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egk4d avatar image
egk4d asked

Smart solar mppt75/15 load output wont restart

I have install, 2 weeks ago, new mppt75/15 with a new 105ah battery to run a small 40l camp fridge which draws 4-6 amps and has a spike of about 8.8 at startup. I want to run the fridge on the load output so set it up with the jumper removed set set my voltages through Victron Connect.

Connected the fridge, plugged the battery in and away we went fridge cycled in and out for 2.5 days before the low voltage occurred and load disconnected.

I have the solar disconnected at present as I want to test the load output connect/disconnect.

The wording in Victron connect is a bit odd with the High voltage.

I left both the mppt75/15 and the fridge connected and charged the battery using 15amp Victron battery charger overnight and through the next day, at some point it had reached float but the load did not reconnect.

I played around with the voltage settings and still did not reconnect. I set the load to always on using victron connect. The load did not reconnect. Victron connect always says load off.

Reread the manual and I find nothing that would suggest a cause, check on here and find some reference to unit could need resetting. Unplug fridge and battery from the Mppt75/15 leave it for 5 min, plug both battery and fridge back in, turn fridge on, runs for another 2 days I can turn the fridge on and off and it starts every time..

Until it reached cut out and the same problem occurs. I recharge the battery again, reset the unit, do a factory reset. With the fridge disconnected switching between always on and always off the Load shows on/off in Victron connect as expected.

However if I connect the fridge and turn it on, the fridge starts and runs. But if I switch between always on, always off and then back to on, victron connect shows load as off. There is no error lights, Nothing in victron connect to indicate that there is an error.

Reading through the forum it is behaving like some have suggested in other posts as over current, but why would the fridge cycle for days starting and stopping many times.

I have checked in Victron connect that the firmware is up to date.

Help please.




MPPT Controllerssolar
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klim8skeptic avatar image klim8skeptic ♦ commented ·

Hi,

" I want to run the fridge on the load output so set it up with the jumper removed set set my voltages through Victron Connect."

Check the latest manual. https://www.victronenergy.com/upload/documents/Manual-BlueSolar-charge-controller-MPPT-75-10-75-15--100-15-EN-NL-FR-DE-ES-SE-ul.pdf

Page 65, figure 3. Jumper on pins 1 & 2 for load disconnect/connect.

Fingers crossed.

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greenhairdo avatar image greenhairdo commented ·

I had a problem which sounds very similar to yours.
I configured the user-defined setting with the low and high threshold values:

  • User defined algorithm 1:

    OFF when Vbatt < Vlow.

    ON when Vbatt > Vhigh.

Vlow = 11, Vhigh =12.8

So I expected the load to turn on once the charge level reaches Vhigh again, but when I came to check it, the battery was at 13.01V, but the load was off. So the load didn't automatically restart once the charge was sufficient.

To restart the load I had to change it to "always on".
Did you find a solution to in your case?

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3 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

I would say if the fridge is connected and the load output want to turn on the MMPT thinks there is a shot circuit because of a low resistance of the fridge.

Maybe you can connect a relay to the load output and the fridge to the relay instead directly to the load output.

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egk4d avatar image
egk4d answered ·

Why does it start the fridge in the beginning and the fridge cycles for days, wouldn't it detect a short circuit then or does the firmware only check on a load restart... firmware issue?

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Matthias Lange - DE avatar image Matthias Lange - DE ♦ commented ·

I think so.

A similar problem I had noticed with the Battery Protect.

I had some LED lamps connected to a BP if the lamps are switched on and then I shwitch on the BP (via remote or connecting +in) the lamps flash for some ms and then the BP turned off with error 1 (Short circuit detected).

But if I switch on the BP first and then the LED lamps it works with no problem.

I solved the problem by using a relay so there is a short delay so the BP can turn on without load.

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egk4d avatar image
egk4d answered ·

Thanks M.Lange, I was thinking of going to a battery protect as my next option, but now I'm not sure.

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Matthias Lange - DE avatar image Matthias Lange - DE ♦ commented ·

You don't need a BP that wars only the solution for my problem. :)

You can try to make it like so:

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