While I may be a newbie to this forum I feel like something of a dazed veteran after reading 23 pages of advice regarding the auxiliary battery. Very useful information thank you.
I am wondering why the Optima D51 yellow top wasn't mentioned much. The fellow at elearnaid.com had been recommending the Exide but, since it was not currently available, he said I should get the Optima D51.

The Optima D51 has specs that are nearly identical to the Optima Prius battery - 38 Ah, 450 amp, and similar dimensions. The one significant difference I see are SAE posts on the D51 which fit the Camry. The D51 also has an opening for a vent tube - many people said that the vent tube was not a necessity but if it has a vent tube, why not?

Several posters either used or recommended the Prius battery in the Camry. The D51 does have fewer amp hours and lower cold-cranking amps than the D34 (48Ah) and the D35 (55Ah) but will that make much difference given the role of the auxiliary battery in the Camry hybrid? All in all, the D51 appears to be a quick and easy solutiion - is there any reason not to go with the D51?

Thanks in advance, David

 

Let me add that my TCH has around 350,000 miles on it. Wha?? Yeah, bad on my part that I didn't spring for a CarFax report prior to purchase and discovered much later that the odometer had been rolled back 245k. Lesson learned. Let me say, however, that, other than oil consumption, it had run quite well for a year and a half.

I first got the dreaded Check Hybrid System/VSC warnings two or three thousand miles ago, removed and cleaned the traction battery, and the car did pretty well for a few weeks - no warnings. When the warnings did come back I used the Toyota software to look at the traction modules and the voltages were quite consistent from block to block. I kept driving as the warnings would come and go and the warnings seemed to be related to the traction SOC at shut down. When the traction SOC began to top out in the blue (no green) I began to investigate the role of the auxiliary battery and, thanks to this forum, decided to give it a repair and recharge.

Since then (a week or two) the traction battery consistently rises to green... yea! and thank you. By no means do I believe that the problem is solved because the initial voltage on the auxiliary battery is pretty low so I'm ready to spring for a replacement auxiliary in the near future. Understandably, I am not looking for a five-year replacement but nor do I want to invest a nickel in a battery that might be inadequate from the start.

Thanks for reading and may you take some comfort in knowing how far a TCH is capable of going.

 

Rolling back an odometer is a federal offense, and should be reported. However, the TCH has an electronic odometer that is virtually impossible to roll back. I suspect your car had a failed odometer that had to be replaced at some point.

 

In the end it was an obvious decision. The standard replacement battery is an Optima D35 and the D35 also fits my Tacoma and Corolla should the TCH bite the dust.

My only concern was venting but that concern had been pretty well discounted in this thread. The fit was spot on using half of the plastic tray that came with the battery. I had to reverse the battery in the compartment to orient the two poles properly but there was plenty of cable slack to make it work easily.

Thanks for all the helpful information.

 

Alan, odometer can be rolled back on any vehicle. You simply have not seen vehicle assessors videos where they log into all vehicle systems that register mileage and check on actual mileage. That said, I am not even talking Camry. I am talking such advanced whales like Mercedes, BMW or Rovers - with actual mileage completely changed. And I am not talking old models. 2016, 2017. It's all done.

But anyhow. YT Optima is rather expensive by now replacement. It still may be cheaper than dealer OEM one but, there are very functional and hovering around $100 batteries that will work. Personally, I'd rather pay 2 times less and get one of them now. Especially when venting is not a concern. It's easy online search, I don't really want to endorse any particular battery. Judge for yourself.

 

Well, the 12V battery in my '07 TCH kicked last weekend. So I replaced it with the Optima YT.
Unfortunately, somewhere between the removal and install, I managed to misplace the temperature probe.
I check with Toyota, but they're sold as part of the battery.
Does anyone know of a source for these?

 

My 2 cents -- Lead-acid batteries are harmed by high temperatures, cold temperatures, being drained (sitting in the driveway listening to the radio without the engine running), cranking the engine to start it, sitting unused on concrete (don't ask me why), dirt on the case (combines with moisture to short out the terminals gradually). Once they've been run dead they never fully recover, and will let you down hard some cold winter morning. Those YouTube videos that claim you can restore one are just looking for a sucker.

Jumping a modern car with a dead battery can be an excellent way to trash sensitive (expensive) sensors in either car, but especially in the one with the dead battery.

My wife had a '98 Buick Riviera with the 3.6L engine that the engineers at GM were extremely proud of. It fired so fast, you barely touched the key to crank and start the engine. Battery lasted 10 years, then failed with very little warning.

She now has an '09 Camry Hybrid so, again, there's no cranking going on. Original battery will be replaced soon just because it's been over 10 years. It's always garaged, we drive it to Florida to avoid Michigan winters. 115,000 miles, original brake linings.

My '05 Prius has not been so lucky. Leaving it behind for 2 months of winter is hard on the 12V battery -- I've gone through 5 batteries in under 15 years. Dealer prices for the OEM have gone from $125 in 2008 to $220 in 2019 (???). The Optima yellow-top has always been around $240 (I got one free because the first only held a charge for a little over 2 years before I got a trickle charger for the winter). There is some scuttlebutt about Optima making junky batteries when they were bought by Johnson Controls. Considering their 3-year warranty, I may try them again anyway.

I've used an OBDII reader (under $15) with the Torque Pro smartphone app ($5) to keep track of the voltages in each individual cell in the traction battery. So far, so good -- they all read the same voltage at 110,000 miles (also original brake linings).

 

FWIW I've grown to believe that corrosion on the terminals of each cell may be what causes some major problems. Taking the traction battery out of the car just to loosen, clean, lube (DeoxIT, for example) and tighten a bunch of nuts may sound crazy, but it could explain any cell that has wild fluctuations in its voltage.

 

Since the conversation has changed to Prius batteries, I can say I won't touch an Optima. I've heard many folks working part store folks say they've seen lots of returns in recent years. I routinely pull them out at the 2-3 year mark. I had one that was 1 years old nearly melt down. Was too hot to touch and was venting so forcefully, it was whistling. Up until recently about 1.5 years ago, I was still pulling originals out of the Prius - here in Phoenix.

Want to protect the 12V of a Prius? Simply disconnect the large white plug on top of the positive terminal. No tools needed. The Yuasa made batteries are very durable. They also hold their charge a VERY long time and only lose about 20% per year.

I recently did a reserve capacity test on a 2 year old Prius battery. IIRC, RC is 67 minutes. This 2 year old battery tested at 55 minutes.

Lastly, Toyota warranty is 7 years, 2 year replacement, 5 year prorated.

 

Based on my experience with about 300 failed HV batteries, this is absolutely, positively not true. In extremely corrosive environments, it can cause problems with the sensing harness, but even on the most corroded bus bars, one always sees a clear face of copper in contact with the module terminal even when the rest of it is black. That face is responsible for about 98% of the conductivity of the bus bar.

Expanding my experience to additional data sets I can access from people I trust indicates that out of over 1,200 failed Toyota batteries over the last 5 years, not a single one was caused by corroded bus bars.

Yes, it can happen, but it is an extremely rare event.