12 volt battery... what am I missing?

I have wondered the same thing myself. I know AGM is best to help prevent excessive gassing (the battery is inside the passenger compartment after all) but why for example wouldn't this battery work:
Mighty Max Battery 12V 35AH SLA Battery John Deere Tractor Riding Mower brand product

Built for vibration, AGM, SLA. It even mentions being used in medical equipment, which would have to have pretty stringent requirements on emissions.

Posted via the PriusChat mobile app.

 

300-350 bucks for a 12v battery for my 2016 Prius. That is, if the dealer can even find one.

 

If your Prius has a smart key system, there could a vampire voltage which would destroy a cheap 12 battery in no time.
A $20 lawn tractor battery is designed for an instantaneous surge for starting, and not for sustained drain.

 

Prius camper uses a wheelchair battery in his car. I wonder how long his battery's last?

 

When the ice is running the 12v is getting a small charge, and a non venting 12v is spewing noxious gas in the cabin, the OEM is tiny (not size) but it's a deep cell, meaning it can can be discharged then recharged in a cycle, unlike non deep cell.
it's easy to leave a light on or a door open.
it's OEM, the least expensive part placement possible, Toyota is very good at making a profit.
if the 12v is poor, or dying, it's taking more of a charge than a health 12v that eventually tells the Prius that it's full, so eventually a poor 12v is going to make the ice run more.

On the other hand, schlepping around a ten pound battery that spews whatever into the cabin beats schlepping around a 40 pound battery, except for the extra ice cycles.

 

Typically batteries that are designed to be in the trunks of cars are both pressure sealed and vented. They only vent if the internal vapor pressure goes beyond a certain pressure. The vent tube assures the hydrogen gas gets vented out of the car. Any replacement battery should have those 2 safety devices.

 

likely an economy of scale thing. prius battery is unique, and just aren't enough prius needing replacements to bring the cost down.
idk why the battery for your neighbors caddy battery was so high, but a normal car battery is around a hundred bucks.

 

for instance, if you plug in a 2008 camry into the sears website, theres a ton of batteries for 70 bucks and up

 

I will miss those days....

 

My 12v is in the engine bay. And it sure looks like a regular ol' battery. Maybe just a bit smaller. I can't tell. Toyota is making a killing on those things. Hopefully it will last for 6 years, if I'm lucky?

 

You do understand that this the Gen 2 forum for Prius built from 2004 to 2009 don’t you)

 

Doesn't matter, Skibob. Posters cross forums all the time. A Prius is a Prius is a Prius. Just the looks are different. A Disneyland car with a battery under the back seat.

"Can't we all just get along?"
-- Rodney King

 

Ah, good point, on the gen2 the air that moves from the cabin to the traction battery for cooling and is then taken via duct directly to the 12vbattery where it has a way to the outside, it's rather efficient, while the gen3 moves air from the cabin to the traction battery then to the rear spare tire area then to the 12vbattery then to the outside, I prefer the gen2 method.

Of course the gen4 put the 12v up front with the ice, in the boot.

 

i've never had to replace a prius battery, so it's not much concern to me

 

My current car came with a yellowtop that the PO said was brand new. It's been discharged twice (my fault for leaving the smatkey on) and now reads bad battery on my charger. Since I don't have a receipt, the local Optima dealer wouldn't warranty it.

I bought a new normal AGM from a local Interstate Store, but the terminals where on the wrong side and too big. I modified the terminals, but I expected more from the yellowtop. I don't know the age, but I bought the car 10 months ago.

In my first 2004 Prius, I modified the clamps to use a $30 motorcycle battery. I think I got the idea here.

 

So you can supply Zero help? Why you post?