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Hey folks,

 

 

 Looking to change my battery. Mine is over 5 years old right now. Recently, after driving on the highway for about a tank of gas, it wouldn't turn the starter over. I had to get a jump from a fella while in Wyoming yesterday. Also, my lights will dim when I turn on any electrical accessory or touch the brake (even if at highway speeds/high rpms) Local auto parts store has a couple options for $140-$180 (both have the same numbers...CCA: 640, CA: 800), but my sam's club has an AGM battery with 36 month replacement for $145 (CCA: 640, CA: 800). I've read a little bit about AGM's needing special charging systems, and that they can be over charged. Any thoughts? 

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The chemistry of an AGM battery is the same as with any lead acid battery, its the physical construction that is different.  Optima is a leading supplier of AGM batteries and in my opinion, they are the best batteries because of their spiral construction.  But Optima sells a line of battery charger/maintainers, which are also good products, but a little (lot) more costly than some more commonly available brands.  They kinda hint that only their chargers/maintainers are safe to use with AGM batteries, but I don't see where they out right say that because it is not true.

 

There are some cheap low current (trickle) chargers that are not maintainers that can damage an AGM battery if left on too long, but they damage all other car batteries if left on too long also.  The important thing is if you don't use your car for long periods of time and require a charger to maintain the charge on the battery, any battery AGM or conventional, make sure it is a charger/maintainer.  If you drive the vehicle at least once a week, you don't need an external charger/maintainer so it doesn't matter.

Edited by keith3267

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Lights dim with electrical load while running? Car wouldn't start after a long drive?

 

Sounds to me like you have a charging problem, not a battery problem.

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Yeah, I'd say the brushes in the alt probably took a dump.

  

Lights dim with electrical load while running? Car wouldn't start after a long drive?

 

Sounds to me like you have a charging problem, not a battery problem.

Wouldn't I have a gauge-cluster light coming on if this were true? Or is the alternator just barely not doing its job?

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It's certainly possible that it's not charging and you don't have a warning light. Get a Multi-Meter (if you don't have one, get one. If you have a Harbor Freight near you, it's about $5), and test the voltage across the battery while running. Should be ~14.5v.

 

Or, go to almost any auto parts store, they usually have a hand-held battery/alternator tester that they can bring out to the parking lot and test it quick.

 

Does the battery light come on when you first turn the key on? If the warning bulb burns out the alternator will not charge.

Edited by Numbchux

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It's certainly possible that it's not charging and you don't have a warning light. Get a Multi-Meter (if you don't have one, get one. If you have a Harbor Freight near you, it's about $5), and test the voltage across the battery while running. Should be ~14.5v.

 

Or, go to almost any auto parts store, they usually have a hand-held battery/alternator tester that they can bring out to the parking lot and test it quick.

 

Does the battery light come on when you first turn the key on? If the warning bulb burns out the alternator will not charge.

All of the usual lights turn on when I turn the key. 

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The chemistry of an AGM battery is the same as with any lead acid battery, its the physical construction that is different.  Optima is a leading supplier of AGM batteries and in my opinion, they are the best batteries because of their spiral construction.  But Optima sells a line of battery charger/maintainers, which are also good products, but a little (lot) more costly than some more commonly available brands.  They kinda hint that only their chargers/maintainers are safe to use with AGM batteries, but I don't see where they out right say that because it is not true.

 

There are some cheap low current (trickle) chargers that are not maintainers that can damage an AGM battery if left on too long, but they damage all other car batteries if left on too long also.  The important thing is if you don't use your car for long periods of time and require a charger to maintain the charge on the battery, any battery AGM or conventional, make sure it is a charger/maintainer.  If you drive the vehicle at least once a week, you don't need an external charger/maintainer so it doesn't matter.

I meant that I had read that the vehicle's charging system may overcharge the battery while on a long trip. 

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I meant that I had read that the vehicle's charging system may overcharge the battery while on a long trip. 

No, it won't.

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seems like the previous battery gave you OK service, what brand is it?

 

"Napa Power'   had a sticker on it that said 11/12. I was told that that is the delivery date for it. 

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Optima is junk now - sent production to Mexico. LOTS of stories of premature failure in recent years. Terrible quality control and they switched away from pure lead to lead alloys. Crap IMHO.

 

Odyssey is where it's at. They (Enersys) designed the spiral core that optima uses and their new flat plate design is 15% more dense. Their design life is 12-15 years.

 

GD

Edited by GeneralDisorder
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I wouldn't consider an AGM battery an upgrade. Buy a new battery from your Subaru dealer I bet it's cheaper than $135.

 

Last one I bought listed for $85, had like a 72 month warranty.

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I wouldn't consider an AGM battery an upgrade. Buy a new battery from your Subaru dealer I bet it's cheaper than $135.

 

Last one I bought listed for $85, had like a 72 month warranty.

 

 

It's certainly possible that it's not charging and you don't have a warning light. Get a Multi-Meter (if you don't have one, get one. If you have a Harbor Freight near you, it's about $5), and test the voltage across the battery while running. Should be ~14.5v.

 

Or, go to almost any auto parts store, they usually have a hand-held battery/alternator tester that they can bring out to the parking lot and test it quick.

 

Does the battery light come on when you first turn the key on? If the warning bulb burns out the alternator will not charge.

 

 

Lights dim with electrical load while running? Car wouldn't start after a long drive?

 

Sounds to me like you have a charging problem, not a battery problem.

 

New Battery installed. My headlights are less yellow... but dimming still happens. I had my alternator tested, and it passed all inspections... I had the auto center test it about four times just to see if there'd be an issue once it warmed up.. I've also recently added 5 new grounds to the engine compartment. One connecting the alternator to the body. Each body-point has been ground to metal... No change in the dimming. I did find a blown bulb in my rear passenger-side tail light. The housing for the bulb-socket was actually melted/deformed. I removed the bulb to find it rusted... The dimming/idle shuttering is slightly less... I'm assuming that I have a (many?) bad grounds in my wiring harness for the lights? 

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The dimming happens because there is voltage drop between the battery and headlamps when there is an extra load put on the supply. Upgrade your headlamp harness to a switched positive style harness with relays near the battery and that won't happen as much.

It will still happen to some degree no matter what you do, simply because of the way lead acid batteries discharge energy. Whenever a sudden high current load is placed on the battery (brake lamps, power window motors, hi amp subwoofer,etc) the battery voltage will drop temporarily.

Ypu will see that voltage drop visually as the change in light output from the headlamps because you're looking at the light output directly. It happens in every other circuit on the car as well, you just don't visually see it.

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Battery in my 96 Impreza died, looking for a replacement, even the cheap ones aren't cheap.  I have an Odyssey in my Outback and it's great but I don't want to buy another $300 battery.  Local Subaru dealer wants $124.  Rockauto sells a Deka Intimidator for $175.  Considering a junkyard battery, don't plan on keeping this car for more than a year.  Any other deals out there?

 

Sooberoo - did you make sure the battery light comes on when you turn on the key?  My friend had problems with one alternator that wouldn't charge since he had LED bulbs for some of the idiot lights and that was enough of a change to keep the alternator from charging.  Check voltage at the battery, not the alternator, with the car running and making sure it's at least 14.  Also, your brake lights shouldn't be a high current load.

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If you’ve got a round plug alternator (Gen1 legacy’s), these can drop a phase and not charge properly but will manage to maintain the battery in general.

 

I’ve “upgraded” my ej22 alternator to a Gen3 square plug unit as I’ve heard these are a better design/unit that doesn’t have the same issue. So far so good.

 

Could be something to look into.

 

Cheers

 

Bennie

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Actually picked up a Subaru battery last week. 84 month warranty, 2 years free replacement. $97 w/tax

This is for the 35 size which most of the older 4 cyl cars used. Other sizes may be different.

 

Also, your brake lights shouldn't be a high current load.

They are. Hence the reason other lights in the car dim when you press the brake pedal.

Edited by Fairtax4me

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