Battery always dead

[JohnM]

Hello All,

I was wondering what test or suggestions you might have in regard to my battery always being dead. I have had the alternator checked and it tested OK

I put it on a battery charger and it fires right up etc, If it sits for 7-10 days not enough power to kick it over. The only thing electrical that is running is the second hand on a dash clock

Looking forward to any ideas

thanks

John

[joe g]

You have an electrical short somewhere in your system,or the battery ground wire maybe loose or dirty where it connects as a ground.
joeg

[JBCOBRA]

Hi John
I had that problem too.
Checked everything, still ended up being the alternator. The alt charged great, but killed the battery over night. The internal regulator was very sensitive with no internal switch. I should have bought regular stuff, instead the Nascar stuff.
Live and learn.

[DAVID GAGNARD]

Originally Posted by JohnM

Hello All,

I was wondering what test or suggestions you might have in regard to my battery always being dead. I have had the alternator checked and it tested OK

I put it on a battery charger and it fires right up etc, If it sits for 7-10 days not enough power to kick it over. The only thing electrical that is running is the second hand on a dash clock

Looking forward to any ideas

thanks

John

My 65 Mustang does the exact same thing, only thing "on" is the clock/radio settings drawing power... My car sometimes sits for 2 weeks or so and will not start it,but does turn the battery over too slowly.....

It may take a while, but pull out one fuse at a time, start with the one that handles the clock, that way by doing it one at a time, you can isolate the problem to one circuit....once you find the "bad" circuit, then began disconnecting things on that circuit one at a time to fing the offending source..........

it's slow process, but it works...........

David

[Dangerous Doug]

Break out the DMM and set it to Amps.

Shut everything off, then pull one side of each fuse up, and then touch the DMM leads one to the other end of the fuse, and one to the clip. Look for any current flow.

DD

[mickmate]

If you don't have a Digital Multi Meter you can disconnect one side of the battery and put a test light in series with it. If it lights (glows dimly) you have a current draw. Then go through the fuses one by one and the components on that circuit as suggested till the light goes out. Good hunting.

[Blas]

Have you had the battery load tested? Could be a bad cell.
A short would tend to blow fuses, or melt wires...

[FWB]

Originally Posted by JohnM

Hello All,

I was wondering what test or suggestions you might have in regard to my battery always being dead. I have had the alternator checked and it tested OK

I put it on a battery charger and it fires right up etc, If it sits for 7-10 days not enough power to kick it over. The only thing electrical that is running is the second hand on a dash clock

Looking forward to any ideas

thanks

John

had the same issue it ended up not being a slow drain on the battery.
the distance between the battery and the alternator made the wire size a critical factor. the alternator wasn't pumping enough juice rearward to fully recharge the battery. between the fans and the msd i was slowly draining the battery driving and i wouldn't notice unless i was starting the car. i am using a one wire alternator, i used heavy guage wire from positive battery right to the alternator post.
just check charging volts at the battery not at the alternator to verify this you should get 13.5-14.0 at the battery to have the battery charge.

just my 3 cents

Fred

[JohnM]

Thanks all for the suggestions, they all make sense. On the next rainy weekend...or this fall!!

I will start to isolate the problem and see what happens

regards

John

[mickmate]

John's got the best suggestion, drive it now and work on it in fall. Atta boy!

[kobrabytes]

Install a battery disconnect switch in the mean time.

[Slick61]

Originally Posted by kobrabytes

Install a battery disconnect switch in the mean time.

Amen... I always throw my battery disconnect once the cooling fans have shut off.

[Cobra #3170]

Originally Posted by JohnM

Hello All,

I was wondering what test or suggestions you might have in regard to my battery always being dead. I have had the alternator checked and it tested OK

I put it on a battery charger and it fires right up etc, If it sits for 7-10 days not enough power to kick it over. The only thing electrical that is running is the second hand on a dash clock

Looking forward to any ideas

thanks

John

This is a shot in the dark, but if you have an MSD ignition and if the main feed wire (heavy gage red wire) is not fed through a relay or other switched source. The MSD will drain the battery in about a week even if the control wire from the ignition switch is off. I use a battery disconnect switch because of this and have used the same Optima battery now for 5 years with no problems even after letting it sit for 6 months with out charging.

[DAVID GAGNARD]

This is a shot in the dark, but if you have an MSD ignition and if the main feed wire (heavy gage red wire) is not fed through a relay or other switched source. The MSD will drain the battery in about a week even if the control wire from the ignition switch is off. I use a battery disconnect switch because of this and have used the same Optima battery now for 5 years with no problems even after letting it sit for 6 months with out charging.

Could be,cause I'm runing an MSD system in my car, never thought of that.........I just disconnect the battery when I know I'm not gonna use the car for more than a week........

BTW: my Optima battery is 6 or 7 years old....I just put the positive cable back on and it fires right up, haven't charged the battery is at least 5 years............

David

[HI Cobra]

David - that is exactly what I do with my CR, and get the same results.

[Blas]

My car can sit for weeks without the MSD draining the battery. My MSD main feed comes straight off the hot side of my main circuit breaker.
I would suggest you look further into this if you think your MSD is your problem...or just keep using the battery cut-off switch...

[DAVID GAGNARD]

I don't know if it is the MSD or not, mine is wired per the instructions, did it too many years ago (at least 10 years) to remember how.....

At the time, I also changed my dash panel/gauges (65 Mustang fastback) from the factory panel to a custom made panel with analog gauges, also added a JVC radio with a clock and the memeory thingy for the radio settings, that's when it would run the battery down, takes at least 2 weeks......

I chased down some stuff and found one thing and fixed it, but it kept doing it, so it is too easy just to pull the positive cable off the battery, so, being a lazy fellow, that's what I started doing and since being in the habit, it's no problem for me, but still didn't fix the problem, and after 10 years, it'll probably never get fixed correctly by ME............

David

[Blas]

I'm sure all have you have searched for the source of this issue on your cars. I would probably approach the issue in the following ways.
Have you ever just disconnected the MSD box for the usual period of time required to drain the battery? Same thing for removing one fuse at a time for the same duration. At lease you would determine the circuit the drain is assosiated with. The most common things I've seen are: a bad cell in the battery, improper charging because of a faulty voltage regulator, bad alternator, improper cable sizes, wrong location for wire connection from voltage regulator...and the biggest electrical problem...bad/undersized grounds. Hope you find it or a good work around...

[JohnM]

A quick update. I do have an MSD ignition, and a battery disconnect. I have the radiator fan on direct feed so that it can run when I put the car away in garage after driving with the battery disconnected. The fan takes alot of juice to run but doesn't run very long after the car is put away..just 2-3 minutes

The only other direct wire is the clock with it moving second hand.

I will look into this MSD situation

thanks

John

[mickmate]

A fan cooling a shut off car with no coolant being circulated never made any sense to me??????