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dg27
Joined: 01 Jan 2002 Posts: 433 Location: Coeur d'Alene, ID
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Posted: Sat Sep 11, 2010 12:25 pm Post subject: taking car off road: disconnect battery or use charger? |
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My new job requires that I travel for a month at a time several times per year.
I have a brand-new BMW battery and a BMW charger that I've never even taken out of the box.
I planned to use the charger to maintain the battery while I'm gone but wonder: Are there any disadvantages or long-term dangers to simply disconnecting the battery?
I know I'd have to reprogram the clock and reenter the code on the head unit and I assume I'd have to fully charge the battery upon my return, but that's not a problem since I don't drive every day when I'm home.
I rent a private garage and I feel kind of funny asking the landlord to let me keep the charger plugged in the entire time I'm away.
I'm also not crazy about leaving the hood ajar the whole time.
Any advice would be greatly appreciated. Thanks.
dg _________________ 1998 Morea Green 328is 5-speed sports pkg
~165700 miles |
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PJK
Joined: 14 Feb 2002 Posts: 1829 Location: Shingle Springs, CA
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Posted: Sun Sep 12, 2010 12:21 pm Post subject: |
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I see no problem in disconnecting the battery other than the bother of doing so and re-entering the radio code and setting the clock.
If the temp and humidity ore not extreme I would not expect to have to recharge the battery after one month.
If you leave the battery connected and do not use the float charger you will lose a good bit of the charge in one month.
Phil |
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dg27
Joined: 01 Jan 2002 Posts: 433 Location: Coeur d'Alene, ID
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Posted: Sun Sep 12, 2010 12:58 pm Post subject: |
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Phil:
Thanks for your reply.
I'd really rather not use the charger, so this is good news.
Question though, re: this:
PJK wrote: | If you leave the battery connected and do not use the float charger you will lose a good bit of the charge in one month.
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I was under the impression that if I did not use a charger and did not disconnect the battery that it'd definitely be dead upon my return. Do you think this is not true?
I want to make sure I don't do anything that shortens the life of the battery (which I just replaced), because I'm going to have to do this every two or three months.
dg _________________ 1998 Morea Green 328is 5-speed sports pkg
~165700 miles |
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PJK
Joined: 14 Feb 2002 Posts: 1829 Location: Shingle Springs, CA
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Posted: Sun Sep 12, 2010 11:41 pm Post subject: |
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Hi dg,
I seem to remember measuring ~30 mA of leakage in my e36. Figuring 30 days in a month that works out to about 22 AH in one month. Now days they don't state the AH capacity of automotive starting batteries but I will quess 70 AH. After one month I would expect you car to start. I wouldn't do two months and three months is really pushing it.
Storage batteries have several hundres charge / discharge cycles before they are worn out. It is looking like one month with out disconnecting your battery or connecting the float charger is obout 1/3 of a cycle.
Id doesn't look like a huge deal but I would expect you would get longer battery life if you disconnected the battery or connected the float charger.
Of course if the charger is not properly calibrated it could depleat the electrolyte in the battery.
Phil
dg27 wrote: | Phil:
Thanks for your reply.
I'd really rather not use the charger, so this is good news.
Question though, re: this:
PJK wrote: | If you leave the battery connected and do not use the float charger you will lose a good bit of the charge in one month.
|
I was under the impression that if I did not use a charger and did not disconnect the battery that it'd definitely be dead upon my return. Do you think this is not true?
I want to make sure I don't do anything that shortens the life of the battery (which I just replaced), because I'm going to have to do this every two or three months.
dg |
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dg27
Joined: 01 Jan 2002 Posts: 433 Location: Coeur d'Alene, ID
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Posted: Sun Nov 21, 2010 11:46 am Post subject: |
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Update: Took my chances and used no charger and didn't disconnect the battery. It was fine when I got back.
dg _________________ 1998 Morea Green 328is 5-speed sports pkg
~165700 miles |
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