If so, just wondering where you might've hidden one. I realized last week (after hearing of a friend whose battery died) that I have no way of knowing, other than the alternator light, if my battery's dying. It'd be nice, I think, to have a hidden gauge to show me voltage.

Either that or I thought of wiring up an LM339 comparator circuit to show me if battery voltage dropped below a certain setpoint, and light up a BFL (big freakin' LED) if it did. But that wouldn't be as helpful as a gauge would be.

 

I don't think I get it. You want an indicator for when it is dying from lack of use (car not running), or other times (car is running)?

 

he wants a digital gauge showing the voltage of his batery.. like a gauge that says air/fuel ratio.. instead it would be voltage the battery has

 

TomP - I am assuming by your information that you do not have the full gauge cluster. What about swapping in the full cluster? You can get them pretty cheap at the wreckers.

However, there is still one flaw with a voltage gauge. It is basically just an indicator as to whether or not your alternator is working (whether or not it is above 12 volts) because unless a battery is completely dead with absolutely no juice left (to even light an interior bulb) it will often be unreliable with its volt reading and read close to or even 12 volts. I had a situation once where all I got was the relay click (no turning over) and yet the battery still read good voltage on the multimeter.

The true test (what the autoclubs do when they come to give you a jumpstart) is a "load test" to tell you if your battery is still any good.

 

Guage won't help at all to let you know if the battery is going bad.
It will help show that your alternator is going bad though.

 

I like ammeters. I've been considering adding one to my TA, even though I do have a full gauge cluster with volt meter. Sorry, looks like we don't really want to answer your question, huh?

 

I have an audiobahn cap that informs me digitally of the charge status of the system.

 

What's this?? Can you explain it a bit? Seems interesting.

 

he has a capacitor for his stereo. it stores juice for when the bass really hits. then recharges in a split second. and it has a volt meter on it.

 

YEs thats exactly right, I will try to get a pick at night

Will

 

so what is the purpose of the cap (aside from the voltmeter)??

 

the purpose is to store extra power, so when the bass hits hard there is a reserve of power that it can use with out causing a power spike on the cars power system. Probably only useful if you have a high power stereo system.

 

actually they are useless. They are just an extra drain on your electrical system. If you have a high drain system you need thicker under hood wire (batt,alt,ground) and a high out put alt. All the cap is going to do is cause more of a drain. Look into the car audio section there is a post about them.

 

They aren't useless by a long stretch, they just shouldn't be used as a charging system band-aid. If you use them right they give an instant high power charge to the amplifiers when they need it most: When the bass hits hard. If your charging system voltage drops below 13v when your car is running, you have other problems that need sorting that won't be cured with a cap. With a high output system, it can help a great deal with SQ, allowing tighter and more accurate bass response.

TomP- you can find small voltmeter gauges at most aftermarket parts places, but like zepher said, it's only going to indicate a bad battery if a cell is bad. To test properly, you'd need to do a load test on it. That would tell you your cranking and cold cranking amps. I haven't seen any portable version of the meter for that yet, but you never know