Battery voltage too low?

[madeej11]

A normal car only has a parasitic draw of about 50 milliamps. That's not enough to pull the voltage down on a healthy, fully charged battery to 12.4 volts. Even a worn battery will show higher than 12.6 volts right after being fully charged. They call this the surface charge. After sitting for a while, the voltage goes back down to it's normal full charged state.

I got a new Interstate battery a couple weeks ago and charged it up before installing it. The initial voltage after taking it off the charger was 13.2 volts. After I installed it and started the car and turned it off, (thus removing the surface charge) it read 12.7v.

If you got an initial reading of 13.2 V why would you have taken it off the charger in the first place? It's a brand new battery so it's usually standard procedure to get it 100% charged before installation

12.2-12.3 vs. 12.6-12.7? That's pretty minimal and could even be from the resistance in the voltmeter cables.

That is hardly what I would call minimal. The difference in those figures is a 1/2 charged battery to a fully charged battery.

 

[madeej11]

If you got an initial reading of 13.2 V why would you have taken it off the charger in the first place? It's a brand new battery so it's usually standard procedure to get it 100% charged before installation

That is hardly what I would call minimal. The difference in those figures is a 1/2 charged battery to a fully charged battery.

My bad ripcord please disregard that portion of my post, don't know what I was thinking. Sorry.

 

[bbhero]

 

[alarmguy]

I would just replace it, good or bad after 4 years.
To me, every car should get a new battery after 4 years of use or sooner!

 

[Wolf359]

I would just replace it, good or bad after 4 years.
To me, every car should get a new battery after 4 years of use or sooner!

It really depends where you are. In cold states, batteries last longer. I've got an AGM one right now that's 13 years old. Voltage still seems fine. It's at 11.8 with the car off and maybe 50 degrees. But that's with the radio on, nowhere near a no load voltage. If I turn the seat heaters on, it drops down to 11.6. My car shuts things down once you go below 11 volts. It doesn't really get below 11.5 even in 20-30 degree weather. Oh and the battery is in the trunk so it doesn't get heated up like other cars that have it in the engine compartment.

 

[bbhero]

Key words... Battery in the trunk.

That helps immensely with battery life.

 

[alarmguy]

Yes, agree, batteries in engine compartments do not have a long life in the South.
When we moved here form the Northest now over 12 years ago, we would blow through batteries every 2.5 to 4 years.
Our summers here are hotter then Florida for a solid 8 weeks we are always 95 to 100 +/- 3 degrees and then still warm before and after that.
Walmarts free 36 month replacement was fantastic.

I know BMWs have trunk mounted batteries, interesting to me, our new to us 2017 Traverse battery is someplace under the back seat. First thought that came to mind was, maybe I can wait 1 year to change it, so going to put it off until Spring of 2021,

 

[Wolf359]

Key words... Battery in the trunk.

That helps immensely with battery life.

I have another AGM battery that's in the engine compartment that's 10 years old at this point. It does have a plastic cover over it so maybe that protects it against some of the heat from the engine compartment.

 

[bullwinkle]

I wouldn't replace that battery until it fails a load test, or cranking speed starts dropping on a cold start. I replaced the OEM Panasonic in the '05 xB in my sig at 7 years old because it tested a little weak, and the JC made AAP Gold replacement leaked battery acid all over & stripped all the paint off the front undercarriage on that side after only a couple years. The Panasonic soldiered on for 4 more years in my brother's old Tercel before he finally killed it.

 

[RichardZ]

So I had my battery tested at a local garage. The results were:

Replace Battery
Voltage: 13.00V
Measured: 472 CCA
Rated: 650 CCA
Temperature: 54'F

Thoughts? I invested in a portable lithium battery jump starter. I think I'll keep running the battery for a while and see what happens..

 

[RichardZ]

Test results..

 

[bbhero]

Well that has 72 percent of it's rated CCA. 5 years old is pretty ok for being a OE battery.

Just go ahead and replace it.

 

[Davejam]

What's the CCA required for the car, what was the original OE battery CCA?
Because sometimes aftermarket batteries have much higher CCA than is required.
A quick search for a 4runner and it might be 530CCA?

I think you are ok.

 

[Donald]

The stores will use a Midtronics conductance tester which should be temp compensated. It will tell you the % of the rated capacity.

The best test is a carbon pile load tester where you put 50% of the CCA load on battery for 15 seconds, it will beep. Then quickly read voltage on temp compensated scale and disconnect. But battery should be fully charged for the true load test.

 

[eljefino]

Well that has 72 percent of it's rated CCA. 5 years old is pretty ok for being a OE battery.

Just go ahead and replace it.

Midtronics used to say maybe at 60% and replace at 50% of original CCA. I'd keep going.

 

[Wolf359]

And I'd also put it on a charger. Fully charged batteries last long than partially discharged ones.

 

[E150GT]

Is never got more than 3 years out of a panasonic battery and I've had two of them. You done good but I will think you'll be shopping soon

 

[bbhero]

Midtronics used to say maybe at 60% and replace at 50% of original CCA. I'd keep going.

I know you are correct.... And I knew that when I put that post up.

However... Those battery testers can be wrong and it happens a good bit. Ask me how I know... .

At 5 years... A lot of OE batteries have already been replaced. And I would rather not be surprised or stranded. Buying a jump box is a good idea. Just me... For the money of that... Just get a new battery.

 

[painfx]

View attachment 32387

Awesome chart.

 

[Davejam]

Just as a point of reference - My battery was reading 11.9V this morning, it was 40F.
I was a bit nervous as I may have jinxed myself with the advice given on this thread.
But fired up crisply.