question

mosep avatar image
mosep asked

MPPT 100/50 - very low PV voltage (1.8 V max), zero current

I just got the MPPT from Amazon as "like new" for a discount -_-

Situation:

PV open circuit voltage is 32v, when connected to PV input of MPPT 100/50, voltage at terminals drops to almost nothing. Zero current, zero wattage shown by the MPPT. Zero charge to battery. (PV polarity is confirmed)

I also tried it with a DC bench power supply on the PV input terminals.

From 12v up to 90v, with current set to max (about 3.1A), the voltage didn't go above about 1.8V and the current stayed maxed out.


Is there an internal shunt to short the PV circuit? If so, is it resettable? The manual says that the internal protection is not resettable or serviceable.

From my perspective, they just packaged up and sent a damaged unit. Would love for that to not be true, lmk if you have any suggestions.

Thanks guys.

MPPT Controllers
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2 Answers
ffvictron avatar image
ffvictron answered ·

if the mppt detects the battery fully charged, it wont send any current. It may explain what you are seeing. did you setup the config in the mppt right?

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Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi @Mosep,

I suspect the unit you have purchased has been damaged and resold to you.

We have a pre-RMA (warranty) testing protocol available which runs through a testing procedure to help you clarify the fault.

You can find it here:

https://professional.victronenergy.com/downloads/repairs/

You will need to create a free Victron Professional account.

Depending on the results of those tests you could choose to pursue the matter with the seller, or begin the support request process - http://professional.victronenergy.com/support/

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snoobler avatar image snoobler commented ·
I have Pro account, am logged in, and that link doesn't work for me.


403 Forbidden.

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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ snoobler commented ·

Hmm - I will link it directly here until I work out why that is - Pre-RMA testing - rev 01 - EN (P).pdf

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pre-rma-testing-rev-01-en-p.pdf (847.0 KiB)
snoobler avatar image snoobler Guy Stewart (Victron Community Manager) ♦♦ commented ·
I also joined to the "Repair Files" for Dropbox, but it's not clear where those appear in Dropbox.
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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ snoobler commented ·

They are the same thing, so if you aren't seeing the forms as below; then you won't be seeing anything in your dropbox either.cleanshot-2022-12-07-at-212453.jpg

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cleanshot-2022-12-07-at-212453.jpg (234.9 KiB)
mosep avatar image mosep commented ·

Thank you Guy!


Unfortunately return will be my best option. Unfortunate because the "as new" one I bought knocked the unit down to my price range. (About $100 off)

As an update:

I brought the battery voltage down with a load to well below the charge parameters I had set to be sure it wasn't just too close to begin the charging cycle.

With one 255w Canadian Solar panel (37.4V OC V, 30.2V Op V, 9A Short current):

Max V at PV terminal was 2.1V, line current was 7.2A with clamp on amp meter.

In not quite as good sun: 1.7V at terminals, 4.3A on the line.


I really appreciate the response!

Hopefully I still end up with a Vectron at the end of this :/

I need to have this all dialed by Christmas for an overland camping trip :)


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