(sigh!)1 wire alt.-i know i know! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BUXMAN66 · 11-17-2002, 02:35 PM

alright guys,so i ain't the brightest lite bulb here,crusify me!lol!! so anyhoo, i got me a nice purty chrome 1 WIRE alt. and i hook it up,from the back post of alt. down to the battery post terminal on my starter.simple ,eh?. i thought it would be for even me, a novice! well,come to find out the dust cover on top of the alt. houses 2 spade terminals and the plug,or wires that need to plug in here are nada.what makes it more sweet, is that when i took off my old alt.w/ the external voltage regulator i clipped off all my old wires!!duuuuuhhh,yup-yup! well, it says 1 wire dont it!so,how do i get this sumb---h to run correctly and keep my battery charged correctly?yes,i've seen the search topics for 1 wire alt. conv. but it still doesn't seem to click w/ me....... the wires they speak of... blue, brown,red..etc....... i dont have!is a simple solution to just jump a wire from one spade connector,(under dust cover) to the other spade connector? or will this just continually drain my battery- which is a brand new interstate batt.come on guys help a moron out!!lol thanks.

**68 Stepside** · 11-17-2002, 03:07 PM

I believe a wire goes from the right (as you're looking at the back of the alternator) spade terminal, to the battery stud, but I could be wrong. Just bringing this back ttt, someone will know

TJ

*Piston* · 11-17-2002, 03:22 PM

If its a true one wire alternator you should only need to connect the output wire. Something doesnt sound right... Anyhow, if you wanted to buy a pigtail harness for the alternator most parts stores have them.

If you want to try and connect the alternator using the pigtails, check this thread out. http://67-72chevytrucks.com/vboard/s...threadid=30531

Looking at the back of the alternator you'll see the output wire and to the right up top you'll see the 2 spade connectors. Left connector is WHITE (on aftermarket pigtails) which connects to your brown wire of the old regulator. The RED wire connects to the back of the alternator (to make things simple).

BUT.... MAKE sure you dont have a one wire alternator. if you try to hook this up like a regular alternator, your going to have problems with wiring. Not to mention a burned regulator in the alternator.

BUXMAN66 · 11-17-2002, 03:40 PM

68 step,piston thanks for the replies! piston you said make sure that it is a true 1 wire........well isn't that what it is?or does the connection of the plug to the spade connectors make it NOT a true 1 wire? even if i did buy the pigtail conn. can i make it work by jumping a wire from one of the spades to the battery post on the back of the alt.?

*Piston* · 11-17-2002, 03:43 PM

A true one wire only needs the output wire connected. There will be a cover (as you mentioned yours had) to block off the spade terminals.

BUXMAN66 · 11-17-2002, 03:59 PM

so if i'm not getting any voltage coming back from the alt. to my battery i need to have the connection to the spade connectors.so does this now mean i do not have a true1 wire alt. setup? i'm just confused as to what is the purpose of having the brown wire from the old ext.voltage reg. connecting to the spade conn. on the alt., if everything is internally regulated ........1 wire to a postive battery source(either straight to the battery or to the pos.post on starter) and presto your'e done.....!! what is the reason of having to use the plug in then?isn't it internally excited?

*Piston* · 11-17-2002, 04:04 PM

hehe, ok...

Here's what you should have:
1 wire alternator - connect the output wire to the battery and your done... UNLESS the alternator doesnt work. Dont attempt to hook wires up to this model because the correct wiring has already been done to the regulator inside the alternator.

Standard 3 wire - connect output wire to the battery, connect the RED wire to the output terminal and connect the white wire to the brown that used to go to the old regulator.

Dont try to add wiring and connectors to that 1 wire or you'll have trouble. The alternator could just be bad.

BUXMAN66 · 11-17-2002, 04:26 PM

just got back from the local napa store coupla hours ago they put it on a bench tester and it tested at 14.5 volts...... so i know my alt. is good i just need to make it work!spent 89bucks for a chrome "1 - wire alt." now to see it 's not a 1 wire but a 3 wire! yeah, your'e description was perfect 1 wire to battery ....your'e done.except mine dont put any voltage out! the 3wire sounds more like it ......hope i can salvage the ends from my old v.r. in my harness to run a wire from the brown wire to the white wire of the pigtail i'm gonna have to buy!thanks for your time piston,and also thanks(while i got ya here!)for sharing you story 'bout the can of pork-n-beans!we all need a little something to think of at times. i doubt if i'll forget that.later,man.

Yellow Cheyenne · 11-17-2002, 05:23 PM

Did you get to watch as they tested your altenator? Did they use the extra spade connectors? If they didn't use the spade connectors there, you shouldn't need to either. I've heard that the one wire altenators require about 3000 RPM to start charging. Due to pulley sizes, I would guess that engine RPM would need to be about 1200-1500 RPM. Once they start charging, the RPM's can come back down and the altenator should keep charging as long as needed.

tom hand · 11-17-2002, 05:28 PM

Ok, 1st if it is an 1 wire alternator, most I have seen still have the spade terminals under a plastic cover. 1 wire alternators are self exciting and will not charge at idle[or at all] till you rev the motor to get it going. I think you have to get the motor to about 1500 rpm before they kick in. After they kick in they charge like normal till the next time you shut the motor off. If it is not a one wire the terminal on the back needs to go to the battery, and the field spade terminal needs to go to a switched power source that is on a different circuit than the coil or the motor won't cut off with the switch once started. If you just run it to the terminal on the back of the alternator it will run the battery down. The last spade terminal is for an idiot light. Heres a diagram with pictures.

http://www.derbypro.com/tut4.html

*Piston* · 11-17-2002, 06:25 PM

It wont run the battery down unless the diode trio is bad (same as any alternator). Gm uses this same wiring technique on the J body cars in the late 80's. The white wire requires a small amount of voltage to excite the alternator usually 4-5 volts and is either supplied by a resitor wire OR an idiot light. When the regulator fails this circuit is grounded which causes the light to illuminate. They use the light bulb as a resistor for the circuit... If the bulb burns out the alternator will not charge. Just as the other guys have, I've run this same setup for about 7 years on the same alternator. Just recently I routed the output wire directly to the battery for more of a direct charge.

Thats good info on the 1 wire though, I didnt think about the rpm factor.

Longhorn Man · 11-17-2002, 06:59 PM

Another thing I have heard about the one wire deals, they do need a good ground. If you just painted your brackets, this could be the cause.
Everyone is right about revving the engine. Depending on your pully sizes, you could have to rev any where from 1200 to 3000 RPM to get the alt to 'turn on' untill you hit the magic number RPM, you'll just be running on the battery.

BUXMAN66 · 11-17-2002, 09:18 PM

thats exactly whats happening.i'm continually running on my battery and it's not being recharged or kept at a constant voltage.the alt.i bought on line(dragracing.com) on e-bay said it was a new not reman.alt to be used w/ 1 wire applications or if necessary utilizing the spade connectors for 3 wire applications.and also yes,i was standing right beside the guy at napa when he bench tested it,and it was putting out 14.5 volts.so which still leaves me wondering still how i'm gonna get this alt. to work and not have wasted 89 bucks.

BUXMAN66 · 11-17-2002, 09:27 PM

also forgot to mention earlier, using the approach that the engine rpm needs to be anywhere from 1500-3000,how come the battery still is losing its charge (did a load test on a diagnostics check at firestone to track down prob.involving my brand new interstate battery,tech. showed me where there was zero voltage returning to the battery from the alt.......there was my prob.) even with a serious shake down test up to 95mph.i'm pretty sure i reached the rpm's needed to excite the alt.

11-17-2002, 02:35 PM	#1
BUXMAN66 go bucks! Join Date: Jan 2002 Location: MIAMISBURG OHIO USA Posts: 803	(sigh!)1 wire alt.-i know i know! alright guys,so i ain't the brightest lite bulb here,crusify me!lol!! so anyhoo, i got me a nice purty chrome 1 WIRE alt. and i hook it up,from the back post of alt. down to the battery post terminal on my starter.simple ,eh?. i thought it would be for even me, a novice! well,come to find out the dust cover on top of the alt. houses 2 spade terminals and the plug,or wires that need to plug in here are nada.what makes it more sweet, is that when i took off my old alt.w/ the external voltage regulator i clipped off all my old wires!!duuuuuhhh,yup-yup! well, it says 1 wire dont it!so,how do i get this sumb---h to run correctly and keep my battery charged correctly?yes,i've seen the search topics for 1 wire alt. conv. but it still doesn't seem to click w/ me....... the wires they speak of... blue, brown,red..etc....... i dont have!is a simple solution to just jump a wire from one spade connector,(under dust cover) to the other spade connector? or will this just continually drain my battery- which is a brand new interstate batt.come on guys help a moron out!!lol thanks.

11-17-2002, 03:07 PM	#2
68 Stepside huh? Join Date: May 2000 Location: Washington, Illinois Posts: 5,692	I believe a wire goes from the right (as you're looking at the back of the alternator) spade terminal, to the battery stud, but I could be wrong. Just bringing this back ttt, someone will know TJ __________________ Someday when I'm lonely, Wishing you weren't so far away, Then I will remember Things we said today. RIP El Jay

11-17-2002, 04:26 PM	#8
BUXMAN66 go bucks! Join Date: Jan 2002 Location: MIAMISBURG OHIO USA Posts: 803	just got back from the local napa store coupla hours ago they put it on a bench tester and it tested at 14.5 volts...... so i know my alt. is good i just need to make it work!spent 89bucks for a chrome "1 - wire alt." now to see it 's not a 1 wire but a 3 wire! yeah, your'e description was perfect 1 wire to battery ....your'e done.except mine dont put any voltage out! the 3wire sounds more like it ......hope i can salvage the ends from my old v.r. in my harness to run a wire from the brown wire to the white wire of the pigtail i'm gonna have to buy!thanks for your time piston,and also thanks(while i got ya here!)for sharing you story 'bout the can of pork-n-beans!we all need a little something to think of at times. i doubt if i'll forget that.later,man. __________________ '68 swb 1/2t 350/350th '86 lngbd 3/4 TON parts getter '49 gmc 1/2 t 5 window 350/350th '96 gmc sonoma sle ext-cab. hey it's a 4cyl. 5 spd and good on gas y'know?

11-17-2002, 05:23 PM	#9
Yellow Cheyenne Registered User Join Date: Jun 2001 Location: Eastern Kansas Posts: 488	Did you get to watch as they tested your altenator? Did they use the extra spade connectors? If they didn't use the spade connectors there, you shouldn't need to either. I've heard that the one wire altenators require about 3000 RPM to start charging. Due to pulley sizes, I would guess that engine RPM would need to be about 1200-1500 RPM. Once they start charging, the RPM's can come back down and the altenator should keep charging as long as needed. __________________ '72 Cheyenne. AC, PS, PB, Rear slider window, tilt. Light yellow (grapefruit yellow according to new sales literature from '72) '56 Chevy short step V-8 (My dad bought it new!!) '70 Olds 442 convertible '70 Olds Rallye 350

11-17-2002, 05:28 PM	#10
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	Ok, 1st if it is an 1 wire alternator, most I have seen still have the spade terminals under a plastic cover. 1 wire alternators are self exciting and will not charge at idle[or at all] till you rev the motor to get it going. I think you have to get the motor to about 1500 rpm before they kick in. After they kick in they charge like normal till the next time you shut the motor off. If it is not a one wire the terminal on the back needs to go to the battery, and the field spade terminal needs to go to a switched power source that is on a different circuit than the coil or the motor won't cut off with the switch once started. If you just run it to the terminal on the back of the alternator it will run the battery down. The last spade terminal is for an idiot light. Heres a diagram with pictures. http://www.derbypro.com/tut4.html __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

11-17-2002, 03:22 PM	#3
Piston Account Suspended Join Date: Oct 2002 Location: Olathe, KS Posts: 2,301	If its a true one wire alternator you should only need to connect the output wire. Something doesnt sound right... Anyhow, if you wanted to buy a pigtail harness for the alternator most parts stores have them. If you want to try and connect the alternator using the pigtails, check this thread out. http://67-72chevytrucks.com/vboard/s...threadid=30531 Looking at the back of the alternator you'll see the output wire and to the right up top you'll see the 2 spade connectors. Left connector is WHITE (on aftermarket pigtails) which connects to your brown wire of the old regulator. The RED wire connects to the back of the alternator (to make things simple). BUT.... MAKE sure you dont have a one wire alternator. if you try to hook this up like a regular alternator, your going to have problems with wiring. Not to mention a burned regulator in the alternator.

11-17-2002, 03:40 PM	#4
BUXMAN66 go bucks! Join Date: Jan 2002 Location: MIAMISBURG OHIO USA Posts: 803	68 step,piston thanks for the replies! piston you said make sure that it is a true 1 wire........well isn't that what it is?or does the connection of the plug to the spade connectors make it NOT a true 1 wire? even if i did buy the pigtail conn. can i make it work by jumping a wire from one of the spades to the battery post on the back of the alt.?

11-17-2002, 03:43 PM	#5
Piston Account Suspended Join Date: Oct 2002 Location: Olathe, KS Posts: 2,301	A true one wire only needs the output wire connected. There will be a cover (as you mentioned yours had) to block off the spade terminals.

11-17-2002, 03:59 PM	#6
BUXMAN66 go bucks! Join Date: Jan 2002 Location: MIAMISBURG OHIO USA Posts: 803	so if i'm not getting any voltage coming back from the alt. to my battery i need to have the connection to the spade connectors.so does this now mean i do not have a true1 wire alt. setup? i'm just confused as to what is the purpose of having the brown wire from the old ext.voltage reg. connecting to the spade conn. on the alt., if everything is internally regulated ........1 wire to a postive battery source(either straight to the battery or to the pos.post on starter) and presto your'e done.....!! what is the reason of having to use the plug in then?isn't it internally excited?

11-17-2002, 04:04 PM	#7
Piston Account Suspended Join Date: Oct 2002 Location: Olathe, KS Posts: 2,301	hehe, ok... Here's what you should have: 1 wire alternator - connect the output wire to the battery and your done... UNLESS the alternator doesnt work. Dont attempt to hook wires up to this model because the correct wiring has already been done to the regulator inside the alternator. Standard 3 wire - connect output wire to the battery, connect the RED wire to the output terminal and connect the white wire to the brown that used to go to the old regulator. Dont try to add wiring and connectors to that 1 wire or you'll have trouble. The alternator could just be bad.

11-17-2002, 06:25 PM	#11
Piston Account Suspended Join Date: Oct 2002 Location: Olathe, KS Posts: 2,301	It wont run the battery down unless the diode trio is bad (same as any alternator). Gm uses this same wiring technique on the J body cars in the late 80's. The white wire requires a small amount of voltage to excite the alternator usually 4-5 volts and is either supplied by a resitor wire OR an idiot light. When the regulator fails this circuit is grounded which causes the light to illuminate. They use the light bulb as a resistor for the circuit... If the bulb burns out the alternator will not charge. Just as the other guys have, I've run this same setup for about 7 years on the same alternator. Just recently I routed the output wire directly to the battery for more of a direct charge. Thats good info on the 1 wire though, I didnt think about the rpm factor.

11-17-2002, 06:59 PM	#12
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Another thing I have heard about the one wire deals, they do need a good ground. If you just painted your brackets, this could be the cause. Everyone is right about revving the engine. Depending on your pully sizes, you could have to rev any where from 1200 to 3000 RPM to get the alt to 'turn on' untill you hit the magic number RPM, you'll just be running on the battery.

11-17-2002, 09:18 PM	#13
BUXMAN66 go bucks! Join Date: Jan 2002 Location: MIAMISBURG OHIO USA Posts: 803	thats exactly whats happening.i'm continually running on my battery and it's not being recharged or kept at a constant voltage.the alt.i bought on line(dragracing.com) on e-bay said it was a new not reman.alt to be used w/ 1 wire applications or if necessary utilizing the spade connectors for 3 wire applications.and also yes,i was standing right beside the guy at napa when he bench tested it,and it was putting out 14.5 volts.so which still leaves me wondering still how i'm gonna get this alt. to work and not have wasted 89 bucks.

11-17-2002, 09:27 PM	#14
BUXMAN66 go bucks! Join Date: Jan 2002 Location: MIAMISBURG OHIO USA Posts: 803	also forgot to mention earlier, using the approach that the engine rpm needs to be anywhere from 1500-3000,how come the battery still is losing its charge (did a load test on a diagnostics check at firestone to track down prob.involving my brand new interstate battery,tech. showed me where there was zero voltage returning to the battery from the alt.......there was my prob.) even with a serious shake down test up to 95mph.i'm pretty sure i reached the rpm's needed to excite the alt.



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