Moparts
Charging system modifications
Posted By: feets
Charging system modifications - 01/25/12 06:09 AM
I'm very familiar with the ammeter bypass that so many people do to these old cars. I did it on the hot rod.
On the Imperial, I'd like all of the stock gauges to work properly. I also want my electrical system to survive a few upgrades.
The plan is to clean and inspect all the wiring in the charging system and under the dash. Once that's done, I'd like to put the high amp consumers on relays. Headlights and the amp for the stereo are the first that come to mind. I'd also like to pt the blower motors on relays too. They draw lots of power and I've got two of them in the Imperial.
Here's what came to mind.
A high output alternator wired into the factory harness. A second heavier line would come off the alternator and into a separate power distribution system that would supply juice to the relays for the heavy consumers.
That should take the load off the bulkhead connector and ammeter, right? Would the ammeter read normally in this configuration? I realize it would not be able to real the draw from the heavy power leads but it should still reflect the power consumption of the standard electric bits.
The only time the alternator would be hitting the factory harness with a heavy load would be if I was playing with the high current systems and draining the battery while the engine was off.
Am I missing something here? Would this work as intended?
Posted By: astjp2
Re: Charging system modifications - 01/25/12 06:33 AM
NO, the alternate wires would bypass the amp gauge and give no reading. Tim
Posted By: NachoRT74
Re: Charging system modifications - 01/25/12 06:56 AM
first word... parallel wiring
second word... nice high amp alt at iddle ( 50-55 amps average iddling should be enough)
third word... relays hooked up to alt side. No need to be hooked up directly to the alt stud, just somewhere between the alt and the ammeter. MYSELF I have 6 relays being feed from AMMETER STUD alt side, high beams, low beams, heater blower speed and one of each A/C blower speeds. True all 6 never work at the same time, and max 3 could be activated.
with everything of this met, will have not problems at all and ammeter barelly will sense anything but not because you are bypassing, really because you have the system perfectly balanced.
Posted By: Twostick
Re: Charging system modifications - 01/25/12 07:25 AM
I would eliminate the main 12v bulkhead connection and run a min 8ga wire thru the firewall thru either a grommet or an isolated stud and never have to worry about spontaneous bulkhead connector combustion again. I also ran an 8ga cable from my alt to my battery so any big charge loads have a path of least resistance. High school electricity class was too many decades ago to remember if this will wreak havoc with you ammeter function or not. I think 73 should have the shunt style ammeter so it shouldn't be a crispy critter like the one in my 66 was.
Kevin
Posted By: 451Mopar
Re: Charging system modifications - 01/25/12 09:34 AM
Your thinking is correct, but the issue would be that you now have a high output alternator that could supply too much current through the stock wiring if the battery is pretty low. Also, if the alternator stopped and all those accessories are still on the current to them would come from the battery through the ammeter wiring.
The alternator output will take the path of least resistance, so you really do need the bypass back to the battery.
Running a bus wire from the alternator to the relays is a good idea to take the load off the dash wiring and switches, just make sure to add protective fuses.
Posted By: 70Coronet500Vert
Re: Charging system modifications - 01/25/12 01:39 PM
I ran the alternator output to a distribution block. Then I powered everything from there. Works fine.
Alt feed in one end, batt connection out other end, in the middle is the feed ot the relays, the main dash harness, the radio, and the amps.
Posted By: NachoRT74
Re: Charging system modifications - 01/25/12 03:12 PM
451Mopar is correct. But the correct procedure in case of a discharged batt is charge it back OUT of the car. Thats the correct procedure on ANY situation ANY setup, ANY car. And a battery suplying the power what the alternator is not able to give won't be that high ( more close to nothing ) on a correct alternator setup, matched with your car needs. And once again, the ammeter even 40 amps one will be able to hold the regular stuff charge and discharge. Will be nice they were higher ? yes, but necesary ? no.
All that you need is to know HOW to read and understand the ammeter reading. Ammeters are not really an alternator gauge like factory stated, is really a batt status. It's imposible to get an alt being discharged because they dont "storage" power so how you can read DISCHARGE on an "alt" gauge ? Of course you can read the alt is or not working propperly or is enough with the gauge reading, but is really a BATT status
70Coronet500vet is correct BUT not with the original idea of the poster about keep the ammeter reading.
Bulkhead conectors can be still being "used" if they are still good or just need some mantenience, just the parallel wire will take all the extra/High load by Ohms Law. The stock bulkhead wires will be ther allmost just for originality.
However if your bulkhead is already damaged, you can rid off the stock wires going there and run simply thicker wires ( 8 is enough ) through it without terminals... or using HEAVY DUTY terminals, or buss bars somewhere if you care versatility about unplug everything
Shunt ammeter systems appeared by the first time I think on 75 or 76s
Posted By: RapidRobert
Re: Charging system modifications - 01/25/12 03:23 PM
Yes your thinking right. Nacho's bulkhead parallel bypass. clean ALL connections. relay everything from the alt side. An alt that adequately puts out at idle. Strive to keep the ammeter needle at (or close to) 12 o'clock most of the time. This'll keep the ammeter accurate. Dont forget the correct as in dielectric lube for connections
Posted By: NachoRT74
Re: Charging system modifications - 01/25/12 03:30 PM
thaaaat's it!
At least ONE GUY on board has been able to check and test PERSONALLY what I say and I have done, sharing my experience with this... and that it means I'm not insane, like when I began with this I was jugded LOL
Posted By: Andrewh
Re: Charging system modifications - 01/25/12 03:46 PM
The amp meter would not read correctly while charging.
it would only read correctly when the engine is off during discharge since the battery would have to back feed through it.
This should not be an issue with the original harness provide no electrical loads are added to the car. AND the original wiring and amp meter are any good.
I think you are asking for more trouble than it is worth, but if you want it to read correctly and in both directions, you need to add a shunt resistor to the system, run all the power across that, then have the amp meter modified to read across the shunt and provide indication.
I would figure it should not run over 200 bucks to get all of this done.
OR, find a volt meter that reads both ways in the proper range based on the shunt and just replace the face with the amp meter face you have.
might run under 100 that way.
http://www.allaboutcircuits.com/vol_1/chpt_8/4.html explains what a shunt does.
http://mgaguru.com/mgtech/electric/et221.htmwhy you need a shunt
http://www.powerwerx.com/fuses-circuit-protection/current-shunt-resistors-100-amp-max.htmla place to look for shunt resitors.
Posted By: 440newport
Re: Charging system modifications - 01/27/12 05:39 PM
I don't think it's as critical to bypass the ammeter on your Imperial compared to your '65. The later cars use a shunt ammeter so not all the current in the system is passed through the ammeter like in the earlier cars.
All I did on my '73 was add an extra fused wire from the alternator back to the battery to take some of the load of the rest of the wiring.
Posted By: feets
Re: Charging system modifications - 01/27/12 07:36 PM
Doesn't that extra wire mess with the ammeter reading?
I didn't want to bypass the ammeter. What I wanted to do was run a parallel line to power the heavy consumers like the stereo amplifier.
Posted By: Supercuda
Re: Charging system modifications - 01/28/12 12:20 AM
All the ammeter does is read the current to/from the battery. If you powered your stereo from the alternator stud it will have ZERO effect on the ammeter or the accuracy of it's readings.
Posted By: RapidRobert
Re: Charging system modifications - 01/28/12 12:22 AM
Quote:
All the ammeter does is read the current to/from the battery. If you powered your stereo from the alternator stud it will have ZERO effect on the ammeter or the accuracy of it's readings.
Exactly, & you want as little current as possible in or out of the battery
Posted By: Supercuda
Re: Charging system modifications - 01/28/12 12:40 AM
Quote:
Quote:
All the ammeter does is read the current to/from the battery. If you powered your stereo from the alternator stud it will have ZERO effect on the ammeter or the accuracy of it's readings.
Exactly, & you want as little current as possible in or out of the battery
Correct, in a running setup all the electrical load is fed by the alternator before the ammeter. The connections still go thru the bulkhead though. You may wish to use a heavy gauge wire to bypass the bulkhead connection, just run it in parallel to the stock alternator to ammeter wiring.
Posted By: ahy
Re: Charging system modifications - 01/28/12 01:11 AM
Quote:
I'm very familiar with the ammeter bypass that so many people do to these old cars. I did it on the hot rod.
On the Imperial, I'd like all of the stock gauges to work properly. I also want my electrical system to survive a few upgrades.
The plan is to clean and inspect all the wiring in the charging system and under the dash. Once that's done, I'd like to put the high amp consumers on relays. Headlights and the amp for the stereo are the first that come to mind. I'd also like to pt the blower motors on relays too. They draw lots of power and I've got two of them in the Imperial.
Here's what came to mind.
A high output alternator wired into the factory harness. A second heavier line would come off the alternator and into a separate power distribution system that would supply juice to the relays for the heavy consumers.
That should take the load off the bulkhead connector and ammeter, right? Would the ammeter read normally in this configuration? I realize it would not be able to real the draw from the heavy power leads but it should still reflect the power consumption of the standard electric bits.
The only time the alternator would be hitting the factory harness with a heavy load would be if I was playing with the high current systems and draining the battery while the engine was off.
Am I missing something here? Would this work as intended?
I believe it would work as intended (get the load off the stock wiring and give ammeter function). The ammeter would still register current flowing to and from the battery which is its intended function. Also, your added loads would be off the stock wiring... as long as the alternator is working and making power. As you said, it would "back feed" with the alternator not working/spinning. As long as the added loads aren't real high, brief periods of back-feed once in a while wouldn't hurt. I'd just make sure to get an alternator with strong idle output so it doesn't have to backfeed every time you come to a stop light.
Posted By: ahy
Re: Charging system modifications - 01/28/12 01:48 AM
PS... assuming you have and plan to keep the AC this may be a job for the "big Chrysler"
Posted By: feets
Re: Charging system modifications - 01/28/12 04:33 AM
I had a 130 amp Nippondenso alternator on the hot rod. They're easy to find and making brackets is easy with the tools I have at home.
Posted By: 383man
Re: Charging system modifications - 01/28/12 07:07 AM
All the Ammeter does is show current flow into or out of the battery. If you went straight from the battery to a hot junction block and powered the accesories like that what would happen is the alt will have to show all the current going into the battery plus all the current to the junction block because the alt output would have to go thru the ammeter and to get back to the jubction block and feed the accesories. So the ammeter will show more then just the current going into the battery it will also show the current feeding the accesories. Now as long as you hook the hot feed to the accesories that you plan on and take the hot feed from the alt side of the ammeter the ammmeter will now only show the current going into the battery like is should. Thats because the alt will put out the current to feed all the circuits but that current wont go thru the ammeter. Now the voltage reg will still read when the battery volts gets to low and will make the alt put out enough to feed all the circuits and keep the battery volts up where it belongs and the ammeter will only show the current going into the battery. The ammeter does not tell you how much the alt is putting out it just shows how much current is going into the battery to keep the volts at the correct level. So by hooking the hot feed to the relays after the ammeter that means with the car running all the alt output to feed the relays will go from the alt output wire and to the relays and not go thru the ammeter. Only what the battery needs to keep a charge will go thru the ammmeter. Course if you turn on any of it without the car running then it will go thru the ammeter to the relays. Ron
Posted By: feets
Re: Charging system modifications - 01/28/12 04:02 PM
I was talking about taking the lead from the back of the alternator so the heavy loads did not pass through the factory harness.
I understand the ammeter will not be affected unless the alternator isn't producing and the power has to feed through the harness from the battery.
Posted By: Jeremiah
Re: Charging system modifications - 01/28/12 07:05 PM
I did something similar in my red Charger. The stock wiring (running through the firewall bulkhead connector) runs the following:
Gauges
Interior Lights
Head/turn/stop lights
Starter Relay
The secondary electrical system, which uses a master relay, fuse panel, and component relays runs the following:
MSD 7AL
MSD 2-step
Electric Fan
It works well and headlights do not dim at an idle (~950-1000 RPM).
If I were to rip out the factory wiring I'd run the headlights off of a relay as well as the heater blower motors as you had mentioned.
The other item that is often overlooked is windshield wipers. I am not sure if your Imperial is the same as others, but all of the high current switching is done inside of the factory switch that must have been designed by Rube Goldberg. The hurdle to overcome would be varying the voltage output to the w/s wiper motor. In my 66 b-body the heater motor is piggy-backed off of the w/s wiper switch which seems insane to me but what do I know.