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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: bidda-boy on July 30, 2011, 11:31:01 pm

Title: battery dies after 2 weeks?
Post by: bidda-boy on July 30, 2011, 11:31:01 pm
1987 silverado  battery dieing after 2 weeks of sitting. put in new battery  same thing happened 2 weeks later? would a alternator cause this if diode blew?nothing has been left on.still charges after being jumped.  any ideas where to start?/thanks
Title: Re: battery dies after 2 weeks?
Post by: reload on July 31, 2011, 12:13:26 am
Go put your hand on top the alternator.  Is it hot/warm?  Obviously do this after the engine has been sitting off for a few hours (read: let it sit overnight).  If its hot your voltage regulator is probably toast, get a new alternator.
Title: Re: battery dies after 2 weeks?
Post by: topp on July 31, 2011, 01:59:17 am
Truck off,Disconnect + battery cable
Put test light between cable and terminal.
If it lights up, you have a drain....Pull fuses until that light goes out, Drain is on that circuit
Title: Re: battery dies after 2 weeks?
Post by: VileZambonie on July 31, 2011, 11:01:14 am
Much safer to disconnect the negative. Just search parasitic draw on here and you'll find several threads covering this topic
Title: Re: battery dies after 2 weeks?
Post by: choptop on July 31, 2011, 06:36:23 pm
Any truck with an ecm or clock will have a parasitic draw. All of mine will kill the battery in a few weeks and the only draw on two of them is the clock. I disconnect the batteries if they're gonna sit for a while. Only takes a minute and saves lots of trouble
 Batteries are expensive.
Title: Re: battery dies after 2 weeks?
Post by: greg1984GMC on July 31, 2011, 09:52:46 pm
Any truck with an ecm or clock will have a parasitic draw. All of mine will kill the battery in a few weeks and the only draw on two of them is the clock. I disconnect the batteries if they're gonna sit for a while. Only takes a minute and saves lots of trouble
 Batteries are expensive.

Agreed.
If your stereo has a clock or remembers preset stations, it is
draining down your battery.
Title: Re: battery dies after 2 weeks?
Post by: DustyRusty on August 01, 2011, 03:33:56 pm
I've had the same problems in another vehicle of mine.  At first, I also disconnected the battery.  Then I found this:  http://batterytender.com/battery-tender-junior-12v-at-0-75a.html   You can install directly to the battery and run the cord out through the grill and merely plug it in whenever you want.  You might find cheaper prices elsewhere.

Here's another of similiar ilk but probably more functions:  http://www.ctek.com/   Click on the North America link.  As before, shop around for better prices.

Just another solution is all.

Rusty
Title: Re: battery dies after 2 weeks?
Post by: reload on August 01, 2011, 03:42:06 pm
Walmart also sells a nice 1.5amp tender, not sure the brand (sad because i have three of them  >:().  Last one I bought was $24.99, I have form for my bikes/quads extra batteries. 
Title: Re: battery dies after 2 weeks?
Post by: beastie_3 on August 01, 2011, 03:43:47 pm
it shouldnt die after 2 weeks from just the stereo memory and clock. something else sounds like its draining it.
Title: Re: battery dies after 2 weeks?
Post by: griffo2k on August 01, 2011, 07:50:27 pm
it sounds like the isolation diode is shorted when it shorts it will drain the battery. The isolation diode is inside the alternator you can probably find one at radio shack.
Title: Re: battery dies after 2 weeks?
Post by: bidda-boy on August 03, 2011, 11:24:20 pm
hi thanks for the info problem was the alternator  it was charging ok  but wasn't shutting off when engine was stopped. internal regulator diode was bad  installed new alternator and cured problem   thanks again   cheers