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wossam avatar image
wossam asked

Victron BlueSolar MPPT 100/20 - Load output is always on

The load output on my Victron BlueSolar MPPT 100/20 wont turn off and is always on.

What happened before:

  • Update to the newest firmware v1.54 for the Smartsolar and v2.25 for the Bluetooth interface.
  • Connecting an inverter with 4kW total max power to the load output, but with no load to the inverter. The MPPT was giving error codes which I didn't write down.
  • Reset to factory values

Setup and beheaviour rigth now:

  • App on the phone will let me set load output to always off and always on.
  • No measure on power and current on load output
  • Fuse on the smartsolar is ok / not broken
  • No jumper set
  • Street light function off
  • Everything else is working just fine

I was thinking of an update error, but the inrush current of the inverter might have damaged the load output possibly.

Did anybyody experience a similar effect and have hint on what might cause / how to solve this?

MPPT Controllerssoftware
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4 Answers
wkirby avatar image
wkirby answered ·

When I read "Connecting inverter with 4KW" I immediately thought that the Load Output mOSFET would not survive this.
In the first milliseconds, this is a few hundred Amps, no chance for that output MOSFET.

Short circuit MOSFET is most likely the problem.

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Jörg Becker avatar image
Jörg Becker answered ·

This is an old thread, but I have experienced the same problem recently. Output MOSFET was fried after trying to switch ON a 350W (!) inverter.

The reason for the fried MOSFET is most likely not the high inrush current (as the output is advertised as short circuit proof!). It ist most likely the inductive voltage spike when switching OFF wehn the unit detects the high inrush current. There does not seem to be any supressor diode on the output! So even switching longer cables may destroy the output MOSFET.

After adding a 82V suppressor diode to the output, the second MPPT 100/20 is now happy switching the inverter ON and OFF repeatedly!

For me this is a real big issue with the load output on this device! Having short circuit protection without overvoltage protection is not enough! Perhaps one of the Victron people can shed some light into how the output is supposed to be used ....

Best regards, Jörg.

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k-k avatar image
k-k answered ·

Hallo @Jörg Becker,

What type of diode is it exactly, and how is the polarisation?

Thanks in advance

(De: um welche diode handelt es sich - wie ist die typen bezeichnung und wie muß sie gepolt werden? Vielen dank im voraus )


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Jörg Becker avatar image
Jörg Becker answered ·

I have used a P6KE82. This is available as unidirectional (P6KE82A) or bidirectional (P6KE82CA).

I would prefer the unidirectional type, cathode (white or silver ring) connected to plus.

The diode can be soldered directly to the pins of the output connector which can be seen between the radiator and PCB. Sorry, the unit is in use on in a hardly accessible space so I can't take pictures...


3 comments
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nickdb avatar image nickdb ♦♦ commented ·
The manual is clear that inverters shouldn’t be connected to the load port directly.
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Jörg Becker avatar image Jörg Becker nickdb ♦♦ commented ·

No, this is simply not true.

The manual that I have says that only inverters with a higher permanent or inrush current than the MPPTs output current of 15A (20A) have to be connected to the battery instead.

So if this condition is not given you are allowed to connect the inverter to the output directly.

But this is not the problem at all as the output is said to be short circuit proof.

The problem is that even a small inductive load (cable to the dc load, relay, ...) may kill the output because there seems to be no overvoltage protection at all inside the unit.

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k-k avatar image k-k commented ·
Bedankt
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