Thread: Battery Disconnect Switch (Help)

Tweet

I need your help.

Last night, I installed a Hella battery disconnect switch (2 terminals) on my car. The switch has cables already attached. Since the battery is mounted in my trunk, someone suggested that I connect it to the negative side of the battery so the switch isn't hot when turned off.

One cable has a terminal clamp that I connected to the negative battery post and the other cable has a cone shaped fitting that attaches to the original battery cable. The switch works fine. However, I have a problem. My voltage meter is now screwed up. It pegs to the right and stays there when the car is running.

What did I do wrong?

Help!!!

Thank You in Advance

Pat

What's the voltmeter reading with the ignition on and engine not running? If its 12 or so, the gauge is working. If so, the alternator is overcharging. The switch you installed is causing the regulator to get a false value somehow.Bypass the switch and try it again, see if the high voltage persists.

When I turn the ignition on with the motor NOT running, it still moves off the gauge to the right? Still need suggestions as to what's causing this.

Thanks

Try a different gauge. With the engine not running, the voltage is only what the battery is supplying, 12 volts.

Originally posted by Pat Monaco
When I turn the ignition on with the motor NOT running, it still moves off the gauge to the right? Still need suggestions as to what's causing this.

Thanks

have you tried it on the + side? maybe its not made for the - side.

Good point lt1s10...I will try that tonight. However, I didn't want the back of the switch to be hot when it was turned off. That's why someone recommended that I install it on the negative terminal. If it works, I guess I won't have a choice. Thanks again!

Have a great weekend.

Pat

Denny...thanks for the diagrams and comments. I am running VDO gauges with Painless wiring in my Brookville A Bone that is 5 years old.

The gauge has worked exactly as you said until I installed the battery disconnect. I have it hooked up as in your first diagram. The battery is in the trunk, however, due to hot start problems I've installed a remote solenoid before the starter. Do you think that is what's causing the problem??? If so, what would I do to remedy the situation?

Thanks Den

Denny...I'm new to the street roddin' scene, but could it really be a bad gauge if it read correctly without the switch? Remember, the car is 5 yers old with 10K miles.

I had a mechanic friend help me connect the solenoid according to the directions so I'm "assuming" it's hooked up correctly???

Will I damage anything if I conenct it to the positive terminal to try it out?

Thanks

Denny...the remote solenoid is hooked up exactly like your diagram. If I connect the disconnect switch to the positive terminal do you think it will work, or will I have the same problem as on the negative terminal?

Yes, I have a copy of the directions, but I'm at work right now. I will send you a copy tonight.

Yes, I'm referring to the main terminals of the battery.

Thanks Den, that's what's confusing about this problem. Even though I'm not an electrical wizard, I know that all it supposed to do is turn power on and off. I'll upload the schematic tonight.

Thanks

Originally posted by Pat Monaco
Thanks Den, that's what's confusing about this problem. Even though I'm not an electrical wizard, I know that all it supposed to do is turn power on and off. I'll upload the schematic tonight.

Thanks

You don't have 2 bat. in the car do you? Sounds like 24 volts. I believe you got something crossed up and the gauge is really showing a dead short, but reading backwards. should be going to - side of gauge.

Have you tried removing the switch, and returning the setup to the way it was before you put the switch in? If everything returns to normal when you do that, then there is something that is being overlooked. In theory, this should work, but theory is just that- theory.

It sounds to me as if you are getting a reversed polarity to your voltmeter - and probably, the rest of the system, too. Is there a smaller gauge wire ground jumper from your battery to the frame, at the battery clamp? It may be, that when you open the disconnect, you're not completely disconnecting the negative feed. I really can't figure why you would get the reversed polarity, but that's sure what it sounds like to me.

As to the swithch terminals being hot, there is still going to be a potential between the terminals when the switch is open, only it will be in the negative, instead of the positive polarity. Not being able to see your setup makes troubleshooting difficult.

Problem Solved! Thanks to everyone who replied to my post and tried to help. Denny thank you so much for trying to troubleshoot by email. I checked all of the wiring and it was correct.

Turned out to be a broken wire at the gauge. lt1s10 got me thinking when he said dead short. I have no idea how the wire broke, since I never messed with the gauges when I installed the disconnect. Oh well, prblem solved and thank goodness it didn't end up costing any thing but time and aggravation.

Thanks again for EVEYONE'S help!

Pat