12V Aux Battery Alternative

The 26r is a flooded battery, not approved for use inside the vehicle. In case of a rear end accident, you may regret saving the $50 or so from buying an optima battery.....which is an agm battery that fits without modification

 

Vitriolic ventilation anyone?

 

In a rear end accident that compromises the battery, a flooded lead acid will spray sulfuric acid around the inside of the cabin. AGMs do not have any liquid electrolyte and so are considered much safer for applications inside the vehicle.

 

1. In an extreme case, an unvented battery can EXPLODE from the hydrogen gases while charging.

 

Short of that, if the flooded battery is not sealed and vented as the AGM was it can leak hydrogen sulfide gas into the cabin during charging. Normally for this type of battery this happens outside the vehicle in a ventilated space and so is less of a concern.

 

Oh for pity sake.
Who makes an UNVENTED flooded cell battery ? Hint: Nobody.

There are two potential dangers:

The vent tube comes loose from the battery and allows hydrogen, oxygen and some acid fumes inside the cabin.
The danger is slight even then......unless maybe you have a smoker who rides in the back seat.

For whatever reason, the case cracks and acid leaks out.
That would usually only happen if the temp falls below -50F or in an accident.

The risks are relatively small but they ARE there.

 

Well 1 explosion is too many

 

I don't get it. "Cranks the car?" The 12V aux battery has a very small role in a Prius. Basically, it's there to run accessories when the car is not in ready-mode, and turn on the computer and that's about it. After that, the car barely knows the 12 aux battery exists, despite what some "experts" have said about the way it affects the way the car runs, fuel economy, filtering power for the computer, or any other of that nonsense. On a bet, I'd take the 12V aux battery out of the car while its turned on, and drive it for days to prove the point.

 

Yeah, CCAs are pretty much irrelevant in the Prius. Capacity and discharge tolerance are generally much more relevant. A flooded starter battery will generally have more amps available (which you don't need) but likely be even worse with regard to discharge tolerance than the OEM. My guess is also that the Prius's charging algorithm, which is already on the weak side for an AGM, is going to even more chronically undercharge a flooded battery which also won't help the lifespan out any.

You probably could take the Aux battery out and have it run fine after booting. My guess is the observed issues of a failing 12V are due to the battery itself loading down the Voltage on the 12V line as it tries to charge. A weak or failing battery can actually be a lot worse than no battery at all. Funny things can happen to the controllers when their voltage is not what it should be. The filtering argument is not a bad one either, the inverter and dc:dc are very noisy which can also really cause problems in a micro controller. Its debatable why it happens, but after a decade plus of evidence there is little doubt that a weak 12V can cause strange things to happen. Perusing the history I'm sure you could find hundreds of threads with apparent major malfunctions (apparent HV battery, inverter, ECU failures) that were cured by simply replacing the battery. Interestingly even the all electric Leaf seems to suffer from similar odd behavior when the 12V gets weak.

$340 is ridiculous, but when you can get an optima or orbital deep cycle AGM for ~$150 I don't see any value in trying to go the flooded route. If you wanted to get even cheaper than that, I'd try something more creative like a smaller sealed UPS or Mobility battery (which there's a thread on somewhere) or a small Li-ion pack before I went flooded. A $30-50 10Ah battery would probably work just fine as long as you don't spend much of any time in ACC mode.

Rob

 

Being a bit old-school, I expected a bit of RFI to go along with the Prius, due to the large amounts of current being switched and converted/inverted, but so far, I haven't experienced it. Circuits have improved considerably in recent years with regard to reducing electromagnetic emissions. I won't say the battery doesn't filter the 12V power in the system, but I'd be surprised if it plays a large role in doing so. I welcome input from those with more knowledge of the subject.

 

Excerpt from the video: "...I'm gonna go ahead and lift this battery outa here...", then he reaches in with one hand, grabs the battery, lol.

I was changing the battery on our daughter's Pilot, the afternoon of New Years Eve. The thing was about 3 times the size, weighed maybe 30 lbs, and of course really close quarters, you can hardly get fingers under it, cables trying to snag on it. That was fun. Anyway:

OP, how the heck can the OEM battery be $340? Assuming you're in the States? Is that with labour?? I did a preemptive price check: a dealership up here could sell me the 3rd gen OEM battery for something around $210. That's STILL pretty steep: that Pilot battery was $150.

 

There is a ready market (unfortunately) for those who judge quality by the price alone. Millions are made this way, selling very mediocre products with exorbitant price-tags to throngs of (and I use this term thoughtfully) idiots.

 

^ Ever listen to the Age of Persuasion, On CBC radio. They cited one case: a new product was not selling, they raised the price significantly, and sales took off.

 

I listen to that show, and it's great. Personally, I know someone who had trouble selling a horse; no one seemed interested, until they tripled the price, and then they had plenty of interest. They got their asking price for it.

The old adage "you get what you pay for" is not always true, and it can lead you to getting scammed.

 

No you don't.
You just troll for arguments.