Originally Posted by kingtal0n
1997 Chevrolet K2500 ECSB, 0411, 454, headers w/ Exhaust, MSD, 28lb injectors "Biggin"
Yeah I can't afford to buy things like that. I dont even have a boost gauge for the car. I use 87 octane half the time. It isn't going to happen but its a great idea.
I have lots of great ideas I can't put into motion because effectively a poor college student.
Sorry I come to this a bit late... however, for what its worth;
1/
Alternators can fail in many ways, one is that a single diode fails, then they go low output even if everything else is ok... can be caused by overheating, corrosion, or for example using a welder without disconnecting the Alt...
2/
They can also fail due to overrevving. I broke 2 before I realised that now my car went to over 6500 rpm, the alternator was at 3x that, which is simply beyond its limits!. Underdrive pulley needed... or rev it lower, lol. When this happens, you won't notice a thing except its stopped charging.
3/
I suspect this advice is too late, but if you have an older (up to around 2002 I think) car, then a later AD244 alt is much better, and tougher, than the one fitted to firebirds etc. as standard. Its a direct swap, at least on my FB, where it sits below the exhaust manifold, although it is slightly physically bigger.
4/
Alternators are temperature compensated: as the temp goes up, the voltage output goes down...
5/
our (and most) alternators have a remote voltage sense wire which you can use if you like, its just left unused, at least on my '99 FB and I believe on most others. If you have a 2 wire setup then its not connected.. you can wire it to a suitable point to get a sensible sense voltage (as standard, the 2 wire setup just senses the volts on the big main "battery" lead, which can lead to it under/over charging somewhat).
6/
The field connection (2nd wire, that I think you've been playing with) is essential for the alternator to generate any real charge, without it it may generate something...but not a lot... I'd strongly advise its connected to ECU as standard.
hope it helps,
kr D.
99 TA, Texas Speed LS376, PRC heads, 233/239 cam, Fast 92mm, 95mm TB, card style MAF, Tick TR6060, Strange 4.11 12 bolt axle & clutchpack diff, Strano springs/dampers, Vette 18" wheels, Vette disks, CTS-V calipers, 16lb flywheel, long tube headers, no cats.
This is the 4 pin connector, hopefully your alt uses this;
ls-alt.gif
The wire shown with resistor is the field, it needs a resistor (protection) and it needs to be switched or your battery dies. If the resistor is too small, the alt dies (fries the field winding), if its too big, the alt just does not work very well (low charge)..
On MY car, the ECU controls the alt in a basic way, (it only turns it on or off, it does not control the charging) by varying whats on the 'B' line. But on some cars/ECUs its not done like that...
The other pins have the L (lamp) output, used to indicate charging on some vehicles, and the S(ense) wire, used to detect battery volts sometimes. Err I forgot the other one, lol.
Last edited by dermotw; 08-10-2018 at 11:38 AM.
99 TA, Texas Speed LS376, PRC heads, 233/239 cam, Fast 92mm, 95mm TB, card style MAF, Tick TR6060, Strange 4.11 12 bolt axle & clutchpack diff, Strano springs/dampers, Vette 18" wheels, Vette disks, CTS-V calipers, 16lb flywheel, long tube headers, no cats.
Thank you,
I finally got off my behind and took 2 minutes to go under the car and ran a wire to the drivers seat from the back of the alt so I could compare in car voltage vs alternator output volts
Here are the results
With every electronic on (lights/fans) The alternator seems to put out 13.0v at idle and 13.4v during rpm > 1100 or so.
Meanwhile inside the car I believe was showing about 12.4 to 12.6volts.
There appears to be a 0.35 to 0.55 (or more) voltage drop from alternator to battery. It was usually around 0.4v but varied
So it does indeed seem that the wire I used is a bottleneck (its about half the diameter of the rest of my system for the first couple feet because I re-used the OEM wire from the original engine... because it has that cool ring terminal and I was curious to see if that wire would handle the job)
However it still concerns me slightly that 13.4v seemed to be the maximum voltage output from the back of the alternator, and I didn't realize the resistance decreased the voltage output. If what you are saying is true then the larger the resistance, the longer and smaller the wire, the less the field will turn on alternator output. I could have added a resistor but you are saying this decreases output voltage?
Edits for progress:
Tonight I Pulled the battery expecting to find it somewhat dead, but when I brought it inside and checked I get 12.6volts exact. Like its been charged "full" to 12.6volts
I was under the impression Lead acid battery would only charge 12.6 when new/full.
However today I bought a "battery maintainer" $10 harbor freight (returnable in 90days) says it puts out 13.2v and maintains batterys. I put it on for only couple minutes and already see the battery is holding 13.0v by itself. Will it stay charged up "that high" and how high can I go? This would be the first time I ever used a "trickle" charger or bought anything of this sort so all of this is new new new to me.
I came back to it 40 minutes later and now the battery is 12.7v instead. Disconnected charger gives me 12.7 battery. I wonder if this maintainer thing is alternating the voltages or cycling the charge somehow. first time not sure.
Sure enough 2 minutes later its 12.64v. I think it goes down and up. So what, catch it on the way up? What is this dark magic
edit2:
I love electronics so I got curious and bored.
FARMIE9IIUKCAI3.LARGE.jpg
This place is a good read
https://www.instructables.com/id/Battery-Float-Charger/
Alright, his is probably different than mine but I guess the concept is the same. His is using 5v cell phone charger to drive an inductor with a 555, I think using it as a flyback circuit? It looks like the inductor is switched off by the 555 thus cutting it off from ground and causing a high voltage potential to exist after D3 and filling C3, and C3 bleeds while the 555 waits to come back on.
SO anyways. Looks like 12.6v is around 90% charged. I think during the day I am able to hold 90% full but during the nighttime with headlights I see 12.2 on the battery so it must be struggling at 50-60% full. I'll fix the silly 3 feet long 1/4" thick wire that feeds 25 feet of battery relocated alternator fuse box stuff and put all this behind me hopefully lol. But somebody wanted me to look at float chargers...
Last edited by kingtal0n; 08-20-2018 at 10:43 PM.
The reason it's showing 13.0 after just being on the charger is because it has what's called a "Surface charge." The battery JUST had 13.2v applied. After removing it the battery will slowly bleed off this charge and be in its normal "steady state" charge. Just like when you throw 13.5v at it with an alternator for an hour, eventually it will settle out to 13.2 to 12.7. There has to be a potential difference between the alternator and the battery to result in current flow... and what you're seeing is normal once you take away that potential difference.
I'll agree that you NEED to remove that smaller gauge section of wire between the alt. and the battery. Electricians like to call them "fuses." Mechanics call them "convenient splices." But what they are is bottlenecks and problems. I would look up wire guage required for X length runs for Y amps and you'll see what size wire you really need going there. And you'll need enough to allow the battery to absorb anything the alternator sends it... since if your fuse block only draws 40amp with everything on, but your alternator is pumping out 100amp... that current either needs some place to go or your alt is going to crank down your output voltage to keep itself alive.
1997 Chevrolet K2500 ECSB, 0411, 454, headers w/ Exhaust, MSD, 28lb injectors "Biggin"
Thanks again!
So today I went out and replaced my super thin wire (pic coming soon) with a proper gauge alternator wire.
Annnd.... Drove it around.... SAME BEHAVIOR D:
Still dropping to 12.40 volts almost exactly with rpms held up and headlights/fans all on.
However it seems to hold 12.67 volts with the headlights off at least letting me keep a fully charged battery while driving in the day time.
I'll try two things next. One simply I will turn off fans and headlights to see where it goes next (didnt have computer in car to manually switch off fans atm)
I've done that before and still managed only a feeble 12.6~v output
and two
I will start poking the alternator wire to see where the voltage drop is actually occurring. I do have a good 3-5 feet of unneeded length in the alt cable I can get rid of as well. I was keeping it in case I wanted to move the fuse box farther but maybe it has something to do with this issue. Could simply be looking at alternator max output and the resulting natural drop through so much length. Its got to be a voltage drop issue (??⌐), since I do recall see 13.4v at the back of the alt and only 12.4 at the battery
Last edited by kingtal0n; 08-21-2018 at 06:40 PM.
https://www.calculator.net/voltage-d...s=50&x=90&y=29
Don't poke holes through the insulation. That's a bad idea, especially with a battery cable.
What is the gauge of wire going from your alternator to your battery? Where did you source it from? Didn't you do something with the ground at your battery? Is it the same size as your positive lead?
1997 Chevrolet K2500 ECSB, 0411, 454, headers w/ Exhaust, MSD, 28lb injectors "Biggin"
thanks for questions!
There is some length of "amplifier wire" that very large red wire popular in audio with very fine strands. I suppose it would be considered automotive wire. The rest of the length is battery cable, from the starter to battery on another car, I took that cable and using it for the alternator now to feed the amp wire at some point. So I can simply test the fuse box lug for voltage drop due to length then hopefully remove some length and it will get a bit better. Either that or there is a surface area problem where the battery feeds the fuse box since i used the OEM plugs maybe they are too small? I didn't want to run the alternator right to the starter battery cable because I wanted the OEM alternator lug in the fuse box working as intended, and I didn't want to have to add an ignition switch type circuit to kill the alternator and get the car to shut off. If thats still a thing. zomg also I dont think I tested the fuse box field wire with the +battery terminal disconnected either.
Last edited by kingtal0n; 08-21-2018 at 10:23 PM.
At least its a large wire... but the actual gauge size is important to the discussion/troubleshooting process. Is it 4ga? are they both the same gauge?
1997 Chevrolet K2500 ECSB, 0411, 454, headers w/ Exhaust, MSD, 28lb injectors "Biggin"
the corvette LS1 alternator is controlled by the corvette pcm using pwm (pulse-width modulated) signal. unless the pcm you are using has those outputs, it will not operate correctly. a friend of mine has one in his s-10 pickup and using s-10 ecm. it doesn't operate correctly. your best bet is cs series alternator with ign and battery feed. optional voltage sense terminal can be utilized with diode to drop sense voltage and increase output approx. 0.6 volts. with 2 wire set-up, it will regulate by temperature sensor built into internal regulator inside of alternator. the mounting may be a challenge if you are relying on corvette accessory bracket.
Last edited by DGS; 08-26-2018 at 03:41 PM.
Ad244 and relays just saying
https://github.com/sparcules/DRuino4...e/DRuino44.ino
Ive been considering making these for sale. This is someone elses design that doesnt have some of the features I would have, but it will work.
323482.gif. here's the wiring. it's pcm controlled by a pwm (pulse-width modulated) signal. if it's from the vehicle you claim it is. if you are running 25 feet of wire, your best bet is arc welding cable. the resistance alone from small wiring will cook/over-heat your alternator. if it's not damaged, the heat alone trims the temperature compensated regulator down and the small wire drops the voltage to the battery. if you ran a 12 volt battery feed and a 12 volt ignition feed from your vehicle wiring to the alternator, you likely damaged the alternator. the alternator needs to be removed and tested. you will still need to address the control of the alternator like above or a different style that is compatible with your vehicle wiring. terminal "D" is the sense wire I described in post above ran back to the battery positive terminal or install diode (1N5397/IN5397) to drop sense voltage and attach to the alternator output (large stud). this will trick regulator and jack up output approx. 0.6 volts. silver stripe on diode towards terminal "D". good luck. you have all the information you need with this post and the others above.
Last edited by DGS; 09-02-2018 at 12:14 AM.
Youre joking right? Anything other than that wire that goes to the B terminal draws about 100mA max. See thosae numbers like .8 and .5? That wire size in metric is 18 and 20 gauge respectively going to the regulator.
Last edited by matty b; 09-01-2018 at 11:35 PM.
just to clarify. yes, all of the wires to the regulator plug can be "small" just like the factory wiring. the cable I described goes to the battery 25 feet away as he stated. if you read my post I stated the 12 volt feed and 12 volt ignition feed are his existing factory wiring ("small"). common sense applies here as well as reading. if he can't fix it with all of the info in this string of posts, he needs to find the services of a certified automobile technician.
Last edited by DGS; 09-02-2018 at 12:52 AM.
The fact you modified it a half hour after I posted means I didnt read your MODIFIED post, only the post I quoted. The IGNITION feed to the regulator needs to be the same size as it is from the factory, that circuits job is to turn on the regulator so not as to leave it running at all times and kill the battery. The Sense wire(the secondary wire from the battery to the regulator) can also stay small as its job is to tell the regulator what the voltage is at any point its hooked to, typically, its left out as it will sense internally, but you can account for voltage drop of the wiring from the battery to the B terminal by sensing at the battery itself as opposed to the voltage at the alternator itself .
Regarding the diode you said to use, there is no need if you wire ignition to the F terminal. If you wire ignition to the L terminal, then yes, you need a diode or better, an incadencent bulb as thats what that circuit of the regulator is made for. You wire ignition to one or the other, not both.
The alternator WILL NOT be damaged if ANY wire going to the alternator is undersized or remains the same size as it is from the factory. The bat lead can be damaged and possibly the bat terminal on the alternator if wiring is undersize and it overheats. The alternator itself will not inherently be damaged because the wiring is small and for the factory alternator in question anything larger than 4 gauge is pushing it as far as necessity and if the battery cable to the starter is properly sized, it should be connected there so you can run an 8 or 6 gauge lead from teh alternator to the starter.
Ill say it again, that alternator is not going to be damaged by wire size alone though.
Last edited by matty b; 09-02-2018 at 01:04 AM.
My point is that one can't run 100 amps + thru 25 feet of 6-8 ga. wire w/o voltage drop to a point where it will not charge the battery or keep up with loads. If battery is mounted under hood where most are, running 3-6 ft. of 6-8ga. wire is adequate on the output terminal to the starter/battery/fuse panel. It is the resistance dropping the voltage, heat limiting internal regulator, wiring size, connections, distance from alternator, alternator control, etc.. The point of an external sense is to pick up voltage at the furthest point from the alternator which will then regulate at a higher voltage to make up for the drop from the high resistance 25 ft. run. The point of the welding cable for such a long run was b/c it will carry all of the amps the alternator will put out w/o dropping voltage and have adequate insulation durability. It's also more flexible to work with. It's probably cheaper than buying 2 ga. or 1/0 ga. bulk wire to run 25 ft.. He still needs to address how to control the alternator or all of these changes will be for nothing. He needs to test the alternator. He needs to test the battery even if "new" since it's been run down. If the battery is partially shorted, it will limit voltage. We don't even know what type of battery he is using. Deep cycle, maintenance-free, AGM, CCA rating, etc. We don't know the crank/alternator pulley ratio. I believe the alternator it rated at 6,500 rpm. It could be under-spun. It sounds like a degraded cobble job at this point that needs to be properly set up.
Last edited by DGS; 09-02-2018 at 11:17 PM.
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