Still have a battery drain, ideas?

[Bushwick]

95' Legacy wagon. Alt was replaced as was the battery. No radio in the car. 

 

 

I thought it might have been something wonky with the power locks, so I pulled the underhood fuse and still getting drained after 24 hours. I do have a seat heater from a 97/98' Outback, but that's a key-on only via cig lighter. No lights are staying on. Thinking it has to be something connected to the engine at this point. Ideas? 

[idosubaru]

disconnect alternator and see if the drain stops.

disconnect battery as well and make sure the battery isn't weak/problematic?

 

have you tried testing for the drain?

disconnect terminal and place a meter between the terminal and battery post and measure how many milliamps of drain it has?

(keep in mind that leaving the door/trunk open will cause increased draw through interior lights or other interior items that work with key off like automatic seat belts in an XT6).

 

then start pulling fuses until it drops - issue will be on that circuit.

Edited December 21, 2017 by idosubaru

[Bushwick]

I'll put battery on charger today to double-check it's health. It's the 2nd one this year (gotta love 5 year warranties), and was just put in. Last one was staying around 11.5 volts (disconnected) and would drop rapidly after a charge. No interior lights. Car is a spartan winter vehicle atm to avoid salt on other car. It's falling apart and what's left of body probably won't make it longer than this winter, but having the dead battery constantly is annoying.

 

I'll check the drain via the cable method and see what happens.

[1 Lucky Texan]

is there 12V unswitched supplied to the hatch? maybe an abraded wire in the boot from the body to the hatch?

 

same question about trailer wiring...is it a possible drain?

[idosubaru]

To get through winter find the fuse that’s causing it and pull it out or toss that fuse on a switch conventinetky installed. That’ll get you through a winter easily without much effort.

 

I had a pair of small needle nose on my drivers side floor one winter just to get to summer when it was more convenient to troubleshoot.

[sirtokesalot]

get a 12v light bulb unhook the positive battery terminal hook one end of the light bulb up to the battery cable and the other end of the light bulb to the battery terminal. the bulb will be glowing if u have a drain occurring. start removing fuses one at a time until the bulb goes out. relays can cause drains as well ive seen it so pull relays as well. when u find the fuse that is causing the drain then u have to go through that circuit and start un plugging the items on that circuit one by one until the light goes out again and that would be the source of your drain.

[rocketman]

Very good on light bulb trick,I have same problem on my winter rat so I take negative battery cable off when not in use.

[1 Lucky Texan]

why the battery replacement so quickly? maybe an alternator problem.

[forester2002s]

+1 on alternator diodes being faulty.

[Bushwick]

I had a 130 amp alt. from a Tribecca (casing needs some dremel work to physically fit, one extra rib on pulley closest to radiator is unused if you leave Tribecca pulley on, but otherwise it's 100% straight with narrower factory belt alignment; really hard current pulls can stress the slimmer belt to squeak so a little extra pre-tension is needed as well excellent belts) on for years and accidentally shorted a couple of it's diodes after the alt. 12v+ constant trigger "on" hit the casing. Diode(s) was shown as bad through multimeter. I swapped in a tested junk yard alternator from I think a 97' (was already pulled). I verified it's diodes were OK (no back current) and that it charges, though I think they swapped the factory plug around from a 95'? I have a soldered in wire on a spade lug for the trigger as the 95' plug wouldn't work with the Tribecca alt.

 

 

Car sat for several months and battery was toast. Replaced battery. Started car one time with that battery and 130 amp Tribecca, then drove around the block to make sure it'd be OK for snowfall, then parked it with battery disconnected. Once other alt was procured, I pulled my battery charger out and let it charge. That battery went to 100% charge, but would drop to 25% charge sitting out of circuit in roughly 30 minutes. Also noticed it's sitting voltage was in the middle 11v range, so took it back and got another (all under a 5 year warranty from the 1st).

 

Now, with the newer alt and battery, I'm still getting a drain. 

 

Haven't been able to test the pos+ cable off for the actual drain yet, but will try soon.

[Bushwick]

OK, either the guy that gave me the battery (most recent one) GAVE me the same battery back replete with a red cap on the terminal, or something is just destroying these batteries almost instantly. Battery voltage was back in the mid 11v range almost immediately after shutting the engine off (I could see the voltage just ticking down). 

 

Before returning this one and making a fuss to them as I can't really do a drain test, is there anything you guys/gals can think of that would legitimately drain a battery so HARD it just insta-kills it? Do 97'-ish alternators also get a constant 12v+ ON to the terminal plug like a 95'? 

[Bushwick]

Nvm, battery rebounded and appears OK.

 

 

Tried the milliamp setting between the positive post and disconnected cable clamp, and got a 0.00, so maybe it's intermittent atm? Kinda stumped as this thing has been draining the battery hard.

[idosubaru]

I bet it’s the alternator causing all this grief.

 

Subarus sells alternators for $60-$80 for 96ish legacies.

 

0.00 means the test is inaccurate as all cars have a parasitic drain from computers, clocks, stereos, device memories, etc.

 

You have to be really careful it’s easy to blow the meter fuses (or the meter itself) trying to measure milliamperes. If any light or system in the car was on (door open, etc) then the second you attached the cables the fuse or meter blew.

[Bushwick]

Car has no radio, no clock, no interior bulbs. Alt tested OK when it was installed (no bad diodes, and it's charging) and door lock fuse underhood is pulled.

 

I'll try and find my test light and see if it comes on. 

[idosubaru]

Got it. I’d still be suspect of the alt but sounds like you’re confident.

 

People have said the ECU and TCUs also have a parasitic draw, if that’s true then you should still show something. But I’ve never verified if that’s true or not. There’s also glove box and trunk lights.

[Fairtax4me]

Nvm, battery rebounded and appears OK.

 

 

Tried the milliamp setting between the positive post and disconnected cable clamp, and got a 0.00, so maybe it's intermittent atm? Kinda stumped as this thing has been draining the battery hard.

bad connection or the meter fuse blew.

The computers in the car will pull a few amps turning on after a battery disconnect.

 

Two quick tips: 1 you should be working with the Negative terminal, not the positive. Disconnecting the positive you're leaving a closed ground and possibility for a voltage short to ground through your meter if you drop a meter lead which will either blow out your meter or at the very least blow the fuse in the meter.

Two, when connecting the meter leads between the battery and cable you're running all current for any electronics/computers in the car through your meter. This initial connection can be too much current for most meters to handle which can either blow the meter or fuse(s) in the meter.

To safely work around this take a 14-16awg wire about 18" long and strip back about 4-5" of insulation on one end. Disconnect the battery Negative cable, wrap the long wire end around the negative post and twist it on itself to keep it tight around the base of the post. Clip the black meter lead to the other end of the wire.

Reconnect the negative cable to the battery. Then clip your red meter lead to the negative cable. Turn the ignition On, then back off and be sure to remove the key. Now remove the negative cable from the battery and set it aside taking care not to dislodge the red lead from the cable, or the black lead/wire from the battery post. Initial readings may be 200mA or more depending on how much current the various computers draw during their idle/awake stages. After a few minutes you should see that drop as they fall into sleep modes and draw less current. Eventually they will all be in sleep modes and current draw should be less than about 30mA. Typically this takes 10-15 minutes (but some vehicles such as GM can take several hours). Once you're sure all computers are in sleep mode and current is still high start pulling fuses in the underhood fuse box to narrow down which circuits may be drawing too much current.

 

If your meter still reads 0.00 the current draw may be too high for the meter to read properly. In that case, try the 10 A current setting on the meter (be sure to properly reposition the leads on the meter if necessary). If it still reads 0 after that then you either have a major draw, which will pretty much only come from one place, or the meter/ internal fuse is blown.

[Fairtax4me]

Got it. I’d still be suspect of the alt but sounds like you’re confident.

 

People have said the ECU and TCUs also have a parasitic draw, if that’s true then you should still show something. But I’ve never verified if that’s true or not.

 

They do. When they're asleep it's not enough that I would consider them to be parasitic. A battery left on its own in storage will have enough internal resistance to drain itself below its ability to start an engine in about a year. One left in a vehicle parked outside, even disconnected, about 6-8 months. A ~15mA draw from computers will typically take about 5 months to drain a battery below starting ability.

[Bushwick]

Finally got a bulb in my test light and tested on the neg cable. Light was bright. Pulled all relays and underhood fuses, no change. Pulled the alt "on" trigger and light went out. Triple-checked and each time light went out/on.

 

IS there something that changed with alternators between 95' and 97'? A 95' has an always "on" trigger hot-side, right? Both alts are/were (factory 95 and 97; not referring to 130amp Tribecca one) a 2 wire plug. One is for dummy light, other is "on"? 

Edited January 5, 2018 by Bushwick

[Fairtax4me]

Bad diode.

Replace the alt.

[idosubaru]

Yep, my first sentence in three different posts all pointed to alternator.

 

Do online listings say they’re the same alt?

 

I would assume 95 and 97 the same but I think 95s do have a couple of odd differences from 96 I jus can’t recall what they are. if the plug is the same I would think the 95 and 97 would be Interchangeable.

 

If you’ve had multiple similar failures I would be looking at wiring issues or asking fairtax and others if something can cause the diodes to fail?

[Bushwick]

Diodes are not bad. They were checked before installing, and checked again just now. .457v one way, no voltage when reversed, no display change to show a short. 

 

 

 

DO later alternators have a constant hot trigger "on"? What side of the plug is constant hot ON the alt for 97'? 

[Bushwick]

Think I see what's wrong. I assumed the "dummy" light in the circuit was not needed, so it was never used with the Tribecca alt. On these older alts however, it looks like it might be needed as part of the "on" circuit. Only way alt would charge was by using the right-side spade lug (if looking down at engine from front) and ignoring the left-side lug; right-side is apparently supposed to get a key-on from the dummy light circuit if I'm understanding the diagram correctly?

Edited January 6, 2018 by Bushwick

[idosubaru]

Hmm I’m unsure of wiring. Yeah if you’ve got custom/repaired wiring I’d be checking that.

 

Can you just match the FSM wiring?

[Fairtax4me]

95-98 alternators are all the same Afaik, with the exception of the higher output alts for the Outbacks.

 

I don't remember off hand exactly which wire goes where on the alt. There's only two choices...

[GLBorchert]

Parasitic battery drain seems quite common, though I'd think that the parasitic problems that emerge over time should be fairly common.  That is, other owners should experience the same issues. 

 

I have 113,000 miles on my 2013 Outback Limited 2.5i, and have had no electrical problems at all in the five years I've owned the car.  Suddenly one day my one year old battery was dead - completely dead - so I replaced it with a new one and charged up the dead one, leaving it in my garage.  The next day the brand new battery was dead - completely discharged - wouldn't even unlock the doors.  I put my charged up old battery in, started the car and then tested the alternator and the voltage regulator.  Perfect readings on both.  The battery is being charged while I'm driving but something is draining the battery overnight.  For something to completely drain a brand new 650 CCA battery literally overnight, there has to be a serious parasite.  

 

Tomorrow I'll check the drain with the car off, and start my troubleshooting.  I really am surprised, though, that I haven't been able to find reports of that kind of culprit on the web, on this or any other forum.  There's likely a common problem, a particular switch or relay, that is staying engaged when it's supposed to turn off.  I have of course turned off all the interior lights in the car, turned off all manual switches (lights, HVAC, radio, etc.) overnight.  Anything I can turn off is off.  That has made no difference.  

 

Once I figure out what is happening, I'll report back, and maybe that information will help someone else in the future.  If anyone here has had a similar experience, I'd appreciate knowing their culprit(s).