My 05 G35 will drain a battery (Optima) in one week after being fully charge with a battery charger. The battery is just 4 years old. My digital voltmeter says I get over 14 volts while the engine is on. Also my meter shows a current drain of 100 milliamps. Is 100 milliamps too high for the 05 G35? The car does have an aftermarket stereo and amp. I can't see anything that stays on anywhere.

 

It reads 14 volts while the engine is on..... what do you have running while this test was taken? You should be in a charging state +12.5 volts with every accessory running....high beams, stereo, heater/fans. If you can't stay in the 13-15 volt range while those things are running then you have a charging issue.

 

The voltage was 14.2 volts with engine on, AC on high, high and low beams lights, radio and 500 watt amp on. I just read there is a TB stating that re-programming the ECU might be necessary due to the alarm performing tests that draw nearly 1 amp for about 20 minutes every so often. Thus it can weaken a battery if the car is not driven enough each day. I just drive 18 minutes twice a day. Have you heard any truth to this?

 

100mA is likely normal for a parked g35 considering you're running the clock, the alarm system and the keyless entry receivers. 100mA (.1A) is barely any drain so I really wouldn't worry about that. If there is a TB on this then it's probably worth getting the ECU reprogrammed if that's a possible cause. 1A is way too high for 20 minutes on a parked car if it's doing it several times a day. Is it possible your amp is turning on by accident? Have you installed any other modifications to the car?

Driving the car short distances is an issue because you're removing a lot of amps to start the car and not giving adequate time to recharge the battery while driving but 15-20 minutes each way should be ok, I would think. if you drove 3-5 minutes each way then i'd say your more at risk for prematurely discharging the battery. The techs at infiniti may have a better idea of exactly how long you need to drive to replenish the starting power to your battery though.

 

Yes I will pick the brain of my Infiniti Dealer and see if that TB concerning re- programming the ECU is giving positive results.
Thanks for your inputs.

 

Hi avion, I'm sorry to hear about the issues you've been having and I'd like to offer some assistance. We recommend typical alternator output to be somewhere in the range of about 13.7-14.7 volts and nothing I've read here would suggest that would be the issue for you. However, given what you posted about your 100-milliamp draw, I would like to share some numbers with you and let you decide if your draw is an issue or not.

I don't know what kind of Optima you purchased, but since you have installed an aftermarket stereo system, I'll use the D35 YellowTop as the example, because it has more reserve capacity than the RedTop and is designed for deep-cycle use, including car audio. That battery has a reserve capacity of 48 Ah. If your car is drawing 100 milliamps, that means it is discharging the battery at a rate of 2.4 amps (.1 x 24 hours) per day.

That means the YellowTop will be completely discharged (0% state of charge), if it sits for 20 days (48/2.4) without any charge going to the battery. These calculations assume the battery is fully-charged when the vehicle is parked (most are not) and does not take into consideration climate, which can shorten (Las Vegas heat) or lengthen (moderate temps) these timeframes.

It should be noted that different vehicles will require a different minimum voltage to start, which is probably something above 0% state of charge. It's also worth mentioning that even if a vehicle does not sit long enough to completely discharge the battery, this repeated partial discharge and the sulfation that will be caused by the battery resting in a discharged state, will cause long-term reductions in performance and life. This is why we emphasize the importance of maintaining at least 12.4 volts and recommend a maintenance charger for any vehicle that is not used regularly.

Daily drivers tend to have fewer battery-related issues, because the batteries tend not to sit unmaintained for extended periods of time. Expecting an alternator to recover a deeply-discharged battery can also shorten the lifespan of the alternator, leading to a cycle of dead batteries and jump-starts, until either the battery or alternator fails. How you drive your car can also impact performance. If you are driving 18 minutes in stop and go traffic with your stereo and AC on, your charging system may not be able to keep pace with the electrical demands of your vehicle and maintain proper voltage in your battery. Are you running a stock alternator and wiring?

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

 

Thank you for the information. I'll give you more details in hopes to find a solution. It's a Red Top with 40 months of use. The stereo in use with amp have been in the car for about 3 years. No other electrical modifications since then. Until recently, I have never had any issues unless the car was not started for 3 weeks. Now I drive the car daily, park it Friday, and by Monday, it barely turns over. I either must drive the car during the weekend or put it on a charger on Sunday afternoon. Then I'm sure it will start Monday morning. I live in Florida so the strong winter days have not yet arrived. So my problem is bound to to get worst as the weather gets colder. As mentioned before, 14.2 Vdc with everything I can turn on in the car. My research tells me 100 ma draw is normal for my G35. So that rules out parasitic electrical drain beyond normal. My next step is to load test the battery after charging it over night. I have been charging at a 2 amp rate for at lease 12 or more hours. Old School batteries have always wanted a slow charge for longevity of the battery. By Optima's web site, The Red Top should be able to be charged at a 10 Amp rate. My charger is a 2 or 6 Amps. Perhaps I should try charging at 6 Amp rate overnight, then have the battery load tested? What are your recommendations?

 

If you live in Florida, the damage to your battery is really being done in the summer months. The colder temperatures in the winter just help manifest the damage done in the summer. As I mentioned before, RedTops are not designed (or warrantied) for deep-cycle use, including car audio applications. That doesn't mean they won't work in such scenarios, but that a YellowTop will work better and last longer.

I still don't know what size RedTop you are using, but the Group 35 RedTop actually has less reserve capacity than it's YellowTop counterpart, so a 100-milliamp draw will completely discharge that battery in closer to 18 days. While a 100-milliamp draw may be considered normal for a G35, it is considered excessive in general. The typical key-off load on a vehicle is about 25 milliamps.

The important thing for you is to get your voltage back up to a fully-charged state (about 12.6-12.8 volts) and try to maintain that whenever you can. It might be worthwhile to check voltage shortly after parking your car, to see if it is being maintained properly during a normal day of driving for you.

Our batteries can be charged at a maximum rate of 10 amps and that higher rate might help break up some of the sulfation that has formed in your battery and restore some performance. A battery disconnect may also help prevent your car from discharging your battery during long periods of non-use, although you would lose presets by doing that.

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

 

Last time I checked mine it was 135ma

 

After much research I think my battery problem might be solved. Like I said I would do in the previous post, I charged the battery over night and had it tested the next day. I took it to my local Discount Auto and the battery checked fine. The tech there said Optima batteries like a higher charge rate (10 Amps verified) and charge it longer then over night. So I next charged it at my highest setting of 6 Amps for 24 hours.The charger pulled about 5 Amps at the start, then about a minute later started dropping to below 2 Amps. Ten minutes later it was below 1 Amp on the charger's meter. Next day I had the battery tested at a reputable automotive repair shop and the battery tested fine 3 times, better then 90% reserve power. A week later, and I have not had any issues with the battery. Perhaps all it needed was a long deep charge.
I'll keep you posted if I have any more issues in this matter. Thanks for all your inputs.

 

Anything under 50 milliamps is acceptable. No Infiniti should have over that after the bcm goes to sleep. The most common causes of parasitic drain on our cars are the audio unit(very common). I know you said yours was aftermarket. Also we have a lot of G35's come in that have previously had a system called mobile guardian installed and these systems are junk. Hope this helps

 

After the high amp charging (6 Amps for 24 Hours) as stated in my previous post, my battery works great. It has been a month now and I have not had any issues. No other changes were made. Great Battery, one needs to just charge it correctly according the manufacturer.
Thanks Again for for all your inputs.

 

Im dealing with the exact same issues right now with a new battery this season. Im pulling about 110ma when the car is off. I had to pull the HU fuse because it was pulling close to a 1amp. 110ma leaves me dead the next morning however so im trying to figure out if battery is bad or what frustrating trying to find a drain.

 

Wow.. I've seen the same problem over and over in the G35 websites.
The "normal" drain by the G35 experts is near 100 ma as measured with a digital voltmeter with the alarm on. Troubleshooting can be a pain, I know, I just went through it and I'm an Electronic Technician by trade. Here is a list of things to check so you may isolate your Problem.1, What is charging voltage with a full electrical load (headlights,stereo,high AC,ect) Should be near 14 VDC .2, Check condition of the battery terminals top and bottom. Should be super clean, free of corrosion. 3, Charge battery at Maximum Manufacture recommended charging amperage for 24 hours,(Some may be as high as 10 Amps.). 4, Have the battery Load tested professionally the next day. By this time you should solved your problem. 5, Last resort, go to your Infiniti Dealer and have them perform the Technical Bulletin that reduces the high current self tests that are performed every few hours.
Good Luck

 

Yeah in process of doing this I'm gonna hook it up and give it a really go's charge then take to be load tested. Sounds like a base for our cars is 100ma so that makes me feel a little better. I never gave the battery a really full charge so maybe that will help. At a rate of 100ma though I still would need to leave hooked up to battery tender and I never had problems before leaving off. Which made me think I was having a draw.