Trailer Light Connections

[tom4bren]

Take your VX (or just the battery) to your local parts store. They'll usually check it for free.

[SlowPro48]

Weird.

There's no way the voltage should be dropping that much between the battery and the back of the car. It's natural to get some voltage loss due to resistance in the wire but the VX isn't very long so we're talking miniscule voltage drops here. You wouldn't even be able to measure the difference with the x000 count meter you're using. Something's wrong in your wiring or connectors. Do you get that much voltage drop at the parking lights? Head lights?

I'd start with wire brushing the battery posts and terminals and checking your grounds. See Y33TREKker's post above. If that doesn't fix the voltage drop problem, start tracing wires. You've got too much resistance somewhere...


You might want to check the voltage regulator after you figure out the voltage drop problem. Assuming the meter is accurate, your readings across the battery are slightly low. Ideal lead acid SLI charging voltage is 13.9V - 14.3V, below that you're sulfating too much and above 14.4V you're gassing (and if you don't stay on top of the water level you'll soon be stinking like a rotten egg!) Ideal fully charged resting voltage is 12.6 volts but that's open circuit potential. With terminals connected, 12.5V - 12.3V is more realistic. So at 11.7 you're a little low there too. Maybe because it's going bad or maybe because it's not getting a full charge...

But - although your battery won't last as long charging at 13.3V - your voltages are high enough to take care of your Starting, Lighting and Ignition needs so - I'd delve into the weird part first and then do what Tom said - get battery checked at a parts store. If it's bad, throw a new one in there and see if that wakes the alternator up. If not, parts store will usually check your alternator/VR too so take advantage of that before your battery gets sulfated - whether new or old.