Battery Installation by Independant mechanic

That is reasonable. Do a telephone book or web search in your area for a mechanic that will work on Japanese cars, ideally specializing in Toyota.

Suggest that you call your two Toyota dealers to find out what is the price of a 12V battery from the parts counter. Should be around $130.

I personally don't see the point of buying the Optima and having to install the new battery terminal connectors, if you can buy the correct battery from the Toyota dealer for that price.

 

So are the Toyota and modified Optima batteries the only games in town?

I admit I never thought about 12V battery replacement when I bought my Prius and was surprised to find out how expensive it is. But looking at the batteries that fit my 1996 Corolla, those seem a lot more expensive than I remember them costing in years past.

 

Consider the requirements for the Prius 12V battery:

1. Absorbed glass mat (not liquid acid). In the event of an accident that hits the right rear fender, you don't want acid everywhere in the passenger compartment.

2. Vent fitting so that in case the battery is overcharged and hydrogen gas is emitted, that will go through the rubber hose which leads to the car exterior.

3. Physical size fitting the small space provided

4. ~35 Ah capacity

If you are willing to give up some of the above parameters and can fabricate your own terminal connections, then you can certainly find a cheaper battery made in China.

The Toyota battery is made in Japan and comes double-boxed. Those are two reasons for its cost being what it is. Not sure what Optima's reason is for its cost.

I recently bought a replacement battery for my HiHy which physically is a similar size to the Prius battery. That cost ~$90 from the Toyota dealer. Two reasons: made in Mexico, and liquid acid technology. The HiHy battery is mounted in the hood area, so AGM is not required.

 

If you are looking for a database of mechanics that customers like, I use this:
Car Talk. Car tips, advice, and troubleshooting. | Mechanics Files

 

Toyota's battery has a 1 year warranty & is a bit of a PITA to replace.

 

Yes, unless you want to do your own modifications and/or craft an installation kit. To be clear, eLearnaid sells an installation kit for the Optima, the battery itself is not modified.