100AH lithium battery holds MORE power than 100AH lead acid??

[Chotu]

This one is for the electrical engineers.

Talking about lithium batteries in a different thread, my mind wandered to something.


A 100AH lead acid battery is anywhere from 13.6 to 12.2V in the normal usage range, delivering 50AH over this discharge cycle.

A lithium battery is at 13+ the whole time delivering 50AH during the same discharge cycle.

Putting aside the ability to more deeply discharge a lithium battery for a moment….

If I’m getting 10 amps over 5 hours out of a lead acid battery and half of that is in the 12V range, while I’m getting the same 10 amps over 5 hours from a lithium but it’s all over 13V, isn’t the lithium actually delivering (and storing) more power by definition?

After all, that definition is Watts(power) = VOLTS x amps.

So given the same 100ah of power in both battery types, the one returning the higher voltage through that discharge is actually returning more watts (power) for the same discharge in AH we usually talk about.

I think that makes a 100 amp hour lead acid battery and a 100 amp hour lithium battery not equivalent in terms of their ability to return energy. We never talk about this. We talk about amp hours.

Yes, we say we can discharge a lithium more deeply, but we don’t talk about the fact that it’s returning more power even in the same cycle the lead acid is in.

Yes? Comments?