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Charging system-stupid newbie question

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C

capitalcitycars

Jedi Trainee
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Hello again. After a few weeks if driving my 76 Midget, I am seeing why British electrical and wiring have the rep the have.

My battery never stays charge. The alt is brand new from Jan and is a Bosch reman. purchased from Murrays. Battery brand new from March and purchased at AutoZone. It seems like I drive about 50-100 miles before the battery goes dead. I get a jump to get home, charge the battery, and away I go. My tach and gas guage I have off and on. I have the temp and speedo. No turn singals or brake lights despite have new switches and no wipers. I have head, tail and side lights. Please point me in the right direction. /ubbthreads/images/graemlins/mad.gif
 
Brian, without knowing how you have the charging system wired, it's hard to offer advice. Another question is, how comfortable are you troubleshooting electrical systems?
Have you done the basic checks, such as doing an output test of the alternator, as installed? Have you done any parasitic draw testing?
I'd need some more information before I could even try to help.
Jeff
 
well, the off and on tack and gas guage may be significant (could point to an intermittent short that is draining the battery), but I suspect you have a charging system problem too.

If you charge the battery and then let it sit for a day, does it drain the charge?

50-100 miles sounds about the right distance you can go on a battery w/o an alternator, so I'd really focus on the charging circuit first. Double check your connections and then have the alternator tested (autozone will do it for free).
 
Well Jeff, trouble shooting electrical is not my strong point and I have no idea what a parasitic draw testing is. Plan to go to autozone tomorrow to get alt tested. I used a electrical probe and the dizzy, coil, selenoid, starter all have power going to them. Also, checked to see if any of the wires are causing the system to ground out. Fuses are good. Installed an engine ground strap which has made starting easier. Has anyone ever put in an alt that produces higher voltage? Just fustrated that the engine is running good but the electrical keeps fustrating me.
 
[ QUOTE ]
Well, Rob, it appears that both of us are headed in basically the same direction!
Jeff

[/ QUOTE ]

Both clicking the submit button at the same time too! /ubbthreads/images/graemlins/grin.gif
 
Brian, since you have a multi-meter, here's an easy test:

Measure the voltage across the battery terminals with the engine off. Should be around 12V. Now start the car and measure the voltage again. You should see the voltage go up, maybe around 13.5V.


If the voltage goes up, your charging system is working (at least when cold. many electrical faults are temperature sensative) If it doesn't go up, maybe even drops, your charging circuit is malfunctioning.

FWIW - that's just a general test, nothing MG specific. Lucas alternators may put out 16V for all I know /ubbthreads/images/graemlins/laugh.gif

As for parasitic draw testing, basically, you'll measure curents on circuits to see if any are out of line (indicating a short in the system). Most multi-meters can do this. Do you have a setting on the knob for 'mA', 'A' or amps? The only warning about measuring curent is you do it in SERIES, not PARALLEL. Basically, you disconnect a wire from the fuse panel, and put one terminal of the meter on the fuse panel conductor and one on your wire. I'll elaborate if you get to that point.
 
A possible easier way to test parasitic draw is to unhook the battery negative (with the engine stopped and ignition off) and hook a 12 volt light bulb between the battery negative terminal and the ground wire end. If the light lights-up then you have a problem! If no light then you are PROBABLY OK.
Bill
 
Brian, do you have a multimeter, by any chance? Or, at this stage, a voltmeter?
If you have, or have access to, either, check your battery voltage with everything off. Assuming a fully charged battery, it should read somewhere in the neighborhood of 12.6 volts, going from terminal to terminal on the battery.
Now start the car, and repeat the test. It should now be reading above 13.5 volts. This will tell you if your alternator is pumping anything back into the battery.
If you are above 13.5, the battery or the wiring between it and the alternator is suspect.
If, on the other hand, your reading is at or below the first reading, with everything off, that leads us to the next step.
Connect the meter from the B+ terminal on the alternator, (the big wire), to a good ground, such as the block. If the alternator is putting out, it will probably be around 14~14.7 volts. If it is, then your problem is between the alternator, and the battery.
That's enough for now. Try these simple tests, and see what you get.
Remember, I'm only an hour or so from you, depending on which side of Lansing you are on.
Jeff
 
Oh, Crap!! Here I go again, formulating a plan of strategy based diagnostics, while all you hot shoes just tell him how to do it! I feel so embarrassed!
I'm not worthy.
Jeff
 
[ QUOTE ]
Oh, Crap!! Here I go again, formulating a plan of strategy based diagnostics, while all you hot shoes just tell him how to do it! I feel so embarrassed!
I'm not worthy.
Jeff

[/ QUOTE ]

LOL, thought I was having deja-vu for a second! /ubbthreads/images/graemlins/thumbsup.gif
 
You guys are funny.

Guess you had a good fourth.

God Bless America
 
Thanks to you all. Yes, I have a mutli-meter. A club member told me these were madatory to have in the tool box with Lucas wiring. [I wonder why? /ubbthreads/images/graemlins/wink.gif] I will start with these tests.
 
I'm gonna guess my usual thing here.....REGULATOR

Their cheap......Buy 2 /ubbthreads/images/graemlins/grin.gif
 
"Remember, I'm only an hour or so from you, depending on which side of Lansing you are on."

What a very nice offer. Wish someone lived withing an hour of me. I only know of two other bugeyes and they are an hour and a half east and west.
 
Well, that depends. The alternator is internally regulated. So if you do the ouput check on the alternator (probe between the big connector and ground), and get something more than 14.7 volts or less than 14, the internal regulator/diode pack is shot, and you should replace the alternator. Since you bought it recently, there should be some warranty with it, right?

There's a second voltage regulator that's under the dash, which smootth out the electric flow to the gauges. This may be suspect if all your gauges are acting funny. It's a spall can, about 1 inch x 1/2 inch by 1/2 inch on the right side of the bulkhead inside the glovebox, near the turn signal flasher, with 2 wires coming out of it, if I remembrt correctly. This may or may not be one of your shorts to ground.

Good luck, and keep us posted on what you find.
 
Think, just think I would take the alternator to a testing station at autozone or where I got it if it is local.
 
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