MPPT charge controller: complete oxidation PV+ terminal

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bramepc asked Jan 14, '24

MPPT charge controller: complete oxidation PV+ terminal

I have a 6 year old MPTT 100/30 charge controller that I stopped using about 3 years ago since I could not tighten the PV+ terminal screw anymore and I needed a more powerful unit anyways. As I want to use it for a different project I tried to loosen it again today but no matter what I tried the thing was stuck. Finally I got the cover of, and cut open the side of the connector and the thing is just completely oxidized.

I am going to try and find similar terminals to replace it (if someone knows which type they are I am listening) but anyone any idea why this thing is so rusty ? It was never in contact with water unless maybe condensation, but all the other terminals are in pristine condition so I would expect them to be affected too if it is condensation. Some kind of chemical reaction that only happens at PV+ ?

I would like to understand the issue to make sure it does not happen to my much more expensive current unit.

Googling the problem does not give me any hits.

EDIT: I just found the terminal on farnell, it is a MULTICOMP PRO MC000232

MPPT Controllers terminals

mainboard-small.jpg (95.2 KiB)

oxidized-small.jpg (111.8 KiB)

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Answer 1 · 2024-01-14T01:59:04Z

Paul B answered · Jan 14 at 01:59 AM

definitely water entry plus a loose connection maybe.

looks like the water has run down the inside or outside of the wire itself as this maybe a way it got there.

as a suggestion remove the whole block and solder some wires directly to the board and then put two anderson plugs on the 4 wires on for in one for out. or use some mc4 connectors

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