Let There Be Light
I’ve updated the wiring and the charging system of my 1956 Chevy. It works fine but I would like to make the stock “idiot light” operational. Is there a way to that with an aftermarket one-wire alternator?
Via the Internet
Thanks to their ease of installation, one-wire alternators have become extremely popular. They are generally capable of supplying all the amperage required to operate the array of electrical items found on today’s street rods. But while there are obvious benefits to a one-wire alternator, the drawback is they lack the circuit necessary to activate the “idiot light” found on many stock instrument clusters.
To keep tabs on a street rod’s electrical system a voltmeter has become the norm and an ammeter can occasionally be found as well. But while both types of instrumentation are valuable the fact is a bright red light indicating a problem will probably get your attention faster than either of them.
A simple method to incorporate a warning light with a one-wire alternator is with the use of a voltage sensor from Ron Francis. Found under PN LS-11, the connections required are a keyed 12V source, a ground, and a lamp. Any time the vehicle’s voltage drops below 11 V the sensor will activate a light. An LED, small indicator lamp, or an existing factory idiot light (including the one that’s in your 1956 Chevy) can be used, along with an existing voltmeter or ammeter.
I thought I would pass on a warning so what happened to my friend won’t happen to anyone else.
Several members of the local car club decided to go for a Sunday afternoon ride down to the local doughnut shop. We all met at one of the member’s homes only to find the garage door open and the battery of his 1955 Chevy on a charger. We didn’t know this at the time, but the charger was on the highest setting, as our friend didn’t want to keep us waiting.
As I walked around the front of the car I detected that smell that often comes along with charging a battery. About that time my friend disconnected the charger, which we later realized hadn’t been turned off. The next thing that happened was an explosion that sounded like a shotgun going off and we were both covered in battery acid. I got hit in the face with acid, fortunately I had on sunglasses that protected my eyes and the hood of the car kept my friend from getting a face full of acid as well. Our quick-thinking friends guided us to the laundry sink in the garage and we washed ourselves off. Fortunately the only real damage was a blown-up battery and one of my favorite rod run T-shirts. All kidding aside, this could have ended up much worse.
Please advise your readers to be extremely carful when removing, replacing, and charging batteries
Name Withheld By Request
Sooner or later most street rodders will have to charge or remove and replace a battery, and like everything else there’s a right and wrong way these tasks should be accomplished.
Batteries do pose a hazard due to the hydrogen gas that may be present during and after charging that can be ignited by a spark. For that reason when a battery is removed from the car always disconnect the ground cable first—if the wrench hits ground there won’t be a spark because the battery is already grounded. With the ground removed, if the wrench hits metal while removing the positive cable there won’t be a spark because there isn’t a complete circuit with the ground removed.
General Charging Guidelines
There are a variety of battery chargers on the market and most will work for all types of batteries except Gel Cell batteries. However, it should be pointed out that AGM (absorbed glass mat) batteries (such as the Optima) have very low internal resistance, which in some cases will cause a conventional charger not to work when the battery is in a very low state of charge.
Overcharging or charging a battery too quickly that can create hydrogen gas must be avoided. Many older chargers must be stopped manually to prevent dangerous over-charging while most contemporary chargers have a microprocessor to monitor the process and keep it within safe limits. These digital chargers will stop the process automatically when the battery is fully charged and will also work on deeply discharged AGM batteries.
Using Jumper Cables
On occasion jumper cables are a necessary evil. Use them properly by:
1. Connect the positive clamp to dead battery being careful not to let the any of the other clamps touch.
2. Connect the positive clamp to the positive terminal of the good battery on the donor vehicle.
3. Attach the closest negative clamp to the negative terminal of the good battery and the other negative clamp to an unpainted bolt on the engine.
4. Start the car with the good battery and rev the engine just above an idle for 30 to 60 seconds.
5. Start dead car. Remove the cables in reverse order, then allow the car to run for approximately 10 minutes to charge its battery.