Help with key switch

[65 Cobra]

OK...I am trying to figure out the switched power on my 2005. Everything is working, just trying to figure it out. This is what i have..

With charger plugged in and key off:
12 V on one post
24V on one post

With charger plugged in and key on:
12 V on one post
12V on one post

Charger unplugged and key off:
48 V on one post
0V on one post

Charger unplugged and key on:
0V on one post
0V on one post

I am using a volt meter, not a multi meter. 12V is the min my meter will read.

thanks

[glassk]

What is your ground reference ,?


Key on in picture is 48V key off 0V

[Sergio]

The voltages You are taking with the charger plugged represent your meter interaction with a live circuit.

The charger when running always has a higher voltage potential than your pack, otherwise current would not flow into the batteries.

The positive wire from the charger goes to pack positive, so they are a common reference point.

The negative wire from the charger however, goes into the OBC. The OBC switches that circuit on/off at the appropriate point in the rectified sinewave to regulate the average voltage output to the battery pack and control the current flowing.

When you placed your meter between the Key Switch (pack positive) and the pack negative, You created a parallel return path for the charger current to flow (through the meter around the OBC).

Your measurements with the charger OFF are accurate, the Green wire is always +48v (from the Tow/Run switch) and the Blue wire is the switched or Cold side of the Key Switch.

Also, those meters with LEDs for voltage levels are only good to detect voltage, not to make actual measurements.

[65 Cobra]

Why are both 0V with the key in the on position?

Main reason I am trying to find the switch power...I am thinking on installing a meter than requires a switch power connection. My current meter is the one with the tabs and capacitor, so only - and + connections are needed.

[65 Cobra]

Just checked again grounding to the battery...

Green is always 48V

With key on blue is 48V

I guess I was expecting it to be 12V...not sure why. I appears my converter is not switched, rather is a constant 12V regardless of key position .

I will just use it for all 12V needs and use switches as needed. Key position will have no impact on 12V power.

thanks

do you want converter switched on with key ?

[65 Cobra]

Originally Posted by crash test dummy

do you want converter switched on with key ?

I thought that was how it worked, Should I want it switched or not?

some do ... some don't
i don't cause sometimes i want to use lights and don't want to hunt down keys