2009 370Z, car has only 6000 miles on it - battery keeps draining, once so bad that it wouldn't even jump start. Dealer still scratching his head, no help. Any ideas out there?

Maybe your alternator. Thats the main thing I can think of. Either that or just a bad battery. I got a new battery from a Nissan dealership in MD in October and it died two weeks ago.

Alternator's charging fine (14+ volts on meter). Might pony up for a new battery if the dealer doesn't offer it under warranty.

That'd be my first attempt to fix it. Good luck man. Let us know. Since the stealership is scratching their head I bet that they just don't want to admit to a bad battery.

What's the voltage across the terminals with the engine off, Immediately after shutting the engine off? Just curious here.

Sorry, don't have a VM. The meter I was referring to was just the display in the car.

Pulled this from my how too's

Batteries 101

Batteries are just batteries right?
NO, Unfortunately I know too much about batteries and that is way wrong. To keep it simple were only going to talk about car batteries.

Most car batteries are rated at 12Volts, some race cars use 16Volt applications but let’s stick to 12Volts. 12Volts is the Nominal voltage, not the actual. The actual voltage on a car battery will range from 13-14.5 while charging via the alternator.

Car batteries use primarily flooded lead acid technology or sealed tinned lead acid batteries. Flooded or wet batteries are typically OEM type. They are filled with sulfuric acid, and can be topped off with distilled water. Sealed tinned lead acid batteries, aka non-spillable, aka gel batteries use a gelled acid that cannot be topped off. Both batteries in 12 volt form consist of six 2Volt nominal cells connect in series to make the sum of 12Volts.

What are cranking amps?
Good question, they are a rating that is set by that manufacturer to identify discharge power. Each battery company sets its own formula to determine this rating so if you ask me its complete fiction. The real rating of a battery is in Ah Amp hours which are a calculation of current discharge over time. The other good rating is watts per cell. This is a power rating of the individual battery cell vs. time.

End Cell Voltage?
All batteries have an end cell voltage rating. This rating is represented in voltage of a particular cell. If the battery voltage drops below this voltage while discharging damaging to the lead plates occur. Discharged under this also create more internal heat causing the plates to separate and crack. This can lead to shorted or open cells.

Thermal runaway and Temperature
Per Battcon the battery standard organization, batteries should be maintained at 77 degrees. This is the perfect temp for a battery, but lets face it doesn’t happen. Higher temps offer more battery capacity, but internally dry out the battery causing cell cracking and cell swelling. Colder temps prolong battery life, but limit the capacity of the battery. Too hot or too cold is bad so keep that in mind with battery location

What size battery to use.
Well bigger does not hurt IF it's the right type. However, using the wrong type of battery can strip the starter teeth tight off. I have seen it happen, my own fault.

Normal VS Deep Cycle and why not to use deep cycle in a car.
Your battery is meant to start the car and that’s it. The alternator is sized above the current draw to run the car and recharge the battery. Technically once the car is running you can disconnect the battery. A standard car battery is designed for these short, high current discharges such as starting the car. Deep cycle is designed for a small to medium discharge over a long period of time. A short high current draw on a deep cycle battery provides more power then needed and can burn up starter winding, and even over spin a starters teeth off. However with a proper set up, in audio applications deep cycle batteries are recommended.

Optima red/yellow tops, Odyssey spiral cell, Gel cell batteries
These batteries are very similar to UPS batteries, but are designed for outdoor temperatures. They used a gel electrolyte and tinned lead acid technology. They offer greater starting power at lighter size and weight, but have negatives. These batteries are designed to be float charged. Our cars alternator does an okay job at that, but alternators have a lot of noise on them so they tend to wear these batteries down fasted then flooded type. The life cycle of these batteries is rated in 5 years but we only see 3, flooded are rated at 10 years and you can see up to 7 on those. Because these batteries are designed to be float charged you should never use an automotive battery charge on them. Those chargers don’t limit the voltage at the proper lever of under 14 volts for these batteries. They will ramp the voltage up to 19 volts and shut off when the current gets under a half an amp. A float charger will control the voltage and current charge of the battery a proper level, and then continually keep the battery on a stead float charge of 13.5 volts which is perfect for a 12V nominal battery.

Electrolyte aka Acid.
Never pour it out then fill the battery with water, its ruined if you do that. Test the acids specific gravity with a micrometer. The specific gravity should be 1.25 or the green ball on those floater types. Then fill the battery with distilled water to the fill line then charge the battery before use.

Clean spilled acid with ammonia and water 20% ammonia 80% water, or sprinkle baking soda on the spill to neutralize the acid. Then clean with water. Acid will eat metal and clothes. Always wash your hands and wear gloves, touching your eyes with acid on your finger can cause you to go blind.

BOTH THE BATTERY AND ALTERNATOR CHECK OUT GOOD, BUT AFTER A FEW DAYS MY BATTERY DIES?

Parasitic battery loss is the technical term for this problem. It is caused by two root factors.

A – A circuit or device in the car that stays on drawing current. All cars have circuits that do this such as the ECU, clock, and headunit memory. Those items are not issues usually, unless something breaks down in these devices causing them to draw more current. But if you have added new devices like amps, caps, engine electronics, they could be wired incorrectly causing them to stay on all the time. The other thing that can cause this to happen a nick in a harness shorting to ground. It may not be a hard short due to a painted surface, but if there is a current loss you will drain the battery.

B – The other thing that causes this… A leaking battery. When a battery dips or leaks it leaves a trail of electrolyte down the side of the battery. The chassis is grounded so if the battery is leaking a little (like a single drip that runs down the side of the battery) it will make a trace to ground. Kind of like a tiny solder trace on a board. Current flows down this trace to ground causing a small but stead discharge of current. If you battery is leaking replace it. If you have wet mark around the terminals or green fuzzy looking stuff known as copper sulfate on the terminal replace the battery and cable.

And Ace I'm watching you

was this ever resolved OP? I have an 09 370zed with similar issues but even stranger... A few weeks ago my navi unit freaked and stopped unit, will only cycle on the opening nissan logo, radio stopped working and AC stuck on high. Dealership is replacing entire navi unit under warranty but had to order the parts which takes 3 weeks. Last week my battery drained and I had it towed to the dealership, they replaced battery. I picked up car today and went for a drive just now and noticed the battery voltage drop from 14.5v to 14v on a short ~5 mile drive????? I am going to drop the car at the dealership friday and tell them I want a loaner until the navi unit is fixed so they can figure out whatever the problem is...

Hi,

I have a 2009 370z with Satnav fitted. The issue I am experiencing is that after a short time of running, approx 5 mins, my satnav, radio, heating and ac shut down, often with the a/c coming on by itself and getting stuck on.

I have taken it to my dealer who says I need a new "screen" which will be about £1500 fitted, not happy about that and not sur that's the issue!

My first thoughts were a battery issue, the car starts at approx 14V and then after a few minutes of running dops to 13V, a coincidence??? It happens everytime I drive the car except when I take it on a long run of a couple of hours or more. My local garage have checked the battery with a VM and says all is ok, although he's certainly not a 370 specialist.

I have a local independent car electrics specialist on the case but at the moment he's stumped too. He's checked all of the connectors behind the centre console and also looked for dry joints, but nada...

Has anyone else experienced this issue and a way to repair / solve it?