New 12V battery discharges after two days

you need to start with the battery fully charged. a new battery isn't necessarily.

then hook it up and measure the voltage again.

measure the voltage every day without using the car or even turn it on.

if it is dropping rapidly, you have a short somewhere, but finding it is the tricky part.

the pump is certainly a smoking gun. you can disconnect it and do the experiment again.

 

New batteries often come almost fully DIS-charged and must be charged before use.
So, find a small charger and charge it up good once. Might take 24 hours.
If that does not solve the problem, you might have gotten a bad new battery.

 

A brand new battery in decent shape, that's had moderate time sitting on a shelf, might have a modest voltage drop, but should still bounce back fast with a few days driving. I'd suspect either a dud or OP's car has some high phantom load.

Anyone buying a new battery these days should be entitled to an electronic load test of the battery. It takes 5 minutes tops, protects and enlightens both parties in the transaction.

 

Did you wait for 30 - 40 minutes before checking the current? The car quiesces in a few stages over 40 minutes before it is totally dormant. At that stage, it should be drawing 16 - 20 mA with the occasional spike to 50 mA.

I do believe some of the things that shut down later are on that DOME circuit.

 

You REALLY need to pay attention to what he is saying here.
Because if you don't you are likely to waste a LOT of time and maybe money too.

You need to leave the hood open so that you can access the battery or jump points WITHOUT opening the doors.
Best to not have a FOB nearby either.

 

You aren't listening.
It is NOT a "serious fault".
It is normal for this design.......maybe, depending on exactly what you did.

When the FOB approaches the car, some systems "wake up" and a slight additional power draw is expected.

 

Opening any door will give a 500ma draw, with ALL interior lights off. As dolj has stated, a 16-20ma draw AFTER the vehicle has gone dormant. I've measured these numbers myself. A 1.7a draw is huge. 78ma is also rather high.

 

SIGH.

No you STILL aren't listening......and/or not understanding.
NOBODY said to do it that way.
That will NOT prove what you need to prove.

You need to restore all systems to normal, including the fuses, BEFORE you start the long rest period.

 

I kinda like your "pull all fuses, then put them back one by one". At least one full fuse box worth. Hopefully with all fuses pulled you'll see amperage drop right right down, after the removal of all fuses. If not, try the other fuse box first?

I think imperative you take several good pictures first, to avoid mix ups. Also, if it's the in-car fusebox you're doing, clamp the door-open switch on the door you have open, to spoof a closed-door condition.

 

How do you measure current? A clamp meter on one of the battery cables?

 

1) You replace the fuses and charge the battery.
2) You arrange your meter connections so that you do NOT have to open a door to see the meter.
3) You let it sit for.....maybe 6 hours just to be sure.
4) Then and only then do you read the meter and see what the "resting" current draw is.

IF.....that appears to be OK, really low, then you check the voltage of the battery after it's rest.
If the battery voltage is below 12.6 (it really should be more like 12.9) AND your resting current is really low,
then you have to suspect that the battery is not as healthy as it should be.......new or not.

 

swede70, I think the concern some people might have is that your testing procedure may involve having a door open or not waiting long enough, so that at least some of the current drain you're observing is normal. With a careful procedure, that current drain should be given a better chance to approach zero, and your tests will be meaningful.

They may already be just fine.

Also, my guess here is that it has nothing to do with the hybrid battery, so debugging this is mostly just like on a regular car.

The procedure above should work, and may be best depending on what tools you have, but alternatively, what I would do on my car, having the tools I have (specifically a DC clamp Ammeter) ...

replace the fuses and charge the battery. Then when ready to test ...

Unlock the car.

Pop the hood, so you'll later be able to access the fuses.

Open the rear hatch. Use a screwdriver to fool the latch into thinking it has hit the striker bar and the hatch is now closed. That will allow the car to turn the interior lights off and go to sleep, even while the hatch is conveniently open.

Attach a DC clamp Ammeter (measures current by sensing the induced magnetic field when current flows through a wire) around either the positive or negative cables coming off the battery on the right side of the trunk (that's where the 12V battery is on my 2012 v - not sure where it is on your car). If yours is in the engine bay, you can skip the part about opening the hatch.

Lock the doors, take the key fob sufficiently far away that its presence won't be confusing the car.

Go back and watch the current measured. For my Prius, and most cars, within a matter of several seconds to a minute or so it is close to zero (less than 100 mA, hopefully around 20 mA). One of my other cars takes 16 minutes to hit the deep sleep mode, but I think these cars are not so difficult.

At this point, if the current is 1+ Amps, I'd pull and replace fuses one at a time, starting with the ones you already know are problematic. Pay attention to the current intitially, after pulling a fuse, and after replacing that fuse. This is just the beginning of the debugging, so see what you can figure out.

A 1+A drain would definitely drain your 12V battery as you are observing. Once you isolate which circuit it is on, you'll then need to trace it to the actual root cause and fix, replace, or remove it.

Good luck.

 

Well that evidence does point to something "running" that shouldn't be...or longer than it should.
I think you are going to need a detailed wiring diagram to trace what feeds from what fuses to take your investigation any farther.

Note, however, that keeping something plugged into the ODB port is a known cause of battery drain.......so you might need to test again with that removed.

 

So that does seem to indicate there is a parasitic draw. It is now a matter of removing fuses one by one (without opening any doors) until you see the draw drop down to around 20 mA.

Once you have identified the circuit or circuits that are drawing higher than normal current (the 1.03 A), you will then need to track down what is on that circuit to see if you can identify the component that is drawing the current.

Good luck.