jstluise

'87 SR5 4x4 22RE

I am at school during the week, so my truck is only driven on the weekend...it sits during the week. I was having problems with the battery being dead when I got home for the weekend (accessories still worked but not enough to start). We were having cold weather, and being that my battery was 9 years old, I automatically assumed it was the battery. NOTE: In the past 4 years I've been going to school (and the truck sitting most of the time), I've never had a problem like this.

I picked up a refurbished Optima Red Top (800CCA/1000CA) two weeks ago to replace the battery. Got it all installed (fully charged) and I thought everything would be good. Well, I went to start my truck today after a week and a half of it sitting, and the battery was drained!

Here are the accessories my truck has that could be draining the battery:
-Alarm (installed 5-6 years ago) *power linked with door locks.
-Power Door Locks (installed with alarm) *power linked with alarm.
-CD Player (Pioneer...installed before alarm)

Other than that, it could just be the trucks systems that are drawing from the battery?

I got the ammeter out and took some readings:

*As it sits (alarm enabled, radio connected, etc): 20-25 mA >> 0.24-0.30 Watt (there is a flashing LED for the alarm)
*Alarm disabled: 17 mA >> 0.204 Watt
*Radio Unplugged, alarm enabled: 18-23 mA >> 0.216-0.276 Watt
*Radio unplugged, alarm disabled: 14 mA >> 0.168 Watt

*Alarm disconnected, radio disconnected: 6-7 mA >> 0.078 Watt

So it looks like radio accounts for 2-3 mA (0.03 Watt), and the alarm/door locks account for 8-17 mA (depending on if its enabled or not). Something unknown to me is pulling 6-7 mA (the ECU?).

ALSO, I should note that these readings were not taken with the battery fully charged...the battery was only around 11 volts when I took readings.

These ratings seem very small to me, what do you guys think? Does anyone know the typical current draw on a vehicle?

Like I said, in the past 4 years I've never had a problem with the truck sitting for a week (sometimes more) and driving it on the weekend. After I stuck a new (refurb) Optima in it and have the same problem, I don't know what to think. I do have a 1 year warranty on the battery.

Thanks

raddude666

take the altenator the advance and get it checked!

jstluise

I don't quite understand your sentence. Do you mean get the alternator checked? My alternator is charging, I verified this.

Besides, my problem is not that if I drive the truck around the battery goes dead (the truck is actually fine if I drive it every day, since the alternator keeps it charged), but the battery goes dead after the truck has been sitting for a while.

ZUK

iTrader: (1)

I have 2 questions...
1---how did you determine the alt wa sgood? What voltage did you measure with the truck idling?

2---For those amp values you mentioned, did you place the amp meter bwtween the battery post and the terminal connector????...someplace else?

Sportsmanphil

I assume you placed your DMM between a batt term and the batt post.

I also assume you removed the interior lamp during your testing.

Only pulling the radio and alarm isnt enough, you need to remove the fuses one at a time. Even with both the radio and alarm removed, your drain is too high.

How exactly did you elminate your circuits?

You stated that at rest you were pulling 20-25 mA...... which one did it settle on? They usually dont jump around, regardless its too much. You should be in the single digits.

jstluise

Good info here guys! Thanks.

Okay, so about the alternator. It is not an issue, since my battery is not being drained when the motor is running...if this was happening I would have got the alternator checked out before I bothered you guys. The voltage across the battery with the truck running is fine...don't remember the exact voltage but around 14.5-15V?

The DMM was placed between the battery terminal and the battery post, yes.

The dome light was not on during testing (door shut). With the door open my readings were around 500 mA due to the dome light.

Eliminating my circuits: For the alarm I disconnected the only power to the unit (this is also shared by the unit for the power door locks). When I wired up the alarm/door locks some 5 years ago I tapped off of a fuse in the engine bay...it was an easy disconnect. For the stereo, I simply unplugged the main harness plug from the back of the stereo unit.

The reason for the fluctuation (20-25mA) is because there is an LED flashing for the alarm...when the LED is off it is around 20mA and when it is on its around 25mA.

My next thing to do is removed fuses one at a time like you say. BUT, if 20-25mA is too high, and I already found that the alarm by itself pulls between 8-17mA (8mA when its disabled, 12-17mA when enabled).....so does this mean my alarm is causing a problem?

You say I should be in single digits...well without the alarm and without the stereo, I am in single digits (6mA). Still too high?

Thanks for the help...at least I know that my drains are too high and its not my new battery!

jstluise

So I was just playing around with some numbers. The Optima I have is rated for 50 Ah (before it drops to 10.5 V). If I am drawing 25 mA from this battery, ideally the battery should last for (50 Ah)/(.025 A) = 2000 h = 83 days before it drops to 10.5 V.

Even if my battery is not ideal (say 50%), it should still last for over 40 days before it drops to 10.5 V (at 25mA). So why was my battery drained in only 7-10 days?

That's why I feel like 25mA is not a big deal, but I don't have anything to compare it to.

I may be mis-using the Ah rating of the battery, but from looking around it seems like that is a standard calculation for determining how long a battery will last at a steady current draw. Please correct me if I am wrong.

Sportsmanphil

Take the B+ off the back of the alt and retest.

swampfox

Anything that you think is draining the battery try leaving unplugged during the week and see what happens.

dntsdad

Your alternator is NOT fine if it is charging at 15V, or you have some serious cable issues.

You could have a bad regulator, corroded cables, defective diodes, etc.

Check again with alt disconnected as advised.

Sportsmanphil

If is batt is weak and he has a high demand on the alt, it could reach 15v, however if the battery is floated and he isnt running anything, it should be in the 11-12 v range.

You have plenty of fused circuits to test, but nothing kills the alt. The voltage reg could be causing your drain. Take the B+ off the back of the alt (tape it up cause its live) and then retest your drain.

James Woods

iTrader: (1)

x2 on the alternator, it may seem like it is good, but they can drain batteries. Also I don't know about the older cars, but newer cars will have to sit for about 30 min to let the computers go into sleep, I tested a car once and when I first hooked it up it was at about 20 ma, let it sit and it went down to 8 ma. every time you open a door or reconnect the battery the computers would wake up and be at 20 ma again.

BigSwole

I've had several optima red tops and one thing I noticed is that once it gets killed 100% it enough where it won't crank. The battery never returns to 100%.

I left my radio on all night in a jeep I once had with the red top in it. About noon the next day I heard it on when I walked by. It started right up. But shortly after I left town with it on and over the weekend it killed it. After that it would die in just a short amount of time. Warranty replaced it.

Once again it died completely. This time in my z71. Left the lights on for a while when I was outside one night. noticed they were dim so I went to crank it. Nada. Instead of waking my neighbors at midnight with that loud truck I waited till a.m. Like 6 hours. Once again warranty replaced it.

Then I sold the truck and let them keep the battery.

So if you got a refurb and has to charge it before use. It might be bad already. Get it checked out and go from there. Hopefully you got a warranty on it.

That is just my exp. With them take it for what its worth. I just never had one last long after it was killed.

jstluise

Thanks everyone for the replies and the help. I took the battery out and charged it overnight. I will get it back into the truck and re-test (including disconnecting the alt).

Since we already determined my drain was too high (20-25mA), what is the point of doing all these tests when I know my alarm/door locks make up a majority of this drain (17mA)? Doesn't this tell me my alarm is the culprit? I don't think so but I am just wondering...

If it is at the alt, wouldn't I see drains higher than .25mA (technically 7mA because the alarm and radio account for the rest)?

Thanks for the help...I'll report back.

jstluise

When I picked up the refurb red top, it was fully charged (voltage was 12.7 I believe). That's why I thought everything was going to be fine.

I charged the battery last night (w/ voltage/amp recommendation from optima), and right now it is sitting at 12.85 volts.

I have a 1 year warranty on it, thankfully. If nothing comes from my tests I will have the battery checked out.

Sportsmanphil

Personally, I would chunk the alarm. I cant count the problems I had to solve that were alarm related.

jstluise

Okay, updates:

My battery is fully charged, and is sitting at 12.9 V. I took it in to get tested and the results were 720CCA/920MCA. When I bought the battery the case was bare (no stickers or model number). I know the case is from a 34/78 Red Top (800CCA/1000MCA), but the results from the testing match more with the 75/25 Red Top (720CCA/910MCA). Either way, the battery is good.

So here is what I did. Hooked up the DMM and starting eliminating circuits one by one. Here is the order of eliminating and the resulting change in current.

Starting: Alarm/Door Locks hooked up, alarm disabled. Radio plugged in. Key is off. Dome light is off. Door is shut (there was a slight change if the door was open, because the alarm senses the door position).

-----------------
Starting current draw: 21.1 mA

Disconnect Radio: 18.0 mA (3.1 mA)
Disconnect Alarm/Door Locks: 9.35 mA (8.65 mA)
Pull Fuse #9 (15A): 5.23 mA (4.12 mA) EFI Circuit
Pull Fuse #8 (15A): 5.23 mA (0 mA)
Pull Fuse #7 (15A): 5.23 mA (0 mA)
Pull Fuse #6 (15A): 5.23 mA (0 mA)
Pull Fuse #5 (15A): 5.23 mA (0 mA)
Pull Fuse #4 (15A): 5.23 mA (0 mA)
Pull Fuse #3 (7.5A): 5.23 mA (0 mA)
Pull Fuse #2 (7.5A): 0.40 mA (4.83 mA) Dome Light Circuit
Pull Fuse #1 (15A): 0.40 mA (0 mA)

Pull AM1 Fuse (40A): 0.20 mA (0.20 mA)
Pull AM2 Fuse (30A): 0.20 mA (0 mA)

Pull Headlight Fuses (10A): No change
Pull Charge Fuse (7.5A): No change
Pull Haz/Horn (15A): No change

Lastly, disconnect Alt: 0.00 mA (0.20 mA)
---------------

So, besides the alarm and radio:
Alarm/Door Locks (disabled) >>> 8.65 mA draw
Stereo >>> 3.1 mA draw
Fuse #9 >>> 4.12 mA draw
Fuse #2 >>> 4.83 mA draw This could be because I had the dome light switched off (bulb not removed) but I had the door open when I was pulling fuses. I will re-check this. I rechecked this and no matter if the door is open or closed (light turned off), the "dome light circuit" is always pulling 4.83 mA. So my question is, what else is on the dome light circuit besides the dome light? Anything?
Fuse AM1 >>> 0.20 mA draw
Alt >>> 0.20 mA draw


My battery was at 12.9 Volts. After all the testing, I put everything back together and started it up. I let the engine get to operating temp and checked the voltage across the battery >>> 14.5 Volts. So is this too high? My volt gauge in my truck has always been the same (ie the reading before and after starting the truck is always the same). Optima recommends the alternator to be charging between 13.3 V - 15V. It seems that 11-12 V is too low, especially when the nominal voltage of the battery is 12.8 V.

Just checked the FSM. The specs say the alternator should be putting out 13.9V to 15.1V. Looks like I am within spec.

Thanks for the help.

There is a reason I put an alarm in my truck (it was stolen twice before I had the alarm). The alarm has saved my butt a few times since, so I am glad I have it and do not want to get rid of it.

Sportsmanphil

As for the alarm, in a prior life I owned a tow service and yes, repoed cars. The hardest cars to drive off were not the ones with alarms, it was the cars with a hidden kill switch.

They are simple, a soft touch button that has to be held while cranking. However this might be a PITA on a vehicle used off road.


BTW, alarms usually do not sense door position, they are triggered by the interior light activiated by a closed door switch.

Looks like the issue is between your alarm and door circuit. BTW,, see if you have a glove box light.

Also, if your alarm has a battery backup, take it out.

camo31_10.50

do you mind telling me where your volt gauge sets with your truck running?

with my 4runner running (3vz, all stock basically, atleast electrical wise) mine sits wayy towards the right of the gauge...??? not sure if it should or not, i figured it should sit closer to the middle....

reason i ask is because here within the past month or so, my battery will die over a 2 or 3 day period...need to figure it out....lol

130amp MR2 alt here i come

jstluise

I have a hidden kill switch too

I usually try not to keep valuables inside my truck, but on a hunting trip my passenger side window was busted out by some idiots. Luckily my alarm scared them off, saving my GPS, camera, and other stuff that was in the truck. Yes, they wouldn't have been able to drive the truck because of the kill switch but without the alarm all my stuff would have been gone. Just an example why I like my alarm.

When I said "senses door position", I meant that the alarm is linked to my door switches that trigger my interior light...like you say. The alarm is tapped into the wire going to each door switch, and when the door is open, the wire is grounded via the switch and the alarm unit knows that a door is open. This is the only connection the alarm unit has to that circuit, so I don't see a problem with it. If there was a problem with that circuit being grounded, my dome light would be on also.

I do not have a glove box light...I wish I did sometimes.

I'm still puzzled why my dome light circuit is drawing from the battery. I unplugged the "seat belt warning relay" since it is linked to the dome light circuit, but it did not change any readings.

Regardless what is drawing from that circuit, it is less than 5 mA. About that same as the ECU circuit. I am still looking back and those calculations and wondering if 25 mA is enough to drain a battery like that....uhg I hate debugging electrical issues!

I just checked a friends '90 4runner (3VZE) and he is pulling 14 mA. This is comparable to mine since he does not have an alarm installed on his. If I didn't have an alarm we would have roughly the same numbers. Beats me. I am going to hook everything up like normal and monitor the battery voltage throughout the week.