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Thread: Radio draining the battery

  1. #1
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    Talking Radio draining the battery

    Hello Car Audio Experts,

    I found out that my new Pioneer DEH-P3700MP satellite ready radio with a Pioneer compatible Sirius tuner is draining my battery if the car is not driven every day. With the aid of a test light, I took all the fuses out and one by one plugged in and the testing with the light. Fuse #9 (Radio) was the culprit. the light stayed on all the time. I followed Crutchfield wiring and installation instructions and used their part # 12070-9195 wiring adapter. I also had to use the PAC OEM-2 interface recommended by Crutchfield for 1992 E36 325i BMW and spliced and wired all and had it plugged into the ne Pioneer radio and to the tuner.

    I know that the Radio and the tuner would require Hot all the time (Yellow wire) power. Is it possible that there is a problem internally with the Raio, or the Tuner or the OEM-2 that is draining the Battery? I never had this problem with my stock radio/cassette unit.

    Anyone with suggestions or recommendations of what to do? This is my Labor weekend project.

    Thank you
    Moe

  2. #2
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    There should be a draw for those components, to maintain memory and such. What you want to use is a Digital Multimeter and read the current draw of the circut, it should only be an amp or two for the audio system that would be normal. I doubt that is the culprit if it is all wired correctly.

    Maybe a weak battery that no longer holds its charge? Good luck.

    Dave-

  3. #3
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    Thank you for the reply.

    I had the battery checked more than once at Autozone and was told that the battery is as good as new. I also had the altenator checked and was told the same thing as the battery.

    Any other possible senarios?

    Thanks
    Moe

  4. #4
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    If you are running a powerful amp, I would recommend purchasing a capacitor. Basically, it acts as a alternator and makes it so that the amp does not drain the battery.

    I have one for my 1200w amp and have never had a problem. A friend of mine had a similiar problem to yours and had a capacitor installed and problem solved! They are around $100 for a nice one.

  5. #5
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    Quote Originally Posted by ChaseBimmer
    If you are running a powerful amp, I would recommend purchasing a capacitor. Basically, it acts as a alternator and makes it so that the amp does not drain the battery.

    I have one for my 1200w amp and have never had a problem. A friend of mine had a similiar problem to yours and had a capacitor installed and problem solved! They are around $100 for a nice one.
    Do not do this... Waste of money.

    Get a DMM put it in series with the positive battery terminal (with car off) Set it to measure current. Now start pulling fuses (start with your #9 fuse for the radio). Keep pulling/ replacing (so you dont forget where they go) untill you see a big drop. I believe a draw off around 2 amps is normal for all the electronics maintaining some sort of memory ( I may be off a bit). If the DMM doesnt show a large draw then we are back to a bad Battery or faulty Alternator.

    Dave-

  6. #6
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    Question

    Hello TWKTCC,

    I used a DMM to test the Amps draw as you mentioned. I set the DMM on 10 Amps and had the test leads in series with the positive battery cable. The +ve cable was disconnected from the battery.

    With only Fuse #9 removed, the Amps reading showed a steady .02 reading. ThenI plugged #9 back in the fuse box, and as soon as I had the test leads touch the battery +ve cable end and the battery +ve post, the reading started at about 1.5 amps and drops immediately to a steady .02 Amps.

    As I mentioned before, the battery and the alternator were checked okay at Autozone. I am planning on leaving fuse #9 out for few days without driving the car. Then I want to see if it starts. If it does start, should I take the Radio out and try to figure out what may have went wrong in the installation?
    Thanks
    Moe

  7. #7
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    Anyone can help?

  8. #8
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    At a .02 amp draw with all fuses in place shouldnt cause a problem. The jump up to 1.5 when connecting is normal as things are powering up for a second or two and it settles down to a nice low number quickly.

    Very odd. Id leave the fuse out just for your piece of mind and see what happens. Im betting you will still have a problem.

    I know there are things that can go bad in an alternator that will drain a battery when sitting yet still test good for charging. I had GM alt. do that to me once a long time ago. What a PITA that was to figure out.

    Dave-

  9. #9
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    Thank you TWKTCC.

    I am going to give it couple of days wthout fuse #9 and see if the problem still exists.

    By the way, the voltage across the battery when the car is idling at 1500 rpm is 13.65 V. Is this a sign of weak alternator?

    Thank You
    Moe

  10. #10
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    Quote Originally Posted by moe707
    Thank you TWKTCC.

    I am going to give it couple of days wthout fuse #9 and see if the problem still exists.

    By the way, the voltage across the battery when the car is idling at 1500 rpm is 13.65 V. Is this a sign of weak alternator?

    Thank You
    Moe
    Normal sitting voltage should be 12.5-12.8ish volts, running/ charging should be 13.5-14ish volts to charge normally (so yours is charging "ok"). Ive had a few vehicles charge at 14.5 My audio systems loved that

  11. #11
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    your battery could still be bad iv known a few people that went to autozone and they said it was good when in reality they had a dead cell.

    and ya most cars charge right around 14 give or take. my honda would hold 14.7. my amps loved it

  12. #12
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    Guys and Experts,

    After three days without starting the car and having fuse #9 removed, I was able to start the car without any problem. I pulled out the Radio and checked my wiring and the wiring to the Siruis tuner. All wiring looks correct and in order.

    Am I dealing with a weak battery even though the guys at Autozone had it checked more than once and under their equipment load tester, the battery showed as good as new?

    Thanks
    Moe

  13. #13
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    i ordered a head unit from crutchfield and they said that i needed a pac oem-2 but when i put everything in it barely worked, then i tryed it without the pac oem-2 and it works perfect

  14. #14
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    Quote Originally Posted by moe707
    Guys and Experts,

    After three days without starting the car and having fuse #9 removed, I was able to start the car without any problem. I pulled out the Radio and checked my wiring and the wiring to the Siruis tuner. All wiring looks correct and in order.

    Am I dealing with a weak battery even though the guys at Autozone had it checked more than once and under their equipment load tester, the battery showed as good as new?

    Thanks
    Moe
    Put the #9 fuse back in, remove the radio and sirrius tuner or just unplug each of them so no power is going to them. Now go a few days and see. Torture, I know without audio. This will be the final test to see if it is indeed the audio equipment or something in the car.

  15. #15
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    Okay. I'll do that today.

    One observation I would like to make. I installed the Pac oem-2, is it possible that this unit draw any power? I know that the power wires go straight thru it, but what about the antena/amp wire?

    thx
    Moe

  16. #16
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    Quote Originally Posted by moe707
    Okay. I'll do that today.

    One observation I would like to make. I installed the Pac oem-2, is it possible that this unit draw any power? I know that the power wires go straight thru it, but what about the antena/amp wire?

    thx
    Moe
    It may draw a slight bit, but the overall current draw readings you reported shouldn't be enough to kill a battery in a few days unless the battery is indeed bad.

  17. #17
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    mxp...

    I was advised by Cruchfield of not to hookup the new aftermarket unit without the OEM-2. I know what you are saying. You may have to adjust the gain blew adjustment screws on the OEM-2 to get the sound. I love the sound without the OEM-2 but I was told that the stock amp & speakers are not poweful enough as the new aftermarket units and if you don't use the oem-2, things weird may happen; like amp overheating or speakers damage.

    If anyone else in this forum can tell me that it is nonsense what crutchfiled is saying, I would love to take the oem-2 out and I'll get better, crispier and louder sound.

    hope this helps and not make you confused.

    Thx
    Moe

  18. #18
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    To all who had been following up on my battery/radio issue: HELP>>>>>

    After three dyas of not starting the car and with fuse #9 installed while the radio with the Sirius tuner unplugged, I had no problem starting the car. The battery kept its charge.

    Now, What do I do with this mystery? Battery or Radio issue? I have no problem buying a new battery if it i for sure the problem. But i do not want to waste my money and it turns out that I would end up with the same issue.

    Thanks
    Moe
    1992 325i

  19. #19
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    Im still going to say it is a bad battery, if the audio equipment is wired in properly. That equipment doesnt draw enough (as per your findings with a DMM) to drain the battery that fast. Hang tough, electrical gremelins are a pain in the butt.

  20. #20
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    Cool Problem figured out and solved

    For all who have been following up on the problem with my dead battery. Finally the probelm is solved and surprisingly it was related to the Pioneer Siruis Tuner.

    Crutchfiled support and the installation instructions insist that the Tuner should be wired direct from a +12v power supply. This is why the provided power supply has the yellow wire for +12V and the black wire for ground.

    Finally and after checking the Amps draw only to the tuner with a DMM and at a setting of 200mAmp, the reading jumped beyond the setting while the car is off indicating a high amperage draw. this is why my battery goes dead within 48 hrs if I do not drive the car.

    Therefore, I disconnected the power supply for the tuner from the constant 12v and wired it to the red wire (accessories). Now, I do not have any problem and I do not loose my Siruis radio presets. I do not understand this but it is working.

    By the way, I rewired the pioneer radio without the Pac oem-2. The sound is great.

    Thank you all for your help and I hope this thread will benefit others who are running into the same probelm.

    Moe
    1992 325i E36

  21. #21
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    WOW!! Fantastic!!! Glad you finally figured it out. Feels good huh?
    Weird that the sirrius tuner was the cause.

  22. #22
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    My Z4 2004 2.5i has the same issue

    Hello Moe707,


    I know it is a very, very old thread you posted at the forum but I would like to share my experience with you since I am having exactly the same problem with a BMW Z4 2004 2.5i right now in 2017.

    After doing all the tests with the DMM I found that the radio is draining my battery exactly after two days as you described. In my case my radio fuse is number 50. When I meassure the batery consume it's 0.49 or equal to 490 micro ampers when the normal consume should be below 0.05 (equeal to 50 micro ampers) so I am sure there is the drain.

    With the fuse 50 in, I disconnect the radio source cable and the DMM dramatically drops to 0.002 (20 micro ampers) as it should be, and like you, I have no problems with the battery again, since I made a test during a visit to Canada and my car after 20 days of not use started perfectly !

    My question is: Do you know if there is a special circuit or elecronic part into the radio that is not avoiding the battery drain? in that case I could repair that part and that I could preserve my car as it was from factory (original).

    On the other hand I could take the car to the car electritian so that he could connect the radio dirctly to the switch, in that way the radio will consume energy only when driving or the switch is on.

    What do you think about?

    Thanks in advanced for the advice.

    Armando

  23. #23
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    Hi Armando,

    Last post from Moe707 was over 12 years ago, I doubt he/she is still looking on this forum.

    You could also swap in a known working radio module to test, if that works and there's no drain, then you'll know your module is faulty so you can look to see if a specialist car audio electronics repair company can refurbish your unit or you can purchase another module that's working.

    Cheers, Dennis!

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