Anyone else having 12V battery issues?

Allande, I doubt a separate part would even be required. It would be a software issue, with just a change in programming. It's amazing how many simple mistakes car manufacturers - even the better ones - make in new designs. I drive a Leaf (the PIP is my housemate's) and I have to regularly charge the accessory battery, block the grille in Winter, and had to install a spare tire myself because Nissan decided that down-rated cheap OEM tires wouldn't be a problem, and if one did blow a sidewall, the $180 goop in the rear compartment would fix it right up...

 

Michael33 - I tried responding to your points. It got too long. I am sorry that you do not enjoy the obviously responsible care which you give your cars. Cars are made for the "average" customer. Neither you nor I are "average".

I enjoy taking care of my cars. My wife calls it "bonding".

I think this thread has done an important service and will get the attention of Toyota (or has already). There may be an elegant 12v battery solution in future Prius cars. For now, there are some good ideas for us to use with our very own cars.

 

The car already has undervolt protection for the traction battery and it's reliable enough that we don't hear stories of people running the traction battery down to the point of no return.

Anyone can do much better than the factory by themselves. The discussion here seems to me more focused on where that leaves customers without the electrical knowledge and/or inclination to improve upon the design.

 

"Better than factory" often incurs higher cost and higher risks to the individual. Occasionally it can mean a better idea overall, but for most of us, the factory configuration is a well-thought-out balance of safety, economy and convenience. I don't intend to modify my Prius very much; those days are far behind me. I want to keep it in something close to factory condition, so that when I sell it, I can get top-dollar.

 

That's true. I never make modifications that can't be reversed later.

 

As a data point, my 12V battery just crapped out at the 26 month point, after 4 really hot days under the sun in an airport parking lot. Jumped it with a tiny UPS battery and makeshift 12 ga cables. Replaced it with an Optima Yellow Top - hoping to get 4 or 5 years out of it.

 

Toyota built the car and I use Toyota parts. No exceptions.

 

There is a retailer here, who countered the "genuine factory parts" argument with the fact that they were buying their parts from the same manufacturers as the automakers, and selling them for much less. The fact is that many dealers apply huge markups to parts, on the assumption that the customer has no choice, because they believe the marketing line that "only genuine parts" are good enough.

A similar tactic is being used by pharmaceutical manufacturers whose patents have run out, and they are telling us that their "genuine" brand name is better than generic alternatives, which are priced considerably less. The truth is that they have the same active ingredient, and there is no empirical evidence to suggest that one is superior to the other.

Consider whether you would pay 30% more for a brand-name gasoline that claimed to be "genuine" in comparison to other brands. I'd be very surprised if many people could be duped that way.

 

Here's another data point. My car is 29 months old. I parked it this past Wednesday night. Went to plug it in this evening (Sunday, so 4 days unused) and the thing was totally dead, no lights anywhere, no reaction to remote, nothing turned on at all.

I connected a battery charger to it under the hood and it started right up. Let it sit for a bit, took it for a quick drive and everything seems ok, but we'll see how it goes tomorrow morning. It's plugged in now, but it doesn't start charging until, 620AM.

I routinely use my car, monday through Friday, very occasional weekend use. But it's been fine since I got the car, never any hint of weak battery or impending battery failure. It sucks because all my trip meters and ev/hv numbers are gone.

 

Bummer! Please keep us posted. My car is also 29 months old, and also sat unused from Wednesday until Sunday (morning) but everything was normal. I hope I don't have to start worrying about the auxiliary battery this soon.

 

Unless you have invested in a deep-cycle or AGM-type battery, allowing it to go flat entails a significant risk of degradation of capacity or permanent destruction.

As for losing the stored data, I'm surprised that such a sophisticated machine still uses volatile memory. I'm contemplating wiring in a secondary battery to maintain memory. Of course, I'd have to design some type of protection circuit to prevent draining it as well. I'll need to feed power to the computer without having it drain back to the other battery, by using some sort of rectifier bridge..

 

It was dead again this morning. Not as dead as it was last night when I got home because the small white LED that illuminated the charging port was at least flickering this morning (last night it didnt light up at all).

I already ordered a new battery (the Optima thats always suggested here) but it wont be here until Thursday. I'll put the 12V charger on it tonight and leave it for a few hours to see if it brings it back to life at least a little bit until I get the new battery. When I started it up last night, including my short drive, I probably had it on for about 10 minutes? I guess that wasnt enough.. or the battery is just toast.

 

The Optima is good, but certainly not the only AGM battery out there. Standard lead-acid batteries seem to be designed to fail. Good luck.

 

I think it was actually your post I found in a different thread where you also listed the Exide battery. But since everyone here seems to be happy with the Optima, I just went with that one. Of all the things I worry about going wrong, the 12V battery is definitely near the bottom. So I dont want to be the pioneer of trying out something different.

 

I installed an AGM battery in my Dodge Ram in 2007; since that time, and over 150,000 miles later, I haven't had a spot of trouble with it. I can't remember the brand name off-hand, but I bought it in anticipation of trouble I might have making it through another winter with occasional -40 temperatures. It cost me about $200 as I recall, and it has paid for itself many times over.

After it went dead a few times due to phantom current-draw, and since I rarely drive it anymore (except for fishing trips) I installed a battery maintainer, and since then, everything has been flawless.

 

Trackside, you haven't had any prior problems with the battery, but I'm wondering if you might have run it down at any time using the radio in accessory mode as has been discussed in other threads. If it was low but still had enough power to get you going, it may not have been noticeable. I've read that with these little batteries it takes only limited times of running down to shorten their life. For that reason I never use accessory mode for anything. I'm by no means a techie or engineer, so please excuse me if I'm totally misunderstanding what I have read.

 

I've noticed that acc-mode shuts off after a number of minutes. This would normally protect a regular battery which is in reasonably good condition. However, I believe other factors can cause the battery to go dead, and cause it to become damaged to the point where it goes dead before the acc-mode times out.

I received my new PiP with a battery that went dead after a few minutes in acc-mode. I took it back for service, where they tested it and replaced it free of charge. The salesman indicated that the car had been in the showroom for a long time, and the battery went dead "very frequently." This explains why the battery was in poor condition, going dead so quickly and causing the car to require a boost.

 

Yeah, I know what you and greg mean. But I really dont use ACC that much. I dont even remember the last time I sat in the car and used it, to be honest.

I put the battery charger on it last night for about 3 hours, charging at 10A. I'm not sure if I'm reading the battery gauge correctly (it shows amps and battery % on the same gauge), but it looks like it was hovering around 60% battery capacity (?) and at somewhere around 7-8A. I pulled off the charger around 10PM. I didnt want to charge overnight because I wanted to see if the battery would be strong enough in the morning to get me to and from work. It was OK this morning, hopefully OK when I go home.

Either way, I'm changing out the battery when the new one arrives this Thursday.

 

and you got your car right off the boat, didn't you?

 

I'm not too worried anymore, now that I've had a new battery for awhile. But I still carry this, just in case:

But this unit won't work in the Prius without this:

Because the lighter socket is dead unless the ignition is turned on.