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tiranna avatar image
tiranna asked

75/15 Smart Solar not charging since firmware update to v1.54

75/15 Smart Solar not charging since firmware update

I logged into my charger and had to apply a couple of firmware updates. Now the bulk light is on but no currents /watts are showing on the app. voltage 38-40 volt from panel before connection to mppt, (2x 80w) but zero watts or amps. I can connect fine with BMV-712 and battery sense. I reset to factory defaults, but still not working. Any suggestions?

MPPT SmartSolar
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5 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

Check all switches and fuses between the MPPT and the battery. There is also a fuse directly at the MPPT.

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petro avatar image
petro answered ·

I have the same issue with my 75/15 since Saturday, although I believe it was the 1.56 update that just happened. I would be interested in trying a previous version firmware if anyone has one available.

PV voltage is fine when measured directly, but drops to practically battery voltage when connected and shows 0 amps. Have tested different PV panel, isolation switch etc.

Have also tried resetting to factory defaults to no avail.

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sacjec99 avatar image sacjec99 commented ·
I have exactly the same problem, 
have a 75/15 mppt with 90 watt solar panel and 2 12 volt lead acid batteries I have 19.67 volts at end of wires, but as soon as I connect them to mppt it shows more or less the same volts as the battery volts. Any help would be appreciated ... 


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klim8skeptic avatar image klim8skeptic ♦ sacjec99 commented ·

Does your panel have 36 cells?

What is the panels Voc?

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sacjec99 avatar image sacjec99 klim8skeptic ♦ commented ·

Our panel is 21,2 voc and yes it’s got 36 cells.

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klim8skeptic avatar image klim8skeptic ♦ sacjec99 commented ·

I would be testing the panels Isc with a multimeter.

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sacjec99 avatar image sacjec99 klim8skeptic ♦ commented ·

I’ve tested it with a multimeter and it’s all ok

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klim8skeptic avatar image klim8skeptic ♦ sacjec99 commented ·

You shorted the panel out and got 4 amps?

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sacjec99 avatar image sacjec99 klim8skeptic ♦ commented ·

Sorry don’t understand

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klim8skeptic avatar image klim8skeptic ♦ sacjec99 commented ·

If you dont understand, learn.

Testing a solar panel Voc and Isc.


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klim8skeptic avatar image
klim8skeptic answered ·

PV voltage is fine when measured directly, but drops to practically battery voltage when connected and shows 0 amps.

This will be the result of a high resistance joint. Please check your fuses, connectors and wiring on the PV side of the Mppt.

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petro avatar image petro commented ·

If it is only so simple! I thought I had checked everything but based on your comment I went back and double checked the MC4 connectors which looked fine, no signs of physical damage or melting. Upon removing the conductors I found that one of them had evidence that water had gotten in at some point previously and there was some rust. I have re-terminated but alas it was dark by the time I finished. Fingers crossed it was just this and a happy coincidence with the firmware.

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0x4 avatar image
0x4 answered ·

I have the same problem, too

the voltage displayed in the app is dropped from 36 to 6v - and not charging anymore.

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0x4 avatar image 0x4 commented ·

Addition: in the evening the voltage increased to normal level (36v) but today I have 6v again.

Any idea what is the issue?

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klim8skeptic avatar image klim8skeptic ♦ 0x4 commented ·

No idea.

Plz post a pic of you mppt history.

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0x4 avatar image 0x4 klim8skeptic ♦ commented ·

solar.png
Here my current history of the last days. Vmax is always in the evening.

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solar.png (170.8 KiB)
klim8skeptic avatar image klim8skeptic ♦ 0x4 commented ·

You seem to have more than 1 charger?

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0x4 avatar image 0x4 klim8skeptic ♦ commented ·

Yes it‘s a campervan - I can charge externally too

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dwyer50 avatar image
dwyer50 answered ·

75/15 Smart Solar not charging since firmware update. Last week I logged into my charger and had to apply a couple of firmware updates.



my gift card site

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klim8skeptic avatar image klim8skeptic ♦ commented ·

My crystal ball needs clues, to direct you to a solution..........

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0x4 avatar image 0x4 klim8skeptic ♦ commented ·

Has someone new informations about this? I see other posts here in the community with the same problem.

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klim8skeptic avatar image klim8skeptic ♦ 0x4 commented ·

Please open a new question. Your problem seems unrelated to any firmware issue.


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