MPPTs stop charging after driving thru a tunnel

Question

question

Rubik Klaus asked Apr 8, '24

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 SmartSolar smart solar charging behaviour

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kevgermany answered · Apr 08 at 02:57 PM

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 answered · Apr 09 at 10:33 AM

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 commented · Apr 09 at 10:55 AM

Thank you

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Daniël Boekel (Victron Energy Staff) answered · Apr 10 at 08:41 AM

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 commented · Apr 10 at 12:54 PM

Thank you for this update, I‘ve contacted my supplier now.

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Modifications Space

Node Red Space

Answer 1 · 2024-04-08T11:28:51Z

onrbikes answered · Apr 08 at 11:28 AM

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

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Rubik Klaus commented · Apr 08 at 11:32 AM

what do you mean by "location on with thee app"?

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onrbikes Rubik Klaus commented · Apr 08 at 10:53 PM

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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Answer 2 · 2024-04-08T18:57:28Z

Rubik Klaus answered · Apr 08 at 06:57 PM

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 ♦♦ commented · Apr 09 at 02:07 AM

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 kevgermany ♦♦ commented · Apr 09 at 05:30 AM

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 ♦♦ Rubik Klaus commented · Apr 09 at 05:53 AM

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

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Answer 3 · 2024-04-09T06:00:32Z

Rubik Klaus answered · Apr 09 at 06:00 AM

I did, see above

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kevgermany ♦♦ commented · Apr 09 at 06:04 AM

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

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Rubik Klaus kevgermany ♦♦ commented · Apr 09 at 07:21 AM

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 ♦♦ Rubik Klaus commented · Apr 09 at 08:02 AM

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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Answer 4 · 2024-04-09T08:14:12Z

Rubik Klaus answered · Apr 09 at 08:14 AM

Is this the graph you are looking for?

img-5226.jpeg (341.6 KiB)

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