mystery battery issue

[killster1]

old agm battery dies (6 years old so thats fine) replaced with new regular ever ready, battery lasts 2 weeks then dies, purchased trickle charger charged to full, starts suv fine a few times then dies after a week. Suv runs fine with out battery connected, battery charged full started suv driven 100 miles then disconnected to make sure no parasitic drain. Lasts one week not plugged in starts suv a few times then dies and requires jump pack. Took it back to Walmart they say battery is bad and needs to be replaced. So now they have another new battery. Did the suv kill the last one ? Is there something I should tell them to do differently next time ? I have read to pull each fuse at night to see if there is a big spark to see what could be draining the battery. Sorry for bad grammar etc

 

[herm0016]

whats the alternator charging at?

 

[killster1]

whats the alternator charging at?

14.4... 750 cold crank battery should be enough

 

[ondma]

I think his thought was that the alternator might be overcharging the battery. That would be my suspicion.

 

[RLGL]

750 cold crank battery should be enough

Install the battery the manufacturer calls for, not the one you THINK should be enough!

 

[Torn Mind]

You can buy something like the Quicklynks BA101 to test your battery and alternator; it also can check the starter. It can check ripple as well.

 

[killster1]

Install the battery the manufacturer calls for, not the one you THINK should be enough!

It calls for 550 my point is its more then enough

 

[NutBucket]

Maybe there is an intermittent in the alternator? Try measuring the battery voltage before you drive and then after with the car off.

If only cars had proper gauges like they used to!

 

[killster1]

You can buy something like the Quicklynks BA101 to test your battery and alternator; it also can check the starter. It can check ripple as well.

Thnx it's actually just a problem I'm helping deal with but ill buy that and add it to my tools. Maybe a better model that does more for a little bit more ? I'll research it after I get my work done

 

[Paperdoc]

If a new, fully-charged battery is dead within one week, that is NOT likely to be a battery problem. You may have something in the vehicle constantly draining it. It could be a light that is on - inside you car, or maybe in the trunk where you don't notice it. An electric seat heater? Could even be bad diodes in the alternator that allow current to leak back when not charging. You need a proper diagnosis, and not a simple replacement of the battery. Doing that will only give you the same problem.

Finding a current user causing the leak is not nearly as simple as pulling a fuse to watch for a spark. Any item that draws enough current to make an obvious spark when you pull the fuse will be a BIG! current draw that would drain the battery in a few hours. If you are familiar with using it, a amp meter can help. You disconnect the GROUND cable at the smaller battery post, then connect the amp meter between that post and the cable clamp. That will show you the amount of current flowing in total, and for most cars with nothing operating, it might be a few milliamps for the security system or something. Then you can start pulling fuses one at a time and replacing. If pulling a particular fuse suddenly drops the amp reading, you have found one circuit that was using whatever that power drop was.

To check for bad back-leakage though the alternator, you need to disconnect the main output cable from the alternator. Be CAREFUL! - this cable is connected to the battery + terminal and is LIVE, so do NOT let it touch Ground. Now connect your amp meter from that cable to the alternator terminal. The current flow when NOT operating should be almost nothing.

Here's another cause that is rather common. The alternator (more precisely, some components inside it) may have partially failed so that it is not really re-charging the battery, even though a voltage reading says it should be. This can be tricky to diagnose for the backyard mechanic, and a garage needs to do a proper test of the alternator. In my city, there are some garages and parts shops that will do that test for you for free if you remove the alternator and bring it into the shop. Sure, they want to sell you a new one, so they may be a little biased, but if you trust your shop this is the way to test for a bad alternator. If you are not up to the removal task, most garages can do the test for you on the car for a fee.

 

[Torn Mind]

If a new, fully-charged battery is dead within one week, that is NOT likely to be a battery problem. You may have something in the vehicle constantly draining it. It could be a light that is on - inside you car, or maybe in the trunk where you don't notice it. An electric seat heater? Could even be bad diodes in the alternator that allow current to leak back when not charging. You need a proper diagnosis, and not a simple replacement of the battery. Doing that will only give you the same problem.

Finding a current user causing the leak is not nearly as simple as pulling a fuse to watch for a spark. Any item that draws enough current to make an obvious spark when you pull the fuse will be a BIG! current draw that would drain the battery in a few hours. If you are familiar with using it, a amp meter can help. You disconnect the GROUND cable at the smaller battery post, then connect the amp meter between that post and the cable clamp. That will show you the amount of current flowing in total, and for most cars with nothing operating, it might be a few milliamps for the security system or something. Then you can start pulling fuses one at a time and replacing. If pulling a particular fuse suddenly drops the amp reading, you have found one circuit that was using whatever that power drop was.

To check for bad back-leakage though the alternator, you need to disconnect the main output cable from the alternator. Be CAREFUL! - this cable is connected to the battery + terminal and is LIVE, so do NOT let it touch Ground. Now connect your amp meter from that cable to the alternator terminal. The current flow when NOT operating should be almost nothing.

Here's another cause that is rather common. The alternator (more precisely, some components inside it) may have partially failed so that it is not really re-charging the battery, even though a voltage reading says it should be. This can be tricky to diagnose for the backyard mechanic, and a garage needs to do a proper test of the alternator. In my city, there are some garages and parts shops that will do that test for you for free if you remove the alternator and bring it into the shop. Sure, they want to sell you a new one, so they may be a little biased, but if you trust your shop this is the way to test for a bad alternator. If you are not up to the removal task, most garages can do the test for you on the car for a fee.

I think he said that he disconnected the battery after driving and I'm assuming he kept it on a trickle charger. It still went bad after that.

Diagnostic is a waste of money compared to throwing parts at it, actually. For the 80-100 dollars spent on a check, it could have went to a new alternator.

He can check for AC voltage with his own meter and revving it up ; I'm assuming he has one since he sees the DC voltage. That's the most likely issue as far I can see based on everything he presented so far. .

 

[BonzaiDuck]

I was going to suggest to check your stop lights and the stoplight switch, but I think we've moved past that? That's the problem I'm having at the moment with my brother's truck. Battery only lasted 3 years, but it should've gone for 5. If there was a warranty, I decided the way to go was with a better AGM battery, as opposed to a low-priced standard model. And Dang! I just replaced the stoplights including the little ones in a string at the top-rear of the cab -- about five months ago. I will guess that some may not last as long as I would like. PITA.

 

[killster1]

I was going to suggest to check your stop lights and the stoplight switch, but I think we've moved past that? That's the problem I'm having at the moment with my brother's truck. Battery only lasted 3 years, but it should've gone for 5. If there was a warranty, I decided the way to go was with a better AGM battery, as opposed to a low-priced standard model. And Dang! I just replaced the stoplights including the little ones in a string at the top-rear of the cab -- about five months ago. I will guess that some may not last as long as I would like. PITA.

im pretty busy, when i get around to it i will use a amp meter and check the drain, it could have been the battery was damaged from so many drains and recharges that it wasnt holding a charge anymore (lady at walmart said the cells where fine). i bet i can figure out what is causing the drain, there are no obvious lights on of course. ill check each fuse for how much resistance or use the amp meter and pull each fuse, both ways look like a decent way to check. thanks everyone for the help and ill update this thread when i figure out the answer.

 

[Torn Mind]

I was going to suggest to check your stop lights and the stoplight switch, but I think we've moved past that? That's the problem I'm having at the moment with my brother's truck. Battery only lasted 3 years, but it should've gone for 5. If there was a warranty, I decided the way to go was with a better AGM battery, as opposed to a low-priced standard model. And Dang! I just replaced the stoplights including the little ones in a string at the top-rear of the cab -- about five months ago. I will guess that some may not last as long as I would like. PITA.

I think AGM matters less than manufacturer. Johnson Controls is bulk brand, built to fail at the OEM"s/suits pleasure, such as Toyota True-2s dying every 3 years(and stressing the starter to premature failure). Deka/East Penn is the longevity product maker.

 

[killster1]

interesting enough, i just went to walmart and got a new battery, installed it and they had zero issues since and its been 1+month so it must have just been a bad battery.

 

[BonzaiDuck]

interesting enough, i just went to walmart and got a new battery, installed it and they had zero issues since and its been 1+month so it must have just been a bad battery.

I assume your final battery replacement was under Walmart's warranty or howsoever they cover a warranty from the manufacturer. If so, you saved yourself some money. If not, I'm thinking the alternator would have cost at least as much or more . . .