battery advice? or is it the alternator? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Adam12 · 10-09-2003, 10:05 PM

yesterday I was in my truck and it was getting a little hot while I was idling (215 degrees), so I shut it off and then like 5 mins later It wouldnt start again, at this point I thought mabye the starter got hot and wasent working, so I went home for a couple hrs then went back to the truck and it wouldnt start still. It would start to turn over but then just stop. So today I had a friend jump me and that worked. I decied to drive around for a while to recharge the battery but the truck died while I was making a U turn 5 minutes later. So I jumped it again and it died after like 2 mins of driving ( across the street from my house luckley). could this be the altranator? also I have noticed that every time I start it there is a possability its not gonna start because the battery is dying or just not cranking enough? the battery has 700 cranking power and 550 cold. Do I need a better battery for a motor that is built up like mine? any advice would be awesome!
P.S. sorry for the long post just trying to give some detal.

jewels. · 10-09-2003, 10:20 PM

you sound just like me! i have been having the same kinda problems for the past year.... and as it turns out, i've now replaced both the alternator and the battery (which fixed all problems)....

but that doesnt help you, eh?

my best piece of advice would be to take it to a shop which can test your battery and alternator in one shot.... i happen to have this done at Sears, but a lot of shops can do it for cheap or even free --- they can hook a machine up to your battery (while the truck is running), and test for battery power, and charging power (from the alternator)..... that way, you can pinpoint the exact problem....

that's my suggestion....
anyone got any others?

good luck!

jewels.

Spoof · 10-09-2003, 10:22 PM

Sounds to me like your battery is giving up the ghost. If you disconnect the battery while it's running and the engine dies it's probably your alt. This test can cause problems to electronic ignitions. I've used it many times with out probs but be warned. Jewels has the best plan but mine is quicker and more exciting.

70c10 · 10-09-2003, 10:31 PM

Be careful when buying a cheap reman alternator. I had to buy 3 before I got a good one. It's free to test them at the local parts store providing you carry them in.

Hooter · 10-09-2003, 10:35 PM

when the truck is running, put a volt meter on the battery, if you are getting over 13 volts, then your alternator is fine, if its around 12 volts or lower then your alternator is shot, or you have a bad wire going into the charging system

Bryan68custom · 10-09-2003, 10:43 PM

Dont take it too Sears they will charge you ($10.00 around here anyway ) just to check the battery even if it is there's. Iwould go to wally world or auto zone it's free.

71GMC_3/4T · 10-09-2003, 11:08 PM

Heck, just try the screwdriver to the back of the alternator trick. If the rear bearing cap on the alternator will attract a screwdriver with a vengeance, the alternator is working.
Make sure you've revved it once (mine takes over 2k RPM) to get the alternator to start charging.
If the battery is over 4 or 5 years old, dump it - winter's coming...

Southpa · 10-10-2003, 12:17 AM

If you get a low reading across the batt poles after replacing/rebuilding the altranator then you have some voltage (electromotive force) going to ground. I was reading 10.5 V across the batt (while running) before and after rebuilding my altronater and replacing the battery. So check all ground straps. I also heard the horn relay is notorious for grounding problems. I looked, probed and tested for bad wires etc but couldn't nail the ground leak down. The sure fix is to run a heavy wire from the main terminal of the ultranator to the pos. battery terminal. As soon as I did this my voltage was reading 13.8, plenty of charging power.

krue · 10-10-2003, 12:33 AM

Sounds like alternator to me. Sounds like the battery is running everything until its voltage drops too low to run anything. Try cranking the truck and pulling the negative cable off of the battery. If the truck dies the alternator is toast. Unfortunately totally discharging ur battery as many times as you have usually kills it!

krue · 10-10-2003, 12:35 AM

Another thing, we have a local auto electric shop that will totally rebuild an alternator for about 1/2 what a rebuilt one costs and warantees it for a couple of years. Might be worth checking on.

zombie man · 10-10-2003, 12:52 AM

Replace the Alt. test you batt. That should help or do the trick.

Adam12 · 10-10-2003, 01:07 AM

Thanks for the advice, I did forget to mention that the alt and battery are both about a year old but only have about 30 miles on them, The alt is the summit chrome one and the battery is from costco ( they will take anything back) I will test the battery like you guys suggested then get a refund for the battery and spend the extra money to get a really good battery. Another problem I know isint helping is the electric fans not on a switch or thermostat. I will change this before a new battery also. Thanks again anyone have any more suggestions now that I gave more detals hehe. Thanks so much!

Chevy Wrench · 10-10-2003, 02:03 AM

One thing that I have noticed, you never put a full charge on your battery. An alternator will not charge a battery like a generator will. It just maintains its charge level. Before doing any tests, you need to have a full charge on your battery. To me, it sounds like your alt. is toast, however, it could even be bad cables or a bad ground. I would take some time with an ohm/ volt meter and start checking your cables for both power and resistance. Good luck.

Chevy Wrench · 10-10-2003, 02:06 AM

Also, you need to get your fans on a relay or at least an on/ off switch. When you are cranking your engine, those fans are trying to turn on as well, taking much needed cranking amps away from your starting system.

landon4421 · 10-10-2003, 11:21 AM

Quote:

the battery is from costco

What kind of battery?

If i were you I would go and get a Interstate Battery ! I have had mine for 4 years and have had not a problum with it ! They are great batterys IMO !

busterwivell · 10-10-2003, 12:02 PM

I agree about the screwdriver test, I've done that. I have Interstate batteries in all my vehicles (except the 47, cuz it don't need one yet!), but even they die eventually. Is your alternator a one wire? Did you run a big enough wire on it to the battery? You only have 30 miles on it? You might check that too.

bpmcgee · 10-10-2003, 01:59 PM

Quote:

Originally posted by Chevy Wrench
One thing that I have noticed, you never put a full charge on your battery. An alternator will not charge a battery like a generator will. It just maintains its charge level.

I'm not sure I agree with this. Do you have any data to support?

My understanding is that the alternator is going to try to maintain about 13v in the system. That is sufficient to give the battery a nice charge!

Brian

Chevy Wrench · 10-10-2003, 03:27 PM

Yeah, just ask any alt. rebuilder. I work on cars every day, and can testify to it. When you buy a new alt. it comes with a data sheet. In large print ( usually) it will tell you to charge the battery fully because it will not charge a weak battery. An alternator will maintain 14 volts, not recharge the battery to 14v. While the vehicle is running, there are many things that need this voltage to operate, thus relying on the alt. output. It will put a little bit of a charge back into the battery, but will not fully recharge it.

ckhd · 10-10-2003, 07:29 PM

It sounds like an alternator to me. Parts stores like Checker & Autozone will test both the battery and alternator for free.

It might be both now. If your alternator is toast, and you've drained you battery that low a few times, it could be bad too. I'd pull the battery, put it on a charger, then pull the alternator and take it to get it tested.

ckhd · 10-10-2003, 07:35 PM

Quote:

Originally posted by Chevy Wrench
An alternator will not charge a battery like a generator will. It just maintains its charge level.

I have always heard this too and charge batteries before I install a new alternator, etc... I don't know if I agree with it or not. I've completely killed the battery in my '72 'burb several times (I leave from home before sun-up and get to work once it's light, so I leave my lights on a lot). When I kill the battery (it's deader than a doornail), then I just jump it and head home. By the time I get home (about a 45 mile commute), the battery is charged all the way up.

I would agree that in some cases, it won't charge your battery, like maybe stop & go, low rpm stuff, but cruising 65mph for 45 minutes seems to charge mine just fine.

I partially think that the alt. manufacturers put that in there so that you don't put an initial strain on the alternator. Let it break in easy, instead of going full blast for the first little while of it's life.

Adam12 · 10-13-2003, 10:46 AM

I decided to get a new battery so I now have a interstate battery with 800 CCA, I put it in then bought a volt meter and my alt was bad, to double check it took it to pep boys and they told me it was bad. The thing that sucks is I bought it from summit almost 2 years ago and it was sitting for about a year in my house and then when it was put on the truck it only had about 100 miles on it if that. Im going to see if they will at least give me some credit for it.

busterwivell · 10-13-2003, 11:15 AM

I had a bearing go bad in a one-wire alternator. I took it to a local shop and they repaired it for cheap. You might want to consider doing that, too.

Adam12 · 10-13-2003, 11:40 AM

Good Idea, I will look into that. when I looked at it closer it looks like the fan is warped or it could be the shaft because the fan does not spin straight.

A.P. · 10-13-2003, 12:45 PM

My alternator is a one wire set up and it puts out 14.5V. My battery charger that I have in my garage puts out the same 14.5VDC and 10Amps. I know my alternator puts out more than 10Amps, so how in the heck won't it charge a dead battery or partially charged one? I got to disagree with some of the comments in here.

Chevy Wrench · 10-13-2003, 01:08 PM

Ok, you see, the problem here is that everyone is thinking volts when you should be thinking amps. Lets say that your alt. is only capable of producing 100amps. Your battery has a maximum output of 700 cold cranking amps. You run your battery all the way down, and is completley dead. So, you jump start your truck and figure that you will just run it for awhile to charge. Well, you will charge the battery up to 100 amps. You are still needing the extra 600 amps that are required to completley power your vehicle. Yes, it will "appear" to have a complete charge. Yes, it may start your truck, but you have never restored its full capacity. Since your alternater will only produce 100 amps, thats all that will be put into the battery. Volts are completley different that amps. If you run the battery dead, it still could read 12 volts, but put a load on it, and you will not have sufficiant amperage to power your truck. This is why you need to have a complete charge on your battery before you install that nice, new and expensive alternater. Otherwise, the alternater will never have a chance to "catch up" to recharge your dead battery. I hope that this explaines it better. Im not here to give false information, Im only trying to help those who dont know. I have many years of hands on training and school. I fix cars every day, and if I didnt know what I was talking about, then I would be working at Mc Donalds or something. Good day.

10-09-2003, 10:05 PM	#1
Adam12 I hate trannys Join Date: Dec 2001 Location: Bakersfield,CA Posts: 160	battery advice? or is it the alternator? yesterday I was in my truck and it was getting a little hot while I was idling (215 degrees), so I shut it off and then like 5 mins later It wouldnt start again, at this point I thought mabye the starter got hot and wasent working, so I went home for a couple hrs then went back to the truck and it wouldnt start still. It would start to turn over but then just stop. So today I had a friend jump me and that worked. I decied to drive around for a while to recharge the battery but the truck died while I was making a U turn 5 minutes later. So I jumped it again and it died after like 2 mins of driving ( across the street from my house luckley). could this be the altranator? also I have noticed that every time I start it there is a possability its not gonna start because the battery is dying or just not cranking enough? the battery has 700 cranking power and 550 cold. Do I need a better battery for a motor that is built up like mine? any advice would be awesome! P.S. sorry for the long post just trying to give some detal. __________________ 70 SWB 481 ci, TH-400, Edlebrok Victor Jr. intake, Holley street avenger 770, Dynomax ceramic coated headers. Dual flowmasters. and only 3516134 more little things to do.

10-09-2003, 10:20 PM	#2
jewels. Registered User Join Date: Jul 2001 Location: Munster, IN Posts: 1,100	you sound just like me! i have been having the same kinda problems for the past year.... and as it turns out, i've now replaced both the alternator and the battery (which fixed all problems).... but that doesnt help you, eh? my best piece of advice would be to take it to a shop which can test your battery and alternator in one shot.... i happen to have this done at Sears, but a lot of shops can do it for cheap or even free --- they can hook a machine up to your battery (while the truck is running), and test for battery power, and charging power (from the alternator)..... that way, you can pinpoint the exact problem.... that's my suggestion.... anyone got any others? good luck! jewels. __________________ 68 C10 Red Step 350 my first child & main focus 58 3200 Apache LWB Step the upcoming project

10-09-2003, 10:22 PM	#3
Spoof Registered User Join Date: Jul 2000 Location: Victoria,BC, Canada Posts: 1,300	Sounds to me like your battery is giving up the ghost. If you disconnect the battery while it's running and the engine dies it's probably your alt. This test can cause problems to electronic ignitions. I've used it many times with out probs but be warned. Jewels has the best plan but mine is quicker and more exciting. __________________ 71 GMC 1500 LWB Last edited by Spoof; 10-09-2003 at 10:26 PM.

10-09-2003, 10:31 PM	#4
70c10 67-72 Addict! Join Date: Feb 2002 Location: The TAX State! Posts: 7,857	Be careful when buying a cheap reman alternator. I had to buy 3 before I got a good one. It's free to test them at the local parts store providing you carry them in. __________________ Jim 1970 C/10 Fleetside w/Ghost Flames Lowered 4.5" front and 4" rear (Raked) 355/350 Turbo w/shift kit 10" Redneck Performance Verter w/2500 stall Hooker Super Comps part#2808-1 Performer RPM Air-Gap 12 Bolt w/3:73 gears- Eaton Posi Comp Cams XE262 with 1.6 Crane Energizers, Road Demon 625 and Brodix IK 180 heads

10-09-2003, 10:35 PM	#5
Hooter My other Love Join Date: Aug 2001 Location: Castlegar B.C. Canada Posts: 4,085	when the truck is running, put a volt meter on the battery, if you are getting over 13 volts, then your alternator is fine, if its around 12 volts or lower then your alternator is shot, or you have a bad wire going into the charging system __________________ Castlegar B.C.The great white North (Canada Eh!) Hooter_5@hotmail.com First generation Monte Carlo club pictures of my life

10-09-2003, 10:43 PM	#6
Bryan68custom Registered User Join Date: Aug 2003 Location: Denison, Tx. Posts: 189	Dont take it too Sears they will charge you ($10.00 around here anyway ) just to check the battery even if it is there's. Iwould go to wally world or auto zone it's free.

10-09-2003, 11:08 PM	#7
71GMC_3/4T Weapons Of Construction Join Date: Apr 2000 Location: Colorado, USA Posts: 1,095	Heck, just try the screwdriver to the back of the alternator trick. If the rear bearing cap on the alternator will attract a screwdriver with a vengeance, the alternator is working. Make sure you've revved it once (mine takes over 2k RPM) to get the alternator to start charging. If the battery is over 4 or 5 years old, dump it - winter's coming... __________________ 1971 GMC 2500, 402/TH400 4.10 Daily Driver Lafayette, CO

10-10-2003, 12:17 AM	#8
Southpa Registered User Join Date: May 2000 Location: Victoria, BC, Canada Posts: 2,410	If you get a low reading across the batt poles after replacing/rebuilding the altranator then you have some voltage (electromotive force) going to ground. I was reading 10.5 V across the batt (while running) before and after rebuilding my altronater and replacing the battery. So check all ground straps. I also heard the horn relay is notorious for grounding problems. I looked, probed and tested for bad wires etc but couldn't nail the ground leak down. The sure fix is to run a heavy wire from the main terminal of the ultranator to the pos. battery terminal. As soon as I did this my voltage was reading 13.8, plenty of charging power. __________________ 1970 GMC 1500 Custom Original 350/TH350 Victoria, BC, Canada You can wish in one hand and crap in the other. See which one gets filled first. Last edited by Southpa; 10-10-2003 at 12:19 AM.

10-10-2003, 12:33 AM	#9
krue Designated A-hole! Join Date: Mar 2003 Location: South Mississippi Posts: 36,450	Sounds like alternator to me. Sounds like the battery is running everything until its voltage drops too low to run anything. Try cranking the truck and pulling the negative cable off of the battery. If the truck dies the alternator is toast. Unfortunately totally discharging ur battery as many times as you have usually kills it! __________________ "If it ain't broke, fix it 'til it is!" Being stupid ain't illegal. We're Still Debt Free Except for the House!!! www.daveramsey.com 70 GMC SWB Stepside project "Green Booger" soon to be 6.0l/4l80e 93 S-10 "Poppaw's Truck"

10-10-2003, 12:35 AM	#10
krue Designated A-hole! Join Date: Mar 2003 Location: South Mississippi Posts: 36,450	Another thing, we have a local auto electric shop that will totally rebuild an alternator for about 1/2 what a rebuilt one costs and warantees it for a couple of years. Might be worth checking on. __________________ "If it ain't broke, fix it 'til it is!" Being stupid ain't illegal. We're Still Debt Free Except for the House!!! www.daveramsey.com 70 GMC SWB Stepside project "Green Booger" soon to be 6.0l/4l80e 93 S-10 "Poppaw's Truck"

10-10-2003, 12:52 AM	#11
zombie man Registered User Join Date: Oct 2003 Location: hollister ca Posts: 7	Re: battery advice? or is it the altranator? Replace the Alt. test you batt. That should help or do the trick.

10-10-2003, 01:07 AM	#12
Adam12 I hate trannys Join Date: Dec 2001 Location: Bakersfield,CA Posts: 160	Thanks for the advice, I did forget to mention that the alt and battery are both about a year old but only have about 30 miles on them, The alt is the summit chrome one and the battery is from costco ( they will take anything back) I will test the battery like you guys suggested then get a refund for the battery and spend the extra money to get a really good battery. Another problem I know isint helping is the electric fans not on a switch or thermostat. I will change this before a new battery also. Thanks again anyone have any more suggestions now that I gave more detals hehe. Thanks so much! __________________ 70 SWB 481 ci, TH-400, Edlebrok Victor Jr. intake, Holley street avenger 770, Dynomax ceramic coated headers. Dual flowmasters. and only 3516134 more little things to do.

10-10-2003, 02:03 AM	#13
Chevy Wrench former desert rat Join Date: Feb 2003 Location: salt lake city, utah Home of the 3 M's Mormons, methlabs and minivans Posts: 320	One thing that I have noticed, you never put a full charge on your battery. An alternator will not charge a battery like a generator will. It just maintains its charge level. Before doing any tests, you need to have a full charge on your battery. To me, it sounds like your alt. is toast, however, it could even be bad cables or a bad ground. I would take some time with an ohm/ volt meter and start checking your cables for both power and resistance. Good luck. __________________ 94 Chevy Silverado Ext cab 4/6 drop w/ 18's and 2500watt system (work truck). 67 Chevy swb under const. frame off custom, 20's, bagged and a large rat under the hood,and a 1940 Chevy truck under const.

10-10-2003, 02:06 AM	#14
Chevy Wrench former desert rat Join Date: Feb 2003 Location: salt lake city, utah Home of the 3 M's Mormons, methlabs and minivans Posts: 320	Also, you need to get your fans on a relay or at least an on/ off switch. When you are cranking your engine, those fans are trying to turn on as well, taking much needed cranking amps away from your starting system. __________________ 94 Chevy Silverado Ext cab 4/6 drop w/ 18's and 2500watt system (work truck). 67 Chevy swb under const. frame off custom, 20's, bagged and a large rat under the hood,and a 1940 Chevy truck under const.

10-10-2003, 12:02 PM	#16
busterwivell Registered User Join Date: Jan 2002 Location: Sahuarita, AZ USA Posts: 2,033	I agree about the screwdriver test, I've done that. I have Interstate batteries in all my vehicles (except the 47, cuz it don't need one yet!), but even they die eventually. Is your alternator a one wire? Did you run a big enough wire on it to the battery? You only have 30 miles on it? You might check that too. __________________ Bill - Tucson, AZ 47 Chevrolet 2 dr sedan 56 Chevrolet 210 2 dr sedan 66 Chevrolet Malibu 2 dr 4 speed 71 Chevrolet C30 Longhorn 86 Chevrolet Monte Carlo SS (Sold) 01 Chevrolet Tahoe IM - BUSTERWIVE@aol.com



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10-10-2003, 03:27 PM	#18
Chevy Wrench former desert rat Join Date: Feb 2003 Location: salt lake city, utah Home of the 3 M's Mormons, methlabs and minivans Posts: 320	Yeah, just ask any alt. rebuilder. I work on cars every day, and can testify to it. When you buy a new alt. it comes with a data sheet. In large print ( usually) it will tell you to charge the battery fully because it will not charge a weak battery. An alternator will maintain 14 volts, not recharge the battery to 14v. While the vehicle is running, there are many things that need this voltage to operate, thus relying on the alt. output. It will put a little bit of a charge back into the battery, but will not fully recharge it. __________________ 94 Chevy Silverado Ext cab 4/6 drop w/ 18's and 2500watt system (work truck). 67 Chevy swb under const. frame off custom, 20's, bagged and a large rat under the hood,and a 1940 Chevy truck under const.

10-10-2003, 07:29 PM	#19
ckhd Registered User Join Date: Oct 2000 Location: St. Johns, Arizona Posts: 2,660	It sounds like an alternator to me. Parts stores like Checker & Autozone will test both the battery and alternator for free. It might be both now. If your alternator is toast, and you've drained you battery that low a few times, it could be bad too. I'd pull the battery, put it on a charger, then pull the alternator and take it to get it tested. __________________ my 2¢ - t.i.o.l.i. Bowen 1968 K20 fleet 1969 K10 swb fleet 1972 K10 Suburban 1972 C10 lwb step 1992 K1500 'burb 1995 K2500 'burb 1997 C1500 'burb 1999 K1500 2000 K1500 'burb Why do I own so many Suburbans?

10-13-2003, 10:46 AM	#21
Adam12 I hate trannys Join Date: Dec 2001 Location: Bakersfield,CA Posts: 160	UPDATE I decided to get a new battery so I now have a interstate battery with 800 CCA, I put it in then bought a volt meter and my alt was bad, to double check it took it to pep boys and they told me it was bad. The thing that sucks is I bought it from summit almost 2 years ago and it was sitting for about a year in my house and then when it was put on the truck it only had about 100 miles on it if that. Im going to see if they will at least give me some credit for it. __________________ 70 SWB 481 ci, TH-400, Edlebrok Victor Jr. intake, Holley street avenger 770, Dynomax ceramic coated headers. Dual flowmasters. and only 3516134 more little things to do.

10-13-2003, 11:15 AM	#22
busterwivell Registered User Join Date: Jan 2002 Location: Sahuarita, AZ USA Posts: 2,033	I had a bearing go bad in a one-wire alternator. I took it to a local shop and they repaired it for cheap. You might want to consider doing that, too. __________________ Bill - Tucson, AZ 47 Chevrolet 2 dr sedan 56 Chevrolet 210 2 dr sedan 66 Chevrolet Malibu 2 dr 4 speed 71 Chevrolet C30 Longhorn 86 Chevrolet Monte Carlo SS (Sold) 01 Chevrolet Tahoe IM - BUSTERWIVE@aol.com

10-13-2003, 11:40 AM	#23
Adam12 I hate trannys Join Date: Dec 2001 Location: Bakersfield,CA Posts: 160	Good Idea, I will look into that. when I looked at it closer it looks like the fan is warped or it could be the shaft because the fan does not spin straight. __________________ 70 SWB 481 ci, TH-400, Edlebrok Victor Jr. intake, Holley street avenger 770, Dynomax ceramic coated headers. Dual flowmasters. and only 3516134 more little things to do.

10-13-2003, 12:45 PM	#24
A.P. Black 72 Chevy Join Date: May 2002 Location: Los Angeles, California Posts: 662	My alternator is a one wire set up and it puts out 14.5V. My battery charger that I have in my garage puts out the same 14.5VDC and 10Amps. I know my alternator puts out more than 10Amps, so how in the heck won't it charge a dead battery or partially charged one? I got to disagree with some of the comments in here.

10-13-2003, 01:08 PM	#25
Chevy Wrench former desert rat Join Date: Feb 2003 Location: salt lake city, utah Home of the 3 M's Mormons, methlabs and minivans Posts: 320	Ok, you see, the problem here is that everyone is thinking volts when you should be thinking amps. Lets say that your alt. is only capable of producing 100amps. Your battery has a maximum output of 700 cold cranking amps. You run your battery all the way down, and is completley dead. So, you jump start your truck and figure that you will just run it for awhile to charge. Well, you will charge the battery up to 100 amps. You are still needing the extra 600 amps that are required to completley power your vehicle. Yes, it will "appear" to have a complete charge. Yes, it may start your truck, but you have never restored its full capacity. Since your alternater will only produce 100 amps, thats all that will be put into the battery. Volts are completley different that amps. If you run the battery dead, it still could read 12 volts, but put a load on it, and you will not have sufficiant amperage to power your truck. This is why you need to have a complete charge on your battery before you install that nice, new and expensive alternater. Otherwise, the alternater will never have a chance to "catch up" to recharge your dead battery. I hope that this explaines it better. Im not here to give false information, Im only trying to help those who dont know. I have many years of hands on training and school. I fix cars every day, and if I didnt know what I was talking about, then I would be working at Mc Donalds or something. Good day. __________________ 94 Chevy Silverado Ext cab 4/6 drop w/ 18's and 2500watt system (work truck). 67 Chevy swb under const. frame off custom, 20's, bagged and a large rat under the hood,and a 1940 Chevy truck under const.

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