Topic: How much should a battery drain?

[scott.475]

I've been trying to solve a battery drain problem for months now. I just got a new Red Top, and the problem persists. I have disconnected all accessories, so now all the is feeding off the battery is the fuse box and starter. With just these the battery is draining at about 1/100 (.01) volt/day, and is now at 12.61v, I started at 12.67 several days ago, removing more accessories each day. I know .01 doesn't sound like much, but once it gets below 12v my truck won't start. I just disconnected the main ground, so there should be no drain now. With nothing connected, how much should I expect the battery to discharge daily?

[Willy Mammoth]

The battery should not drain down by it's self for months. Try disconnecting the negitive battery cable and use a test light between the cable and the battery post. If there is anything draining off the battery the light will light up. If all the fuses are in and the light is out then the battery has a shorted sell.

[NUb]

If you have a drain with everyting off try disconection the alternator and see if you still have it. you might have some bad diodes that are alowing a path to ground

Jeff

[Uncle Jesse]

If you have an ammeter, put it inline with the ground cable instead of the test light.  On vehicles with an ecu and stereo, you should get no more than 50 milliamps (.050 amps) of current draw on the battery.  Older toyota trucks don't have to many "always on" accesories, so look for items that should be off, like dome lights and glove box lamps.  You can also use the test light trick across fuse terminals of suspect circuits.

[scott.475 [OP]]

Thanks for the suggestions all. With ground disconnected from the battery and small ground wire disconnected from the body, I am still getting voltage when I touch the neg post to the neg wire. Disconnectin the alternator had no effect, so I guess it probably has something to do with the starter, or maybe the strap that is grounded on the engine block. This is with nothing connected to the negative post at all.

I am going to pull the starter today or tomorrow and check the grounding strap as well as the starter. I think I remember seeing a procedure for testing the starter several different ways in the Chilton's manual. I replaced the contacts a few months ago and found that one was badly corroded. Maybe the corrosion caused some other damage, causing my current problem.

Any other thoughts or suggestions you all might have would be appreciated!

[brainlessfool]

year?

[scott.475 [OP]]

 

'91 V6 3VZE

[guywithuglyyota]

I had an optima for a while, Had it in my 85 supra. I was having some really strange electrical bugs here and there, voltage spikes, drops, batt draining etc.... turned out to be a bad spiral cell in the battery. I love optimas but this one was a hand me down with an unknown past       try swapping in another battery jus tto rule it out.

[scott.475 [OP]]

It shouldn't be the battery, since I just replaced it, yet the problem persists.

[Mike D]

Have you checked the wires under the insulation to see if there is any corrosion

[guywithuglyyota]

Well if all else fails and you can afford it, I recommend a good electrical shop. It may end up being less painful to just bite the bullet and have someone else troubleshoot. I had a similar problem with my truck and it was a bad wiring harness that I had no clue about. I ended up spending over 100 bucks on miscelaneous parts, and it turned out to be a few 25 cent terminals and 60 bucks in labor to find them.  Good luck!

[GrimReaper]

The ECM and stereo both have memory and will put a very slight drain on the battery. The drain should be so slight that a test light between ground and the battery should barely light and in the day time it would not be bright enough to be visible. with a Ammeter .06 amps should be all you see between stereo and ECM.

 Get one of those solar trick charger and put it on the dash if the truck sits outside. On a lead acid its best to charge often. Not sure if the Optima is the same.

 Never cared for the Optimas because of all the weird crap I hear about them that sometimes include poor charge retention in temperature swings. Early death at 2 years. They have their place I know but the Duralasts I have run in all my cars and trucks for the last 5 years have as yet to let me down even when they sit for weeks at a time. I have a 454 Sub sitting in my drive that has not been started in 2 weeks and I know it will fire right off first try.  My wife has left lights on over night to the point no lights would come on and a charge and it was fine and doing great 2 years after that when I sold the truck (the battery was 5 in that truck). Personally if you don't have some weird sideways mounting requirement or a venting issue with mounting in a enclosed space save your money and get a conventional Lead acid. 

[scott.475 [OP]]

The quest continues. The starter contacts are still in good shape, no corrosion at all. The battery is not draining at all with nothing connected to it; in fact, it has gained .03 volts from when I tested it while connected to the starter. the positive and negative cables each show .1 ohm of resistance, even when I twist and kink them. The posistive terminal on the starter is sufficiently isolated, no resistance between it and the starter body, start switch terminal, or the cable that goes between the solenoid and the pinion/housing on the main body. I found a small dirt clod between the negative cable wire and the starter body, inside the solenoid housing, making contact with both, but I don't think this would cause the problem. SOOOOO, I think I am okay between the battery and starter and I'm going to start working my way from the starter up to the components in the cab. I think I will replace the cables just for good measure, then hook the starter all up again, but with the starter switch connected, and see what happens. 

[GRM]

Good luck. I am having the same problems. On optima #3. I keep killing cells. Seems every 6 months it gets soo low it wont recharge. Somehow, this one was able to be recharged. I even found it draining with the battery disconnected, but not enough it wont start the truck. I found my charge wire was badly corroded inside the insulation. Replaced it, and I THINK its better, but I really cant tell.

Let me know what you find. I really would love it if I didnt hear a click every time I let my truck sit for 3 days.

[scott.475 [OP]]

I will keep you posted. In the mean time, you might check into something like http://www.battery-sentinel.com/ to maintain your battery, just plug here in every day. There is also www.batterytender.com , but it is only a three stage charge cycle.

[scott.475 [OP]]

Well, wasn't the battery cable. Today with the ignition off, no key in, I checked all the fuses for voltage. I found 11.5v when I tested the stop light fuse. I can't imagine that circuti should have any voltage going through it except when the pedal is actuall applied. I pulled the fuse and am running the truck now th get the battery charged again, then I'll see if battery drains still with the fuse pulled.

[Uncle Jesse]

I believe the stop lamp circuit is a constant battery circuit.  The brake lights light up with the key off right?  Anyway, the fuse is before the stop lamp switch in the circuit.  That means that there is battery power to the fuse without the brake lamps on.  It's called open circuit voltage.  Or, the voltage present with no loads on.  I think you need to find an ammeter and install that to check for drains.  A circuit can have voltage present, but that doesn't mean that there is any current flow.  It's the current flow(amps) that drains your battery.

[kneedownnate]

  Ditto on the battery tender, if you have a garage it's pretty easy to set it up so you can just hook it up every night.  You could try putting a solar charger on top of the truck, but that's more of a maintainer than a charger.
  GRM, which optima are you using?  It's my understanding that the yellow tops like to be nearly drained then recharged, helps them to retain their memory.  I thought about running two, seperated by an isolator and a switch and leaving on my lights every now and then to drain one of them.  Not that I wanna buy two, just have two and want them to last.
  A battery tender is also a good idea too, if you aren't bothered by the beaping.  It helps to keep the plates clean and when left hooked to a battery can actually help to bring it up slightly,   Nate

[scott.475 [OP]]

Ahhhh, I think I am finally on the real trail. Things really started happening once I realized the .5 amp fuse in my multimeter was blown. After blowing 3 or 4 of the little buggers I realized that you cannot test more than a 10 amp circuit on anything other than the 20 amp multimeter setting, and that I need to take my time and make sure I am moving the red probe to the 20 amp socket on the multimeter, not the black one. Soooo, testing all the fuses for current, the only two I found that were drawing current were the two headlight fuses in the engine compartment. I have not really gotten a chance to go much deeper than that, but I did pull the headlight relay and still registered a drain, as well as pulling the fuses showed. I might be able to get into it a little more tonight.

Lesson for the day: SOME functions will still work on your multimeter even with the 1/2 amp fuse blown!