Victron MPPT Controller Issue

[JK_Boston_Catalina310]

Good Morning,

I am having a little bit of an issue with my Victron BlueSolar MPPT Controllers, well really just one of them. I'm hoping I can get some suggestions on how to address this issue.

Here is a little background of my array and batteries. I have 4 Trojan T-105RE batteries in series, parallel for a 450 Ah bank. I have two arrays of panels. The first is the "Hard Panel" array consisting of 200 watts of hard panels wired in parallel to a BlueSolar 100/15 controller. The second is the "Semiflex Panel" array consisting of 300 watts of cheap, Chinese semiflexible panels also hooked up to a second BlueSolar 100/15 controller. Both controllers are programmed the same and below is a screen shot of the programming. Both controllers are connected to the same ANL fuse at the charge distribution buss next to the batteries.

Below are a couple of screen shots of the each controller taken at the same time. You can see that the Semiflexible panels controller is reading about 0.4 volts higher than the Hard panels controller. And this difference seems to increase the higher the voltage gets. This results in the controller for the semiflexible panels spending most of the day in float and not actually charging the batteries. I have tried disconnecting both controllers from both the battery bank and the panels and then reconnecting them but this hasn't changed the problem.

Any suggestions?

Thanks

 

[Stu Jackson]

I have tried disconnecting both controllers from both the battery bank and the panels and then reconnecting them but this hasn't changed the problem.

Jesse, have you tried switching the panels and controllers? Hard panels to "bad" controller? See if it's the panels or the controller?

 

[Hello Below]

The first is the "Hard Panel" array consisting of 200 watts of hard panels wired in parallel to a BlueSolar 100/15 controller. The second is the "Semiflex Panel" array consisting of 300 watts of cheap, Chinese semiflexible panels also hooked up to a second BlueSolar 100/15 controller.

An observation and a suggestion from a non expert of solar energy systems.
1. Observation - The readings shown in all your screen shots all add up. Watts = Voltage x Current. And MPPT Watts In = MPPT Watts Out (minus a bit for inefficiencies) in all cases.
2. Suggestion - Let's assume both controllers are operating correctly. Given the controllers are connected in parallel at the ANL, there must be a voltage drop between the fuse and the hard panel controller. So do what Stu has recommended and also take a known good (accurate) voltmeter, measure the voltage at the battery bank(s) and at each of the controllers output terminals. Compare the results to what your device's readings are showing and let us know the results.
3. Observation - Both of your controllers are undersized for the panels you have (ie the panels are over dimensioned). For example in the case of the 300W panels, the controller o/p, in ideal conditions, could be upwards of 25 peak watts. According to Victron documentation, this is acceptable and will not hurt the controller but the output of the charge controller will always limit the output to 15A.

 

[JK_Boston_Catalina310]

An observation and a suggestion from a non expert of solar energy systems.
1. Observation - The readings shown in all your screen shots all add up. Watts = Voltage x Current. And MPPT Watts In = MPPT Watts Out (minus a bit for inefficiencies) in all cases.

Yes, that's not the part I am questioning.

2. Suggestion - Let's assume both controllers are operating correctly. Given the controllers are connected in parallel at the ANL, there must be a voltage drop between the fuse and the hard panel controller. So do what Stu has recommended and also take a known good (accurate) voltmeter, measure the voltage at the battery bank(s) and at each of the controllers output terminals. Compare the results to what your device's readings are showing and let us know the results.

I should have added that the voltage displayed on the Hard Panels controller matches my battery monitor and readings taken with a multimeter. So it's the Semiflex panels controller that's reading high for some reason.

3. Observation - Both of your controllers are undersized for the panels you have (ie the panels are over dimensioned). For example in the case of the 300W panels, the controller o/p, in ideal conditions, could be upwards of 25 peak watts. According to Victron documentation, this is acceptable and will not hurt the controller but the output of the charge controller will always limit the output to 15W.

Your reading of the Victron controllers is off. The 100/15 can handle 100 volts and 15 amps. Wired in parallel the 300 watts of semiflex panels produce approximately 12 amps at 19-21 volts (theoretically they could produce 5.4 amps each but I have never seen that in 4 years, even with a previous controller). The hard panels also produce around 12 amps at 19-21 volts. So both arrays are within the controllers out put. Actually should have saved a few bucks and got the 75/15 controllers.

Also, the 100 volts and 15 amps is on the input. I oftern seen more like 16 amps thanks to the mppt.

I helped a friend install a 48 volt home panel (@6 amps) on his boat using a 75/15. It's a large panel and it produces a ton of power. He runs a dorm fridge off a cheap Chinese inverter and a box fan off the inverter.

Fair winds,

Jesse

 

[JK_Boston_Catalina310]

Jesse, have you tried switching the panels and controllers? Hard panels to "bad" controller? See if it's the panels or the controller?

That is my plan for this weekend.

 

[Hello Below]

Jesse,
Using your multimeter, please confirm that the output of each controller right at the controller's output terminals (BATT +/-) agree with what your iPhone app is showing you. I believe that the semiflexible controller must be faulty. Maybe in the data collection end of it. Looking at your "History" screen shots again, I note that there is very little difference over the 4 days shown, between the "Batt V - Min" of the 2 controllers but the difference in the "Max" is significant. Obviously the Battery Voltage should both be very close to each other. I don't no the location of each controller wrt to the battery bank, so small discrepancies maybe expected. I do see that the semiflexible controller shows a Max Batt V of 15V 2 days ago. I would not expect that high of a voltage unless that controller was set to the Equalization mode.

Your reading of the Victron controllers is off.

Jesse, I sent you several links by PM, as to why I understand (ie my take on it) that the output current of the 100/15 controller is limited to 15A. Since then I also read in the BlueSolar MPPT 100/15 Manual - Section 5 - Specifications (part of):
Maximum battery current is 15A
Nominal PV Power, 12V is 220W (and a footnote states "If more PV power is connected, the controller will limit input power.")
Max. PV Short Circuit Current is 20A (and a footnote states "A PV array with a higher short circuit current may damage the controller.")

https://www.victronenergy.com/uploa...ntroller-MPPT-100-15-EN-NL-FR-DE-ES-SE-LU.pdf

From one of the links I sent you in the PM:
"Victron FAQs
What do the numbers mean?
The first number is the max voltage open circuit allowed into the regulator
The second number is the max charge current out of the regulator

What is the current limiting?
An MPPT will current limit at the given rating, you can go over this rating but it will be limited, eg. Putting 45amps into a 30 amp controller will still charge at 30amps."

http://www.lowenergydevelopments.com.au/index.php?route=information/information&information_id=7

Good luck and keep us abreast of your findings because I have 3 of the Victron MPPT charge controllers.

Len

 

[SycloneDriver]

Other than a bad controller I would suspect a high resistance connection between the controller and the battery. Check both the positive & ground.

The temperature compensation doesn't look correct to me, but it's close enough.
FYI: You can sometimes use temperature compensation to correct for differences in controllers or make small changes to float voltages. Example: My controller doesn't have adjustable float voltages but I can adjust the temperature compensation if I really want to change the float voltage.

 

[SycloneDriver]

After quickly looking over the manual for your controller, the temperature compensation doesn't appear to be adjustable. Sorry for the confusion.

 

[JK_Boston_Catalina310]

Hey Len,

Thanks for your private message and post. Sorry for my delay. Actually had some charters this week plus some boat problems to deal with including the dreaded sanitary hose and head replacement.

Jesse,
Using your multimeter, please confirm that the output of each controller right at the controller's output terminals (BATT +/-) agree with what your iPhone app is showing you.

I've done this. And it does appear that the problem is with the controller.

I am thinking of adding the Victron Sense. It add temp and voltage monitoring to the batteries and communicates the data to controllers via Bluetooth. If the controller is still off I could persue the warranty replacement.

Jesse, I sent you several links by PM, as to why I understand (ie my take on it) that the output current of the 100/15 controller is limited to 15A. Since then I also read in the BlueSolar MPPT 100/15 Manual - Section 5 - Specifications (part of):
Maximum battery current is 15A
Nominal PV Power, 12V is 220W (and a footnote states "If more PV power is connected, the controller will limit input power.")
Max. PV Short Circuit Current is 20A (and a footnote states "A PV array with a higher short circuit current may damage the controller.")

https://www.victronenergy.com/uploa...ntroller-MPPT-100-15-EN-NL-FR-DE-ES-SE-LU.pdf

From one of the links I sent you in the PM:
"Victron FAQs
What do the numbers mean?
The first number is the max voltage open circuit allowed into the regulator
The second number is the max charge current out of the regulator

What is the current limiting?
An MPPT will current limit at the given rating, you can go over this rating but it will be limited, eg. Putting 45amps into a 30 amp controller will still charge at 30amps."

http://www.lowenergydevelopments.com.au/index.php?route=information/information&information_id=7

Yup. It appears I was wrong. They are limited to 15 amps out. But this doesn't really matter for what I'm doing. The hard panels will produce 5.6 amps at around 20 volts. So going through an MPPT I would expect around over 15 amps (say 16.3 amps) first thing in the morning when my battery voltage is say below 12.3. But the panels don't produce full power then. By say 10am the battery voltage is up over 13 so they aren't producing over 15 amps through the MPPT controller.

The semiflex panels have never produced the 5.6 amps they are rated for, more like 4.5 amps. But they are lighter and have more mounting options than hard panels. So I accept the reduced performance. When I look at the app during full sun I haven't seen over 14 amps from the whole array of semiflex panels. So I'm not too worried. But I might be making some changes soon and this is good info to have. Thanks

Good luck and keep us abreast of your findings because I have 3 of the Victron MPPT charge controllers.

Len