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busdennis avatar image
busdennis asked

MPPT yielding no power

Hi All.

So my smart solar was working fine last year but has been unused over the winter months. Recently I've upgraded some wiring and fitted the Victron shunt into my system and connected the 2 Victron's with VE direct. i have 2 x 110ah of AGM battery

So checking my system the smart solar as never recorded anything but zero watts and zero amps and the sky today was clear so would have expected to record something. I have factory reset both Victron's and checked the inline fuses and the built in fuse of the smart solar.


My smart solar does not connect via blue tooth when it is dark, is this correct or indicating it is a problem with the battery connection. The minus 4.70A was to introduce a load as the battery was full charged, also the state of charge is currently 90% with no change. My understanding is that if PV voltage is 5 greater than the battery voltage i should be receiving some charge to the battery?

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MPPT SmartSolar
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5 Answers
wkirby avatar image
wkirby answered ·

It is almost certain that the battery is not connected to the Smartsolar due to a bad connection of fuse / circuit breaker.
During the night the Smartsolar Bluetooth should still work using battery power, this makes it very likely that the battery is disconnected in some way.

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busdennis avatar image
busdennis answered ·

thanks for the reply. i would agree but why can i measure the actual battery voltage across the terminals of the MPPT controller?

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seb71 avatar image seb71 commented ·

Even during the night or when PV is not connected?

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busdennis avatar image
busdennis answered ·

easy to check as its dark out side. 12.7 volts at the actual battery terminal and 12.7 at the battery terminal of the MPPT. Zero volts at PV terminals (as expected) and the Victron as no lights and does connect with blue tooth

unfortunately i have no 48a wire to experiment by bypassing all the breakers and fuses and wire direclyt to the battery, will have to order some. Could i use some 10a thinwall wire for the purpose of diagnosis

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wkirby avatar image wkirby ♦♦ commented ·

You now say it does connect with Bluetooth, is that without PV?
I failed to ask which model of Smartsolar you have. Is it one with a fuse at the bottom near the terminals? If that is the case, what is the state of that fuse?

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busdennis avatar image busdennis wkirby ♦♦ commented ·

Mornings. It will only connect with Bluetooth when I have PV power. The fuse was checked as working and replaced.

So I summary it will only Bluetooth when I have PV. I have the same voltage at the battery and the battery terminals of the MPPT charger. But I’m getting no charger to the battery. I recently put the shunt in which is working perfectly.

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klim8skeptic avatar image klim8skeptic ♦ busdennis commented ·

You have not mentioned the exact model of your mppt?

Early versions the mppt was powered from the pv array.

Later versions can be powered from either pv or battery.

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busdennis avatar image busdennis klim8skeptic ♦ commented ·

MPPT 75/15 bought new 6 months ago

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klim8skeptic avatar image klim8skeptic ♦ busdennis commented ·

A bluesolar or smartsolar version? 2 or 3 leds on the mppt??

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busdennis avatar image busdennis klim8skeptic ♦ commented ·

Thanks for all the help. It’s smartsolar with 3 pairs of connection. PV, battery and load. The load as never been used. Thanks again

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klim8skeptic avatar image klim8skeptic ♦ busdennis commented ·

Given that at night you should have communication with the mppt, it would seem that the problem exists on the battery side of the mppt.


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seb71 avatar image
seb71 answered ·

I just noticed this:

fitted the Victron shunt into my system and connected the 2 Victron's with VE direct

Did you meant VE Smart Networking?

Or did you actually connected the SmartShunt to the SmartSolar with a VE.Direct cable?

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busdennis avatar image busdennis commented ·

VE smart networking. the first thing i did was disconnect the shunt networking then also disconnect the shunt altogether. factory reset the MPPT. All with no effect

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dgnevans answered ·

You will measure at the terminal as this is a physical connection but the fuse could be damage or not installed correctly missing the pins. Did you reverse polarity at any time. you can use a smaller wire just for testing ie to see that it is not a problem with oyur cable but you should not charge high current through this.
when it is power on you can check the settings to make sure it is set to give load when there is no sun. (Street light function) also make sure charge is enabled.

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