How many ampere-hours are in this battery?

[Darek]

I am going to buy a battery charger because the battery in my wife's car is very weak. I want the charger to be compatibile with the battery in my Pathfinder. As far as I know a charger compatibility depends from battery ampere-hours (Ah).

I have the Napa Legend 75 Months battery. From the sticker I can read: 24 BCI, 820 CA, 650 CCA.

There is no model number neither Ah value.

 

Do you know how many Ah could it has?

[Precise1]

Ok, the BCI is just a size chart code:

24

260x173x225

LxWxH

http://www.rtpnet.org/~teaa/bcigroup.html

 

I picked out this battery because it is the closet to your specs and is the same size (larger cells could mean more amp hours) http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=NBD7524_0269022338

BAT 7524

Battery BCI # : BCI #24

Battery Cold Cranking Amps @ 0 Degrees F : 600

Battery Cranking Amps @ 32 Degrees F : 750

Battery Load Test Amps : 300

Battery Posts Type : Top Mount

Battery Reserve Capacity (Minutes) : 110

 

Odds are your exact model isn't made anymore, and here is a tidbit I ran across...

Quote

 

Napa batteries have been made by Deka since early 2009. They make great batteries. At our Napa store, the defect rate is 75% less than when Exide was supplying us.

so I looked up this...

Quote

Exide makes Exide batteries, Champion, Napa and even a % of the EverStart batteries.

cross referenced it here and selected the Exide 24-75 as the comparison and after that, I couldn't find an amp-hour rating. RC (reserve capacity) seems to be the preferred standard due to the many variables in calculating AHs. If I had to take a guess, it would be around 50-65 amp hours.

http://www.interstatedealers.com/IBCatalog/common/comp_x_ref.pdf

 

Then I found this gem!!

Quote

Amp/Hours = (Reserve Capacity / 2) plus 16

So, assuming the RC of 110 (the battery I cross referenced to) the amp hours are 71. My guess was a bit low.

 

 

Ok, all that said, you battery is just a basic lead acid battery and any trickle charger should suffice, it is more a factor of how long you leave it on to recharge. I believe that only the AGM type of battery has specific charging requirements, and that they want more current. I have a 6amp charger that I use on lead acid and AGM alike without issues.

 

B

 

Oh, then there is this...

Quote

To properly charge a battery, you should apply a voltage that causes current to flow (being careful to get the plus and minus hooked up properly!) at about 1/10th the amp/hour rating of the battery to a maximum of about 1/4th the amp hour rating of the battery.

If you care to educate yourself...

http://www.chem.hawaii.edu/uham/bat.html

Edited April 5, 2013 by Precise1

[Trogdor636]

Man. I just buy a battery charger.

[Precise1]

Sometimes I want to know the why or science behind it. Then there is the coffee I drank in the afternoon (and why I usually don't)...

It was worth it to learn the equasion though. As a fine teacher once told me, there is no need to memorize answers if you learn how to derive them.

 

Here, I'll throw you a bone: Machine screw thread OD.

(Size # x .013) + .06

0-80=.06" OD

6-40=.138" OD

10-32=.190" OD

Of course these are theoretical values, actual threads will be .005-.01" smaller for clearance/poorly formed thread

 

See how much fun we are having? Want the metric thread core hole size equasion?

 

B

[Darek]

Precise1, thank you for your research. It was very helpfull for me.

[Precise1]

You are welcome, I enjoyed it and learned things as well.

 

B