Hot Rod Forum banner

how to bypass an external regulator

13K views 20 replies 6 participants last post by  rtyauch301 
#1 ·
ok so how can i by pass my external regulator to test my alt the problem im having is when its idling im at 14 volt normal right but when i cut my headlights on i drop to 12.7 and turn signals im dropping to about 12.2 if i use my heat i can kill the battery when driving trying to figure out if its the alt or the regulator just wanna bypass it see if the voltage goes up and see if it can take a load its a 1970 Pontiac Catalina
 
#2 ·
If the car is charging at 14 Volts while idling, there is nothing wrong with the regulator. When you apply the headlights, the voltage will drop due to draw from the headlights. That is also normal. If you have several accessories turned on at once and there is a huge draw in voltage, you can opt for a higher amperage alternator. You probably have a 65 amp alternator which can be upgraded to 100 amps. That will help, but not make a huge difference. The other option is installing relays to headlights, etc which will reduce voltage draw by taking direct 12V's from the battery versus going through a switch like the headlight switch which causes more draw in voltage. If your curious, you can buy an external regulator they are cheap enough and replace the one you have and see if there is any change. That's one way of telling...
 
#3 ·
the only reason i think its a problem is its a new thing had the car about 4 years and didn't start doing it till this year.... its not charging the battery all the way or anything thought it was a problem with the battery so i swapped it with the new one i had in my rv and still the problem...... headlights turn signels and heat dont seem like alot of accessories to me .... the radio dosnt work no power windows and the cig lighter is disconnected.
 
#4 ·
If your running halogen lights it will draw more voltage. If your battery is not charging? I'd maybe look at the cables or connections particularly the ground straps on the frame or engine. They may be corroded which will also cause a similar problem. Take them off and make sure the metal to metal contact is good. I'm running sealed beam halogens on my car. I'm at 14.1 volts at idle, with headlights, I drop to 13 volts, with brakes, turn signals on, I'm just above 12 volts. With the headlights off, your battery should be charging. You can also take the alternator to a shop and they will check it out. It could be that its not charging at a higher rpm range, or it's a sign the brushes need to be replaced. Good luck.
 
#5 ·
he definitely has an alternator problem.
63A is more then enough for headlights and a heater.


one thing to check.. is the heavy gauge wire from the alternator.. my '72 monte carlo has a FACTORY splice in that wire.. and someway or another that splice 'went bad' and the alternator would charge fine provided there was no load on the alt.. just keeping the battery happy.. the second you turned a load on in the car, it quit charging.. I upgraded to an internally regulated 85a alternator, replaced it a 2nd time, replaced the two smaller wires to the alt, still wouldn't charge.. one day in a fit of desperation while waiting for the battery to charge again at the parts store, I bought a roll of 10ga wire, and some ring terminals, and whipped up a presidential solution of running the heavy wire straight to the horn relay terminal.. and BAM she was charging 14.4v under load no problem. :)

took her home, and worked up a nice proper solution to a new charging wire :) now days I have a 110A CS130 Alternator :)
 
#6 ·
I had trouble with my 63 amp 10si that could not keep up to the load from lights and heater blower at the same time, but seemed to work fine otherwise. When driving at night it went down to about 10.5 volts at idle and only about 11.5 when driving down the road.

My alternator even checked out fine when they put it on the machine at Advance Auto. However, I finally replaced it with rebuilt unit and it resolved all the problems. The old one was just weak and just could not keep up with high amp loads. I also ran the new charge wire directly from the battery + to the alternator, just in case I was losing voltage through the old wiring that ran in a path from the battery down to the starter and then up to the alternator.

Bruce
 
#9 ·
You can actually replace the stator and rectifier on your alternator with a high amp stator, which will give you more amperage from the 10SI alternator. I'm running the 63 Amp and have no problems with enough amperage on my car. Your current alternator can not output enough amps to run all of your additional accessories, thats why you are seeing such low voltage readings, your battery is also trying to supplement current for the lack of output by your current alternator, which is why you are experiencing a dead battery after driving.

I wouldn't recommend purchasing a high amp stator, etc for the 10SI alternator, but recommend instalingl a GM - CS130 or a CS144. The CS130 comes in different amperage output, but 105 amp is pretty standard, 130amp version is popular amongst street rodders who have power windows, etc. The standard version of the CS144 is 120 amps. The CS130 or the CS144 alternators output a higher amperage at idle conditions, which is what you really need to solve your current electrical needs. These alternators have better cooling fins as well which will keep from allowing your alternator to overheat, which is a big factor in killing your alternator.
 
#10 ·
If you pick up a CS-type alternator from the parts house, wait to return your core until you swap out the pulley (if necessary)- most of the later alternators are for serpentine drives.

Most stores won't know or care about the difference between an SI and a CS alternator, but if they DO 'catch' it, the core is as high as $50 from O'Reilly on some CS units.

The adapter pigtails are readily available for a "plug and play" set up or you can splice the wiring yourself to save a buck.
 
#11 ·
my parts store was on the ball and wouldn't let me trade in my SI core for a CS alt.. i got my CS off my 89 cutlass cierra when it got wrecked ;)

the CS130 is actually smaller then an SI... the distance between the mounting lugs is a mm or two smaller. I had loosen my upper bracket and lean down on it to get it to reach the CS.. and you will need a metric bolt for the adjuster, other then that.. :) oh yeah. make sure you get a CS with 180° mounting lugs!

I know for a fact that a 1989 Olds Cutlass Cierra with the 3300 v6 works ;)


as for the low amp SI's.. go figure.. guess that's what happens when you ASSume :nono:
 
#12 ·
The largest output from a stock 10SI was 63 amps. However, I have now switched to a 94 amp 12si, which is a direct replacement. The only change is metric threads on the pivot bolt, but you want to find a 94 amp 12si that uses a v-belt pulley. Many of the later 12si's used serpentine pulleys.

Switching to a CS130 is a little more complicated to wire in, but as Cobalt327 mentioned, the adapter pigtails are easy to find. On my 12si I am using an 8 gauge charge wire running directly to the BAT post, with a 12 gauge fusible link on the battery end.

Bruce
 
#13 ·
belt slipping?

sometimes the belt will slip when you load it up, since the voltage s ok at partial load Iwould check it The alternator on my backhoe sometimes charges and sometimes. not. I had it checked out and the shop said loose connection inside and wanted $ 300. IT only has to start off the battery and run the fuel solenoid valve. so I haven't installed a GM one wire yet.
 
#14 ·
actully the CS130 wires up the same as any other internally regulated unit..

but one thing to be aware of.. loading a CS130 down can cause a normal v-belt to slip.. as far as I know GM always used a poly-v (serp type) belt.

my 86 astro for example had a 4.3l v6 with a 110A Cs130.. it had 3 belts.. the A/C and P/s were your standard v-belt, but the alternator used the flat poly-v belt..
 
#15 ·
kc8oye said:
actully the CS130 wires up the same as any other internally regulated unit..

but one thing to be aware of.. loading a CS130 down can cause a normal v-belt to slip.. as far as I know GM always used a poly-v (serp type) belt.

my 86 astro for example had a 4.3l v6 with a 110A Cs130.. it had 3 belts.. the A/C and P/s were your standard v-belt, but the alternator used the flat poly-v belt..
The serpentine belt system is superior to the V belt style and no doubt provides better performance, however the V belt system will work as well. It's much easier to replace the alternator pulley with the V belt style rather than replacing other pulleys. The alternator bracket is just as important. I had problems using the stock Ford type which has a bolt on the top and the adjustment arm underneath. You had to pull the alternator using either your arm strength or a pipe and while holding it there, you had to tighten the lower adjustment bolt hoping the alternator would not move :D I went with a billet style that uses a turnbuckle to adjust the tension and the V belt doesn't slip or loosen up on me anymore.
 
#16 ·
my point was that a single v-belt doesn't offer the 'traction' to turn a CS130 charging at full tilt.. i've got mine about as tight as I dare go, and I can see it polishing the belt. one day when I when the lotto, or collect the ransom on Bin Laden (lol) i want to get a march pulley system that uses all poly-v belts, I don't want to go true serp.

GM alternator bracket is basicly the same.. pivot at the bottom, top bolt just slides thru a slot.. put tension on the belt, tighten the bolts down. my buddy has a chrome bracket and his alternator is ALWAYS loosening up because of the chrome :)
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top