Brand new Optima battery keeps dying

sounds low. they don't always come charged. put it on a smart charger, the car won't charge it properly.
if that's not the problem, you may have a parasitic drain with the car off.

 

You need a voltmeter to check the actual battery voltage while things are not working.

The 14.x reading you got indicates that the charging system is working right.

Unless there is a loose connection at one end of the main battery cables, this looks like your new battery has failed.
That is not too uncommon for the Optima's.
Their high owner rating has dropped a LOT lately.

 

if you're using the mfd to read the voltage, it should read at least in the mid 12's, because there is some load on it, and a fully charged new battery ought to be close to 13 volts.

at 12 volts, when you try to start the car, the extra load is probably dropping below the acceptable computer parameters.
as sam mentions above, 14.3 when 'ready' is the charge from the inverter going to the battery, not the battery itself.

 

I trickle charge my optima once a week. Prius charging system to weak to keep up. Especially since I run a 5 channel amp off it.

Posted via the PriusChat mobile app.

 

This.

Let the car sit overnight, preferably with hood popped, because even just opening a door to pop the hood will drop voltage slightly. Not that much though, maybe 0.1 volt. Then connect the voltmeter (should be digital) red lead to the jump point, under the hood:



And connect the black (negative, aka "common") lead to a bare metal or bolt, on the car body or engine.

This will give you the battery's "voltage", without the car either drawing it down, or running it up. The at-rest voltage. Which is something. Better than nothing.

But still not the full picture. For that an electronic load tester is good. Any automotive retailers selling batteries (including the retailer you bought from, if it was local), should have a pro-level tester of that type, and be willing to check it for free, give you a verdict on it's condition. Dealerships will do the same but likely want some compensation. You can also get yourself something like a Solar BA9, and DIY.

I'd suspect the "verdict" will be good, but in need of recharge. If that's the case, a smart charger, around 3.5 amps:



A CTEK 3.3 charger would be playing it safe, though I think you good get away with a CTEK 4.3, in particular with the Optima. I probably have the same battery on my 3rd gen, and that's what I'm using on a regular basis, in the "snowflake" mode (slightly higher voltage, suitable for Optima YellowTops.

 

Your not setting the car alarm every night. That will catch 95% of every light left on as it will not arm if light left on. Or at least before going to bed look at the car. See if any lights left on.

In the meantime 3 things

1—A car battery will never ever output 14 volts. Your seeing the battery charging voltage the inverter is sending to the battery.
Has nothing to do with the battery’s capacity,
You want to see what the battery voltage is in acc mode your missing a step In the mfd routine. In accessory mode the car is not on.
2—Do whatever you can to fix this ASAP and stop jump starting it as that had proved fatal for many G2s over the last 10 years. Especially if your jumping it directly to the battery in the trunk. There’s safe and handy jump point under the hood.
3—If forced to jump make sure the donor car is off as there will be a large inrush of current if battery really bad. Engine off will minimize inrush current available. And use the front jump point.

 

You can measure a parasitic draw, but you cannot “feel” a parasitic draw. Your car either has a draw or it doesn't, but unless you measure it, there's no confirming it, although aftermarket stereo systems often go hand in hand with increased parasitic draws. Fully-charged, your battery should measure about 13.0-13.2 volts. If you don't feel comfortable measuring your parasitic draw directly, you can also fully-charge and completely disconnect your battery from your vehicle. It should hold close to that voltage for 12-24 hours afterward.

If it holds voltage when disconnected, but loses voltage when connected, then something in the car is discharging it. If it doesn't hold voltage when disconnected, then the battery has an issue and needs warranty service (contrary to sam's opinion, that would be very uncommon for a new battery).

Whenever any battery is discharged to the point that you need to use jumper cables or a jump box, you should make sure you fully recharge your battery with a battery charger as soon as possible. Relying on your vehicle's charging system can lead to a cycle of dead batteries and jump-starts, until either the battery or charging system fails. We always encourage folks to treat jumper cables or jump boxes like they would a one-gallon can of gasoline. They can get you out of a tight spot in an emergency, but you'll probably be headed to a gas station very soon after to fill the tank. You should do the same with the “electrical tank” in your battery.

Jim McIlvaine
eCare Manager, OPTIMA Batteries
http://www.pinterest.com/optimabatteries

 

just to clarify, there is always a drain in the prius. so a measured drop while connected is not an indication of a defect.
a parasitic drain would be higher than toyota's spec. if you cannot dive that deep, it's easy enough to just put a volt meter on the jump points every morning. if the battery held overnight while disconnected, the daily drop should be miniscule.

the easiest place to start is by fully chrging the battery. that may solve your problem without further testing

 

Done right, there is no real danger.
Ed has a tendency to exaggerate sometimes.
And he goes completely off the track sometimes too.
Done wrong, all kinds of bad things can happen.......and the point of connection makes no real difference.

Given that your jump effort works in one place but not the other is a STRONG INDICATION that you have a bad main battery connection somewhere......and the point where the negative cable connects to "ground" at the body or frame is the most likely suspect.

 

Yes that would be an excellent choice but the most common size is 2 amps at about $15 less.

It is possible that you misunderstand the situation.
The battery might not be CHARGING properly due to a loose connection.......or due to a defective battery........or due to a failed charging system. It may not be "losing" an abnormal amount of charge at all.

And finally, the connection of the main negative cable to ground is NOT something you would normally visit while installing a new battery.

Where did you get your new battery ?
If it was "mail order", you now might have to spend the money that you thought you saved to pay a real mechanic to find and fix the problem.

 

it has been said that it takes 8 straight hours for a prius to charge the battery. that may not be an across the board rule for all prius and batteries. optima may take longer, but i'm not sure. it might be worth a try if you have the time.
supposedly, you don't have to drive it, just leave it ready in a safe place.

 

If the battery is completely discharged, try 16 – 20 hours.

 

That's not good; time to start shopping I think. Does Advanced Auto have batteries? Maybe best to stick with a local retailers.

Maybe Optima's quality is taking a dive?

I installed this in September of 2015. Reading 12.73, and CCA 517, checked it just now:

 

where did you buy the optima? try pm'ing the fella in post #9, he's the man