battery on its way out?

[slybunda]

so my battery an exide size 005 3 and half years old seems to have a high self discharge rate. when fully charged even if left sitting in the garage it drops from 13.2v off the charger to 12.4v in 7 days.
im assuming this is a sign of a bad battery? it still starts the car at 12.1v but didnt start the other day when it was at 11.8v and had to be put on charge.
car is not driven every day usually once a week and for a short trip too. i have a solar panel in the car but im guessing the battery is sulfated to the point a tiny solar panel cant help it much.

any tips on what sort of battery would be good for me for infrequent use pattern?

 

[Lubener]

I have been keeping two infrequently used batteries on battery maintainers, one is eight years old and the other is five, both are Walmart batteries, nothing special.. Both still start the cars fine. Care must be taken to store them fully charged. I would think a once in a week run should keep the battery fully charged. Maybe you need a longer drive when you take the car for a run.

 

[Propflux01]

Sounds more like a parasitic draw than bad battery, considering only 3 years old, but you only drive the vehicle once a week. And doesn't sound like that solar charger is helping much. Get a battery tender or such.

 

[Racer4]

I believe if your battery is holding 12.4 volts after sitting an week that’s is OK and I would call it good. Like others have said get you a battery maintainer if you are concerned and hook it up weekly.

 

[Snagglefoot]

I’ve found through the use of a battery tester ($50 bucks on Amazon) that typically the voltage won’t stay up in the 13 V range except after a fresh charge. It will drop to the 12.6 range rather quickly. If the battery is getting weak, you’ll find it dropping to the 12.2 V range and then lower and a battery tester will show your CCA test will start to be below your battery’s stated capacity. My 7 year old battery showed 12.2 V and 550 CCA on a battery with a 770 CCA rating. It would still do a good start at 32 F but it was on its way out. If it’s dropping below 12 volts, I would buy a new battery. Here is a shot of a test on my battery that was starting to get weak. This all assumes you haven’t accidentally left the lights on or that you have some sort of power draw occurring.

 

[Snagglefoot]

I appreciate the comments on doing weekly touch ups with chargers but honestly, if you are using your vehicle regularly and still need to to put on a trickle charger, then buy a new battery already. That’s one less thing to worry about in life.

 

[Propflux01]

If he is short tripping, no battery in the world is gonna keep a charge.

 

[slybunda]

I ment when it comes off charge in the garage i dont put the battery back in the car and just left in garage after 1 week its at 12.4v.
Iv measured the parasitic draw in the car and its bouncing between 25ma to 35ma in rythem to the flashing of the alarm led in the car so thats normal.

 

[slybunda]

Also forgot to add this battery probably been used with dodgey alternator in the car for a few months after a year of buying the battery. I didnt realise the alternator was a issue till the day i fitted a voltage gauge to the cig lighter socket. Only then i realised and changed alternator. So its probably been in a undercharged state for a few months early in the batterys life.

 

[Nick1994]

You say you have a solar panel in the car. What kind is it? Does it have a solar charge controller? If not, what’s keeping it from potentially overcharging the battery? In the past it may have overcharged it and shortened it’s life.

 

[Donald]

Disconnect one of the battery leads and charge it all the way. Wait 24 hours and measure the voltage. Then measure it every day for a few days. If it stays at 12.4 V or slightly above then it should be OK. But a conductive or load tester are better ways of testing.

Today's cars don't use a lot of power to crank over the engine. It starts almost immediately. I assume you car does that also.

But for the sake of the engine when you start it you want to bring the engine up to full operating temp for 15-20 minutes. So take the scenic route to your destination. Your engine will thank you.

 

[Propflux01]

And don't put battery on the concrete when you store it outside the car. I know, common sense, but you'd still be surprised how many people do it.

 

[slybunda]

Its a 20w panel i have a charge controller too although in winter its not making much power unless the panel is outside the car.
I had a conductive tester but someone borrowed it and not seen it since.
I have battery on wooden plank but always wonder why not to put on concrete

 

[JHZR2]

Sounds more like a parasitic draw than bad battery, considering only 3 years old, but you only drive the vehicle once a week. And doesn't sound like that solar charger is helping much. Get a battery tender or such.

Agree. Some solar chargers dont have, or could have a bad diode, and could allow reverse current under certain conditions.

Id get an ammeter on the vehicle and see what is really going on.

My 98 S-10 will draw the battery down, over the course of a few weeks, faster than other vehicles I own. I havent gotten to the bottom of it, even with an Ammeter, so some draws must be sporadic or something... Hard to tell in these cases...

 

[slybunda]

Multimeter showed parasitic draw used to be 45ish milli amp in the past and that was due to alarm siren battery having leaked out. Removed battery in siren and now parasitic drain is 22-35milli amp so more than acceptable.

My charge controller has block diode and iv also got one block diode directly in the panel itself.
The old charge controller was a bit crappy with around 7milliamp self power consumption and used to charge to 14.8v for 1 hour then float at 13.8v. My new charge controller pwm type custom one is amazing and charges to 13.2v and has 0.8milliamp self consumption which is next to nothing.

 

[Davejam]

If a battery is showing greater than 12.7-12.8V that's because its been recently charged or has a voltage applied.
It should drop pretty drastically to reflect its true state of charge/health. Which for a 3.5 year old battery 12.4V would be a very satisfactory reading.

If it can't handle the winter cold/low voltage then its time for a new battery unless you want to limp along to warmer weather.

 

[slybunda]

Hah if i can limp it to warmer weather then the solar panel will kick it up a notch and i will be seeing 13v+ every time i get in the car. Lol.

I vs seen charts that say 12.7v is full charge battery and 12.4v is 50 percent charge. I thought a charged battery would sit for a month atleast at 12.7v?

 

[wdn]

And don't put battery on the concrete when you store it outside the car. I know, common sense, but you'd still be surprised how many people do it.

I find it surprising so many believe the old wives tale about not storing batteries on concrete.

 

[slybunda]

I find it surprising so many believe the old wives tale about not storing batteries on concrete.

i dont get it either. i dont think a charge can escape from the batterys plastic housing even if battery is sitting on concrete? will have to read up on this.

 

[Propflux01]

I find it surprising so many believe the old wives tale about not storing batteries on concrete.

It’s not about the charge, it’s about if the batteries structural integrity is compromised, and the resultant leakage on concrete. Hence why when you go to a store to buy a battery, you will almost always see them on pallets or metal shelving.

What Happens When Battery Acid is Spilled on Concrete? | Prugar Consulting, Inc.