I'm hoping someone can help. 

I have two strings of series panels connected to their own MPPT as below:

 

String 1 :4 x Sunmodule as per specs below, connected to Victron SmartSolar MPPT 150/85. Settings Rotary 2 for Gel battery. 

Victron Connect readings:

 

String 2 : 3 x ArtSolar as per the specs below, connected to Victron SmartSolar MPPT 150/35. Settings Rotary 2 for Gel battery.  

Victron Connect readings:

 

Both connected via busbar to 48v Gel Lead Acid battery.

 

The issue is the one MPPT is flashing the blue light. I am lead to believe this may mean the voltage from the panels is too low to charge. Yes, it is overcast today so output not great, but string 2 not charging even when brighter. 

Some points:

1. Both strings of panels are next to each other, with no shading at all. 

2. I cleaned all panels to eliminate that being the issue. 

3. Multimeter reading at the PV input on the MPPTs obviously confirms the Victron Connect solar voltage readings. 

4. String 2 has been flashing for a while but still charging until yesterday. That's what is strange. 

5. If one panel in string 2 is faulty, which I'm hoping is not the case as they are only two years old, how do I test? Can I check voltage with a multimeter across the MC4 connectors?

6. Why would the MPPT blue light flash even when voltage high enough to charge previously? 

7. Could it be a faulty Victron MPPT? 

Any ideas of what else it could be as testing each panels is something I'd prefer to do as a last resort (it will mean unmountimg them)?

 

Edit: I was just thinking, if it is a panel fault in series, would there be any voltage at all? 

Edited November 5, 20241 yr by ClintonDBN

on the pic of string 2, the pv voltage is too low for the mppt to start.

connect both smart solar chargers to a VE.Smart network and activate synchronous charging.

my guess is wat happens now, is the one mppt push voltage to the busbar and then the other mppt reads that voltage as the battery voltage and assume that the battery is full and dont charge any further.

I had the same problem but with one blue solar and one smart solar, and the two of them cannot sync charge, only the smart solar can do that.

I had to fit a smart shunt on the battery and get a cerbo gx to control the two mppt's, the mppt's now uses the voltage from the smart shunt to control both of them.

I believe if you have 2 smart solar chargers you can activate sync charging without a shunt to rectify your charging issue, and you need to get the voltage up on the second mppt.

20 hours ago, ClintonDBN said:

I'm hoping someone can help. 

I have two strings of series panels connected to their own MPPT as below:

 

String 1 :4 x Sunmodule as per specs below, connected to Victron SmartSolar MPPT 150/85. Settings Rotary 2 for Gel battery. 

Victron Connect readings:

 

String 2 : 3 x ArtSolar as per the specs below, connected to Victron SmartSolar MPPT 150/35. Settings Rotary 2 for Gel battery.  

Victron Connect readings:

 

Both connected via busbar to 48v Gel Lead Acid battery.

 

The issue is the one MPPT is flashing the blue light. I am lead to believe this may mean the voltage from the panels is too low to charge. Yes, it is overcast today so output not great, but string 2 not charging even when brighter. 

Some points:

1. Both strings of panels are next to each other, with no shading at all. 

2. I cleaned all panels to eliminate that being the issue. 

3. Multimeter reading at the PV input on the MPPTs obviously confirms the Victron Connect solar voltage readings. 

4. String 2 has been flashing for a while but still charging until yesterday. That's what is strange. 

5. If one panel in string 2 is faulty, which I'm hoping is not the case as they are only two years old, how do I test? Can I check voltage with a multimeter across the MC4 connectors?

6. Why would the MPPT blue light flash even when voltage high enough to charge previously? 

7. Could it be a faulty Victron MPPT? 

Any ideas of what else it could be as testing each panels is something I'd prefer to do as a last resort (it will mean unmountimg them)?

 

Edit: I was just thinking, if it is a panel fault in series, would there be any voltage at all? 

It is clear your solar input is low! Is the 3 panels connected in series(3S) You should see close to Voc ~120v as the mppt is switched off! If the Mppt see the battery voltage as fully charged it will go to float it won't switch off. Check each panel in the serie string if the Voc/ pannel correspond to name plate rating then you have a wiring problem. The only time the Victron Mppt will indicate off is if low or no pv input is detected. The flashing led indicate it is waiting for pv input.

The solar input voltage must at least be 5v higher than the battery voltage for the Mppt to start.

Edited November 6, 20241 yr by TaliaB
Spelling

Thanks, I'll need to get on the roof and check each panel. I assume one would need full sun to check VOC on the panels, or not? 

Edited November 6, 20241 yr by ClintonDBN

11 hours ago, ClintonDBN said:

Thanks, I'll need to get on the roof and check each panel. I assume one would need full sun to check VOC on the panels, or not? 

No the panels will reach voltage just below Voc early morning before current starts to flow. You could check voltage even in overcast conditions it affects the current flow not the panel voltage much. The only time the panel voltage will be 0v is at night when it is dark. Disconnect all 3 panels measure the voltage at each panel they should all measure close proximity then add the 3 voltages together. If panels checks out connect them in series then before connecting to the Victron mppt check the voltage on pos and neg wires and it should be the same as what you tallied up on the earlier sum. If voltage checks out ok connect to the Scc and the blue Led at bulk should stop blinking and turn solid on. 

Ensure the Scc is turned on under settings page. If you battle to get it to charge pm me then we can discuss your problem via watsapp. Happy hunting. 

Ps. Check all Mc4 connectors combiner connections and fuses.

Edited November 6, 20241 yr by TaliaB

Talia, thanks so much for your assistance. I disconnected and tested each panel. They all looked fine, which concerned me as I felt I had my resolved the issue. However, it did resolve it! My assumption is that it was indeed one of the connections and by disconnecting, testing and reconnecting, I resolved it. 

Edited November 8, 20241 yr by ClintonDBN

4 hours ago, ClintonDBN said:

Talia, thanks so much for your assistance. I disconnected and tested each panel. They all looked fine, which concerned me as I felt I had my resolved the issue. However, it did resolve it! My assumption is that it was indeed one of the connections and by disconnecting, testing and reconnecting, I resolved it. 

Well done @ClintonDBNand @TaliaBthat is what this forum is all about assisting each other to solve íssues one by one.👏

Edited November 9, 20241 yr by Derek3

@ClintonDBN

Which is worrying.

You should inspect/investigate all connections to be properly crimped.

Edited November 9, 20241 yr by Virwat

I agree with @Virwatyou didn't really find the problem and still might have a loose connection within one of the mc4 connectors. It is now difficult to actually visually inspect each crimp once the mc4 connector contacts is pushed into the housing. There is a method to check for loose connections but you need to do it with caution. You will need a 20~30 amp dc fuse or 20~30 amp dc breaker to do this test. 

1. Switch the Victron mppt off in the settings page under battery 

2. Disconnect the pos and neg solar input wires from the Scc be cautious they don't touch together. 

3. Ensure the fuse holder is in the open position and remove the fuse. Connect pos and neg to the fuse holder pos top neg bottom or vica versa doesn't really matter. Make sure they are thoroughly tightened.

4. Insert the fuse and close the fuse holder (quick action). If you do have a dc clamp meter you should read just below 12 amps(Isc). Do not use a multimeter on amp scale as the max for multimeters is normally 10 amps.

5. Leave it for around 30 minutes in the shorted out state then climb onto the roof and check all the mc4 connectors for arching or hot to the touch. If all checks out ok it might have been a male and female connector not pushed in all the way( you should hear a distinctive " click" when they seat together. If all is ok after 1 hour with panels in full sun at noon you should be ok. Discconect and assemble the process in reverse. Remember to open the fuse with a quick action the last thing you need is arching across the fuse terminals.

DC is unforgiving if there is loose connections that is how your house 🔥 burn down.

Thanks, TaliaB, I'll take a closer look. I might just replace all the MC4 connectors to ensure they are properly crimped. 

33 minutes ago, ClintonDBN said:

Thanks, TaliaB, I'll take a closer look. I might just replace all the MC4 connectors to ensure they are properly crimped. 

It is very important to use this dedicated mc4 crimper below.

Just one thing - sometimes, unexperienced installers make a good crimp, but do not push the pin into the MC4 connector deep enough. Then, the pins in male and female part are barely touching each other.

 

There must be audible click heard when pushing the crimped pin in.

5 hours ago, Youda said:

There must be audible click heard when pushing the crimped pin in.

While we are on MC4 training here😝 take a look at the video from Greenwood solutions trainer Veli for some very good pointers.

 

6 minutes ago, TaliaB said:

While we are on MC4 training here😝 take a look at the video from Greenwood solutions trainer Veli for some very good pointers.

 

I have learnt a few things from this video i didn't know not to wind the wire tight with a pair of pliers before inserting and crimping the wire. Great video thanks.

I know most electricians go bos with a pair of pliers and Gp wire ends before connecting to db breakers🤣 I am waiting for a lashing from the electricians including @TaliaB🤣🤣 Just joking guys.

@Derek3 😁☺️

I am one of the old school sparkies. 

If the breaker has a cage, no twisting. Otherwise take your wire stripper and sommer start stripping from say 30-40 mm from the end, bend the unstripped piece 90 deg and wind a couple of times in the same direction as the winded cores. Then cut to the correct length. No pliers.

Worked for me since I qualified at Olifantsfontein 45 years ago.