Basic Amp Draw on battery? 88 GMC 1500

[88lowrider]

Hi everyone.
I of course, looked in the worthless book I have for my pickup (oh, 1988 GMC 1500 full size step side, 350 TBI,) looking for what Should be the average Amp draw from the battery while parked.
I have one of those viper alarms and stock radio that draws a tad for memory.

I am thinking I need to take the truck back to were I bought the battery as if I come home on Friday night, park it, then Monday morning, the battery is so dead that the Alarm will almost not disarm.

I just pulled the battery cable and stuck in an Amp gauge expecting a large draw but noticed with the 30 amp meter that it almost didn't move the needle.
I put on the DMM with it on Amps (10 max) and seen that it was only .05 of a draw even with the alarm system active.

I am thinking the new battery is no good but still would like to know what the average draw should be.

All the information I have gotten from folks, I print and add to a 3 ring binder.

Of course, I did a search for this information before asking

Thanks for any help...
Joe

[88lowrider]

Originally Posted by 88lowrider

Hi everyone.
I of course, looked in the worthless book I have for my pickup (oh, 1988 GMC 1500 full size step side, 350 TBI,) looking for what Should be the average Amp draw from the battery while parked.
I have one of those viper alarms and stock radio that draws a tad for memory.

I am thinking I need to take the truck back to were I bought the battery as if I come home on Friday night, park it, then Monday morning, the battery is so dead that the Alarm will almost not disarm.

I just pulled the battery cable and stuck in an Amp gauge expecting a large draw but noticed with the 30 amp meter that it almost didn't move the needle.
I put on the DMM with it on Amps (10 max) and seen that it was only .005 of a draw even with the alarm system active.

I am thinking the new battery is no good but still would like to know what the average draw should be.

All the information I have gotten from folks, I print and add to a 3 ring binder.

Of course, I did a search for this information before asking

Thanks for any help...
Joe

Just a quick update
I had the battery checked again by someone else and it shows OK.
I pulled the Alt wires off one night to see if it made a difference.
It made none.
I pulled the Neg battery post off, put a light tester on it. When I open the hood or doors, it would come on. Once the doors were closed and the hood down as so the light would go out, I left it that way for a day - watching it.
The light did not come on but then again, the truck started right up.

IF I can see the light coming on, I will go and start pulling fuses to see if I can find one that causes the light to go out..

My big problem is, once I park the truck, pull the neg post and Check it with the DMM, its only showing that .005 draw....
Something has to be coming on later in the night that is drawing more juice.
Any ideas on something other than the Alt that may cause this??
Anyone ???

Thanks..

[piecesparts]

With all of this info, what was the truck doing BEFORE the new battery? I cannot believe that the battery being replaced started the problem, UNLESS the battery has a bad cell in it. When they tested your battery, did they put a prolonged load on it or just take it up to a full load and then tell you that it is OK. Try putting another battery in place of theone that you now have and then if it goes down, then your trouble is the truck, and not the battery. I know of nothing that will cycle on in the middle of any down time that will pull on your battery the way you are thinking. I run a memory radio and an alarm in all of my vehicles and it takes quite a little while to get the battery to drain.

[ChevyTech]

.05 amp is getting to be a high reading.
.005 amp is very low.

When doing a battery draw test using a meter between the battery post and the battery cable, there is an extra step that must be done to get an accurate measurement of the draw.

Use a jumper wire with and end connected to each of the meter leads to stabilize the system. Then remove the jumper and take a reading. Think of it as having to charge up all the capacitors in all the electronic equipment.

You may find if the battery has been disconnected for a longer time this makes more of a difference in the draw test result (with jumper) vs. (without jumper).

[88lowrider]

Originally Posted by ChevyTech

.05 amp is getting to be a high reading.
.005 amp is very low.

When doing a battery draw test using a meter between the battery post and the battery cable, there is an extra step that must be done to get an accurate measurement of the draw.

Use a jumper wire with and end connected to each of the meter leads to stabilize the system. Then remove the jumper and take a reading. Think of it as having to charge up all the capacitors in all the electronic equipment.

You may find if the battery has been disconnected for a longer time this makes more of a difference in the draw test result (with jumper) vs. (without jumper).

I will have to go back and get a good reading to start with.
I can understand what you are saying to do but being left brain, right brain, I don't always understand well. But, I can do this.

The whole reason for starting this is when I was having issues with the truck not running (bad distributor unit) I noticed that I had less cranking time after I got the truck running again.

I replaced the battery because, over a weekend, (parked Friday night, tried to start Monday) that I would have to jump start it to get her to run.

I will put the meter back on it like you suggest and get a reading.
If .05 (isn't that 1/2 of an amp?, I hate getting old) I will start pulling fuses to see where that starts to drop off to a lower or zero reading.

I remember that in the past that I could let her set for a couple weeks or even three weeks and she would start up just fine with the radio and alarm draw.

I have even tested the starter for draw to assure I am not pulling the guts out of the battery.
I have not taken a voltage check before trying to start every morning but will.

Right now, Its sitting up at the shop were I can see the light tester poking up from under the hood.
The alternator is still hooked up and due to my age, I get up three times a night to go p and I look out the window to see if the light is on.
It never came on though the night.

I have to run into town for a prescription refill so I will get a voltage check before I hook the battery back up, also check draw on the starter when starting it (its one of those inductance meters :-( but gives you some sort of idea)

I have got to were I keep a fresh battery (different post design, not side post like the truck has) in the passenger side alone with the jumper cables to jump it with.

I can't thank you folks enough as if I go to a auto repair center, they just tell me to bring it in and then just start replacing things that at times, are not necessary it seems.
If money was not object, I would just take it in and say Here, fix it.
I do like to continue to learn and try to keep the old gray matter working as much as I can.

Thanks again guys.....
Joe

[88lowrider]

I just checked it again this morning.
Remember, I had the light tester on it all night and no light come on.
I didn't think to measure what it took to light it..
Anyway the battery measured 12.45 volts.

In testing with the DMM, I put the jumper at the end of each probe, waited a few moments then pulled it.
The amperage that shows now is 0.01 and would bump up to 0.02 for just a quick moment then back to 0.01.

Now I am not sure where the .05 or .005 came from, must have been reading it wrong - or, it was .05 and something was pulling on it but from some reason, I was thinking .05 was a half amp.

Fact is, I am not really sure what the average draw is supposed to be?

I am thinking of going up to the shop area, hooking up the battery for awhile, the testing again to see if it will show up with that .05 amp draw. If it does, I will start pulling fuses until it drops.

Thanks guys.

[ChevyTech]

Now I am not sure where the .05 or .005 came from, must have been reading it wrong - or, it was .05 and something was pulling on it but from some reason, I was thinking .05 was a half amp.

I will put the meter back on it like you suggest and get a reading.
If .05 (isn't that 1/2 of an amp?, I hate getting old) I will start pulling fuses to see where that starts to drop off to a lower or zero reading.

.5 would be a half amp.
.05 would be 5 one hundredths of an amp, which is one 20th of an amp.

Fact is, I am not really sure what the average draw is supposed to be?

I went and did some testing because it has been a while since I have checked for a battery draw using an amp meter.
I misspoke because I am getting readings in the .04 to .05 amp range.

At .05 amp draw, a good battery should hold up for weeks without the truck being driven.

.05 was the max allowable for the Corvette’s of the 1985 vintage when we were testing them because it was common for the digital instrument panel would go bad and drain the battery dead.

I had an audio amplifier in one of my cars that would draw the battery dead occasionally and other times it would not. My best guess for being the problem on your truck is the alarm system.

[88lowrider]

For some reason, I don't get the emails telling me about posts?
I will have to investigate that.

My alarm system is on its own fuse. Due to me living up in the Olympic Peninsula of Washington with our closest neighbor being a mile away, privet road, gated, I tend to forget my keys in the truck.
No need to set the alarm so I will pull the fuse and try it again.

Just to Assure that battery is good, those new fangled testers are worth a hoot, I have had the battery disconnected for the last 4 days. I will hook it up this morning and see if she starts right up.

Tonight, I will pull the fuses on the alarm system (viper, no door lock, unlock) and try it again as it has been pulling the battery down Over night when all hooked up.

OH, I took the old battery (2.5 years old) and charged it up, it seems to be holding so my problem with the battery draw has happened around the time the stalling issue.
Only thing I did was replace the computer and distributor module in it - plus checking for any loose connections.
I Did pull some of those connections and use the heavy white (almost dark tan lithium) grease to re-goop some of the connections that were drying out.

Also replaced the brake light bulbs knowing that in the past, I ran onto one rig that it was the brake light causing the slow drain.
Checked the glove box light, most of the simple stuff.

I did pull all the wires off the Alt one night but that made no difference either..

Will keep you and everyone posted on my find..
Thanks for your help !!!

[88lowrider]

I disconnected the alarm system, which was not the cause.
Been Way too busy so I have been disconnecting the battery at night. Hope to get back on it soon to test.

I also checked the starter for draw, seems to be will into the OK area, no drag..
More later.

[88lowrider]

Wow.
Its hard to believe its been since 2008 when my truck started this killing the battery crap.

I just now got her out from under the oak tree and started to replace things to bring her back from the dead.

Still fighting this issue.
One new twist it seems.. Now I find out that it never really Kills the battery.
After about 72 hours, it will pull that battery down to the point the truck will just roll over, roll over, then click click click.
So, whatever it is, it does not Kill the battery but pulls it down to a point were whatever that phantom draw is, quits drawing power....??
Nevertheless, disconnected the Alt, remove glove box light, under the hood light too.

So, since this issue stated Way back when, the truck has yet another new battery in it, plus doing lots of other things to bring her back. Long Long list.

I will get the DMM on it and see what she is drawing now.