55.2-59 Battery draining

[Phungki]

So my battery completely drains overnight. I only have the ignition, starter, distributor and alternator hooked up. Just what is necessary to turn the key and start it. Its a new painless wiring system. The key is taken out so its not accidentally left on acc. Im new to this vehicle restoration stuff. Some days its a lot of fun and some days I think I’m spending money just to be frustrated.
I don’t understand why a battery drains overnight with so little hooked up.
Im using a new optima redtop if that matters

[leegreen]

Disconnect the battery, does it still drain? Then the battery is shorted inside.

If battery is good, then you have a sizable power draw to drain it overnight.
Disconnect battery negative, put a test light or multimeter between battery and ground, Can you see current? Disconnect other circuits (or pull fuses) one at a time until the test light goes out.

The starter, alternator and power to ignition switch, are likely culprits, but there are also some points that always have power regardless of ignition switch, depending how much you have wired or is prewired in the kit harness:
brake lights
4 way flashers
horn
headlights
dome light
maybe other things. You may not have these wired, but the circuits will be live in the fuse block, whatever wires are connected to it and probably inside your steering column if you have a newer column and have the column plugged in.

[unclebrad]

I ended up putting in a simple battery cutoff.

Top Post Battery Disconnect Switch, Qiilu Power Battery Disconnect Switch Negative Terminal

https://www.amazon.com/dp/B0B1TP732B...roduct_details

https://67-72chevytrucks.com/vboard/...1&d=1687017136

[Phungki]

Originally Posted by leegreen

Disconnect the battery, does it still drain? Then the battery is shorted inside.

If battery is good, then you have a sizable power draw to drain it overnight.
Disconnect battery negative, put a test light or multimeter between battery and ground, Can you see current? Disconnect other circuits (or pull fuses) one at a time until the test light goes out.

The starter, alternator and power to ignition switch, are likely culprits, but there are also some points that always have power regardless of ignition switch, depending how much you have wired or is prewired in the kit harness:
brake lights
4 way flashers
horn
headlights
dome light
maybe other things. You may not have these wired, but the circuits will be live in the fuse block, whatever wires are connected to it and probably inside your steering column if you have a newer column and have the column plugged in.

Thank you for the response. I have taken out the battery. It was sitting on a trickle charger for a few hours before I removed it. Does the alternator usually get warm when its charging? Never noticed it before but it was pretty warm. It’s garage kept and not warm inside the garage

[_Ogre]

check the alternator rectifier. if one of the diodes goes bad it will drain the battery

[mr48chev]

A blown diode will cause the battery to drain.

First, take you volt meter and put the positive lead on the positive post and touch around the top of the battery with the negative lead to see if you have any drain across the top in dirt/moisture. If the battery top is dirty this can happen. I've seen one that drained in a little over two hours as it had over a 9 volt drain across the top of the battery.

[leegreen]

Warm alternator: Sounds like either a bad alternator or possibly a wiring error and you are providing voltage to the field coil when ignition is off

[mr48chev]

It takes about five or ten minutes to unbolt the alternator and pack it down to a parts house with an alternator tester. Test, don't start assuming.

Disconnecting the battery overnight is testing,

Checking across the top of the battery with the volt meter is testing.

Having the alternator tested on a test machine is testing.

Walking out a couple of hours after you put it away to see if maybe for some reason the pedal has dropped and the brake lights have come on is testing/checking.

[joedoh]

does your radio lose its memory when you turn the key off?


I have done a bunch of trucks and probably thousands of radios, and I can say with certainty that some aftermarket harnesses and ALL GM harnesses (aftermarket are usually based on GM) have a common wiring anomaly in the radio harness where the CONSTANT 12v is orange or red and the IGN wire is yellow, which is exactly backwards of the EC standards aftermarket radio wiring harness where the constant 12v is yellow and the IGN is red.

so you can see what happens, people hook yellow to yellow and red to red. which lets the radio work fine except the presets go away every time the key is cycled. it also drains the battery because the radio is "on" but not on when the key is off.

i cant say with certainty that this is your problem (you may not even have a radio installed) but knowing this anomaly maybe you have something else installed that requires a constant and an ign both, or something that requires either that can possibly be wired as 12v constant that should be IGN.

[franken]

Originally Posted by Phungki

Thank you for the response. I have taken out the battery. It was sitting on a trickle charger for a few hours before I removed it. Does the alternator usually get warm when its charging? Never noticed it before but it was pretty warm. It’s garage kept and not warm inside the garage

How does removing the battery change anything? Not at all. Just disconnect the wires/cables.
If the alt gets warm when the engine isn't running it's a problem.
You can disconnect the firewall connector while measuring battery current for a quick check.

[mr48chev]

Originally Posted by Phungki

Thank you for the response. I have taken out the battery. It was sitting on a trickle charger for a few hours before I removed it. Does the alternator usually get warm when its charging? Never noticed it before but it was pretty warm. It’s garage kept and not warm inside the garage

Yes it is normal for an alternator to get warm when the engine is running and it is charging,

Remember TEST DO NOT THROW MONEY AT IT. Going out and buying parts to replaceparts that you aren't sure about is not testing.

If you aren't sure about how to do something the right way you can PM me with a question any time, That goes for everyone else too. I do not give BS answers that will mix someone up. I don't believe in that .

[dsraven]

my first check would be to see if the alternator is wired correctly. if that checks out correctly with both a visual wiring trace and also a voltage test to check if the wiring is working as it is supposed to with key on and key off. sometimes new doesn't mean correct. if it still has a draw with the key off then the second check would be to remove the alternator and have it tested. the alternator shouldn't be getting warm with the key off, like LG says in post 7.
phungki, post 4, are you asking if the alternator should get warm with the engine running and alternator charging like usual, or are you asking if the alternator should get warm with the engine off and a battery charger connected? if the latter then the answer is no. alternator should not get warm with key off and a battery charger connected. that is why I suggested to check the wiring for a possible crossed wire or a fuse panel error from the factory and also do mechanical tests for what the wiring is actually doing at the alternator plug with key on and key off-alternator plug disconnected while testing for powered circuits and while key on and then with key off.
you could pull the alt for testing but if the wiring to the alt is incorrect for some reason then the alt will test fine. testing it would be for peace of mind so not a bad thing for time spent
have you checked for powered circuits at the fuse panel when key is off? sometimes things get done wrong from factory or maybe a circuit got inadvertently overloaded and melted some circuits together where you haven't seen them yet. pinch points and places where the wiring passes through something like firewall would be a good place to look

[Phungki]

I removed the battery because leegreen said it could have a short. Never ran into that before and it came off the shelf fully charged but its an easy test. It stayed fully charged. Battery test complete.

I disconnected the alternator. The battery still died overnight. So its not the alternator. Alternator checks out.

There isn’t a radio or any lights hooked up (or even in the truck) so its not that stuff.

I appreciate the suggestions

[dsraven]

I would suggest to use a volt gauge inline with the battery cable and the battery. Disconnect one thing at a time with key off while checking the volt gauge for a drop. Check the state solenoid as well. What have you got for ignition system, fuel system etc. Are there relays? Sometimes a relay welds its contacts closed and keeps the current flowing even though there is no signal to the relay from the ignition.

[Phungki]

Originally Posted by dsraven

my first check would be to see if the alternator is wired correctly. if that checks out correctly with both a visual wiring trace and also a voltage test to check if the wiring is working as it is supposed to with key on and key off. sometimes new doesn't mean correct. if it still has a draw with the key off then the second check would be to remove the alternator and have it tested. the alternator shouldn't be getting warm with the key off, like LG says in post 7.
phungki, post 4, are you asking if the alternator should get warm with the engine running and alternator charging like usual, or are you asking if the alternator should get warm with the engine off and a battery charger connected? if the latter then the answer is no. alternator should not get warm with key off and a battery charger connected. that is why I suggested to check the wiring for a possible crossed wire or a fuse panel error from the factory and also do mechanical tests for what the wiring is actually doing at the alternator plug with key on and key off-alternator plug disconnected while testing for powered circuits and while key on and then with key off.
you could pull the alt for testing but if the wiring to the alt is incorrect for some reason then the alt will test fine. testing it would be for peace of mind so not a bad thing for time spent
have you checked for powered circuits at the fuse panel when key is off? sometimes things get done wrong from factory or maybe a circuit got inadvertently overloaded and melted some circuits together where you haven't seen them yet. pinch points and places where the wiring passes through something like firewall would be a good place to look

I was asking about the alternator getting warm with the engine off and just a charger on it. I did remove the wire that goes from the alternator to the battery. Battery still drained overnight.

I have not checked the fuse panel yet. I will trace the wires and see if anything is shorted. I use rubber grommets when passing thru the firewall. Could be something going on with the 50 other wires I don’t have hooked up yet. I did cap all the ends so they couldn’t short out.

Thank you

[leegreen]

Sounds like enough of a power loss that if you disconnect the ground wire from battery and wire a test light (or headlight etc) between battery and the disconnected battery ground cable it should light up when the key is off.

For a very small current leak you might need to use a LED or a multimeter, but this sounds like it is bigger than that.

then start unplugging things, wiggling wires until you find something that makes the light go out.

[dsraven]

If the alternator is getting warm with the key off then it is getting power from somewhere. Totally disconnect it then check which wire has power with the key off.

[dsraven]

curious, without going through your build thread, what engine do you have and how is the starter/alternator/ignition switch wired up? a couple of pics would be great just so we can see what kind of vintage/era of equipment you have. do you have an old fashioned key switch on the dash with screw on connections or a column mounted ignition switch with a plug in down the column? what sort of starter solenoid do you have, is there a relay anywhere in that system? are you running an electric fuel pump and if so is there a relay in that system? is there an ecm or are you running a carb? is there a spark at the terminal when you disconnect the battery after running it? if you have ANY relays connected check them for proper operation with a test light. possibly one is not turning off due to welded internal contacts even though the wiring to the relay is correct.
here is how I would start
run the engine for a minute then shut it off like normal. does it shut down immediately or try to run on?
go to alternator and do power checks at each connection to see if any are still hot. obviously the battery feed wire will be. carefully disconnect the battery feed wire and put the test light inline with that wire and the alternator terminal it came off. does the test light come on, even dimly? if it does that would indicate a power draw from inside the alternator.
go to battery and disconnect one terminal watching for that spark, which would indicate a power draw somewhere. next install the test light or a volt meter between the battery terminal and the cable. does it light up with the key off? if so there is a draw.
go to the ignition switch and disconnect the main power feed wire. is there a change to the test light at the battery? (assuming it was lit due to a draw in the system) if so then reconnect that wire to the switch and disconnect another wire, one at a time, until the test light goes out. that will be the circuit that is still powering something. now you can see which circuit is still being powered and if it is a switch problem or a circuit problem.

[mr48chev]

Originally Posted by dsraven

If the alternator is getting warm with the key off then it is getting power from somewhere. Totally disconnect it then check which wire has power with the key off.

Alternators always have power to the Batt post on the alternator.

One wire alternators have a built in excitor that is usually triggered when you rev the engine when you start it. Those were originally designed for farm equipment with diesel engines or magnitos that don't have battery ignition systems.

The exciterwire in a normal three wire alternator usually connects to the ignition side of the igniton switch and has either a diode or idiot light in the line to keep the alternator from feeding back to the ignition and keeping the truck running after the key is shut off. We have answered a few of those (I put an alternator on and now it won't shut off) questions over the years that we both have been on here.

Phunkie is just like about half of the 700 beginner high school auto shop students I taught over 13 years. A lot of want to but limited skills because he most likely wasn't around anyone who was able to teach him a lot. It's up to us to give solid and simple step by step instruction on how to test things like this out and so far in this thread we have done that.

I preach "test rather than replace" a lot because over the past 60 years I have seen too many guys waste too much money on things that they changed but didn't need changing as their test method.

Charge the battery and let it sit disconnected and check it to see if it is holding voltage = that is testing. No cost unless you have to pay somone to charge the battery.

Checking the top of the battery with your volt meter (multimeter) to see if you have a drain across the top of it in the dirt and moisture if the top is dirty. Again testing. Plus an easy fix, Clean the battery.

Taking the alternator off and taking it to a parts house or auto electric shop to be tested. Good test Put it back on, test bad either fix it or replace it.

Thinking back, Did you add anything to the truck that ran on electricity between the time it worked good and the time the battery started draining?
Anythign like parts for the sound system, backup camera, or other accessories?

[Phungki]

Dsraven and Mr48 chev, thx for the ideas. I’ll get back on here with pictures.

Mr48chev not far off. I don’t recall there being auto shop in the schools I went to and there definitely wasn’t anyone showing me anything growing up. I fumbled thru changing minor stuff, alternators, mufflers, brakes and other simple things. Always did my own stereo stuff but nothing crazy electrical. If I can see it done then I can mimic easy enough.

It does have a carb and an Hei distributor, Mechanic fuel pump. No electric fans no stereos no lights of any kind. Literally only what I need to turn the key and start it.

Thx ya’ll I get some pictures

[dsraven]

seems like you have something feeding your alternator juice with the key off. do you have an alternator with one large cable that feeds the battery and then a smaller rectangular plug on the side? like this set up shows?
https://smithcoelectric.com/blogs/te...wiring-diagram

[mr48chev]

Originally Posted by Phungki

Dsraven and Mr48 chev, thx for the ideas. I’ll get back on here with pictures.

Mr48chev not far off. I don’t recall there being auto shop in the schools I went to and there definitely wasn’t anyone showing me anything growing up. I fumbled thru changing minor stuff, alternators, mufflers, brakes and other simple things. Always did my own stereo stuff but nothing crazy electrical. If I can see it done then I can mimic easy enough.

It does have a carb and an Hei distributor, Mechanic fuel pump. No electric fans no stereos no lights of any kind. Literally only what I need to turn the key and start it.

Thx ya’ll I get some pictures

Well we try to help you learn the best we can one step at a time. This bunch is one of the better ones as we don't have those clowns who think it is funny to give bad information just to be the jokester like some groups have.

The real good thing about nothing fancy on the truck is that there isn't much to go wrong and figuring it out gets a lot easier.

[mobileortho]

I'm having a similar issue with an Optima Red top. I fully charge it , yet it dies when trying to start the truck. It checked out as being good at the parts store but that obviously cannot be right. I can start it by boosting it off, but otherwise, it's dead.

[dsraven]

Sometimes the parts store has a dinky little digital battery condition tester. Yup, all good.
The best way to actually test a battery is to fully charge it, let it sit for a bit with no charger attached so it can off gas the flammable gasses, then load test it at room temp with a tester capable of applying a load of half the cold cranking amp rating of the battery. For 15 seconds. During this time the battery should not get below 9.6v. If it does its toast.

[dsraven]

Another reason for that, mobileortho, is a voltage drop between battery and starter. Check/clean all your connections. A poor starter solenoid internal connection can also cause havoc. Load test battery, do the connections and cable checks, then do a starter draw test. This basically checks what the starter is drawing while cranking the engine. Engine needs to be set up so it wont attempt to start and skew the load test. No fuel, no ignition.