The challenges of modern car batteries

[Craiglxviii]

This is why RVs often have *two* batteries of oft-similar appearance and nominal AH capacity but very different internals.

The 'vehicle' has huge CCA-provider for 'cold start on a cold day' or 'jump start' cranking.
The 'recreational', like 'off-grid' battery, provides for steady loads: Often sealed 'SLA', best fused to shun CCA stuff.

I've heard of RVs / Motor-homes whose alternators died using 'recreational' to keep vehicle going after 'CCA' start...

Stater battery and Leisure battery. They do pretty much opposite things; one provides high current for a short duration, the other provides low current for a high duration. Interestingly both can be used as internal grids for their respective power systems, dependent on the complexity of the charge controller and battery chemistry.

[Nightwatch2]

This is why RVs often have *two* batteries of oft-similar appearance and nominal AH capacity but very different internals.

The 'vehicle' has huge CCA-provider for 'cold start on a cold day' or 'jump start' cranking.
The 'recreational', like 'off-grid' battery, provides for steady loads: Often sealed 'SLA', best fused to shun CCA stuff.

I've heard of RVs / Motor-homes whose alternators died using 'recreational' to keep vehicle going after 'CCA' start...

Stater battery and Leisure battery. They do pretty much opposite things; one provides high current for a short duration, the other provides low current for a high duration. Interestingly both can be used as internal grids for their respective power systems, dependent on the complexity of the charge controller and battery chemistry.

Ah! (Smacks forehead)

When I bought new batteries for my RV (towed) they were sold with the AH load.

The car and truck batteries are sold with the CCA rating

And Marine batteries (for sailors, not Marines) are sold both ways with some “dual use” depending upon the maritime configuration of the boat.

I always buy the biggest, baddest battery that can be shoehorned into place.

It’s just surprising to me that car batteries whose only real function is to start the car (in sub zero weather) would be rated by Ah rather than CCA.

Learn something new every day

[kdahm]

To my understanding, there are two types of liquid lead acid batteries in common use. The car or truck starting batteries, and marine/RV deep cycle batteries. Starting batteries have more plates in each cell that are thinner, thus a higher specific surface area and the capability for delivering more amperage in one go. Deep cycle batteries have thicker plates and fewer of them, which means that the peak amperage is lower, but that they are more resistant to degradation caused by using the energy and dropping the battery charge.

A starting battery can be killed by draining it ten or twenty times. They're meant to be charged pretty much constantly. Deep cycle batteries are better at draining and refilling, and can do so many times more.

[Craiglxviii]

This is why RVs often have *two* batteries of oft-similar appearance and nominal AH capacity but very different internals.

The 'vehicle' has huge CCA-provider for 'cold start on a cold day' or 'jump start' cranking.
The 'recreational', like 'off-grid' battery, provides for steady loads: Often sealed 'SLA', best fused to shun CCA stuff.

I've heard of RVs / Motor-homes whose alternators died using 'recreational' to keep vehicle going after 'CCA' start...

Stater battery and Leisure battery. They do pretty much opposite things; one provides high current for a short duration, the other provides low current for a high duration. Interestingly both can be used as internal grids for their respective power systems, dependent on the complexity of the charge controller and battery chemistry.

Ah! (Smacks forehead)

When I bought new batteries for my RV (towed) they were sold with the AH load.

The car and truck batteries are sold with the CCA rating

And Marine batteries (for sailors, not Marines) are sold both ways with some “dual use” depending upon the maritime configuration of the boat.

I always buy the biggest, baddest battery that can be shoehorned into place.

It’s just surprising to me that car batteries whose only real function is to start the car (in sub zero weather) would be rated by Ah rather than CCA.

Learn something new every day

Over here car (starter) batteries are sold by both, there is a standard designator for form factor and Ah (manufacturer-agnostic) and then a rating for CCA against that.