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Battery Draining / Bigger amp Alternator


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9 replies to this topic

#1 LostWater

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Posted 15 September 2003 - 11:12 AM

Hey all,

My alternator may be on the fritz as my battery is discharging overnight or after several hours being parked.

I reset the ground to the body thinking that may be the problem, and I unhooked the 8 guage power wire going to the back for amps and such. I am hoping it is something easy that causes the discharge.

Does anybody have any ideas on what to look at next?

Could the voltage regulator in the alt not be working right, or a short in the alt draining the battery? The hatch will run no problem after I jump it and it will start a few times after it is fully charged.

If I need a new alt, I remember talk of using one from an xt6 or something. It supposedly is like 125 amp vs. our 85 in the ea-81. Someone care to verify those values? Also, someone care to comment on wether it is just a straight drop in, or does it need some modification (new belt etc)?

Any help would be appreciated.

Thanks,

Mark

#2 calebz

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Posted 15 September 2003 - 11:21 AM

The XT6 alt is 90 amps, standars EA81 and EA82 alts are substantially lower in amperage.. 55 amps

#3 edrach

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Posted 15 September 2003 - 12:24 PM

XT6 alternator is 90A; EA 81 is 55A and EA82 is 60A.

Put an ammeter in series with your battery with ignition off; current draw should be close to zero (in the low milli-amp area). If it is 1/2 amp or more, start disconnecting fuses one at time and see where the current draw drops to near zero--that'll be the area where you need to look to solve the discharging problem. If you find that there is no apparent current draw with the ignition off, you may have a battery that just will not hold a charge; unusual, but it happens.

#4 baccaruda

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Posted 15 September 2003 - 01:00 PM

someone found a 110 amp alternator from a datsun or chevy luv or something, didn't they?

#5 GeneralDisorder

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Posted 15 September 2003 - 02:17 PM

There was a post a while back where a guy mentioned a 280z alt. Haven't had time to look at one, but it seemed at the time to be a very intentional comment, with an exact model of car..... worth a look next time your at a yard.

GD

#6 edrach

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Posted 15 September 2003 - 02:21 PM

Just a comment. A battery discharging overnight really has nothing to do with the alternator unless it's not charging the battery in the first place or the alternator has an internal short. A higher output alternator will not solve this problem.

#7 LostWater

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Posted 15 September 2003 - 02:23 PM

Of course a bigger amp alternator wouldn't fix a short elsewhere. But in case it is an internal short in the alternator and I have to replace the alternator, why not go bigger?

Thanks for the comment however,

Mark

#8 MilesFox

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Posted 15 September 2003 - 02:25 PM

your battery may be shot. i ahve seen cars that will run with a jump start, run for an hour, and if you turn it off for a few minutes, it will not crank.

i would check out or replace the battery to start with.
if the alt is reading 14 volts then its good.
take your ride to autozone, they have charging system diagnostics for free. if anything is bad, they will tell you, in hopes that they can sell you a replacement!

#9 GeneralDisorder

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Posted 15 September 2003 - 04:14 PM

Not in a subaru, but I fixed a car that had the wrong Voltage Regulator installed. Worked fine, but drained the battery fast. To check if it's the battery, or wireing, check for continuity between the positive battery terminal, and ground. If there isn't, or not very much, then try a new battery. Otherwise - start pulling fuses as sugested to find the offending circuit

GD

#10 goodoldgirl

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Posted 13 June 2005 - 01:12 PM

someone found a 110 amp alternator from a datsun or chevy luv or something, didn't they?

Hi. I was just nosing around looking for replies to my post and I found your message. Doesn't apply to my 95 Legacy but I LOVE the Eisenhoweer quote -- is it real??




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