Tremelune
Posts: 29
Joined: Sat Apr 06, 2019 5:52 pm
Delivery Date: 07 Apr 2019

Weird contactor/Junction Box behavior??

Sun Sep 20, 2020 8:56 pm

My Leaf contactors are behaving strangely (I have them out of the car). When I connect one side of each to a battery, the other side of the contactor is connected as well...The contactors are always "on", as if fused together internally. The power just...always goes through.

The weird bit is that this is true of both contactors. I connect one side of each, and when I test voltage across the other side of each, the full voltage is there, and my test lights shines. Both contactors still "click" prominently when I trigger them, so there's something inside still moving. Am I misunderstanding the design of these things? It seems weird that power would jump across them when they're "off". Maybe I fused one bit while messing around, but there's another bit that's still moving around inside?? They don't seem easy to disassemble to check...

Electrically, would it matter which side is connected to the battery and which side is connected to the inverter?

The Leaf "Junction Box" has the precharge relay and resistor all wired together. Maybe the precharge bit is letting the power leap...?

My assumption is that there should be zero conduction across the posts until they're activated. I am boggled.

User avatar
Dala
Forum Supporter
Posts: 245
Joined: Sun Oct 28, 2018 11:24 am
Delivery Date: 01 Jan 2015
Leaf Number: 316851
Location: Finland
Contact: Website

Re: Weird contactor/Junction Box behavior??

Mon Sep 21, 2020 2:12 am

Contactors should be open when not powered. If they are showing continuity unpowered, they are welded together. Welded connectors will damage the motor inverter, if the IGBT circuit sees voltage when it shouldn't have voltage, it will damage it.

Tremelune
Posts: 29
Joined: Sat Apr 06, 2019 5:52 pm
Delivery Date: 07 Apr 2019

Re: Weird contactor/Junction Box behavior??

Mon Sep 21, 2020 1:19 pm

Yep, that's what I figured. Thanks for confirming!

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