Battery size

[Cornpatch MO]

I have a 1968 Satellite 318 auto with factory A/C . Why is it that the battery box- tray is so large? The stock battery must have been huge. My current battery has plenty of cold cranking amps and is a sealed battery. Today, I received a reproduction hold down kit, and it is for a much taller battery. I had to put spacers on the J hook rods because I ran out of threads before the top clamp could tighten down. And now there is 2-3" of threaded rod sticking up above the clamp. I could shorten the rods but then they might be to short if I go to a bigger battery... Purpose of the stock large battery? ..........................MO

 

[Jerry Hall]

68 Satellite 318 car came with a Group 24 battery from the factory, more than likely it had the yellow caps.

 

[MoparLeo]

Battery technology has improved a lot in the last 50 years. The most common battery size in those days were the group 24 and group 27. Much larger than todays batteries. The closest physically sized modern batteries are for trucks.
https://www.batteryequivalents.com/bci-battery-group-size-chart.html

 

[66383]

Went through that identical thing in April. Had to shorten J Hooks.

 

[vance.dykes]

could put a spacer on the bottom of the j-hook so it would be so noticeable ?

 

[69Bee]

Sit the battery on some 2x4's... jk

 

[Cornpatch MO]

Battery technology has improved a lot in the last 50 years. The most common battery size in those days were the group 24 and group 27. Much larger than todays batteries. The closest physically sized modern batteries are for trucks.
https://www.batteryequivale good info therrents.com/bci-battery-group-size-chart.html

Thanks for the link...very good info there. ...................MO

 

[Cornpatch MO]

Sit the battery on some 2x4's... jk

I just may do that !! Until I decide if I want to go to a bigger battery..........................MO

 

[Cornpatch MO]

Still remains the question of , why do A/C cars have larger alternators ( amps) and larger batteries? Does the compressor need to draw a lot of electricity? ..........MO

 

[Photon440]

I wouldn't think a lot of electricity as the compressor is mainly powered mechanically with the belt. The whole A/C electrical circuit, including blower motors, electric clutch and switches are run through a 20 amp fuse so the draw ought to be less than that. Including the larger sized ancillary items helps justify the high cost of A/C in the consumers eyes.

 

[69bfan]

In regards to the question on the size of the battery tray, back in the day, the correct battery configuration was either a group 24 or 27 battery. Both the 24 and 27 batteries are of the same height and width. The group 27 battery is longer in length due to the extra cells yielding more cranking amps for back in the day.

Generally, the group 24 battery was the standard issue unless special ordered with a group 27. The 440's and Hemi's came standard with the 27.

 

[RJRENTON]

Gentlemen,
I agree with 69bfan's premise, re battery dimensions. It's not adding more cells but more components to the individual cell (more plates).
The battery chemistry is: Lead (Pb) and Lead Dioxide (PbO2) + sulfuric acid (H2SO4 diluted with water) to yield a specific gravity. Each CELL produces 2.0 volts. Six cells = 12 volts when connected internally in series. The more plates per cell equals more power or cranking amps per cell at 2.0 volts / cell or 12 volts total (not more voltage). AGM batteries use the same chemistry but use different manufacturing methods to produce a significantly better battery, with lower internal resistance which results in more energy available.
Bob Renton

 

[Ranger16]

Isn't a fully charged battery 12.6v equaling 2.2v per cell?

 

[RJRENTON]

Rsnger,
Yes, 12v is a nomimal value. The true measure of the bsttery' s state of charge is to measure the specific gravity of the electrolyte, measured with a hydrometer. Typically, 1.260 - 1.270 spgr (corrected for temperature) is considered fully charged. The individual cell volrage will be ~ 2.2 volts or 13.2 volts total. But with the advent of sealed batteries its impossible to measure either specific gravity or voltages of individual cells. As the battery is discharged, the specific gravity will decrease from 1.260/1.270 to 1.100 or less. Charging the battery with 14.0/14.5 volts will reverse the condition and restore the specific gravity value.
Bob Renton