Starter battery drain

Rrplacement for 12 volt battery ranges between 2-4 years. Looks like you are on the short end.

 

welcome to priuschat. wow, a tow truck 'technician' with an electrical engineering degree!

here's what's happening:

1) your 12 volt was in a low state of charge due to age, or more likely being run down at some time prior to parking. this can be from aux use or a light on in the car while the car is off. the 8 days parked was the last straw.

2) you left a dome light on while it was parked and killed the battery.

either way, all the 'tech' did was give you a 12v jump.

you should put a smart charger on it, and then monitor it for a few weeks to make sure it's holding a charge. if not, you'll have to replace it. there's no way a healthy 12v won't last for a few weeks while parked. all the best!

 

or
3) you left a door or the hatch only half-latched.

That will run down the battery in less than three days even if the dome lights are off and the lights at the bottoms of the doors are not on. If the door lights stay on (I'm not sure whether they do.), about one day would kill the battery.

I don't know whether the "technician's" explanation involving concrete is an urban legend or something he made up by himself, but it's certainly false.

 

Wow, I want some of that concrete! Same as the legend of batteries going dead if set on a concrete floor. They don't. They go dead from self discharge over a long period of time because the nut who put them there forgot about them and didn't bother to charge them occasionally.

 

I'd love to find out where this urban legend about concrete and lead-acid batteries came from? How did it get started? And when?

-EB

 

It got started as I implied in my response above. I was told by a mechanic where I worked "I put the battery on the concrete floor, and when, a while later, I tried to use it I found it was dead and had to replace it." After some discussion and "deep thought", he admitted he put it there two years earlier. AND, it was discharged when he did so! Duh!!

People get sidetracked easily. The battery gives them trouble so they remove it and put in a fresh one. Problem solved, the people move on. The battery usually goes on a concrete floor (safest place - it can't fall or contaminate you with acid down there). They usually get forgotten for at least a few months. After bumping into it or having to walk around it for a few months, they finally decide to deal with it. And find it's dead. It MUST HAVE BEEN the concrete floor, right?

As for when, practically forever, or as long as we have been using lead acid batteries.

Just like the people who tell me my Prius NiMH battery will develop memory. NO!!! That was what NiCd batteries did. It -may- be possible to cause a "memory problem" in a NiMH battery (cell) but I haven't been able to do it! And I've tried hard.

 

snopes.com: Do Cement Floors Ruin Car Batteries?

 

That Snopes article actually contains a valid scientific explanation for the "setting the battery on a concrete floor ruins it."

70-100 years ago the cases of lead-acid batteries were made out of hard rubber, which is somewhat porous. Concrete tends to hold a certain amount of moisture too. Since acid leaking out of the battery is an excellent electrical conductor, this actually COULD cause a flow of current out through the rubber case, into the concrete, and back into the rubber case, creating an electrical connection to a different cell inside the battery. It's plausible this might be enough of a current flow to eventually drain a battery.​

However, as stated in Snopes, battery cases have been made out of non-porous hard plastic for many many years.

-EB

 

i always put mine on a piece of plywood.

 

probably a belt and suspenders kind of guy...

If you haven't done so yet, you need to connect your battery to a battery charger intended for AGM batteries, 4A current setting, and fully-charge the battery overnight. Don't think that if you drive the car for 15 minutes, all will be well.

 

elastic waistband.

 

tomorrow is camiile's one week anniversary.

 

I have a 2011 Prius with about 35,000 m iles. On returning from Florida, 2100 miles, the 12v battery should have been fully charged, but it died. I replaced it through Toyota this June...today the car wouldn't start again. What else might be draining the battery? THe nearest Toyota dealer is 1.5 hrs away, so can't just jump start the car and drop it off.

 

you may want to consider owning a jump pack/charger for emergencies.

 

1. See if the 12V battery can be charged using a battery charger intended for AGM batteries, 4A charging current position. This needs to be done at least overnight.

2. Do you make it a habit to lock the car when you park it? If not, try that. The point of locking the car (even if it is in a secure garage) is that if the car accepts the locking command, that proves all doors and the hatch are closed. If the car cannot be locked then you know something is wrong.

3. Obviously, make sure that all interior cabin lights are off when you leave the car.

4. If you want to DIY further, you'll need to obtain a digital multimeter so that you can measure the battery quiescent current draw from the car's electronics when the car is IG-OFF and locked. You need this to determine whether the problem is with the new battery or with the car's electronics. ~0.02A is a normal level of current draw.

5. If you cannot do #4 then jump start the car and drive it to your local Toyota dealer because you won't be able to do much more without developing some insight about your car's situation.