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david-laferney avatar image
david-laferney asked

Solved! - MPPT 100/50 actually getting PV power but "Charger off reason #OR1:Insufficient PV power"

This system installed in an Airstream worked great for 2-3 weeks then the solar suddenly stopped. Everything except solar still works.

100/50 MPPT solar, 3 - SOK 12v 208a lithium batteries wired for a 12v system, 6 100w Renogy mono panels 2-3 panel series arrays in parallel, Victron 500a Smart Shunt, Multiplus 3000, 12/12-30 Orion DC-DC charger, There is no wired monitor or network - I'm using only the Victron connect iPhone app for monitoring.

img-2815-1.png

As you can see the charger is off and it's showing no voltage and no current - but that's just not true. I disconnected the solar wires from the charge controller and they show 68 volts and 7 amps.

Full disclosure - I completed the technical parts of the installation and everything worked fine. 2-3 weeks later I came back to the project to finish the cable management after which I noticed that the solar had stopped working. So of course I thought I had somehow caused the problem during that process. And maybe I did, because I did disconnect and reconnect a few MC4 connections to neaten up the cable runs. The rig was in the shade under the shed it lives in - but on a sunny day it can make 13 watts even in the shade - or at least it could - and the system was turned on. Yes, I now know that wasn't good. I thought I had probably burned an MC4 connection - even with low power - so I went through and checked them, and changed a few for good measure. But they didn't have higher resistance than the new ones did. Ultimately though I pulled the rig out into the sun and checked the power at the controller by disconnecting the wires. 68 volts 7 amps.

You can see that the battery voltage is drawn down to 13.13v well below the charge settings...

1651531293422.png

The settings in the screenshot are a little wonky because I've been messing with them to try to get a reaction, It doesn't act to me like the charger is fried - it responds to Victron connect like normal, the blue light flashes as if it actually isn't getting PV power. Except it actually is.

img-2816.png

Also, I have disconnected all power including solar overnight to attempt a reset, but no joy. I think it might have done this intermittently once before, but I fiddled with the float setting and it came back on - possibly not related - I thought it was a glitch or my inexperience (it's my first time) I also tried disconnecting from the VE net Bluetooth network in case the shunt was telling it the battery was charged or something like that. I'm stumped.

Any help would be appreciated.


smart solar charging behaviour
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7 Answers
david-laferney avatar image
david-laferney answered ·

Solved! In my case replacing the controller fixed the problem - it (at least by the end) was not a wiring issue.

To recap - My multimeter showed good voltage AND appropriate current (ohms) at the wire where it connects to the controller - if the wires were both disconnected. If they were connected to the controller the voltage across them was nil. VIA Bluetooth the charger was off because of "insufficient PV power", and the blue light was flashing. Everything else seemed completely normal to me.

After thorough and time-consuming checks of every part of the wiring, I ordered a new controller - and that did the trick.

Now that it's working I can confirm that if it's working, measuring the voltage across the PV terminal screws on the controller (or the controller side of the disconnect) shows about the same voltage as the Bluetooth app, and about the same as checking the voltage on the PV side of the solar disconnect - in the off position. Maybe not identical, but close.

If you have good voltage and current from the array, but it shows little or no voltage across the cables with the controller connected - my conclusion is that the MPPT controller is (probably?) borked.

I think it is possible (likely) that I borked the controller by turning off the main battery disconnect while the PV was still connected to the controller. Don't do that - apparently, it's bad.

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klim8skeptic avatar image
klim8skeptic answered ·

You have checked that the PV polarity is correct?

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david-laferney avatar image
david-laferney answered ·

Yes, The polarity is correct. I wish that was it.

Of course, now I have to go check. Again. Because at this point I'm nothing but doubt. It is possible (remotely) that of all the times I've checked the voltage with my meter I've overlooked the little negative sign on the display. I'll check. I hope that's it.

Would that cause the exact issue I'm seeing?

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klim8skeptic avatar image klim8skeptic ♦ commented ·

Would that cause the exact issue I'm seeing?

Yes.

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david-laferney avatar image
david-laferney answered ·

Polarity is not reversed - confirmed.

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klim8skeptic avatar image klim8skeptic ♦ commented ·

Polarity is not reversed - confirmed.

You have confirmed the array polarity, array Voc and array Isc with a multimeter whlist the array was disconnected from the mppt.

I can only think of 5 problems that could befall your array / mppt.

PV reverse polarity. (Just for shits and giggles, swap PV polarity input)

Battery voltage higher than nominal preset. Mppt shorts PV input to save battery from catching fire. (mppt would give an error #38 (?) though)

Your 2 paralleled array is wired out of phase, canceling array output. (seems unlikely but possible)

High resistance joint between the array and mppt. (seems unlikely given you Isc reading, and the mppt would pull array voltage down to battery level)

The mppt has curled up its toes and expired, shorting the pv input, while still being powered from the battery and supplying BT data. (possible, but you would want to explore all other options most thoroughly).

PS. If you have used pre crimped MC4 cables, check them thoroughly.

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david-laferney avatar image david-laferney klim8skeptic ♦ commented ·

I went through and replaced all MC4 connectors including fuses and fuse holders, and the problem persists. I'm betting on "The mppt has curled up its toes and expired, shorting the pv input, while still being powered from the battery and supplying BT data. (possible, but you would want to explore all other options most thoroughly)."

I have a replacement coming tomorrow. After I remove and replace the unit I'll report the results whatever they are.

Another symptom I didn't mention in this thread (because I'm not sure it IS a symptom and because you're supposed to keep it to one question per thread) is that when the PV power is connected to the controller the voltage across the cables falls to well below 12v. I will check this on the replacement controller (assuming it fixes the issue) to determine if this is a symptom of a failed controller. I suspect it is.

Edit - This is just idle speculation at this point, but if replacing the controller fixes the issue I suspect that I caused the problem. My system includes a main battery disconnect - which powers down everything. I'm pretty confident in retrospect that at some point I disconnected the battery without first disconnecting the solar array from the converter via its DC breaker/disconnect. Actually, I know I did that. The rig was inside of its storage structure, but can still produce up to 13 watts in the shade on a sunny day. My fault if that's what happened, but I'm thinking that might explain several unresolved threads on this forum.

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csc avatar image
csc answered ·

I have exactly the same situation. Worked fine then failed randomly. Pv array perfectly fine, values always under 250 in the historic, though it topped once at 246v voc.


i suspect these 250v should not be in the product’s name as they are a failure level

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klim8skeptic avatar image klim8skeptic ♦ commented ·
That is interesting.


Perhaps you could open up a question, so as to explore your problem?

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csc avatar image csc klim8skeptic ♦ commented ·

Well as it’s exactly the same problem it might be useful to group everything here

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klim8skeptic avatar image klim8skeptic ♦ csc commented ·
I like the maths of a solar array.


I once saw my array go over Voc for its design/location temp. Interesting.

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csc avatar image csc klim8skeptic ♦ commented ·

6 trina vertex 400 in series


Important difference with David’s case : pv input not shorted. Array on the ground full south with shade at the end of the afternoon

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klim8skeptic avatar image klim8skeptic ♦ csc commented ·

6 trina vertex 400 in series

My maths suggests that 6 >>Trina 400w panels<< would produce 247.2 Voc @ 25C.

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nickdb avatar image nickdb ♦♦ commented ·
The mppt won't fail at 250V, you would need to exceed it by some margin.

The charger can be off for various reasons, failure being one.

Did you update firmware recently?

It would be worthwhile measuring the voltages at the mppt terminals and comparing them to your batteries CVL. Mppt's will also not be on if the voltage they measure is above the batteries set point.

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csc avatar image csc nickdb ♦♦ commented ·

Thanks. firmware 1.59 apparently, interface 2.37

All the voltages match. Just lost pv voltage...

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david-laferney avatar image david-laferney commented ·

I have a new MPPT ordered - I should have it replaced by Saturday afternoon. Check back then and you can see if that was the fix or not.

Edit - it appears from the number of threads reporting similar symptoms that this is not an uncommon issue.

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csc avatar image csc david-laferney commented ·
Yep
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csc avatar image
csc answered ·

Mine works again , impossible to understand what solved the problem between

- charge the battery with the multiplus as it got low and set the smartsolar to 1 day absorbtion

- switch the whole system off with the appropriate sequence

-switch the smartsolar with voluntarily inverted pv polarity as it’s supposedly safe (same message unsufficient pv power)

- reset to default settings and thenlifepo4 standard profile

- switch it again correctly wired and back to life


I may be wrong but I’ll investigate what happens when a washing machine fed by the multiplus keeps rolling because of inertia while the bms stops charging because of unmatched charge level with the smartsolar and thus cuts the multiplus. Probably weird currents there.

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matrixrat avatar image
matrixrat answered ·

Hi folks, i'm new here, browsing. Before I start my first thread, must chime in here. Been sorting out an off-grid setup and sitting on the bench are two dead MPPT 150 | 100 Tr. One works at reduced output and runs hot to the point where you can smell it. The other produces no output and the solar panels get hotter because it's solar input appears as a dead short. Both failed when disconnected from the battery without solar input being isolated first.

Think about it. Battery supplies power for the microcontroller which is supposed to be looking after MPPT math, serial comms etc. and ultimately drives the output MOSFETS. Now, mosfets need drive power to make sure they switch on or off fully and fast. So, when the battery is disconnected, a little bit of residual power remaining in Caps will keep things running briefly but the drive power to the mosfets is likely to be compromised first, a worst-case scenario.

Safe procedure:

1 Thumb your phone and turn charger off.

2. Isolate solar.

3. Then fiddle with wiring.

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