Yet another thread about a dead Optima battery

Yesterday we returned from an 82-day trip off the island. While we were gone, we asked the neighbor to drive our 2006 Prius. The car's Optima battery is 4.5 years old. This neighbor is not mechanically inclined but we talked about the risk of draining the 12v battery by leaving the hatch open or an interior light on.

She drove the car daily for about three weeks, and then she said that during one series of errands the car unexpectedly refused to start. The dashboard lit up with yellow caution lights (check engine, traction control, maintenance required, TPMS) but no red lights. She called a tow truck. She was upset and distracted and she's not sure whether he attempted to jumpstart the car (she's still not mechanically inclined). The car was loaded on the truck's platform and brought home, where it sat in the driveway for two months.

Maybe something in the Prius broke, or maybe she left the hatch unlatched. When I came home and looked over the car, the hatch latch was engaged but not fully latched. Nobody's sure of the events leading up to the problem, and so far I'm unlikely to figure that out. However I'm sure that the 12v battery is discharged.

I can jumpstart the car just fine, and it runs great until it's shut off. Then the Optima doesn't even have enough power to light up the MFD, let alone try to boot up the car. I've read that discharged Optima batteries are very slow to charge from the Prius' charging system, and perhaps it needs more charging time. Each time I jumpstarted the car, the dashboard display went to normal (no yellow lights) and I'm not reading any codes on my old CarMD OBD reader.

I've read other threads on Optima battery issues, and I seem to have three choices:
1. Buy a new Optima battery. But if this is what I get after "just" 4.5 years then maybe I want an OEM battery from the dealer.

2. Buy an OEM battery and forget about Optimas.

3. Buy a battery charger and see if I can recharge the Optima. I'm mildly concerned about the battery's reliability, and a charger might be a waste of time for a shaky old Optima.

I'm tempted to buy a new battery (either Optima or OEM) just to be able to run the car and see whether the inverter is recharging the 12v battery. Are there any specific fuses or relays or fusible links I should check to see if the inverter's battery-charging circuit is still working?

What am I missing? Anything else I should check?

To further complicate matters, the neighbor took the owner's manual out of the car and misplaced it. So now I'm seeking an online reference or even a printed manual-- especially for fuse names & numbers. But that's not a priority until I need to go fuse-picking.

Here's a related dumb question: when the car is shut off, it's supposed to automatically shift the transmission to Park. If the 12v battery is dead, is there any way to shift the transmission into neutral so that the car can be pushed a few feet to get it out of the intersection and into a driveway?

 

Thanks, everyone, I'll just buy a new battery from the local dealer monopoly or (if it's on the island) an Exide. (I had to do the terminal swap for the Optima but I'm pretty sure I have the old terminal in the auto parts cabinet.) While I'd like to have a lifetime 12v battery, apparently I'm just going to have to revert to buying new every four years.

The battery in our 2005 Prius (our second car) is just over four years old. That car normally gets driven only 1000-2000 miles/year, and it happily sat in the garage for at least 82 days-- maybe more than 90 days-- with no problems. But disconnecting the + terminal before we leave is a good addition to our travel checklist. We learned an awful lot about extended travel on this trip.

When I jumped the 2006 Prius (after it sat in the driveway for a couple months) the ICE started very rough, almost as if a spark plug or fuel injector was bad. But in a couple seconds it ran smoothly. Another interesting symptom is that the gas gauge displayed one blinking pip for several minutes after startup. I thought our neighbor had let the car run out of gas and I added a gallon from our storage container. However as I drove the car, within a few minutes the gas gauge went up to four pips.

As for the well-meaning but clueless neighbor-- she has to learn these skills from somewhere and using the car was part of her payment. It was the right thing to do. I'm just sorry that the 12v battery was less reliable than I thought.

Has anyone had to figure out how to push a Prius around when it won't start and it needs to be moved out of the way? I'd hate to learn that the transmission automatically locks in Park when the car is shut off, and is stuck there until the car can be started up.

 

Ah, thanks. Very good to know. I was afraid that the design would be something simple like that.

After I jump-started the car the first time, I drove it to a local gas station to fill the tank. The car wouldn't start after filling up, so I stood there with jumper cables in hand seeking a Good Samaritan. The station manager was quick to inform me that I couldn't use jumper cables near their gas pumps. I had shifted the car to neutral at the pump before shutting it off, but of course when I shut it off its transmission went to Park. I tried to push the car away from the pump but all I accomplished was verifying that the transmission was in Park.

I explained the design feature to the station manager, who grumbled off to consult with their boss. That gave me a couple minutes to jumpstart the car and leave.

As a design feature, the consequences of a dead 12v battery seem pretty severe. It was also an interesting challenge explaining to the average driver why I wanted a jumpstart from their ICE vehicle when my Prius is "full of batteries". And also explaining why the 12v battery isn't under the hood. And then having to explain why, no, we can't just pop up the hatchback to look at a dead 12v battery.

You would hope that during the last decade, nearly every tow truck driver in America would have towed or jumpstarted a Prius. I'd speculate that the botched jumpstart is much less likely than it used to be.

With a choice of losing the radio's presets or draining the battery, I'd prefer to disconnect the battery cable. I'm not sure how long an ECU takes to re-learn its settings but the car sounded fine within the first couple miles. I'll keep an eye on the MPG to see if there's any other effect, but so far everything seems to be good.

I'm hesitant to run more electrical appliances in the house while I'm away on extended travel. During this trip we shut off everything except the fridge, the network router/DVR, and the aquarium air pump. In retrospect we should've emptied the fridge and shut it off too.

Again, you'd hope that the average 12v battery could handle four years of intermittent use. Maybe it helps to be in a tropical climate where the battery never sees temperature extremes.

We've talked about dropping down to a one-car family but its operating costs are low enough that it seems better to promote the marital harmony of his & hers vehicles. I never get any grief about covering "my" car in sand and surf wax, but that might change if it was "our" car.

 

Thanks again for the diagnostic help and the recommendations.

The new battery is in, and the car seems fine. After the swap I had to cycle the power locks before the back hatch would open again. I also had to shut off the backup beep again and program a couple of radio stations.

The new battery is a GS Yuasa S34B20R rated at 20Hr, 35Ah, and 272 CCA.

I called all over the island for an Exide. Exide's website doesn't list a retailer here. I tried Sears, Interstate, and even Battery Bill. Nobody carries it. One rumor is that Toyota has licensed compatible batteries with 2010 model years and later, but not earlier. Amazon won't ship to Hawaii because batteries are considered too hazardous to send outside the 48 contiguous states.

Servco Toyota Waipahu charged $300. That's just for the battery. It took me 20 minutes to do the swap (including replacing the Optimus terminals with the original ones), and I wasn't even going to ask Servco what they'd charge for installation.

When I put the MFD in maintenance mode, the battery read 12.7v. With the car powered up it was receiving a 14.5v charge.

In a few weeks I'll replace the battery in our 2005 Prius: a GS Yuasa S46B24R rated at 20Hr, 45Ah, and 325 CCA. It's actually $10 cheaper even though it's for the SKS model. The two batteries seem to have the same dimensions but I'm not sure whether this one is compatible with a base-model Prius.

Our Series 2 TiVo uses the network to update its two-week programming schedule every few days. My spouse is happily working her way through 82 days of recordings...

I'm glad that job is finished. South shore surf is coming up next week and now I'm ready.