Anyone else having 12V battery issues?

Lurk, You do know that the 12v STARTS the car?

 

Too bad, you probably need another. Possibly when it is plugged in, it is not charging the 12V. To continue throwing in new batteries is a lost cause. And YOU will probably end up paying for them.

 

andy, when you say 'starts the car', what exactly do you mean?

lurk, the portable car starters last a long time.

 

Now really Bisco! In order to initiate READY the 12V has to be healthy. I do not know what a portable car starter is, but it is not addressing the OPs problem. It is bypassing it.

 

he wanted to know how long it lasted so he wouldn't get stuck at the airport. it is bypassing it so to speak, but it may be necessary until a solution is found.

 

Hello Lurk

The product which you need is called a "Battery Tender". I have one for my PiP. This small unit will charge your battery until it is full and then turn itself off. That is how it differs from a trickle charger which does not turn itself off and can eventually damage the battery. I keep a Battery Tender for all of my 12V batteries, especially my riding lawn mower.

It is very likely that you do have a power drain which is causing this problem. Your dealer can help you find that.

Your 12V battery charges when your traction battery charges. I discovered that by measuring the amperage at the 12V battery during charging. If the car is without a power drain, this should be plenty adequate to keep the 12V battery charged.

The jumper/compressor will get you going if you have a flat or are stuck with a dead 12V battery. The Battery Tender will prevent the problem unless the electric draw is simply greater than the charging power of the Battery Tender. It would be wise to fix the electric draw problem when it is convenient.

 

Correct me I'm wrong, but a battery tender needs to be plugged into a 120V outlet, of which there may be none (or none in open parking spots) in the airport parking lot/garage. If they were available, then plugging the car into charge via the L1 EVSE or L2 charging station would do the same thing. It seems like the battery tender is totally redundant for a Prius Plug-in in all situations except where you have a 120V outlet that can handle less than a 15A draw.

The backup 12V battery seems like the way to go. It doesn't even need to be that powerful, since it doesn't power a starter motor like a non-hybrid. It just needs enough juice to turn on the car's electronics, which can then connect the traction battery, which then takes over powering the 12V systems and charging the 12V battery.

 

Your 3rd Para: That is exactly the problem, apparently his 12V is not charging.

 

I see your point. If the 12V battery is full when you park at the airport, it should last until you get home. There should be a 110V plug at home. If the drain is so big that the battery tender would not work this way, it needs repair very soon. As I said, the PiP should keep the 12V battery charged if there is a normal level of electric drain. That is so with my PiP.

 

I believe the problem is that in the design the 12V is not charging when the PiP is not plugged in. The Volt has a similar problem btw.

This seems to be a design flaw. The 12V needs to be able to maintain enough charge to "start" the car after sitting unplugged for an extended period, at least a couple of weeks if not a couple of months. No one wants to come back from a 2 week business trip and find their car dead in the parking lot at 1am.

 

It looks like a lot of assuming going on here. The answer is not hard to find. Plug in the car which needs charging and connect your trusty multimeter to the 12V battery terminals. If the reading is in the vicinity of 14v it is charging. If the battery is not taking a charge it is the fault of the 12v battery. After the charge is over, a healthy battery should read somewhere around 9v. If these things are not happening, there is need for repair as something is wrong.

There is no way that the 12V battery will or can charge when the car is not plugged in. That would allow a continuous drain on the traction battery if there was an electric drain or a bad 12V battery. This is a prescription for destruction of the traction battery.

A healthy 12v battery and a normal PiP will not strand you in an airport at 1:00 a.m.

 

Another approach would be to use a clamp-on ammeter to measure the current flowing out of the battery when the car is off. This might tell you if you have some sort of drain that is causing your battery woes.

 

why can't the pip 12v charge the same way as the non pip?

 

It is exactly the same, but, better. You remember all the 12V battery problems there were on Gen II ? Now the Bat is not only charged while driving, but it is also charged when you plug it in. Now should you neglect that important step, you could have saved a few thousand by getting a non PIP. I see no intelligent reason not to plug in, except situational, live in a condo, no outlets, landlord will not let you, etc.

 

........After the charge is over, a healthy battery should read somewhere around 12.6V.

 

there must be a draw on it somewhere.....I asssume you should be able to leave a PiP for weeks, or month without plugging it in, sitting. If there is no draw the battery should be fine.

If i leave for a month I will throw a tender on mine to be safe. I know its not always possible though.

Dan

 

I wonder what the current draw on a "turned off" Plug-in is. Some things I can think of are the keyless entry system looking for a fob, the security system, and on the Advanced, the Safety Connect cell phone which is always on listening for status and location requests. These are not very much, but they ARE 24/7, and that 12V battery is not very big.