85 Mustang GT batteries keep blowing??

Question

85 Mustang GT has been through more batteries than I can count.  Can?tfigure out what the problem is.  After driving for several miles, youcan smell the battery acid, and have had at least 2 ?explode? (luckilyno one was hurt except a little acid in my face once).  Checkedgrounding, etc - still same problems.  I?m going through a batteryevery month *at least* and this is getting OLD!  Can ANYONE help withthis???  8O

ironrod · Accepted Answer

An alternator is capable of producing more voltage than your battery is capable of handing. The regulator works by limiting the output. The last time my brushes went the problem manifested itself by maxing out the voltmeter. Another place to look is at the alternator sense line, if it is not hooked up correctly it could be signaling for max output.

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.boB · Answer

Too much voltage.  Check your charging system.  Around here, Autozone andPep Boys will do it for free.

mvasil · Answer

> An alternator is capable of producing more voltage than your > battery is > capable of handing.  The regulator works by limiting the > output.  The last > time my brushes went the problem manifested itself by maxing > out the > voltmeter.  Another place to look is at the alternator sense > line, if it is > not hooked up correctly it could be signaling for max output. >  > > 85 Mustang GT has been through more batteries than I can > count.  Can't > > figure out what the problem is.  After driving for several > miles, you > > can smell the battery acid, and have had at least 2 > 'explode' (luckily > > no one was hurt except a little acid in my face once).  > Checked > > grounding, etc - still same problems.  I'm going through a > battery > > every month *at least* and this is getting OLD!  Can ANYONE > help with > > this???  8O > > > > --  > > Posted using the  interface, at author's request > > Articles individually checked for conformance to usenet > standards > > Topic URL: > > >...

ironrod · Answer

Before you try anything else check your brushes first, they are wear itemsand are real easy to fix.  I that doesn't work try the following.  Now I'massuming your 85 is like my 88,  if so then the sense line is one of thethree wires coming from the plug in the side of the alternator.  Theheaviest wire is the one that goes back to the battery and supplies chargingcurrent to the electrical system.  Of the two smaller ones one goes to thewarning light, and the other is the voltage sensing line.  Try disconnectingone of the smaller wires and see what happens.  If your warning light comeson you got the wrong one.  Once you find the right one, a down and dirty fixis to hook up the sense line to the positive side of the battery.  Don'thook the warning light wire up by mistake or you will let all the magicsmoke out of the box.>  > > Visit Topic URL to contact author (reg. req'd).  Report>  > abuse:

cprice · Answer

85 still used a voltage regulator mounted on the firewall behing the battery and starter solenoid. Remove your alternator and voltage regulator and take em to one the shops suggested by Bob below and have them tested.	In the days before readily available test facilities at parts counters, I usually replaced the voltage regulator first (~$20 part)..boB wrote:

ironrod · Answer

Since you don't have an internally regulated alternator, ignore my previouspost.  Like the man said, remove the regulator and have it tested.  You canalso perform a down and dirty test yourself by measuring the voltage fromthe positive terminal of the battery to ground.  Have someone rev the enginefor you while you look at the voltmeter, output should remain constant ataround 14 volts.  If the voltage changes radically or is just plain too highthen your regulator is suspect.  If the regulator checks good then we areback to the possibly of a wiring problem.

85 Mustang GT batteries keep blowing??

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