1987 bobcat 843 Battery Drain.

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jasonzman

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Apr 25, 2009
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Hi im new to these forums and looking for help for my 1987 Bobcat 843. My machine runs great but the problem im having is something is draining the battery. I can take a fully charged battery and in less than 2 hours It will be completely drained, doesnt matter if im running the machine or its sitting in my shop ignition off and key out, if the battery is hooked up its drained, ive tried different batteries. The voltmeter indicates when its running its charging correctly but even with the alternator charging it the battery will drain over it. I assume I should start with the ignition switch but does anyone have any other ideas? I could handle about any problem but an electrical one =) Thanks for looking. -Jason
 

jerry

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May 3, 2007
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That is a pretty heavy short if it will drain the battery as it is being charged. Disconnect all + wires from the battery or starter wherever they are and find out which one is drawing the current when it is touched to the + cable again. If you dont see any current draw you may have a internal problem in the battery itself.
 

vettes

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Nov 16, 2008
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Check the starter for the drain, thats about the only thing i can think could have that much of a drain.
 
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jasonzman

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Apr 25, 2009
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Check the starter for the drain, thats about the only thing i can think could have that much of a drain.
Thanks for the replies, I know its not an internal problem with the battery because i have tried multiple batteries and the same thing happens. I will check the starter, It does not engage without using the key but i suppose it could have a short somewhere? Would it be wise for me to buy a new ignition switch 1st or is it something heavier than that? technically when the key is off it should terminate power to everything but the heavy wire that goes to the starter solenoid correct?
 

Tazza

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Thanks for the replies, I know its not an internal problem with the battery because i have tried multiple batteries and the same thing happens. I will check the starter, It does not engage without using the key but i suppose it could have a short somewhere? Would it be wise for me to buy a new ignition switch 1st or is it something heavier than that? technically when the key is off it should terminate power to everything but the heavy wire that goes to the starter solenoid correct?
Try un-hooking the alternator B+ cable and see if that does anything, if you tap it back to the terminal, look for a spark, if it does its drawing power from a possible shorted diode. If its draining the battery that fast, it has to be putting out heat, feel around and see whats getting warm.
 

vettes

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Nov 16, 2008
Messages
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Thanks for the replies, I know its not an internal problem with the battery because i have tried multiple batteries and the same thing happens. I will check the starter, It does not engage without using the key but i suppose it could have a short somewhere? Would it be wise for me to buy a new ignition switch 1st or is it something heavier than that? technically when the key is off it should terminate power to everything but the heavy wire that goes to the starter solenoid correct?
The starter will drain a battery with or without ign on or off. Have had a few customers over the years with starters that are bad and do this. If your unsure about testing, almost any parts store will be able to do it for you! Andy
 

Skiddy

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Feb 14, 2009
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The starter will drain a battery with or without ign on or off. Have had a few customers over the years with starters that are bad and do this. If your unsure about testing, almost any parts store will be able to do it for you! Andy
I am totally with Taz on this check your alt. This is a scenario that causes fires. I would unhook your battery when not in use till you find the problem. If it is draining the batt that fast something is getting warm. should be easy to find.
 

skidsteer.ca

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Jan 20, 2006
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3,853
I am totally with Taz on this check your alt. This is a scenario that causes fires. I would unhook your battery when not in use till you find the problem. If it is draining the batt that fast something is getting warm. should be easy to find.
Bad diode in the alternator. Unhook the wires and see if the draw goes away. If it has a mondo, swap it for a Delco, they bolt right up.
Ken
 
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jasonzman

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Apr 25, 2009
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I'd also check to see if the solenoid for the glow plugs is stuck and keeping them on.
I cant seem to find anything hot to the touch on a fresh battery, I replaced the ignition switch and the problem still exists, I suppose the next step is to disconnect the starter and alternator one at a time to see if the draw is still there. where is the glow plug solenoid? I have the model with the isuzu diesel not perkins.
 

mrfixitpaul

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Mar 28, 2009
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I cant seem to find anything hot to the touch on a fresh battery, I replaced the ignition switch and the problem still exists, I suppose the next step is to disconnect the starter and alternator one at a time to see if the draw is still there. where is the glow plug solenoid? I have the model with the isuzu diesel not perkins.
Usually behind the coolant overflow tank on the left side. there are 2 solenoids, 1 for starter and 1 for glowplugs
 

mrbb

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Jul 19, 2016
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494
Did you ever figure it out?
the OP hasn;t been back on the site since 2009, so odds are , he won;t be replying to you here

IMO< its a a shame more folks don't come back and let us know what the issue was, so we know and or it can help someone else
but it happens!
 

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