ok so when i go outside and my cars been sittin for a while/over night i start her up and the volt meter is always above half maybe 3/5ths of the way up. Then if i turn on the heat drops down to half, and lights a little lower etc...the altenator is supposedly pretty new, and when i dont use any accessories it stays pretty high? but then after a little bit of using no accessories the volts are normal again...its strange, i cleaned and tightened all the connections to the terminals solenoid etc.? is my Alt. just shot? I guess the best way to tell would be test it with a voltmeter but i dont have one! and what if its reading good? bad battery cause thats real new also~ any tricks someone could help me with before throwing un needed money away! <_<
More battery problems!!
- Thread starter sylert
- Start date
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Did you try disconnecting the POSITIVE (+) battery cable while the engine is running like suggested? If the engine dies when you unhook the cable, the alternator is NOT charging. You can do this on your Bronco that doesn't have a ECM/ computer like the EFi engines do. The other sign that your alt is not working is the voltage drop when anything is turned on, like lights, heater fan, radio, etc.
bluesman17
Spam Terminator
What if his new alt is UNDER powered? On my old one (which was under a year old) the voltage would drop with each flash of the turn signal I dont remember if that was only with the headlights on or just worse with them on, either way I wasnt pleased.
Seabronc
New member
Just a note: Please don't open a new thread on the same problem you were working on before. If you are working on the same problem keep the posts together, that way someone who is trying to help you can easily see what has been previously suggested. Also, please do what is suggested and report the result back in the same thread.
Thanks,
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Thanks,
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vincendebbie
vincendebbie
Check the rating of the altinator you are using. Make sure it is compatable with your year and motor size. You can take the alt off and have it checked at most autoparts stores these days. It does sound like either the alt is dying or it is just not strong enough for your vehicle.
bronco410w
New member
mine did the same thing.... the alt was a lil 95 amp " thats what it calls for" i upgraded to a 160amp! and a optima yellow top and it works great! heat full blast with radio lights and my ck daylighters on!!!
i would deff. upgrade if you need a new alt. but like what was mentioned earlyer ...get it tested first!
i would deff. upgrade if you need a new alt. but like what was mentioned earlyer ...get it tested first!
BroncoJoe19
Active member
shift1313's alternator rebuild post was great... you may want to try that. Its in the tech how to section
Don't they have a set of something like three diodes that can also go bad? I recall checking the diodes in the alternator for my '67 cougar (I think). I think that if one of the three were to fail, then the alt would put out (I guess) 1/3rd of what it was rated for.
If the voltage drops, that may be normal as long as it doesn't drop into the discharge range. So as long as the battery is maintianing 12.6 volts, it should be OK... right?
One word of caution, even if it does go into discharge range, as long as it gets topped off, one coulg get by for a while, but you would want to check your electrolite level in the battery more regularly, because with the regular recharging, you'll have more evaporation and boiling out.
Don't they have a set of something like three diodes that can also go bad? I recall checking the diodes in the alternator for my '67 cougar (I think). I think that if one of the three were to fail, then the alt would put out (I guess) 1/3rd of what it was rated for.
If the voltage drops, that may be normal as long as it doesn't drop into the discharge range. So as long as the battery is maintianing 12.6 volts, it should be OK... right?
One word of caution, even if it does go into discharge range, as long as it gets topped off, one coulg get by for a while, but you would want to check your electrolite level in the battery more regularly, because with the regular recharging, you'll have more evaporation and boiling out.
Seabronc
New member
I didn't hear anything about cleaning the ground connections. Did you do that?, especially the one on the engine block from the battery plus the ground from the rear of the intake manifold to the fire wall. Poor grounds cause all sorts of freaky problems with the electrical system.
Good luck,
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Good luck,
>-Heres what I did so far, I cleaned the connections ALL of them. This did help in the charging process it seemed. When I first start the vehicle the gauge reads almost 3/4 but as i drive it steadily drops and once i run some stuff its below half. if im running nothing it stays at half or a little above. once the heat/headlights/wipers/blinkers are on it drops more with each thing on. I'm looking into one of those high output alternator just because its good to have, i have 6 aux lights with 3 switches 4 on top 2 behind the grill and if i even use one set (2 lights) my battery is workin real hard lol. when i have my heat/wipers/lights on my battery is struggling real hard to stay below half except when its cold out so its a weird scenario, Im guessing the alt is just NOT strong enough for the vehicle. if it sits for a while the battery somehow regains power and is real strong but if i start the car then shut it off, then start the car a few times over, itll die. so maybe its the battery not holding proper charge...I will take the positive terminal off and try that technique, and im assuming if it sill runs then the alt is good. then should i assume its the battery? I apologize for the double post also, i couldnt find my original post..im not used to this forum yet, is there a way to search your own threads? thanks again guys
Seabronc
New member
What gauge are you talking about 3/4, 1/2. I get the feeling you are talking about a charge gauge not a volt meter. A volt meter is calibrated with numbers on it like 8, 10, 12, 14. A charge gauge indicates if the battery is being charged or discharged. A center needle is no charge, to the right of center is charging, and to the left is discharging. All of them are normal things to expect. When you are turning over the engine to start the truck you can expect to the left of center or 1/2. After the start you should see the gauge go to the right of center indicating the alternator is charging the battery, it should eventually settle down to center or 1/2. If you add a load that the alternator is not capable of handling, you could expect it to go to the left of center or the battery is discharging.
The function of the battery in a properly designed system is to only start the truck. Once the engine is running the alternator should take over and recharge the battery as well as supply the demand of lights, radio, ignition, etc. The battery should only have to make up for short comings of the alternator on a momentary basis. If the gauge stays below the no charge line, (center), for any length of time then the alternator is either does not have enough capacity because it is weak or is too small for the job. A system with heavy lighting like you describe should have a high output alternator, probably 130 to 200 amp capacity.
If that is the case then you should consider doing a 3G alternator upgrade.
You should b e able to find your posts by viewing your profile. In the center of the page is a list of your posts. Also, just remember what forum you posted in and look at the list to find your user ID as the person who started the thread.
Good luck,
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Sorry sea, by gauge i meant the dash gauge, and i tested today with a multimeter, When the car was running with NO accessories on except the radio really low, it was reading 13.9. When i shut the car off and tested just the battery it was at 13 even. I checked at both the terminals and connections and the reading was the same so im assuming the connection is good. my car is an 89 5.8 bronco if that helps at all. i have yet to do the removing of the terminal tests yet because by the time i get home its really dark and they are doing construction on the house and i have no outside lighting yet and the one i do have is blocked by a 30yard dumpster...the alternator was definitly charging a little bit.
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Seabronc
New member
Reread what I last posted on that gauge . Charging a bit is all you need if the battery isn't seriously discharged. The dash gauge is not a volt meter it is a charge gauge. From what you just posted, the alternator is working just fine. The only problem may be in it's ability to handle large loads. Throw some load on while it is running and check the voltage at the battery terminals to see if the alternator stays above 12V. The problem could be just a bad voltage regulator, that is if you have a problem at all, at this point I am tending to believe you don't have a problem unless the alternator can't handle the larger loads. The regulator is easy to change, see the "How To" forum http://broncozone.com/forums/index.php?showtopic=15810
Good luck,
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i understand what you are saying about the dash gauge, I realize its not a VOLT gauge, i was just writing quick and basically implying the needle was below half which seems like its not getting a good charge, sorry for the incorrect terminology i know that can throw people off with the diagnosis. I didnt think that using regular accessories would put such a large strain on my battery, I would understand if i was using the flood lights etc but basic functions shouldnt throw it off that much. so heres my two factors. If i test it today with the lights, heat wipers, radio all on, and the dash gauge is only 1/4 the way up, but im getting above 12v reading with my multi meter then is it a bad battery? and if im getting BELOW 12v its a bad/not strong enough alternator?
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Seabronc
New member
Your alternator should be able to handle all loads that were original on the truck. If the dash gauge is below 1/2 way the battery is being discharged because the alternator is not handling the load. You should have above 12V even if the battery is discharging because it is supplying a load the alternator is not. If it discharges long enough it will fall below 12V. In either case the alternator appears to be the culprit.
If your alternator is good, you should be seeing 13+ volts no matter what stock equipment load you put on it. With no load you will get around 13.7 volts, with a load it will fall but should never get below 12 volts. If it can't remain above about 12.5 volts then you may have a bad voltage regulator. See above link. You do not need to do a complete rebuild of the alternator to change the voltage regulator. All you need to do is get a new regulator and install it according to the instructions in the post I referred you to. If you don't think you can do that, go for a new alternator from a professional auto parts store, not a auto parts Big Box store.
Good luck,
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well i put on the lights, heat full blast, wipers and radio blasting and i tested the battery with the car running and i got 13.90-14.00...the dash gauge was like 1/4 of the way up with everything on...and then i tested the battery with the car off and got 12.9. it looks like its getting full charge to the battery but then why would the gauge be so low!!! i feel like getting all new stuf to see if this stops its frustrating i dont want to get stuck somewhere
Seabronc
New member
Yah, I was almost thinking that you were the first guy I have run across that had a charge gauge which actually worked
/emoticons/[email protected] 2x" width="20" height="20" /> . In fact I was going to comment on that before. What I explained earlier is how they are supposed to work.You are better off adding a real volt meter and tap it off the battery side of the start relay. That way you will have a real time view of how your electrical system is actually working. A volt meter is a much better indicator than a charge gauge. Be sure to put a fuse in line with it to prevent a short in the wire from either running your battery down or causing a fire. Go strait from the battery connection to a fuse then to the meter. You can get one from an auto parts store or on line.
Good luck,
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