Anyone else having 12V battery issues?

I'm always happy to hear a satisfactory ending. Thank you for sharing your 12v replacement experience GregP507.

 

Maybe they should listen to them a bit more, and provide a fail-safe method against letting the car become dead in the water when the auxiliary battery goes dead.

 

File not found. Toyota Egypt? Really?

 

It does indeed need to be deep cycle, unless you want to have it only until it's been run down three or four times. The whole point of a battery upgrade is to install one that can handle 12 volt loads for long periods, and then recover with little or no damage.

 

Copy the URL and take the bit off the end.

 

Every car ever made is "dead in the water" if the battery goes dead.........except for cars with manual transmissions that might be push started.

Someone posted a page from the manual about this.
I didn't read it; does it give a good warning about this ??

Anyhow, the OWNER has to assume SOME responsibility for his own actions.
In this case, you can upgrade the battery and/or carry a rechargeable battery booster around with you.

Those are the SAME options available for owners of conventional cars. The only difference it the length of time that the accessories can be used before causing a problem.

Can we move on to the next obsession please ??

 

I'm still annoyed that Toyota makes it so easy to get stranded with a dead battery, when you are packing a 4.4 kWh battery on board.
Ridiculous.

 

+1
You'd think it wouldn't be too difficult or expensive to make an "emergency self jump start" circuit for the Prius (and other hybrids). Especially considering the 12v battery only provides power for the car systems and not power for cranking the ICE.

 

I got myself a rechargeable battery pack that charges and boosts through the lighter socket, but then I realized it wouldn't work without the power on, so I soldered some alligator clips onto it so I can jump the battery terminal directly. I keep it under the seat. I have roadside assistance, but I'd rather not wait an hour or two, if I can deal with it easily myself.

 

IMHO that is the best solution. You can buy a boost pack that should have no problems jumping a Prius for under $50, and just have to remember to plug it in to top it up every month or two.

What you are asking for could probably be done, but it would likely cost a lot more than the boost pack. The high voltage components needed to interface to the HV battery are not cheap, particularly when you get into automotive grade components which would have to be used in a built in solution. At a guess I'd say it would cost in the neighborhood of $500 as an option/accessory.

I believe the main complication is safety. This is the reason the HV battery is isolated until the 12V system can come up and verify that everything is ok, and its safe to energize the HV system. When you are dealing with a battery that can put out about as much instantaneous power as the utility feed into your house, it is essential to be pretty paranoid. Energizing a faulty HV system could result in injury, fire, death, etc.

Its kind of a chicken and the egg sort of problem. How do you know its safe to connect the HV battery to anything else without an independent circuit (with its own power supply) to check it out first? How do you know the HV battery is at a charge level or temperature where it can safely be used as a jump source without being able to power up and talk to the battery control ECU? Not saying these kind of problems couldn't be solved, but their are a number of such issues that would make this sort of thing significantly more complex and costly to build in than one might think.

Rob

 

I believe it already exists in every Prius. There is no special charging alternator; it merely shunts power over from the hybrid system as needed. The problem is that it only does this when the car is in "ready mode," something you can't access, once the auxiliary battery falls below a certain level. That's when you find yourself "dead in the water."

 

Hence the chicken/egg problem. The 12V dc:dc converter can't be safely powered up until the HV controllers have booted and completed their diagnostics. The controllers can't boot without a 12V power source. It would take a major redesign of the whole system, and/or a significant number of otherwise redundant components to add this feature. If there was a safe/cheap way to do this you wouldn't really need the 12V battery at all, and one would expect that the designers (or at least the pencil pushers) would have been all over that.

 

I do acknowledge the design problem; there is no 12V source available to charge the auxiliary battery when the system is shut down. The hybrid battery is over 200 volts at any time, so an independent circuit (outside the operating system) would be required to step the voltage down, to deliver a booster-charge to the auxiliary battery. I agree, it's easier said than done.

 

I'm not aware of any hybrid that has had this feature, but interestingly enough the very first production Prius (NHW10 1997-2001 Japan Only) actually had a charger mounted in the trunk that could do the opposite. It was able to "jump start" a dead HV battery from the 12V

 

That seems like not only a tall order, and I'm not sure why it's necessary, unless that's the only way to get the combustion engine started.

 

Yeah, its not particularly surprising that this feature didn't make it into Gen1 and beyond

 

There is a possibility which is really available. It is called a Battery Tender. Home - Batterytender.com I plug mine in every once in a while and when the light turns green, I know the 12v battery is fully charged. The device turns off when full charge is reached so is fully safe. You can see from the site, this is not expensive. I use this on all my lead acid batteries, especially my lawn mower. I haven't had any problems since I started doing that.

 

The problem isn't the battery going flat from leaving the car parked at home for too long, it runs down when you accidentally leave something on for too long, and then there's no way to start the car, even though you may have kilowatts of power on board.

 

I use battery tenders on two of my cars that don't get driven often. My '02 Lexus has had battery problems since new. I think there must be a drain on it, but the techs have never been able to track it down. The battery tender solves the problem. I also use one on my Miata during the colder months when it doesn't get much exercise. Much easier than having to pull out the regular charger or jumping the battery. My PiP gets driven daily, so no worries there. I learned early on from the manual for my '04 Prius not to use interior lights or the radio without having the car in "ready" mode.

 

I agree, I have had 12 volt problems twice already on my 2014 PIP, both times it has been the rear hatch not being latched. This my third Prius so I am acutely aware of interior lights being a problem and thus I have all of them turned off, even when I open the door, the overhead is set to the off position. The front door courtesy lights are the only ones I could not find a way to turn them off. The rear hatch light is set to off as well.

Had the same issue in my 2010 Prius IV, finally after several times of having to recharge the 12 volt, I bought a deep cycle AGM and that was the end of my problems.