2003 Forester

I am pretty sure there is not a difference but when I looked at batteries on line at Auto zone some say in the description for Manual trans. Anybody have some input on this?

Edited June 13, 201510 yr by desertsubaru

Auto trans cars use a higher amp battery because there is more electrical load on the battery and alternator due to the electronics associated with the automagic trans. (Trans control unit, valve body solenoids, etc)

 

You don't want to put the lower amp rated battery for manual trans in an auto trans car.

Auto trans cars use a higher amp battery because there is more electrical load on the battery and alternator due to the electronics associated with the automagic trans. (Trans control unit, valve body solenoids, etc)

 

You don't want to put the lower amp rated battery for manual trans in an auto trans car.

So what should the minimum crank amps be?

There's no specified minimum that I can find.

Typically the difference in cranking amps is about 50-75 amps. Ex. 475 for manual, 550 for auto. This can vary between battery manufacturers.

 

The FSM does specify base capacity of 48Ah for manual, 52Ah for automatic cars.

Battery size numbers 55D23L, and 75D23L respectively. But I haven't found any cross-reference for those numbers yet.

So is there any advantage to using an "automatic" battery--with higher CCA--in a "manual" car?

Auto trans cars use a higher amp battery because there is more electrical load on the battery and alternator due to the electronics associated with the automagic trans. (Trans control unit, valve body solenoids, etc)

 

You don't want to put the lower amp rated battery for manual trans in an auto trans car

 

Nah,That is not the correct reason at all.

Automatics need a bigger battery because the starter needs to turn the torque converter et all.

 

Same reason the automatics use a gear reduction starter and the manuals don`t.

 

Both use a reduction drive as far as I know. Newer starters use a planetary reduction where the older ones were ring gear and pinion type.

 

Converter is heavier, and the trans pump is driven as well. Valid point there.