Gene Posted February 1, 2017 Share Posted February 1, 2017 Absolutely agreed, don't pull the battery cable as an alternator test. The battery acts to stabilize the voltage in the system, if there is any voltage peak or surge, typically the battery will dampen that out. Without the battery, risk of damage to electrical components is much higher. A surge may occur when the battery cable is disconnected. If you want a really quick, semi-accurate alternator test, with the engine running put a screwdriver or steel wrench near the backside of the alternator case, toward the center. Typically, if the alternator is working, a strong magnetic field is created inside, and it will attract the iron or steel. Another test that may be useful in cold weather. An alternator generates heat when it's running. If the rest of the engine is relatively cool, a working alternator case should be warmer. Of course, if the engine is hot, this test would not be useful. However, you can get a cheap voltmeter or multi meter for about $10. There is no excuse for not having one of these for testing! Gene Link to comment Share on other sites More sharing options...
Gene Posted February 1, 2017 Share Posted February 1, 2017 If anyone wants a laugh: My story about running a car without the battery: Decades ago, I was going to school in Philadelphia. I drove an old Pinto, standard transmission. I parked a block or two off North Broad Street, in a fairly bad neighborhood. One day I didn't get out to the car until after dark, noticed the dome light didn't go on when I opened the door, thought "burned out bulb". Until I put the key in the ignition and turned it, absolutely nothing. I thought "dead battery". Until I opened the hood, when I saw "no battery". Someone had taken bolt cutters to the cables and taken the battery. So I was a student, had no money, and the car was in a bad neighborhood. I didn't want to leave it there overnight. So I stripped about an inch of insulation off each of the cut cables, called a friend, and used jumper cables from the friends battery to the cut off cable ends. The car started and ran. No battery. This was a standard transmission. If I stalled it, I would have absolutely no way to restart it. So I drove about 5 miles down Broad Street, at night, hoping and praying, babying the clutch, to get home. It worked! Gene Link to comment Share on other sites More sharing options...
shaylec Posted February 1, 2017 Share Posted February 1, 2017 That very funny gene! Ive driven without a battery and Ive driven with out an alternator.... A second battery in my passer seat connected to the battery under the hood with jumper cables.... it helps to have some bright moonlight with your headlights off... funny. Link to comment Share on other sites More sharing options...
yxmj Posted February 2, 2017 Share Posted February 2, 2017 Me too. yxnj, have you tested all the features it claims to have? Sorry for the late reply And for hijacking the thread Short answer yes.......here is a fast review If i was to send anyone to my shop to get my old go-to charger they would feel confident when they lifed it.....huge transformer it must weigh 25 lbs This unit on the other hand is stupidly light (when you pick up the box you think it is empty) here are the high points Nice long color coded cables with great clamps, as this it a digital unit it it impossible to reverse the clamps or short them out Large back light led display that you can see from inside the house through the window if need be, and audible beeping notifications when cycles are done. The screen will also give messages for open cells or shorted cells. Voltage feature lets you read voltage of the battery in or out of the jeep and while it is running or not. Alternator check is simple hook it up with the jeep running press the button....it say good....no good,,,,,and you can verify voltage by pressing the voltage button Engine start....this one blows my mind....take a jeep that is so dead the starter is just clicking (we have all been there) press the engine start button....that starts a 90 sec counter....when 90 secs are up it beeps....truck starts every time....how this works without a huge transformer to push power I do not know.....but it works without fail every time....even in Winnipeg at -30 when the jeep has been sitting for a week.(my favorite feature) The battery recondition button .....i can only say this....have a jeep that sits a lot.....battery seems to lose its charge just by sitting....i put the charger on and used this feature....walked away from it for a day or so.....when the cycle was done i took it off......that jeep has so far started every time i have tried it. The only point you need to be aware of is a fully drained battery.....the digital sensor will not recognize it and turn the battery on....some how (Cables, or another charger needs to be used to bring the volts to about 5.....then all is good....maybe there is a way around that I am missing . :MJ 1: . The last Link to comment Share on other sites More sharing options...
Gene Posted February 2, 2017 Share Posted February 2, 2017 One more comment on weak batteries.... At least my 88 uses a GM CS130 alternator, not sure about other years. The CS130 has high output in a small case, so heat is a big problem. The harder the alternator works, the more heat it generates, which can damage and burn out the rectifier and diodes. So to use the alternater to charge a dead battery, or to try to "get by a while longer" with a weak battery can kill the alternator. Too much heat damaging components. Yeah, I know we have all done that and gotten away with it, but it is hard on the alternator. About 15 years ago, after going through several alternators, I found an "Iceberg alternator" with cooling fins. Still going strong 15 years later! I will try to find a link. Gene Link to comment Share on other sites More sharing options...
Gene Posted February 2, 2017 Share Posted February 2, 2017 http://store.alternatorparts.com/7140-140amp-cs130-series-iceberg-finned-high-output-alternator-upgrade.aspx http://store.alternatorparts.com/cs130i-a105-amp-iceberg-series-finned-housing-alternator.aspx links to Iceberg alternator Gene Link to comment Share on other sites More sharing options...
GeorgiaJeeper93 Posted February 2, 2017 Author Share Posted February 2, 2017 Picked up a new alternator (one not from autozone) I will be swapping that in when I get some time. fingers crossed Link to comment Share on other sites More sharing options...
Gene Posted February 2, 2017 Share Posted February 2, 2017 Hi GeorgiaJeeper, Did you get a new battery too? If not can you at least take one of your batteries in to be charged and tested? It really sounds lie a bad battery to me. And, as above, a bad battery can overheat and damage even a new alternator. Good luck! Gene Link to comment Share on other sites More sharing options...
Green Mesa XJ Posted February 2, 2017 Share Posted February 2, 2017 Since you have a muti-meter try this easy test.....with the battery in and connected and the truck running take a voltage reading across the battery terminals....what is the voltage? It should be somewhere between 12.7 and 14.7 volts.....is that what you get? And this may be off topic but I recently got one of these... http://www.catautopower.com/25-amp-battery-charger.html This is cat brand but there are other brands out there.....not only will it charge your battery....but it has an engine start feature (boost) that works (Winnipeg -40 trust me) but it also has simple push button features that allow you to 1) check battery voltage.....2)do an in vehicle alternator check....3)and recondition the battery. and you don't have to guess if the battery is fubar....if it is it tells you right on the screen. . :MJ 1: . Sams club used to sell some great basic battery jumpers, those were replaced with weaker batteries with decent looking "peak" cranking amps that never pulled their weight. The best jumper I've found since then is Jump-N-Carry JNC660 1700 Peak Amp 12-Volt, Amazon has them and this one has jumped everything I could throw at it without fail. One of my first cars was a 87 Supra saved from a junk yard, BHG and a ton of other problems looking back it wasn't worth the time or money spent on it but try telling that to a late teen. Anyway it had a bad battery when I got it, me and friend went to pick it up, jumped it off and the alternator kept it running fine unless extra load like headlights or ac were turned on. Drove it home with my buddy right behind in case it crapped out, and to keep the sheriff dept off my bumper. Some how made it with out stalling or headlights when it got dark. Not sure what year the op has. On my 85 xj with gm alternator (also a gm motor) the alternator is internally regulated, once it wasn't charging in the middle of no where, pulled off the trail and pulled the two prong alternator plug then cleaned the contacts on the plug and alternator up, reconnected it went back to full charging. It would still do it randomly even with new better amp alternators. Years later I replaced the plug with a new pigtail and that solved it. The ho engine I think all have the voltage regulator in the ecu/pcm, so you could have a great alternator but a bad regulator in the computer. Sent from my iPhone using Tapatalk Pro Link to comment Share on other sites More sharing options...
HOrnbrod Posted February 2, 2017 Share Posted February 2, 2017 Me too. yxnj, have you tested all the features it claims to have? Sorry for the late reply And for hijacking the thread Short answer yes.......here is a fast review If i was to send anyone to my shop to get my old go-to charger they would feel confident when they lifed it.....huge transformer it must weigh 25 lbs This unit on the other hand is stupidly light (when you pick up the box you think it is empty) here are the high points Nice long color coded cables with great clamps, as this it a digital unit it it impossible to reverse the clamps or short them out Large back light led display that you can see from inside the house through the window if need be, and audible beeping notifications when cycles are done. The screen will also give messages for open cells or shorted cells. Voltage feature lets you read voltage of the battery in or out of the jeep and while it is running or not. Alternator check is simple hook it up with the jeep running press the button....it say good....no good,,,,,and you can verify voltage by pressing the voltage button Engine start....this one blows my mind....take a jeep that is so dead the starter is just clicking (we have all been there) press the engine start button....that starts a 90 sec counter....when 90 secs are up it beeps....truck starts every time....how this works without a huge transformer to push power I do not know.....but it works without fail every time....even in Winnipeg at -30 when the jeep has been sitting for a week.(my favorite feature) The battery recondition button .....i can only say this....have a jeep that sits a lot.....battery seems to lose its charge just by sitting....i put the charger on and used this feature....walked away from it for a day or so.....when the cycle was done i took it off......that jeep has so far started every time i have tried it. The only point you need to be aware of is a fully drained battery.....the digital sensor will not recognize it and turn the battery on....some how (Cables, or another charger needs to be used to bring the volts to about 5.....then all is good....maybe there is a way around that I am missing . :MJ 1: . The last Nice rundown - thanks. I too am tired of my huge transformer charger. This unit will be perfect for the trolling motor batteries at the pier. Link to comment Share on other sites More sharing options...
GeorgiaJeeper93 Posted February 2, 2017 Author Share Posted February 2, 2017 New alternator didn't do the trick. Can't afford a new battery right now, so this will be on hold for a little while. Link to comment Share on other sites More sharing options...
Gene Posted February 2, 2017 Share Posted February 2, 2017 Can you borrow a battery from another vehicle as a test? Gene Link to comment Share on other sites More sharing options...
GeorgiaJeeper93 Posted February 7, 2017 Author Share Posted February 7, 2017 New battery seemed to do the trick. Its now reading 12.6 while the truck is off and 14.8 while running. Its still idling weird, but I guess that will be my next mission. Thanks for the replies everyone! :thumbsup: Link to comment Share on other sites More sharing options...
Gene Posted February 7, 2017 Share Posted February 7, 2017 Good work! Gene Link to comment Share on other sites More sharing options...
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