After sitting for 9 days, SH was dead
 

Sorry for posting this on the main forum, but I was hoping to get a lot of eyes on my story in case the same thing has happened to someone else.

I left my '17 SH (only 5K miles) sitting for 9 days straight while away on a trip. Upon my return, I approached it - expecting the handles to light up per usual - but nothing happened. I then pushed the door unlock button - nothing again. I hit Unlock on the remote several times; yellow light flashed on the remote, but still nothing. So then I popped out the physical key, and open the door. Completely dead inside - start button did nothing.

Great, I thought, I'm going to have to jump it. I then proceeded to jump it off another vehicle (was a pain to get jumper cables split far apart to connect to both the + terminal and the ground point on the engine side, per the manual). As soon as I touched the grounding point, the car started honking & flashing like I was stealing it. First thing I did was quickly take off the jumper cable, thinking I had damaged it. The next time I connected it again, alarms go off, but this time I hit Unlock on the remote. That stopped it. Weird, because if the battery was completely dead, how did it have enough juice for the lights & alarm? Well, I guess maybe the jumper cables allowed it to suck enough power to run the alarm noises.

After charging it for a couple of minutes (it felt like only a minute or two), I then tried the Start button. The car started right away, and everything seemed normal. I didn't lose audio presets or anything. Gas was still full, so I know I didn't leave it running (don't laugh - I'm sure that's happened to a lot of hybrid owners). The battery showed ~75% full, and I drove it for a short distance on battery power alone. If the battery was seemingly completely dead, I'm surprised that it showed 75%. Maybe it's possible the jump alone charged the battery to that point.

I've read the "parasitic drain" comments about Bluetooth connections and possibly even USB flash drives causing a drain. I do have a Hands-free link connection created, but my phone was with me during my trip. However, I did leave a USB flash drive connected in it. I'm not sure if any of these were the cause. Has there been anything definitive established about any electronics that would cause a complete battery drain?

I had the same thing happen and it was a dead battery. The hard part was the car was parked in the garage engine forward and I had the emergency brake on so there would be no moving the car out if I could not get it started. After deploying an unusual car jumping technique, which I will not share as it was not to be repeated by anyone as it was not safe, when I jumped the car it started immediately like it was cycling on under normal EV-ICE engagement. It could be a fluke or a symptom of a weak battery. Batteries can be bad and you would not know it.....I think.

At least some of the RLX's sold will have a slightly "weakened" battery because they have sat on the lot for quite a while before being sold. Normal parasitic loss during this time drains the battery and lead acid batteries tend to lose capacity when they are discharged below a certain level. If the dealer agrees that the car "sat for a while" before you bought it, I would ask the dealership for a new battery covered under warranty. This request will be refused as it is against Honda/Acura policy, but if you tell them that the dead battery issue has happened repeatedly and is causing you to lose faith in the Acura build quality, they may replace the battery for you. In the mean time, it might be a good idea to use a trickle charger for the battery if your car is going to be unused for an extended period and it might be wise to purchase a good quality battery booster to keep in your trunk or glove box, JUST IN CASE this happens again.

The exact same thing happened a few days after I picked up my new RLX Sport Hybrid and on the first visit to the dealer, they tested the battery and said it fell within normal parameters. The second time the battery died, they saw my frustration and replaced the battery under warranty. With the new battery and despite driving very little, I have had no issues since (although I do carry a battery booster at all times just in case).

Good luck.

That sounds like a bad battery. Normal to get the alarm on a dead battery. Have your dealer test and hopefully replace the battery.

It was $109 plus tax at the dealer for a new battery. I'm out of the standard warranty so it was up to me to pay for it. No issues here.

The high voltage battery that was at 75% does not start the SH, those duties are handled by the 12V battery that you used to connect the jumper cables. I would definitely take the advice of everyone that said to go to the dealer, and try to get the 12V battery replaced. It is most likely that it will happen again......

What tasks are accomplished by the 250-volt system, what tasks are accomplished by the 12-volt system, and what tasks are duplicated in both systems, these things have always confused me.

At some point somebody told me that there was a 12-volt conventional starter, but that the 47 HP motor could also be used to start the car with the 250-volt system.

I guess that's wrong.

My guess is that the traditional 12V battery is used to crank the traditional starter which fires up the ICE and this action initiates the controls for all of the other electrical systems. Once the system is up and running, the controls that allow the 250V hybrid battery to start the engine with the help of the motor attached to the transmission become functional. Why the big hybrid battery can't be used to supplement the 12V battery or to start the engine in an emergency situation is a mystery to me.

Definitely will be talking to my dealer. Thanks for the reassurance that it's happened to others, and the 12V battery itself seems to be the culprit. I do contrast the SH behavior against the Camry Hybrid that my wife drives. When you turn the Camry on, the ICE doesn't kick on for several seconds. It seems possible that Toyota handles their startup differently than Honda. In this case, I wish Honda allowed the engine to start from either the 12V or the hybrid battery pack.

As far as why the battery went dead, do you think it's the USB drive/Bluetooth, or is it more likely the proximity sensors that are always active?

A little technical info:

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Update: I took it to the dealer, and after waiting for almost two hours, they came back & said the battery seems to be good. This is after performing a whole slew of tests, including a check for "parasitic drain" issues. Supposedly only 12-40 milliamps were being used while the car was "off"; that amount was on a diag sheet that somehow didn't make it to the papers I was given. They wish they had found something, but that was it.

Since I couldn't leave it there for a longer time, I suppose I can just leave it at my house & run another vehicle for a week. The service mgr said to have it towed to them by calling AcuraCare instead of jumping it again. Now, I could be wrong, but I thought it was an electronically-controlled transmission. So how would they get the car onto a flatbed if you can't change it to Neutral? I'm going to have to read the manual again, I think. Surely this was already thought about by the engineers.

Was the USB drive plugged in during the test?

Yes, I left it in. Now, did the tech remove it during testing? Not sure, but I would think not if they really wanted a thorough test.

I remember from the PC side how people were leaving USB drive/mice plugged into laptops, and it was draining batteries even when the laptops were supposed to be in sleep/stand-by mode. That usually had to be fixed with a BIOS/software update. Now a car battery is much bigger than a laptop battery, so you would think it shouldn't be a problem, even over many days.

I leave an iPod plugged into the center console storage area at all times and never unplug it. Perhaps I should be....

It seems that if your battery is dead, you will need to either: charge the battery, or change the battery, in order to put it into neutral.....

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This is exactly what I suspected - you have to jump it to get some battery power or at least put it on a charger. So basically the service mgr who told me to have it towed to Acura really didn't understand the RLX hybrid.

I'm going to have to run my own test (let it sit for 9 days), and then see if it's dead. If that's the case, then I'm going to press for a new battery. Probably before I run the test, I'm going to get them to pre-authorize the replacement battery if the original fails the time test. I don't need to jump through hoops again or waste two hours of my life while they run tests that won't find any problem.

FYI my wife's MB SUV has a second battery for "back-up" to allow the vehicle's electrical solenoid shift mechanism to function if main AGM battery is 'dead" such that getting the vehicle into neutral for any type of towing required. Her SUV is AWD and I'm surprised ACURA wouldn't have used a similar design for the RLX models or any AWD models for that matter?? Good Luck with your "troubleshooting" process!! Demosan

Still on the OEM battery with over 60,000 miles, let's see if it will make it though the winter. What is different than other cars that it charges around 13.7 and drops more when the engine if off. I also notice the windows are slower when in electric mode.

Last winter, it sat for days and started each time.

A KC2 is already very heavy, and a battery is relatively costly and weighs relatively quite a bit.

Pardon me while I reach for any excuse I can find.

LOL.... :-)

Years ago I was a process control engineer involved with dry cell battery manufacturing (AAA, AA, C, D size stuff). All cells/batteries (battery is technically a group of cells) involve anodes and cathodes kept apart by separator materials with the entire mass swathed in electrolyte chemicals. Cells/batteries are chemical systems that push out electrons from one battery post into the work to be done (closed circuit) and then receiving those same electrons back into the other battery post. So, anytime a battery is connected to a closed circuit it is providing electrons into that circuit. Additionally, separators are not perfect and electrolyte is always willing and able to transport process chemicals inside the cell, particularly when the temperature of the constituents increase (like the hellishly hot temperatures under the hoods of today's cramped engine bays), leading to deterioration in battery condition resulting in shorter battery lifetimes. Conversely, when a cell/battery is placed into a cold environment, those same electrolyte and anodic/cathodic materials are loathe to move and is why professional photographers take steps to keep their batteries warm when taking winter outdoor shots. It also explains why our car starters turn over more slowly during winter months.

I have the burden of knowledge about batteries and replace our vehicle batteries long before they show signs of weakening. Another rule of thumb is to replace a battery that has entirely drained down as soon as possible. A wet cell battery that has fully drained down may be restored to some percentage of its original capacity but that is not good enough as I require a large margin of safety knowing there will be a security risk or time important event in the future following Murphy's Law dictum, "If it can happen, it will happen". Yes, this is my lecture on the value of seemingly pissing away $150 every two years for a new battery in each of our vehicles.

The WSJ article does present the logic for an additional built-in battery that is software controlled so as to be disconnected from the vehicle charging/discharging circuitry whenever the engine is shut off. That secondary battery could then be physical key activated in the event of the main battery having drained during long term parking to provide unlocking, identification and starting power to get the car going on its merry way. Then again, another angle would be for auto manufacturers to conduct an Apollo 13 kind of electrical drain review to snuff out long term leakage losses by the various microprocessors and circuits so as to provide, say, a 30 day parked battery life.

Me Me Me
 

I have added "put the cars on a trickle charger" on my list of things to do whenever we go away for a week or more. As wstr 75 confirmed, if the battery dies, sure it can be boosted, but it is never the same and never has full power storage capacity again.

Maybe it is time for auto manufacturers to rethink the use of lead acid batteries and update to a deep cycle battery that withstands a deep discharge without losing capacity especially as modern electronics keep adding parasitic draw to their systems. Alas, I think they simply default to the cheapest option and then let the car buyer worry about upgrading to their needs at their own expense.

Thanks again for this. I just picked up a Cobra CPP 7500. I plan to use it quite a bit as it is a multi-purpose charger. I always seem to have issues searching for power when I am on vacation. This should certainly help remedy that problem. And I'll have it with me when I get back if by some chance the Acura won't start!

If I can attempt to add some helpful info ....

I routinely go two weeks without driving our RLX SH without any troubles. (DW is supposed to drive it once or twice a week but sometimes doesn’t.. I haven’t had any problem with 12V battery discharging . I would start by simply asking the dealer to put your battery on their test stand and compare the output results versus new delivery standard. The tester produces a pass/fail result. If there’s a problem with your battery you should get a warranty replacement on the spot.

A trickle charger is a good idea but should not be needed for a two week hiatus.

Bit it it’s good to know the car won’t shift into neutral without at least some battery power. Here in the desert SW, batteries go fast when they go.

So, do you connect the trickle charger to your battery terminals the same as if you were connecting jumper cables?

Separately, if your car is outside (like at an airport's long-term parking), are there alternative ways to connect a trickle charger that isn't obvious from the outside?

I have a very inexpensive small 2 Amp trickle charger that does have small clamps that attach to the battery terminals (similar to jumper cables but smaller).

Unless the parking at the airport has plug ins available, the only thing I can think of is to get a solar trickle charger and park outside (only feasible in areas where snow is not an issue).

I think that if you get a brand new battery with full capacity available, as Scott in AZ said, starting after a week or so at the airport should not be an issue. That said, I'd have a battery booster in the trunk just in case.