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Discussion Starter #1
I tested battery today, and dont understand why it says "good-recharge"
I drive this car everyday,
I had to jump start it back in January, but since then it seems fine.

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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11.9 volts for a "12 volt" battery is essentially dead. A fully charged 12 volt lead-acid battery should show 12.6 volts. Fully charged, each cell puts out 2.1 volts times 6 = 12.6.

battery voltage chart.gif


Using an external charger capable of at least 10 Amperes output, charge the battery for 12 hours or so. See how long it stays at 12.6 after disconnect for at least a half hour. If the voltage drops more than 0.2 Volt overnight while disconnected the battery (one cell) is suspect.

Short hops will slowly deplete a battery - you need to run the car at least 12 - 15 miles or over a half hour to get back to anything close to full charge.
 

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Discussion Starter #3
11.9 volts for a "12 volt" battery is essentially dead. A fully charged 12 volt lead-acid battery should show 12.6 volts. Fully charged, each cell puts out 2.1 volts times 6 = 12.6.

View attachment 585590

Using an external charger capable of at least 10 Amperes output, charge the battery for 12 hours or so. See how long it stays at 12.6 after disconnect for at least a half hour. If the voltage drops more than 0.2 Volt overnight while disconnected the battery (one cell) is suspect.
I agree, but why would it say good?
Also just got home from driving and the display on obc says 14.1-14.3
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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With the engine off the DIC shows battery voltage. While driving/engine running you see system voltage - an automotive alternator/voltage regulator always carries system voltage slightly high with varying amperage output in order to quickly recharge the battery.

DIC running voltage bears NO resemblance to either battery voltage or state of charge - and after you shut down that system voltage will quickly drop to about 12.6.
 

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Discussion Starter #5
So I'm well within the range of 13.5-14.7 volts when car is running.
Just dont understand why tester said battery was good , but needed a recharge when car is driven everyday.
 

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2012 SRX Luxury
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This type of tester is reading the battery voltage and calculating based on the IR of the battery to determine things. If their determining program sees a parameter that is off it will say something in english for you on the screen. In this case Battery is good but put a charger on it and recharge it. Personally, if I saw this on my IR battery tester setup I'd put my desuphination charger on it and recondition the battery. It sounds to me like this battery needs a little help. It's not showing bad but it's showing that it needs more than just driving it. I highly recommend a MUS 4.3 charger as I've used several of these now for a while (even bought a broken one at the flea market and repaired the switch in it) and they are a very good designed charger. There are others that do the same thing of course but here's the one i use.

Steve

 

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Discussion Starter #7
But what's to say after doing a trickle charge and re installing that a month or less later it shows the same problem, ? I drive 30+ km a day, if that's not enough, then what is?
Maybe the alternator isn't up to snuff.
 

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Short drives are a problem. We have a 97 year old friend who still drives. It's a 2001 Toyota Avalon with 41,000mi. And before we knew here she was putting in a new battery every year. Since I've known her she's still put in 3 batteries in 10 years. But for the last two batteries only we've had a battery tender on it. It's the cheapest one possible from Walmart at $19.95 or $24.95 A Schumaker version and the first two she ran over as she backed the car out of the garage! This time I mounted it to the wall in front of the car so the least that happens is she automatically unplugs it from the charger now. But anyways, by keeping a charger on a battery for short trips you will find the battery lasts longer. That's the purpose of it. The cars charging system cant keep a battery fully charged as it doesn't have a change to do that on short trips.

So your call. Either put a cheap Walmart one on it or just suffer with a 1/2 dead battery.

Steve who monitors his with a VYNCS system. It shows all kinds of interesting stuff besides the battery portion but here's an example of what you get with it. This is from my 2017 Honda Ridgeline.
 

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Discussion Starter #9
My 30 kms are all highway,
Just wondering if it dying in January did possible damage to it, think its 3 yrs old
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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If a lead-acid battery is left in a discharged state for more than ?? a day ?? then the lead sulfate gel deposited on the plates as a result of chemically creating electricity begins to turn from gel to crystals and NO amount of charging will drive the sulfate back into solution in the electrolyte. The battery is then seriously or totally compromised.

The electrolyte in a fully charged lead-acid battery has a specific gravity of about 1.265 at about 80 degrees F and it will not freeze. The electrolyte specific gravity in a discharged battery is about 1.00 (pure water) and it will freeze.

A Battery Minder (It's NOT a "trickle charger") prevents sulfation. DO NOT leave an older ferroresonant charger connected to a battery for any length of time past a quickie charge.
 

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2003 Deville Base
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Is the STS battery like the Devilles, under the back seat? If so , if/when you do replace the battery, be sure you get one with the proper venting through the floor to the outside. Safety issue.
 

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2006 STS V8 AWD, '95 Ford Ranger
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'06 STS V8 AWD has the battery under the hood on the passenger side.
 

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Discussion Starter #16
Wondering if actually the low voltage on my battery has something to do with the PCM sending out fault codes...
Read online that if the PCM isn't getting a consistent 12 volts it can start screwing up
 

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08 STS 1SG HUD ACC F55 AWD, 08 STS 1SG Platinum HUD ACC F55 RWD
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Deem - yes - low/bad battery has caused many codes unrelated to the battery.
 

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If you have a 4.6L engine, below is what your battery should be. I had the original battery in the car since I bought it June 2019, and then this year I got the dreaded

P0562 = System Low Voltage.

all of a sudden. After checking everything I could (except the battery) I took the battery to AutoZone and they told me my battery was bad, that was back in April this year. I replaced my battery with the CORRECT CCA battery. That fixed a few issues relating to not having enough voltage. Yet, my old batter still works and started up my car, even though they say it's bad.

TIP: No matter the car you drive, or plan to own, check the engine size and do a lookup on that engine and there is information stating the recommended battery you should have in the car to run efficiently. The image below is for the 4.6L Northstar engine.

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Hope this helps!

Kevin
 
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