Installation of voltmeter or other suitable gauge

[Ducati]

My battery has croaked. I wish I had seen it coming. It would have been foreseeable perhaps if I had some sort of voltmeter, or ammeter or some such gauge to monitor the condition of my charging system. So, once the monsoon season ends & I can work without getting soaked, I will install something. So, this will give me time to research. Has anyone here installed some type of gauge like this in their 123? I am assuming that the installation will be simple, but then again...What did you install? How did you install it? Is there a particular gauge that will work best? Who makes the best gauges?

[leathermang]

That is going to depend on what you call volts up there... you told me about the other conversations you have to do to a car going to there... yall call volts something like Tesla's per newton centimeter or what ?

[leathermang]

I should be able to get this started although I have not done it on a MB... a volt meter should be able to be connected straight across positive and negative terminals... I would use a normally off, push on switch in line with the gauge... this will only give an indication of the volts available from the battery... as compared to an " amp " meter which would be wired to show the relative charging or discharging of your electrical system in general.... Greg

[Ducati]

I will check things out with a voltmeter tomorrow. It seems to me that a few days ago when I was replacing a front signal light (as the orig. unit had bent contact that was not allowing contact with both little poles on the bulb, so I replaced the light socket with a junkyard part) I touched two of the three little contacts together and something went zap and blew a fuse. Yeah, I know, I know - I should have disconnected the negative battery cable, but I thought "I will be careful..."Anyways, I may have damaged the alternator. So, I will likely have to replace the alternator brushes and see if that works. After the little mishap, the red light did flicker a bit before going out. I understand that replacing the brushes is quite simple.
Now to figure out what the hell is wrong with that damn signal light, as the replacement doesn't work. One of the three little posts on the connector broke off so I soldered it - that is when the clumsy mishap occurred.

[DieselHead]

I installed a Voltimeter by connecting it to a fuse terminal in the fuse box that was basically hot whenever the car was on. It worked pretty well and I think was pretty accurate. I also have an anmeter but have not installed it because it seems like it would be more difficult to rig up. good luck

Alex

[william rogers]

I think a volt meter tells you more than an amp meter dose and is simple hook up ,instructions will come with it ,get a good one like VDO.....
William Rogers.....

[RG5384]

I had a neat little gadget on my 300SD for a while, it was a digital compass, gave inside/outside temp, and showed volts. I think it was made by ice warner? anyway, it hooked up to the same power wires as my radio, and after i learned the guage, i could tell you every time when i shut off the car if i could start it again(had a bad alternator), basically, what i learned is that about 13volts when running was normal, if it dropped to 11, i had problems, and if it spiked to 14 i had REAL problems( i think it was surface charging or something?). Just another thought to look into, you may be able to get som other neat fetures with the guage if you shop around
Ryan

[jbaj007]

Ryan,
I've heard of Stewart-Warner (gauges)
I've heard of Borg-Warner (elect and ignition)
I've even heard of Time Warner, Warner Bros. etc
But is ICE Warner a new rap singer j/k

Bruce
300SD '84

[Breckman99]

I don’t think you would have burned up the brushes with a short circuit like that. To test the voltage with a voltmeter just run across the battery terminals when off. Record voltage. Start the car and record voltage. When running <12 indicates that the alternator is charging and that is not the problem. IF the voltage is too great of a denomination (<14) your voltage regulator is shot. Id check the wiring of the lamp to make sure that is not shorting out causing a voltage drain that is just running your battery dead. Good luck

[leathermang]

I am with Breckman99 on it probably not being the brushes.... if anything,,, and this is only if you had the wrong fuse, or no fuse,ie hard wired, a short might blow the diodes in the Alternator... but that is very slim chance... something would be engineered to give way first unless you were touching the alternator post directly....why not have one gauage of each ? You check the voltage available with the push on switch before you crank the starter (this is sop on aircraft), then you start up and the amp guage tells you the second by second relationship between the battery and the rest of the system.... Greg

[P.E.Haiges]

There is no possible way shorting a bulb terminal could have damaged the brushes, alternator or regulator, especially since you blew out a fuse. The current came from the battery, not the alternator.

P E H

[lrg]

I agree with the above. It sounds like you have a short somewhere. Unless your battery was on it's last legs I'd bet it's a short. Was everything OK before the solder job? If so then start there. You may have a piece of solder that is causing a short. This is especially likely since the signal unit is not working as well. Charge up the old battery and check you light cluster again. With luck that will take care of everything.

[240 Ed]

Hi Ducati

The ideal is to have both gauges hooked up. The voltmeter is a cinch, just find a live circuit to hook into when the ignition is on. The minus on the gauge gets hooked into any convenient ground.

Ammeters are great because they tell you how much current you are using, and how effective the battery's condition is. IOW, if the battery is almost dead or dying, the ammeter will show a strong charge condition, instead of the needle being in the middle. The ammeter looks and acts different than a voltmeter in that "normal" condition is in the middle of the gauge. (Look at an old Triumph moto, on the headlight shell)

A drawback to an ammeter is that you must pull the big hot wire coming from the alternator (which goes to the battery) and route it through the ammeter gauge, then to the battery. A minor drawback actually, but worth the hassle. You just need to make sure that the connections on the back of the gauge don't ground out on something, because you will get full battery zap!


I think I will look into a airplane gauge, it sounds like it is two gauges in one...?

[P.E.Haiges]

NO, its not a "short". When a short occurs one of two things happens: you blow a fuse if the circuit is fused or you burn the insulation off the wires if the circuit is not fused. In a MB just about everything is fused so the latter doesn't happen. When you were soldering the wires and the wires touched together, that was a short and the fuse blew out and interrupted the circuit. If you replaced the fuse and it didn't blow out, the short was eliminated.

Why did you have the lights turned on when you were working on them? You don't to take off the battery terminal, just turn off the circuit you are working on. It is doubtful that the short you caused did any other damage other than blowing out the fuse.

I have noticed that when those who know little about electricity say there is a " short" when something doesn't work, it is actually an open circuit, the direct opposite of a "short" circuit. good example of a "short" circuit is to put a wrench across he terminals of you battery for a second and observe what happens: heat and sparks. With an open circuit. nothing happens.

P E H

[lrg]

P E H, you're right. My use of the term "short" was not technically accurate and I stand corrected. To be more clear, I would suggest there is still a wiring/connection problem in the tail light cluster, perhaps a "bridge" between two circuits (eg. tailight, stoplight, directional) that could be the cause of the problem. I would investigate this first before I started replacing alternator brushes, battery, etc. which are very likely still OK.