question

Stan Flowers avatar image
Stan Flowers asked

Accidentally reversed polarity of pv input

Mppt 150/100 appears to be blown due to reversed pv input polarity. Is it possible to repair the damaged unit from this type of fault?

MPPT Controllers
2 comments
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Alexandra avatar image Alexandra ♦ commented ·

@Stan Flowers I have seen reverse polarity made on an mppt from the pv side with the battery connected correctly. It had been like that for several hours. All that happened was the unit heated up. Once the mistake was corrected it was fine and functions as if nothing happened. This is how the manual describes what happens.

If the battery was reversed and pv connected there is a fuse internally that blows at minimum.

Both of these secenarios void warranty.

Opening the unit does damage components if not done carefully as they are bonded inside. But can be done if a person has the patience and skill for it.

Have you tried a firmware update? Or tried accessing the info off the unit? If it is not communicating then it may not be worth fixing.


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alijalush avatar image alijalush Alexandra ♦ commented ·

I had the same issue with my Victron 100/50 MPPT by accidentally installed the battery + to _ pole and - to + pole.

! I have opened and found the fuse 80LET burned and burned 2 capacitors 1000uf / 35v

I have changed the fuse and capacitors and now works perfectly.

hope this will help you.

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5 Answers
erick1974 avatar image
erick1974 answered ·

Sadly same happened to me, one string was reversed and although it should be reversed polarity protected was blown. The MPTT which is integrated in the easysolar 1600 unit this happende on has 3 PV inputs, the other inputs seem to be working. Is it correct to assume the 3 inputs are separated and separately fused internally? As I have no monitor (BMV7xx) I cannot see the the levels but I do see the bulk led on with the other PV inputs correctly connected. Is there an easy way to be sure it still works?


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Alexandra avatar image Alexandra ♦ commented ·

HI @EricK1974 you can check if your battery is charging using a multimeter or a DC clamp meter

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renz avatar image
renz answered ·

Any update on this? Same thing happened onto one of our sites. The sparky said: "Its made a gurgling sound then I tripped the breaker"

I'm suspecting that the mosfets must have fried. Waiting on the unit to return then will update once our electronic specialist is done with his report.

Warranty will be void on this unit however if we can repair it cheaper than the price new, the site will be back and running fast.

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alijalush avatar image
alijalush answered ·

I had the same issue with my Victron 100/50 MPPT by accidentally installed the battery + to _ pole and - to + pole.

! I have opened and found the fuse 80LET burned and burned 2 capacitors 1000uf / 35v

I have changed the fuse and capacitors and now works perfectly.

hope this will help you.



screen-shot-2022-02-26-at-44708-pm.png


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shane-kirby avatar image
shane-kirby answered ·

What happens when you blow a fuse does does it shut down or should l say how do you tell.


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gardner avatar image
gardner answered ·

How much would it cost Victron to put a diode inline?

EDIT: Never mind. I just bought a Renogy Rover MPPT which clearly states in the manual "Reverse protection: Any combination of solar module and battery, without causing damage to any component"

I can't believe a "high end" charge controller like Victron wouldn't have this simple protection.


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