Reed Switch or Valve

[jgtibbs]

My 2009 RXV has a 3-prong charger connection. After looking through many posts/videos, it appears that the “3rd” prong (my best guess) is there to “trip” a mechanical switch (“reed” switch?) that prevents the golf cart electronics from putting power to the wheels, ie a safety feature. It also appears (wiring diagram) that the batteries will be charged even if this “switch” is defective or not activated.
Is this how it works or am I still bumfuzzled?

[cgtech]

It's not that simple. The charge port actually has a circuit board molded inside. The third terminal is basically a data terminal, it let's the charger have access to the temp sensor on the B+ battery terminal.

The circuit board is what "turns off" the blue wire (charger interlock) when the charger is plugged in.

Is yours giving troubles, or are you just curious about its operation?

[jgtibbs]

Mostly curious. My EZGO Powerwise Qe charger quit charging and my initial thought was charger or cart problem? My batts have good voltage & test good under load. In this case, one question was: what is that “3rd prong” for on the charge connector - is charger missing a signal that tells it that it is “safe” to supply charging power? AND, can I test the charger by plugging in the AC power and looking at voltage at the appropriate terminals on charger 3-prong connector, ie with charger not connected to cart?

[cgtech]

No way, the charger has to "sense" that it's been connected to an appropriate cart (with your charge port's electronics) before it will turn on. It wont output any voltage until its requirements are met, the lawyers wouldnt have it any other way. All in the name of safety.

It wont "blindly" output 48v, because an idiot could "blindly" wire it up to a 36v cart, or a 12v car battery & set the whole mess on fire. Ezgos lawyers dont like the prospect of paying for that.

But, in the "Safety nazi's" defense, I have a story to their credit (and my foolish mistake). I test & repair chargers all the time, and have "adapters" to hook anything to anything. I accidentally "tested" a Yamaha 48v smart charger on a 72v ezgo. It was smart enough to just say "yep, these batteries are full" (ready green light). No sparks, no harm, no damage whatsoever. My bone-head move...

I have a small mountain of failed QE chargers, they are the worst. Whatever you do, dont buy another one of those. Unless your charge port green light stays on all the time (even when no charger is connected), that's a failed charge port. Somewhere around here, there's a pic of the circuit board inside the charge port I posted years ago. (After I stripped all the potting materials off).

[jgtibbs]

Great info...thanks for the help.