delco alt battery drain

[DavidLA]

Got a delco rigged up to charge up the battery, everything is working great. I have everything wired up direct.(the heavy red wire going directly to pos batt) out of curiosity I checked with the volt meter between pos battery post and pos battery cable. with the tractor not running i have voltage running through. if i disconnect the heavy red wire off the alt charge stud the voltage drain goes away.

is the heavy red supposed to be disconnected through a key switch(when done properly) to prevent this?

like I said i have it rigged up "temporary" for charging, am I missing something?

thanks
david

 

[souNdguy]

Charge stud to battery should not drain, unless the salt is damaged.

Now, there is a plug with #1 & #2 terminals.

#2 can stay looped to the charge stud. #1 can go to bat hot thru a key and serate switch, or trailer marker lamp and key switch, but can't go directly with no switch or it will drain.

What do you have?

 

[JMOR]

(quoted from post at 21:49:49 01/02/15) Charge stud to battery should not drain, unless the salt is damaged.

Now, there is a plug with #1 & #2 terminals.

#2 can stay looped to the charge stud. #1 can go to bat hot thru a key and serate switch, or trailer marker lamp and key switch, but can't go directly with no switch or it will drain.

What do you have?

ood to see up up and about!

Probably, he should quantify, "drain", as sense will always have a small drain as will a one-wire alt.

 

[Sean in PA]

"Voltage running through" is not a valid electrical phrase. You could have a voltage potential across two points, or current running through a point, but not "voltage running through" anything.

Voltage is an electrical potential. Current (amperage) is the flow of electrical current.

If you want to determine if there is a draw and how much of a draw there is, when the tractor is not running, then you should disconnect the battery terminal and switch your meter to read amps and put it in line between the battery post and the cable.

Lots of other information you left out. If the alternator is wired directly to the battery, how are the starter and key switch hooked up? The rest of the electrical system has to be hooked up somewhere or the starter would never function. Is this a gas or diesel?

 

[Geo-TH,In]

When I replace an alternator I bench test it first.
The last 2 alternators had a few ma draw on one of
the terminals, so I ran both terminals 1 & 2
through the switch. Seems to work OK. Why take a
chance, just switch both?

 

[souNdguy]

Good to be up and breathing.

Yup, the #2 sense might be a few ma, generally not an issue if run every couple weeks.

Never was a fan of the one wire jobs..

 

[old]

One wire or 3 wire alternator??? If one wire not all that uncommon. If 3 wire you have a bad alternator or you have the #1 wire hooked up so it is not a switched wire which it need to be since the #1 is the excite wire

 

[DavidLA]

thanks for the info!
sorry i left out some details, and sorry i've been away-- traveling-- to get back to the forum.

the alt has one large charge stud out the back, and one double pin plug on the side/edge. the double pin has #1 and #2, #1 is a small black wire, #2 is a larger red wire.

i have #1 wire to a toggle switch to a light bulb. i have #2 connected to the large red charge stud which is connected to the pos battery.

my battery is connected to pos solenoid and neg starter ground. i have a single pigtail to the starting pin on the solenoid tied up hanging nearby which acts as my jumpstart ignition switch. i have everything else disconnected.

to start the tractor, i just flip the toggle for the excite light, touch the pigtail to the pos side of the solenoid, and away she goes. the excite light comes on for just a second then goes out. after that my "ancient" meter reads at the battery posts about 2 volts higher than when the tractor was not running. so i figure i'm charging at that point so i flip my toggle on wire #1 to the off position to disconnect. so at that point all that is connected to the pos batt is the solenoid pos and the big red charge wire and #2 red pin wire.

with the tractor not running, i pulled the pos batt cable off the post out of curiosity to see if there was any current passing through. with my volt meter between the pos post and pos batt cable, i get about the same voltage reading as when i check between the batt posts.

the tractor is a diesel. i rigged this up a few weeks ago just to see if the alt was good then when it warms up i was going to wire it up all nice if it worked. in 3 weeks i've run about 10hours on the tractor, and the batt is staying charged like this, but it seems there sholdn't be any current when tractors off. it may be my ancient analog meter which i can barely see meter marks may be what i need to replace at this point. it may not be drawing much if i had a good meter to check. any help is and would be appreciated, thanks!

 

[Sean in PA]

Reading the voltage with the cable disconnected doesn't tell you anything about how much current might be flowing when it is connected. Switch the meter to amps instead of volts and measure between the battery post and the cable when the cable is disconnected and tell us how much current is flowing.

 

[JMOR]

(quoted from post at 13:10:04 01/04/15) thanks for the info!
sorry i left out some details, and sorry i've been away-- traveling-- to get back to the forum.

the alt has one large charge stud out the back, and one double pin plug on the side/edge. the double pin has #1 and #2, #1 is a small black wire, #2 is a larger red wire.

i have #1 wire to a toggle switch to a light bulb. i have #2 connected to the large red charge stud which is connected to the pos battery.

my battery is connected to pos solenoid and neg starter ground. i have a single pigtail to the starting pin on the solenoid tied up hanging nearby which acts as my jumpstart ignition switch. i have everything else disconnected.

to start the tractor, i just flip the toggle for the excite light, touch the pigtail to the pos side of the solenoid, and away she goes. the excite light comes on for just a second then goes out. after that my "ancient" meter reads at the battery posts about 2 volts higher than when the tractor was not running. so i figure i'm charging at that point so i flip my toggle on wire #1 to the off position to disconnect. so at that point all that is connected to the pos batt is the solenoid pos and the big red charge wire and #2 red pin wire.

with the tractor not running, i pulled the pos batt cable off the post out of curiosity to see if there was any current passing through. with my volt meter between the pos post and pos batt cable, i get about the same voltage reading as when i check between the batt posts.

the tractor is a diesel. i rigged this up a few weeks ago just to see if the alt was good then when it warms up i was going to wire it up all nice if it worked. in 3 weeks i've run about 10hours on the tractor, and the batt is staying charged like this, but it seems there sholdn't be any current when tractors off. it may be my ancient analog meter which i can barely see meter marks may be what i need to replace at this point. it may not be drawing much if i had a good meter to check. any help is and would be appreciated, thanks!

"....but it seems there sholdn't be any current when tractors off.".........well, it may seem that way, but that isn't the way those work. The internal VR, inside the alternator on your Delco 10-SI will always draw some tiny current whenever everything is shut down. Reason being that the sense input to the VR (#2 spade lug) is always connected to the battery (via the large charge stud in your set-up). This current is extremely small with a factory GM Delco 10-SI VR....measures 750 micro amperes (that is, 0.000750 amperes). It may be a little more with some after-market VR's and some of the one-wire VR's, of which there are many, so you should expect variations in drain. One particular one-wire that I have measured draws 1800 micro amperes. To put all that in perspective, with a 66 Amp-Hour battery (average battery), given a drain of 750 micro amperes, it would take 9, I repeat nine, years to totally drain your battery! A new battery on the shelf will go dead sooner than that. So, the point is that this tiny drain, as the GM/Delco engineers so determined, is NOT significant. In a modern automobile, this tiny drain is totally swamped by the drain of the computers in the ECM, radio memory, etc., etc. All those things added together will typically drain a battery in a matter of months. Take into account that a battery must be well above totally drained in order to have enough power to start an engine, too.

 

[DavidLA]

got it.
i guess thats why the batt hasn't gone dead in 3 weeks.
next item on shopping list is a good meter so i know exactly whats going on.
thanks for the help!