Is my solar setup faulty?

[monsteruk]

So, to aid in my diagnostics I am looking to buy the Victron SmartShunt 500a monitor.

To do this, as I understand it I need to move all the cables attaching to the negative terminal post, and attach these to one end of the shunt. The other end of the shunt would attach by a single cable to the negative terminal. As you can see below, there are quite a few cables on the negative terminal.




So, the shunt meter has these attachments.



Obviously the dingle lead that goes directly to the battery will fit easily to one side, but I have 8 individual negative wires currently connected to the battery. Would I just connect all of those directly to the ShuntMeter terminal? Or can I buy some form of connection block (a but like is on the battery in pick above) to make connecting all those wires to the shunt meter easier?

Thanks in advance.

 

[Phil_G]

Hankook AGM59520 is not a deep cycle leisure battery, it's a starter battery.

This Hankook dual purpose battery combines both Absorbed Glass Mat (AGM) and Valve Regulated Lead Acid (VRLA) technology to offer the characteristics of two separate batteries to provide both powerful starting and deep-cycle capabilities. 100% maintenance free, this battery provides reliable power, strong durability and comes charged and ready to use.

@monsteruk I wouldnt spend more money on monitoring devices unless you particularly want to, once your problem is sorted you'll rarely need them for a fridge and lights with a 150w panel, unless you're a very heavy user. Until then it wont tell you anything you cant get from your Victron, a multimeter and a spot of nouse

 

[monsteruk]

@monsteruk I wouldnt spend more money on monitoring devices unless you particularly want to, once your problem is sorted you'll rarely need them for a fridge and lights with a 150w panel, unless you're a very heavy user. Until then it wont tell you anything you cant get from your Victron, a multimeter and a spot of nouse

Thanks @Phil_G,

I will spend some time tomorrow trying to reproduce the issue that occurred when I washed the van yesterday (when it was 38W, and dropped to 0W as soon as I cleaned it). I tried to do that today, but there was not enough sun about. Didnt rain / snow but very thick cloud. Max I saw from panel today was about 4W, so would not have been east to spot if it had gone wrong again. Hopefully tomorrow a bit more sun, and be easier to see any meaningful drops.

Re the multi-meter thing then. For diagnosis purposes, is there any easy way of using one to see the AMPS being drawn from the battery in my current setup?



Thanks for taking the time Phil!

 

[t0mb0]

@monsteruk I wouldnt spend more money on monitoring devices unless you particularly want to, once your problem is sorted you'll rarely need them for a fridge and lights with a 150w panel, unless you're a very heavy user. Until then it wont tell you anything you cant get from your Victron, a multimeter and a spot of nouse

I would endorse this, a shunt-based monitor isn't exactly crucial, even if it's nice to have. It's easy to read a load of forum threads and decide you need every gizmo going, but it's not gizmos that make a van - it's the things you do with it! Once you get to know your system, voltages tell you quite a lot.

In terms of diagnosing issues though, I would say a clamp meter is a pretty useful gizmo. Even so, this isn't essential either - it's just that being able to measure actual current flow makes diagnosing things somewhat more straightforward. A £30 clamp meter will also act as a general purpose multimeter for voltages, continuity/resistance tests etc.

 

[monsteruk]

I would endorse this, a shunt-based monitor isn't exactly crucial, even if it's nice to have. It's easy to read a load of forum threads and decide you need every gizmo going, but it's not gizmos that make a van - it's the things you do with it! Once you get to know your system, voltages tell you quite a lot.

In terms of diagnosing issues though, I would say a clamp meter is a pretty useful gizmo. Even so, this isn't essential either - it's just that being able to measure actual current flow makes diagnosing things somewhat more straightforward. A £30 clamp meter will also act as a general purpose multimeter for voltages, continuity/resistance tests etc.

Thanks for that!

I will have a read about clamp meters then. Just so I know I am looking at the correct thing... I am assuming you mean something like this?

Clamp Meter, Meterk 4000 Counts Digital Clamp Meter Auto Range NCV AC/DC Current Voltage Resistance Capacitance Frequency Temperature Measure Diode Hz Tester LCD Diaplay Multimeter: Amazon.co.uk: DIY & Tools

Shop Clamp Meter, Meterk 4000 Counts Digital Clamp Meter Auto Range NCV AC/DC Current Voltage Resistance Capacitance Frequency Temperature Measure Diode Hz Tester LCD Diaplay Multimeter. Free delivery on eligible orders of £20 or more.

www.amazon.co.uk

Thanks

 

[Dilbert]

Also agree with a clamp meter/multimeter. Make sure it can measure DC current. This one is popular (and I have) UT210E Mini Clamp Meter and is available on popular auction sites: UNI-T Voltage Meter, Multimeter, Oscilloscope | UNI-T

 

[monsteruk]

Also agree with a clamp meter/multimeter. Make sure it can measure DC current. This one is popular (and I have) UT210E Mini Clamp Meter and is available on popular auction sites: UNI-T Voltage Meter, Multimeter, Oscilloscope | UNI-T

Many thanks, always good to have a specific product recommendation from someone who knows their onions so to speak.

I will have a google and see if I can work out how I would use it to measure the AMPS draw on my battery. As you all have said, I perhaps dont need to see that info all the time, but being able to see the amps drawn for diagnosis purposes would be useful.

Thanks,

 

[monsteruk]

Hey @Phil_G,

To be fair the converter, he had already agreed to switch the panel if issues continued (but I need to prove they are continuing I guess). We had discussed that any new panel would need to be larger in dimensions than the original, as the original is likely not to come off 100% cleanly. But hopefully if the new one is larger dimension it should cover up any residue from the old panel and look ok?

Re the switch from bulk to float. Thats a good point to raise Phil, and to be honest on this stuff I am rarely sure on anything. On the odd occasion I have seen it in float since March, it has tended to get there via spending some time in Absorption mode. And then when it goes into float mode, I am pretty sure it actually says the current mode under the "State" part of the display, i.e. it shows State as "Float" if in float mode. See below, it actually had a status of "Off" when it went to 0W. I also find it interesting that the battery voltage at that point was 12.46 (less than 80%?), which does not imply it is fully charged, so you would expect it to charge at that point? Finally, the voltage on that panel at that point seems really low too at 13.11? But maybe that's what it would do in float?

View attachment 97803

But just before it went to 0W, it showed status of bulk, 38W from panel and a battery voltage of 13.09v. It also showed a good panel voltage at that time (25.99v). I assume those figures are reasonable for winter sun on a 150W panel?

View attachment 97804

Someone said yesterday that even if the battery is showing 13v or over, if it is still accepting good charge (3 amps going in above), it is unlikely to be near 100% charged so will remain in bulk. So, my understanding is that the above screen shot does not show fully charged / just about to switch to float, but I dont really know.

So @Phil_G, my suspicion is it had NOT gone in to float mode when it went to zero, but nothing is surprising me on this stuff! lol

Thanks.

So, an update on the issue from yesterday where it dropped from 38W to 0W within 5 mins of cleaning the roof. There was a question as to whether the panel had coincidentally gone into float mode at that point, and that could be the reason for the drop to zero. So, to see if that is the case, I have just looked at the history in bluetooth, and this is what it says.



That seems pretty conclusive to me that it never went into float (100% time in bulk mode). Also, interestingly, it shows 5hr 47min in bulk. In the previous day to the fault and also today, it shows over 7 hours in bulk. So, the two hours discrepancy when the panel went to 0W, dont seem to have been counted as any of bulk, abs, or float.

I am assuming that conclusively shows the drop to zero yesterday was indeed a problem?

 

[mmi]

Clamp Meters

Any recommendations for clamp meters? They have been mentioned in a few threads but I can’t find suggested products. Suitable for small mA measurements with dc in the van and elsewhere and also if possible up to mains ac. I’m not sure how much I need to spend for a tolerably decent one with the...

www.t6forum.com

 

[monsteruk]

Clamp Meters

Any recommendations for clamp meters? They have been mentioned in a few threads but I can’t find suggested products. Suitable for small mA measurements with dc in the van and elsewhere and also if possible up to mains ac. I’m not sure how much I need to spend for a tolerably decent one with the...

www.t6forum.com

Again really useful. I have never seen a clamp meter before (only multi-meters with probes).

I found this video which explained it to me.

About 7 mins in he shows how to use the clamp to measure current - a very clever gismo. But his demonstration is a simple one - a single cable feeding one thing.

On my setup the positive and negative battery terminals have multiple (about 6) wires going to them (battery pics above). To see the total current being drawn, can I simply put all 6 cables in the clamp at the same time and see the total amps being drawn for all wires at the same time? Or would I need to test each cable individually (current could be being drawn through multiple cables I guess).

Also, would it show the net amps (difference between draw and charge) ? I.e. if the lights were drawing 1 amp, but the solar was putting in 1.5 amps, would the meter show positive 0.5 amps.

Thanks.

 

[Pete C]

It can do individual and multiple cables.
Your lights will draw current from one cable, and your solar will put current in through a different cable, so you can measure either.

Pete

 

[monsteruk]

It can do individual and multiple cables.
Your lights will draw current from one cable, and your solar will put current in through a different cable, so you can measure either.

Pete

Thats brill, thanks Pete. So, just to play that back to make sure I fully understand. If we took my example of - the lights drawing 1 amp, but the solar putting in 1.5 amps. If I clamped just the solar cable it would read+1.5a. If I clamped just the lights cable it would read -1a. If I clamped both cables at the same time, it would read: +0.5A. Do I have that right?

If I do have that right, it may be cheaper (and way less work) getting a clamp meter vs buying and fitting an inline shunt meter. Sure, the clamp wont show me history or provide instant access to the numbers, but for diagnosis (which is my current issue - no pun intended!) it would do what I need.

Thanks,

 

[mmi]

To see the total current being drawn, can I simply put all 6 cables in the clamp at the same time and see the total amps being drawn for all wires at the same time?

Correct. Just make sure the cables stay "freely" - so that the clamp closes freely by itself. Worth to note - make sure you zero the reading without any cables in the clamp. And do this very close where you are measuring. Also good idea is to check the reading (to be zero) again when taking the clamp out of the setup. The meter also distuinguishes the direction of the current (charge/discarge) - the sum of currents within the clamp.

If I clamped both cables at the same time, it would read: +0.5A. Do I have that right?

Correct.

---------------------
The technology to measure DC using a clamp is totally different than for AC thus the reading you get is usually not stable on long term - especially at milliamp range. If you would look for recognised brands for DC clamp meters you would be surprised they don't even offer milliamp range measurement at resonable price.

Anyways, a really useful gadget for the price. Easy to use as no need to disconnect anything. And as above, you can even sniff individual wires.

 

[Pete C]

Thats brill, thanks Pete. So, just to play that back to make sure I fully understand. If we took my example of - the lights drawing 1 amp, but the solar putting in 1.5 amps. If I clamped just the solar cable it would read+1.5a. If I clamped just the lights cable it would read -1a. If I clamped both cables at the same time, it would read: +0.5A. Do I have that right?

Not 100% sure about that, but you it’s far simpler to measure individual wires - trying to measure multiples means you never know for sure what each wire is doing.
If you turn your lights on, and they draw 1A, then that isn’t going to change.
Definately keep your measuring simple.

Also, these meters time out, so are difficult to use for long term measurement.

Pete

 

[Phil_G]

Clamp meters are great, but on most, the lowest scale is still quite large (mines 40A) so measuring an amp or less isnt going to be spot-on accurate as a multimeter would be, but for convenience of measuring in situ they're ideal. If you have a twin cable, you will need to clamp over one wire where it splits, or deliberately split the cable (ie part the two wires) for a couple of inches. Another tip for measuring low current more accurately, if theres enough wire, wrap several turns through the clamp then divide by the number of turns. A DC clamp meter is so useful, you'll find all sorts of uses for it and for what they cost its an essential in your toolbox!
I'd happily lend you mine, but you can almost buy one for the out & return postage!
Cheers
Phil

 

[monsteruk]

First up, a HUGE thanks to everyone on this forum who has been helping me - if it wasn't for the help and input of the people on this forum I would have zero idea of how to prove if there is an issue or not.

So, I think I have another significant piece of information relating to the issue with the solar panel which proves the issue - please read on. Cast you minds back to the situation I had two days ago. Where the panel showed 38W with 2.9A going into the battery, and as soon as I started to give the roof a clean, it dropped for no obvious reason to 0W and 0a going into the battery. I had done nothing, apart from give the panel a gentle wipe over / clean.

So, as it is another sunny day today, I thought I would try and reproduce the issue again. I have spot checked the readings via Bluetooth throughout the morning. From around 10:30 (a bit misty) the panel was doing around 25W, and this went up as the morning progressed. As it got toward mid-day the panel was up to pretty much 50W, so I decided to see if I could reproduce the "drop to 0W issue", by giving the panel and roof a clean / wipe over.

However, even before I started, I noticed something a little odd. As I was actually watching the bluetooth screen, something odd happened. Although the sunny conditions had not changed, the readings went from 50W down to about 18W (state still showing as in bulk). It then bounced between 18W to 30W for a bit, before finally returning to around 50W. As it had returned to 50W again, I didnt think too much more about it.

I took the screenshot below, at 11:45 just before I got prepared to wash the panel and roof (this was about 5 minutes after I noticed the watts bouncing up and down a bit):

So, good levels of charge going in at that specific point.

9 minutes later, I was ready to start cleaning the roof, but had NOT started yet. I connected the bluetooth so I could watch the figures as I actually cleaned. But... low and behold, it had gone down to zero on its own, before I had even started to clean anythying. I was just about to start at that point, the roof was completely untouched. Here are the figures:



Note that the state is still bulk, showing it is "trying to charge", but there are 0W so it cant. To me It does not look as if the panel had just gone into ABS or float mode, as the app still displays state as "bulk". Also, as the leisure battery is showing as only 12.67 volts at that time, surely it should be charging if it can (i.e. the battery does not looked fully charged based on the voltage)?

It stayed in "bulk" state for another 5 minutes, but the panel volts continued to slowly drop. After about 10 minutes of it being 0W, the state changed to "OFF" as shown below.



Just to check the display was not lying, I left it another 30 minutes and looked in the history to see if it has recorded any time in ABS or FLOAT modes, and it has not. The history showed an additional 30 minutes in "bulk mode" at this point, and not time in float / abs modes (see below).



So, the million dollar question.... Can I take this latest episode (together with the incident from 2 days ago) as evidence there is definitely an issue with the panel? Or is there a valid reason I dont understand that explains why it could suddenly drop from 38W to 0W 2 days ago, and now today from 49W to 0W in the space of a few minutes? If this is categoric evidence I will get back on to the converter now. Thanks again everyone!

For completeness, here are the two screen shots from when the same thing happened two days ago.



Went from 38W to 1W (and then zero soon after) within 5 minutes.

 

[t0mb0]

It’s not possible to be 100% sure but I would say the very sudden drop offs in solar output (and voltage) without change in sunshine or battery conditions are very likely to be the result of a faulty panel or faulty connection. It’s also possible the mppt controller itself is faulty but I would say this is rather less likely.

 

[Phil_G]

Agreed. If conditions didnt change, a sudden drop from 26v to 14v indicates an intermittent panel.
To prove its not the controller, just poke your voltmeter probes into the solar input screws - if the meter and the controller agree its 14v, then it has to be an intermittent panel. I'd even rule out a bad joint on the way to the panel, since your panel voltage seems to be around 25v when the fault is clear, OR around 14v when the fault is present. It seems not to vary as might caused by an oxidised joint, but seems to alternate between specifically 25v and 14v, which suggests faulty interconnects within the panel (which they drilled )

 

[monsteruk]

Agreed. If conditions didnt change, a sudden drop from 26v to 14v indicates an intermittent panel.
To prove its not the controller, just poke your voltmeter probes into the solar input screws - if the meter and the controller agree its 14v, then it has to be an intermittent panel. I'd even rule out a bad joint on the way to the panel, since your panel voltage seems to be around 25v when the fault is clear, OR around 14v when the fault is present. It seems not to vary as might caused by an oxidised joint, but seems to alternate between specifically 25v and 14v, which suggests faulty interconnects within the panel (which they drilled )

@Phil_G and @t0mb0,

Thanks so much for the responses, much appreciated.

I will check the volts at the MPPT entry point as you suggested next time it happens. Interestingly, after a couple of hours of it being 0W and low volts, it does eventually spring back into life again. It did that both times it went wrong, sat at 0W for a couple of hours, then started working again after that. May be coincidence as well, but both times the volt and wattage drop occurred, the panel had been in bright winter sun for a couple of hours. Then, on both occasions when it later sprung into life there was no direct sun light, and it was cooler. So, I do wonder if its the panel warming or working harder that sets it off.

Either way, I think I have enough evidence to go back to the converter certain there is still a problem, which is where I wanted to be.

I will ask him to replace the panel and MPPT (he had previously agreed to do that if I had any other issues).

I am going to ask for an upgrade to these:

12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine

12V solar panel solar charging kits for motorhome caravan boat campervan yacht marine off-grid

www.photonicuniverse.com

and

Victron SmartSolar MPPT 100/20 (up to 48V) Retail - TR

The SmartSolar range from Victron Energy is the latest range with in-built Bluetooth connectivity. This controller is for 48V battery banks. Suitable for 290W (12V); 580W (24V) or 1160W (48V). (6mm2 max terminal size)

midsummerenergy.co.uk

It will cost me another few hundred quid for the more expensive parts, but think it will be worth it (I will ask him NOT to drill the panel this time ;-)). Please shout if you have heard bad things about either of those!

Thanks again gents.

Cheers.

 

[Phil_G]

Thats a serious package! Both are highly recommended.
For your cables, I've used this kind of thing, not pretty but they do the job.
Roof Gland 2 Cable Entry To Solar Satellite Aerial Aircon Motorhome Caravan Boat | eBay