset Vicky to 12V.

 

 

 

 

Edited May 22, 2020 by TheBiscuits
Add a bit

[BlueStringPudding]

24 minutes ago, Tony Brooks said:

No help to your question but it seems Victron MPPT controllers setting themselves to 24 volts and when set back to 12V resetting themselves is becoming more common than it should be for a quality brand. Its not the first time we have heard about this on here. If it were mine I suspect I would be replacing it rather than buying a gizmo to reset it and risking it becoming a regular task.

We don't even know that's what the problem is though, without the additional dongle to tell us.

The controller really ought to be able to tell us basics like what voltage it is set at, if it's incapable of adjusting itself, without buying additional equipment. I wouldn't call that a quality brand. It's either poor design, poor build quality or intentionally trying to milk customers for additional money.

 

So is there absolutely nothing else I can do apart from either buy a new controller (it won't be Victron) or buy a dongle to test and/or adjust this one?

Has absolutely every other possible issue with my solar been ruled out? I don't have much money so it's a big deal that I don't just throw this controller out for no reason. 

 

EDITED TO ADD:

Just seen Dave's reply. I'm going to read it again to be sure I understand it. Not sure I've been reading from the same manual. 

Edited May 22, 2020 by BlueStringPudding

[cuthound]

38 minutes ago, TheBiscuits said:

Again, from the manual:

 

The controller can be reset by short circuiting the output and applying a voltage exceeding 7 V on the input (for example with a small power supply, or a solar panel) during a few seconds. After a reset, the controller will automatically adjust itself to a 12V system, or a 24V system (when connecting a 24 V battery with at least 17,5 V).

 

Just don't try this while the outputs are connected to the batteries!  

 

I'd disconnect one of the input wires - they are not under load so it's OK to do this in daylight.  Then disconnect both the battery connections, and insulate them so they don't short out.

 

Connect the battery terminals on Vicky together with a spare bit of wire, then poke the previously disconnected panel wire into it's connector for a few seconds (5? 10? it will probably flash some lights)

 

Remove the panel wire and reconnect the contoller to the batteries.  This should in theory have reset Vicky to 12V.

 

 

 

 

 

9 volt PP9 from a smoke detector or similar?

[BlueStringPudding]

20 minutes ago, TheBiscuits said:

Again, from the manual:

 

The controller can be reset by short circuiting the output and applying a voltage exceeding 7 V on the input (for example with a small power supply, or a solar panel) during a few seconds. After a reset, the controller will automatically adjust itself to a 12V system, or a 24V system (when connecting a 24 V battery with at least 17,5 V).

 

Just don't try this while the outputs are connected to the batteries!  

 

I'd disconnect one of the input wires - they are not under load so it's OK to do this in daylight.  Then disconnect both the battery connections, and insulate them so they don't short out.

 

Connect the battery terminals on Vicky together with a spare bit of wire, then poke the previously disconnected panel wire into it's connector for a few seconds (5? 10? it will probably flash some lights)

 

Remove the panel wire and reconnect the contoller to the batteries.  This should in theory have reset Vicky to 12V.

 

 

 

 

Thanks. I haven't seen that in the manual. So either the manual I have (which is very short) isn't the right one, or (quite possible) I didn't find or understand that paragraph if I did read it. But thank you for your much needed explanation. It gives me a not expensive option to try before throwing the Victron baby out with the bathwater.

Because the process sounds scary, and because the Victron terminals are dreadful (screw heads are soft and are the flat head screwdriver type, so too much more turning them is going to strip the notches off the screws) I'm going to try to interpret your destructions in simple, brainless Clanger sized steps with as few mucking abouts with the controller screws as I can manage. Please correct me if I get any of these steps wrong or clarify any questions:

1. I disconnect the Victron PV positive cable from Victron PV positive terminal. Insulate with tape.
2. Disconnect from their respective busbars both the positive and negative Victron Batt terminal-to-busbar cables (cables 4 and 6 in the old diagram). This leaves the busbars live and connected to the batteries, but leaves the Victron disconnected from the batteries with two cables hanging out of its arse from the Victron Batt terminals.
3. Join cables 4 and 6 together, even though one leads to the positive Victron Batt terminal and one leads to the negative Victron Batt terminal...? Yes? (This is where my sphincter tightens...)
4. Remove insulating tape from the disconnected PV positive cable and touch the live end to where cables 4 and 6 join. Hold the trio together for 5 or 10 seconds (will this destroy the cables or lugs? Or anything else?) Scary lightening ensues and I cry a little, hopefully my sphincter remains intact.
5. Remove the PV positive cable from the lightning. Insulate with tape again if I'm feeling scared.
6. Reconnect cables 4 and 6 to their relevant busbars.
7. Victron should my be able to read that the batteries are 12v ones.
8. Reconnect PV positive cable to Victron PV positive terminal (does this have to be done after dark?)

Have I idiot-proofed that or have I misunderstood anything?
 

[TheBiscuits]

28 minutes ago, BlueStringPudding said:

Just seen Dave's Pete's reply. I'm going to read it again to be sure I understand it. Not sure I've been reading from the same manual. 

 

Please post a picture of Vicky to make sure we are talking about the same unit!

 

I thought you had the Victron BlueSolar MPPT Controller 100/30 without the optional Bluetooth dongle - the older model not the 2020 version - that came from Jennifer last year and she had fitted in 2016.

 

 

[BlueStringPudding]

10 minutes ago, cuthound said:

 

9 volt PP9 from a smoke detector or similar?

Smoke detector batteries I have. Is that instead of using the live PV cable from the three panels?  Sounds gentler!

Which bit of the battery do I touch to the conjoined Victron cables? And do I just hold it there in a cowardly brave way or do I need to connect it somehow?