05RL, 82k miles

1. I go to open my trunk this morning without the key, but with the car unlocked and it would not open, had to get the fob. it usually opens if the car itself is unlocked.

2. I go to open the door with the fob and it opens, but then I hear it beep as though it was trying to open itself again when the door was open.

3. I get in the car and start driving and realize the moonroof, all windows, side mirrors and memory seat are completely dead. Everything else in the car works including cig lighters, rear sunshade, nav, interior lights, seat power, etc.

I was able to fix this by unhooking the battery for about 20 minutes, but I have no idea why it happened. First time in 4 years. The battery is about a year and half old and I just tested it at 12.36v. FOBS both seem to be working fine, though it has been a while since I changed the batteries, maybe 3 years.

Anyone have any thoughts on why this might have happened??

thanks

 

I know you said 1 1/2 years old, but I would suspect the battery.
When did you measure the voltage? Should be somewhat higher than 12.36 for 100% charged

 

Thanks. Just testedreading 12.33v. What is a full batt supposed to read?

Btw, it's an Acura battery from dealership, I installed it Feb 2010.

If the batt is going bad, that would be the worst batt I have had in 20+ years.

 

right around 12.6v, but depends on temp (at very low temp, it would be less)
12.3 is about 75%
You're at about 2.5 years. I'm on my 3rd battery. First 2 lasted 3 years each

 

Ugh! It's prorated for like 7 or 8 years, but what a PIA.

Is it the Acura batteries that are bad, or is it the car burning the batteries. I have a battery in another car from 05 that still reads 12.2 and I've never had a battery last less than 5 years ever.

 

I am on my 3rd Acura battery in 6 years. I have gotten 2.5 years out of the 1st & 2nd, and this 3rd one is in the car a year now. Since I have gotten them replaced under warranty, I have not shopped for a better / stronger battery. I also keep a portable jumper in the car.

The first 2 failed after some very hot weather, but both gave 'warnings' with steering wheel not fully extending or Memory Settings needing to be selected for about 2 weeks prior to a complete failure. I have not however, experienced any of the faulty sensor warnings (typically AFS, SHAWD warnings, etc.) nor have had to reboot the car.

Whether the batteries are inferior (as I suspect) or simply under-engineered for this car's sophisticated electronics, it is one of the few achilles heels of this car. From reading this forum for 6 years, 95%+ of all electronic gremlins reported here have been battery related.

 

The more batteries are discharged, the shorter the life, especially starting batteries (as opposed to deep cycle).
I suspect it is all the electronics that remain on after key is turned off that keep battery in some level of discharge all the time.
We need a "house" battery in addition to the starting battery

 

The RL stock batteries were the worst I've ever dealt with. I went through two batteries in my less than three years with the RL, and because there are so many electrical systems in the RL, those electrical gremlins are the first sign of trouble.

 

BTW - the cells are 2.1 volts each. I.E. 12.6 charged.

I too had the steering wheel not coming out all the way and the MEM 1 condition was never reached. This happenned twice before a cell was completely dead. This was my second battery from Acura in 7 years. 1st lasted 6 years, 2nd lasted 1 year!
I now have my new 3rd Acura battery and we will see how it goes. The advantage of the Acura battery is that if you buy it as a replacement then it has a warranty of 100 months, I therefore will never have to buy a battery again.
If you recognize the warning signs then you won't get stranded - first sign means "get it checked" before you get the dash light up.

 

LOL @ 1.5 years.

 

Dealer tells me they need to keep battery 3-4 hrs to charge it and then test to see what it will hold under load to qualify as warranty replacement. If it fails, gets replaced. Anyone have similar experience? Shouldn't it just read 12.6 cold, anything less means it's dying?

 

They probably want to make sure that you did not run the battery down by leaving something on for a long period of time and it just has not had time to recharge all the way.

 

I'm going to trickle charge it back to 12.6, see if it will hold the charge

 

Recommend testing your battery every 18 months. I went through two batteries in four years (first at Month 17, second at Month 39). I live in Dallas and our 100+ temps do a great job at testing the weaknesses of any battery. Totally agree that the RL should either have a stronger battery or two separate batteries (one for electronics, one for everything else. Both of which could be mounted in the trunk for easy access and weight distribution.

 

Two batteries obviously adds a lot of weight so the manufacturers will never do that but battery technology has improved to the point where more CCA's are required for the RL and they are readily available. Many cars have similar loads to the RL so it's not a unique problem.

Older imported luxury cars always came with an Ammeter when American cars came with "idiot lights". Then the move was to a Voltmeter due to cost and weight savings. The RL has neither, which is inexcuseable. BTW - I have a battery condition/voltmeter plugged into my cigarette lighter for constant monitoring.

Lastly, some knowledge is required when using a voltmeter: a bad battery will frequently measure 12.6V (12.1v/cell) when measured but it may not deliver the amps required for the applied load. When the current draw exceeds the current capacity available then the voltage drops. I.E. a suspect battery may read 12.6 volts until a load is applied, depending on the size of the load will determine the amount of voltage drop. When the engine is running then the alternator generates enough current to typically supply the load and any excess will be applied to the battery for charging. The charge voltage varies on cars but is typically around 14.5 volts and the amount of current is dependant on the resistance of the battery which decreases will the amount of discharge. An Ammeter not only shows how must current is being drawn but the + or - shows which way the current is flowing - either from the battery to the load (discharge) or from the alternator to the battery (charge).

A battery load tester, as used by your Acura dealer, is a low resistance load that draws near capacity current. That amount of power supplied requires the dissipation of a lot of heat and is therefore a fairly large unit on wheels. You can draw maximum current by connecting the two posts together with a screwdriver but that amount of current draw will arc to the screwdiver, possibly igniting the gases released from the battery and subsequently exploding and covering you with acid and possibly killing you. Do not try to load test a battery with low resistance unless you have a load that can sustain the power and heat dissipation required.

 

For years they have been talking about higher voltage batteries in conventional (not hybrid) cars. Has this happened yet ?

 

No.

A 24 volt battery does not necessarily provide more power. Power = volts X amps so if you double the number of cells but the cells are half the current then the power is the same. The advantage of more volts is that it requires less current for the same power and less current allows for smaller, lighter cables. As cars get more electricaly intensive and the price of copper keeps going up then an incentive to redesign the whole electrical system in a car may be considered.

 

I did not say it did. I'm a EE so don't need an explanation of the basics. And I'm old enough to have worked on several cars with 6V electrical systems. Wonder why they went to 12v ?

Anyway I recall a few years ago reading in the car magazines that 24V car electrical was just around the corner.

Actually it was probably more than a few years ago before the engines started to become more powerful without the continued growth of cubic inch displacement requiring a more powerful starter. The voltage drop in the starter supply used to be significant in 12V systems even with the large diameter wiring. Remember the ignition coil resistors that got bypassed when the starter was engaged ?

More volts, less current could be real helpful as the load goes up (yes the power requirement). Got to get the power from the battery to the load, via the wire/s no ?

Google is my friend and after a little research it looks like the 24v systems are now in big trucks and buses but I don't see cars going that way. They are going to make the big jump to 600v for primary power and small engines to charge the batt.

 

Steve, I was not trying to insult your knowledge but more to help some of the numerous people who may appreciate a little technical information.
Also you probably know that the old 6volt systems had dynamos and not alternators and the only reason for a battery was to start the car. I don't think that a holding current for sustaining volatile RAM was a major consideration back then!

 

I don't follow. The internal resistance of a battery is near constant (slightly dependent on temperature) and increases over the life of the battery. Hence, less current capability.
How many computers and op-amps today run on 6v?

 

Actually the internal core voltage on most computer cpu's is around 1.0v now-a-days.
Power/efficiency/heat issues are what has driven the PC to use low voltage, multiple cores at reasonable speeds. Switching the zillions of transistors on and off fast is the extreme power user. Not that this has anything to do with RL's, especially those a few years old.

Today's non-volatile ram needs a just few hundred micro amps per gigabyte and the eeproms need zero.

Unfortunately, based on reading this forum about RL's sensitivity to battery condition, the RL must be drawing a hundred milliamps or more when parked or the alternator cannot quite keep the battery happy once the battery loses some of its zip. Just speculating.

 

You are correct that resistance is not a major factor in charging. The alternator reverse flows the current TO the battery after the required load is sustained by the alternator. This may be accomplished at idle if you don't turn on all of the toys! The supply voltage is manufacturer preset at around 14.4 volts to the battery and is constantly supplied to re-charge the battery from cranking the engine at start up. Regulation is minimal so a long cranking process requires a long drive to replenish.

 

I can understand all of that, but you asked why they WENT to 12V which was before the modern PC. I would also venture to guess that all of the stereo equipment and lighting played a factor in that as well. There aren't many high-power stereos or incandescents that run at 6V.

 

sorry, no time to help you understand my post
maybe later

 

 

Dealer tested my battery, came out at 12.68. Mine shows about 12.33, so I guess their tester is better. If battery is good, leaves open the question of why my windows, sunroof, seat memory button and door locks all died and then came back to life after I disconnected and reconnected the battery. Software glitch perhaps??

 

Right after you started this thread, my battery started showing the signs of going bad.
(See on my 4th battery thread)
the 3rd battery lasted 1 year 8 months.
I had it tested on a diagnostic tester at an auto shop. I would recommend the same. I'm not a battery expert, but I don't think just measuring voltage is the best indicator.

 

When my second Acura battery started to show symptoms of failing (primarily the steering wheel not telescoping or memory settings engaging) and after a week of symptoms, I anticipated the situation, I stopped by my dealer to have the battery tested. It passed.

The NEXT day it was dead, completely, not even a crank. I called the dealer and they said it would be replaced (even offered to send a tech to my house and jump the car). I jumped the battery myself, drove to the dealer and they tested it, said it was in spec, but would replace anyway (under warranty again). Later I was told the failed battery had a bad cell.

I do not have much faith in the quality of Acura batteries....but as long as I ride the warranty wave, I will deal with it.

 

Was the warranty really 100 months?

I don't really think it is the Acura branded batteries, but rather the drain on the battery at rest. I've gone through 2 non-Acura batteries after replacing the original

 

Mine is 100 months, but I think it's pro-rated after three years. Acura brand.