Re: alternator charging problem
[Re: TrueTripleX]
#179033
12/30/08 06:28 PM
12/30/08 06:28 PM
|
Joined: Nov 2003
Posts: 2,715
closer to Canadian beer!
torkrules
I'm neurotic
|
I'm neurotic
Joined: Nov 2003
Posts: 2,715
closer to Canadian beer!
|
Quote:
68 440 B body. I have a problem with the battery being "cooked".
I have new alternator, regulator and battery. I am registering 17 volts output at alternator, 14.5 at regulator and 16.5 at the battery. I have tried another alternator and still get the same readings. What can I do to get this back in a proper ranges since I am boiling acid out of the battery?
Make sure the regulator has a good ground. Are you using an MP constant voltage regulator. If so replace it with the common variety, off the shelf regulator. It will work much better.
|
|
|
Re: alternator charging problem
[Re: Andrewh]
#179035
12/30/08 08:29 PM
12/30/08 08:29 PM
|
Anonymous
Unregistered
|
Anonymous
Unregistered
|
Quote:
If the sensing voltage is 14.5, then you shouldn't be seeing 17 at the battery.
You might want to check at all your connections to see if you have a bad wire somewhere as well as a good ground.
The only time I had those problems was a bad connection from the sensing line to the VR.
This is a classic problem of voltage drop, and it can be either in the ground system or the positive.
First, forget "ground" Imagine that the "ground path" is actually wiring instead of a body, engine block, etc.
THE REGULATOR CASE MUST MUST MUST be "as close" to battery negative as possible. This means that the path from the battery neg. terminal, through the ground cable, to the block, to the body, and to the reg. case MUST be very low resistance.
The way to check this, is to set up the car at "low cruise" (good fast idle) with the battery "up." Check first with all accessories off, and check again with a load, such as the headlights and heater blower
STAB ONE PROBE of a good meter DIRECTLY onto the battery neg. terminal. Stab the other probe DIRECTLY onto the reg. case. THIS VOLTAGE should be as low as possible, and less than one half volt, the less, the better. If more, you have a poor ground connection somewhere
NOW do the same thing with the positive "end"\
Imagine the circuit---Start with the batt pos, through the cable to the starter relay, through the wiring, through the bulkhead connector, the ammeter, the ignition switch BACK THROUGH the bulkhead connector, and to the regulator connector WHICH CAN BE corroded itself
Once again, low cruise, as above. Stab one probe DIRECTLY onto the batt. positive post. Stab the other lead DIRECTLY onto the regulator ignition terminal. THIS VOLTAGE, as in the ground should be very low, again, LESS than one half volt, the lower the better.
Still more ways to check this is to run a GOOD quality jumper cable from the reg. case to the batt negative and see if the charging voltage drops.
If not, or if it's still somewhat high, run a good big cliplead (say no 10 or so) from the batt. positive directly to the regulator ignition terminal.
|
|
|
Re: alternator charging problem
#179036
12/30/08 09:37 PM
12/30/08 09:37 PM
|
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
RapidRobert
Circle Track
|
Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
|
unless the VR isnt grounded I would clean each connection in both the positive & negative circuits or as 440sixpack said check each "connection" to find out which one(s) are having an excessive voltage drop. With a new alt/reg/batt that only leaves the wiring & unless there's been too much amperage flowing wiring only goes bad at the "connections". Dont forget to check the ammeter terminals & esp the ign switch & the bulkhead(prime problem areas).
Last edited by RapidRobert; 12/30/08 10:15 PM.
live every 24 hour block of time like it's your last day on earth
|
|
|
Re: alternator charging problem
[Re: TrueTripleX]
#179038
12/31/08 03:37 PM
12/31/08 03:37 PM
|
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
RapidRobert
Circle Track
|
Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
|
along with checking the VR ground you might jump 12V DIRECTLY from the batt positive POST to the alt male field terminal ITSELF, the one with the blue lead on it & jump the same 12V DIRECTLY from the batt positive POST to the VR male nub that has the blue lead on it(pull the connector off & take 2 jumper wires & connect the blue & green wires in the triangle connector to the their respective nubs on the VR) or at least check that this triangle connector is making GOOD continuity to the VR nubs when it's plugged in. EDIT I reread your OP & saw that you have a 68 & if you have the original single field system disregard the above  . If it's a single field is your VR an original mechanical type or an electronic replacement?
Last edited by RapidRobert; 12/31/08 03:51 PM.
live every 24 hour block of time like it's your last day on earth
|
|
|
Re: alternator charging problem
[Re: TrueTripleX]
#179039
12/31/08 11:23 PM
12/31/08 11:23 PM
|
Anonymous
Unregistered
|
Anonymous
Unregistered
|
Quote:
I DO appreciate all the input and will try these solutions out today. BUT my biggest concern is why do I have 17 volts at the battery when I am only registering 14.5 volts output from the regulator? I really don't understand the process for this.
If you get your diagram, and re-read my post, I tried to explain it to you. It IS the entire post. The regulator case AND ignition feed terminal MUST SEE the exact same voltage AS THE BATTERY or else as the voltage drops--caused by resistance--in the wiring and ground path, CHANGE THIS RELATIONSHIP.
Once again, if you have a drop through the firewall connector, due to loose connections, corrosion, or damaged wires, the regulator will not be at the exact same voltage as the battery. Either measuring this as I suggested, or jumpering around the wiring with jumpers or cables should show it up. I simply don't know how to put this any more clearly.
Try to imagine the circuit. The vehicle loads are "trying" to load down the battery, the headlights, the heater, or just the battery being "down" from starting.
Let's say the car is NOT running, but the key is on, and let's say you DO have some crappy connections through the firewall connection.
Imagine the battery positive, the path of wiring through the cable, through the firewall, the ammeter, to the ignition switch, back through the firewall connector, and finally the power gets to the "green" lead at the regulator.
You might have, say, 12.2 volts right at the battery. The first bulkhead connector might be pretty good, but might have a tenth of a volt drop. So if you measure it there, you are down to 12.1 volts. Maybe the ammeter is OK, but the connector on the ignitons switch is a little corroded, and maybe the contacts inside the switch are getting a little "on." So maybe you have .2 (two tenths) drop there. Now you are down to 11.9V. So now we head back out to the firewall connector, and maybe THAT wire connection is particularly bad, maybe it drops .2 so NOW we are clear down to 11.7V. To add insult to injury, maybe the ignition terminal at the regulator is slightly dirty, and we have one last tenth of a volt drop. WE HAVE GONE from a starting voltage of 12.2V at the battery---once again with the engine off--CLEAR DOWN TO 11.6 volts through all this wiring.
Now if we ASSUME that this drop is going to be the same with the engine running--and it won't--it will be WORSE because of current draw-- we started with a total loss-- through the wiring--of .8 EIGHT TENTHS of a volt drop.
What this means is, that if our regulator is ATTEMPTING to regulate at 14.5V, WHAT WILL SHOW AT THE BATTERY with the system charging will now be .8 (eight tenths) of a volt HIGHER-- 15.3V.
NOW let's apply the SAME logic to the ground system. If you have several more tenths of a volt drop in the ground circuit, YOU ADD IT TO the difference above, so let's just "say" that you have .6 (six tenths) drop in the ground end. Suddenly we have a battery running at 15.9V!!! --nearly 16V!!!! (15.3 plus .6)
Pleas read this carefully. It IS what "it is."
|
|
|
|
|
