question

Rubik Klaus avatar image
Rubik Klaus asked

MPPTs stop charging after driving thru a tunnel

Configuration:

4 Solarpanels with approx. 450W each, connected in two strings

2 Victron MPPT 150|70-MC4 VE.Can

2 Victron Multiplus 48|3000|35 in parallel

2 LYNX power in 1000

1 Orion-Tr 48|12-30 DC/DC Konverter

1 Orion-Tr 48|24-16 DC/DC Konverter

1 Cerbo GX with GPS antenna

2 Pylontech US3000C Batteries with BMS connected via CAN-Bus


I have the issue, that after driving thru a tunnel with my RV, the charging of the apps drops to appr. 5 watts. Sometimes after driving thru the next tunnel one or maybe both MPPTs starts charging again.

If charging does not start during the day, I need to restart the PylonTech batteries (turn off/on) then usually at least one string starts charging again.

Any idea or hint, why I see this behavior ?


thank you

Klaus


MPPT SmartSolarsmart solar charging behaviour
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7 Answers
kevgermany avatar image
kevgermany answered ·

Guessing that there's no charging from the vehicle alternator.

It would be good to see battery voltage and charge current limit when this happens. How are the connections made between MPPTs and Cerbo? Cable, Bluetooth or both?

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kevgermany avatar image
kevgermany answered ·

Thanks. Yes.

Shows it's not the batteries.

There's a similar problem with a different model of controller. I'll ask them to check this as well.

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Rubik Klaus avatar image Rubik Klaus commented ·
Thank you
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Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @Rubik Klaus


We suspect your mppt's suffer from a hw bug some units had when used at 48 volts.

MPPT 150/70 ve.CAN

tr version: HQ2004 to HQ2101
MC4 version: HQ2034 to HQ2051

Best to replace the units (Warranty RMA through a dealer).

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Rubik Klaus avatar image Rubik Klaus commented ·
Thank you for this update, I‘ve contacted my supplier now.
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Rubik Klaus avatar image Rubik Klaus commented ·
I've got and installed the new MPPTs. They are working fine now, no disruptions anymore.

This was the solution, thank you @Daniël Boekel (Victron Energy Staff)

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onrbikes avatar image
onrbikes answered ·

I have zero experience with RV, but do you have location on with the app?

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Rubik Klaus avatar image Rubik Klaus commented ·
what do you mean by "location on with thee app"?
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onrbikes avatar image onrbikes Rubik Klaus commented ·
In order for me to look at my offgrid system on my phone app, I have have location on as well as Bluetooth.


It's only a thought.


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Rubik Klaus avatar image
Rubik Klaus answered ·

You are right, no alternator charging. Charging of the batteries only via solar or shore power (if available)

The MPPTs are connected via cable with the Cerbo GX

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kevgermany avatar image kevgermany ♦♦ commented ·

There's apparently adequate solar throughout, from looking at the PV voltage.


The batteries have set CCL to zero, twice. Normally means batteries full. It stops the MPPTs from charging.


Looks as if you have little to no load on the system.


After setting CCL to zero the batteries raised CCL to a lower limit than before. Usually means batteries close to full. So MPPTs can charge. However the MPPTs won't restart until battery voltage falls a little. This is the reason for your variable/intermittent restart time.

Power off/on to the MPPTs will put them into a new charge cycle, ignoring battery information. This will be short as the batteries are still close to full.

Your Pylontechs have a very flat voltage curve, there's very little voltage drop as you discharge them, so MPPT restart based on voltage drop is delayed.

Take a look at rebulk voltage offset in the manual. I don't think you need to change it, but it will give more information. Also check the SOC graph for the same period.

Looks to me as if the tunnel is a coincidence and the system is performing correctly.




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Rubik Klaus avatar image Rubik Klaus kevgermany ♦♦ commented ·

Thank you for your answer, you are probably right for the afternoon section of the graphs. The issue occurred around 9:00. I have added some graphs with zoom Tongi’s time frame

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kevgermany avatar image kevgermany ♦♦ Rubik Klaus commented ·

Please add the CCL graphs for this date/time period.

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Rubik Klaus avatar image
Rubik Klaus answered ·

I did, see above

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kevgermany avatar image kevgermany ♦♦ commented ·

Date changed. First batch was from 4th, second batch from 5th.

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Rubik Klaus avatar image Rubik Klaus kevgermany ♦♦ commented ·
I am so sorry, the graphs of the 4th were not showing the issue, my fault. The graphs of the 5th are correct.


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kevgermany avatar image kevgermany ♦♦ Rubik Klaus commented ·
No problem. But we need to trace the cause. If the batteries set the charge limit to zero, then we can rule out the rest of the system. Otherwise we look outside the batteries.

So for that we need to see the charge current limit graph as above, but for the fifth.


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Rubik Klaus avatar image
Rubik Klaus answered ·

Is this the graph you are looking for?

img-5226.jpeg


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Related Resources

MPPT product page

VictronConnect manual

PWM or MPPT

MPPT calculator

MPPT codes

Additional resources still need to be added for this topic