optima yellow tip overrated?

Has anyone tried a Walmart Group 51 or 51R battery? I read somewhere that 51/51R should fit?

 

This got me curious, as I was unaware of Wrongmart selling Prius compatible batteries.
If this is the same group 51R battery you are talking about, LINK, bad idea: lead acid battery. Could not find a Group 51 battery.

The more knowledgeable experts can correct any of my following errors or omissions, but lead acid battery in the small confined space, inside the passenger area is a BAD idea:
*hydrogen gas gets released when lead acid batteries are charged (don't know how much, but I just envision Hindenberg)
*confined space subject to faster rust/corrosion, due to the gas fumes and possible spillage of battery acid over time

The only AGM (Absorbent Glass Mat) batteries for the Prius appears to be: Toyota Dealership, Optima Yellow Top, Exide Edge AGM, Bosch Premium Performance (AGM), O'Reily ($176 & 3yr warranty), and user modified AGM batteries not originally made for the Prius (like member Britprius did).

 

My understanding is that they are all lead acid. AGM means less fluid sloshing around.
The Exide battery for the Prius can be seen here, along with the manufacturer code. In addition to a vent tube, it has skinny posts and the positive terminal is on the left side (when looking at the front of the battery) -- the opposite of most batteries.

Notice how the Toyota OEM is a much better deal ?

 

Wouldn't it have been better for the manufacture just to use the larger 45A hr battery? One battery to stock. One bottom battery tray to stock. Consumers would benefit by an even cheaper battery, because of the larger combined volume of smart key and non-smart key vehicles. Non-smart key vehicles also have an additional benefit of a larger reserve.

When I was shopping around for a battery, the Toyota non-smart key (35A h) battery was a minimum of $20 more than the smart key batteries (45A h). Some dealerships were considerably more than $20. Ugh, Toyota, what were you thinking? One part across multiple models and multiple generations (Gen2 and Gen3 for sure, and maybe the upcoming Gen4).

 

Interesting to note that in the Gen III cars up until just recently, Toyota went back to the 35ah battery as standard with the SKS system. The change to 45ah seems to have happened close in time to the Exide 45ah introduction.

Roland

 

The only advantage with a 35 AH battery is the small saving in weight. A reduced capacity battery cannot help reliability or longevity from a customers point.
From Toyota's point of view it probably saves them a few million $ a year buying a smaller cheaper battery "the price of batteries being almost proportional to there lead content", and then selling them customers at a higher price than the larger battery as replacements.

John (Britprius)

 

If by "less" you mean "none" then you are correct.

The A in AGM stands for "absorbed". All of the electrolyte, which is essentially the same as in a flooded cell battery, is absorbed into the glass mat and if the case is broken little or none leaks out.

 

This Toyota parts store lists the OEM for ~ $145. If combined with other items to defray shipping costs it might be an excellent deal.

 

Adsorbed is not going to be 100%, so 'less' is a more accurate description. This is why, as you say, a little can leak out if the case is penetrated.

 

You seem like an reasonable person so please let's not get into a nit picking argument here.

Maybe my problem is with the term "sloshing".
If properly filled, that is not over filled, the literature on AGM designs suggests that no more than a couple of drops should come out, if any at all.

I have no direct experience with a damaged AGM battery so now I will quit.

 

According to the information I have on AGM batteries is that the mats between the plates are only saturated to 95% of there liquid holding capacity, and are designed so that the liquid that is absorbed does not permeate down with gravity to the bottom of them.
In use it is inevitable that over time the saturation level goes down particularly if battery is charged at a rate, high enough to force it to vent. This increases the strength of the acid absorbed as the vented gasses "hydrogen and oxygen- water" leave the battery.
This I suspect is the reason why the OEM battery does not last if it is deeply discharged. The Prius charges the battery at a high rate when it is discharged, and the battery has a maximum design charge rate of 4.5 amps. This causes it to vent removing the vital liquid content.

John (Britprius)

 

Appreciate the price update. Maybe folks who are in driving distance or willing to drive to Autonation in Houston, TX, will do a will-call pick-up.

Unless Toyota changed the content(s) of their AGM batteries, so it no longer contains a chemical which is considered hazardous, UPS, FedEx, and FedEx Ground won't ship; assumed USPS too won't ship. Only FedEx Hazardous Materials shipping will ship, but the cost is way more than the battery. Found all this out contacting Camelback and Olathe, back when I was shopping for a replacement battery; won't ship, but they would do will-call pick-up.

You would think that if Bosch, Exide, and Optima batteries can be shipped from various websites, who use UPS or FedEx Ground, Toyota could too? Guess Toyota is being overly cautious to prevent litigation.

 

The store says they ship by ground. Perhaps a different carrier ?

 

I don't know who else the online dealers could use that would still be cheap for them and the customer. The online dealers and major companies all seem to use UPS or FedEx Ground primarily, and USPS as a last resort. I can't imagine an online dealer trying to use the same company that Amazon uses when a package doesn't come by FedEx, UPS, or USPS.

I just think its strange that Toyota say their battery contains some chemical, which is considered a hazardous material. Don't know what this chemical is, nor did the parts person I was speaking to. But other companies have no problem shipping a competing AGM battery, using the two large ground shippers: UPS and FedEx Ground; can't imagine all the Prius compatible AGM batteries being chemically different.

Too bad Camelback wasn't located in Las Vegas. An easy road trip with parts pick-up. Oh well.

 

The hazardous chemical is sulfuric acid. I do not know if they would consider lead as hazardous, but it to is poisonous. In the UK we have no problem with transporting ordinary lead acid batteries.

John (Britprius)

 

Where exactly did you find that an AGM battery vents if it is charged faster than 4.5 amps ??
I have never seen that in any spec. that I have looked at......maybe a half dozen over 5 years.
If that is even close to being true, it might explain why there is a nipple for a vent tube on a "sealed" battery.

 

On top of the battery it give the maximum charge rate as 4.5 amps. The maximum charge rate is generally considered the charge rate at witch the catalyst in the top of the battery can no longer recombine the gasses turning them back to water. At this point pressure builds within the battery and the pressure release valves open to vent the gas. Under the correct charging conditions this would not happen.

John (Britprius)

 

I should have added to the above, a flooded lead acid battery does not need to be sealed and the gasses recombined as water can be added to the battery whenever the electrolyte gets low. Charging rates can be high providing the temperature of the battery is monitored, and the battery can gas freely. With a sealed battery there must be some way to return the gas or let it go or the battery would burst.

John (Britprius)

 

i suppose it would help to know the specs, but it may be that the size gives away the volt and amperage.