Accessory mode kills the battery?

Benster

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if your headlights are in automatic they will sometimes turn on and stay on even in acc mode. Noticed this with the long winters of Northern Canada. May be a good habit to turn your headlights off if you're using acc mode often. Something to consider.



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if your headlights are in automatic they will sometimes turn on and stay on even in acc mode. Noticed this with the long winters of Northern Canada. May be a good habit to turn your headlights off if you're using acc mode often. Something to consider.
Yup! That’s how my battery died i think. All the lights started twitching including DLR 😂💀
 

verbalj

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My local town is offering free drive-in movies at local fields to keep everyone entertained during the pandemic. I know the civic battery is weak so once we parked, I turned off the car and didn’t turn it on to accessory mode (one button push) for the audio until the movie started. I also ensured the lights were off and not on auto. As someone else said, the vehicle automatically turned off in the middle of the movie after whatever the predetermined amount of time is.

At the end of the movie, the lights in the vehicle were still working. Headlights still worked. Tried to turn it on and bupkis. Turned off everything and tried again and nothing. Thankfully, had my battery pack in my trunk. Jumped it no problem. Fun fact? The guy next to me, also in a 10th gen civic had a dead battery. Luckily my battery pack still had enough charge to jump his vehicle too.

The movie was Onward (the kids were along for the ride obviously) so it wasn’t exactly as long as the Ten Commandments.

I bring this all up also because about a month ago, when I tried flashing a new tune, the car died in the middle of the flash. It was in accessory mode for what, 10 minutes, tops?

I have a ‘16 that I purchased in ‘17 so I guess I’m coming up on that shortend of the 3-5 year lifespan Of the battery. Looking into replacements.
 

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My local town is offering free drive-in movies at local fields to keep everyone entertained during the pandemic. I know the civic battery is weak so once we parked, I turned off the car and didn’t turn it on to accessory mode (one button push) for the audio until the movie started. I also ensured the lights were off and not on auto. As someone else said, the vehicle automatically turned off in the middle of the movie after whatever the predetermined amount of time is.

At the end of the movie, the lights in the vehicle were still working. Headlights still worked. Tried to turn it on and bupkis. Turned off everything and tried again and nothing. Thankfully, had my battery pack in my trunk. Jumped it no problem. Fun fact? The guy next to me, also in a 10th gen civic had a dead battery. Luckily my battery pack still had enough charge to jump his vehicle too.

The movie was Onward (the kids were along for the ride obviously) so it wasn’t exactly as long as the Ten Commandments.

I bring this all up also because about a month ago, when I tried flashing a new tune, the car died in the middle of the flash. It was in accessory mode for what, 10 minutes, tops?

I have a ‘16 that I purchased in ‘17 so I guess I’m coming up on that shortend of the 3-5 year lifespan Of the battery. Looking into replacements.
I've gotten used to the time in the battery and I don't know how another battery would affect the car. Also, Honda has some battery replacement warranty system where they can pay for your next battery in full for about 3 years if you buy a genuine battery first.

Screenshot 2020-06-10 at 04.52.00.png
 

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I've gotten used to the time in the battery and I don't know how another battery would affect the car. Also, Honda has some battery replacement warranty system where they can pay for your next battery in full for about 3 years if you buy a genuine battery first.

Screenshot 2020-06-10 at 04.52.00.png
Thanks for the info. I’ll check it out.
 

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I've gotten used to the time in the battery and I don't know how another battery would affect the car. Also, Honda has some battery replacement warranty system where they can pay for your next battery in full for about 3 years if you buy a genuine battery first.

Screenshot 2020-06-10 at 04.52.00.png
What people are having problems with is the Factory Battery the car came with new.
These are really bad batteries that drain way too fast with light usage, like in Accessory Mode just using the radio.
1.5+ Hours or more just using the Radio in Accessory Mode will drain the Battery too low to start the car.

The Screenshot you provided are just for Honda Batteries bought at dealerships.

Also, these replacements are NOT free. It will still cost you $$ even if it fails in the first month.
"You are responsible for the labor or installation charges."

For $109.99, you can get NAPA battery that has 40 Amp Hours.
https://www.napaonline.com/en/p/NBP6551R?partTypeName=Battery+-+Automotive&keywordInput=si+battery

My Factory Battery was checked by the dealership, & according to their equipment, it is only a 2.1 Amp Hour Battery.

Pep Boys has a Bosch Battery that costs $194.99 & has 45 Amp Hours (see label on the Battery).
https://www.pepboys.com/bosch-plati...duct/844473/2019/HONDA/CIVIC/4-1498 1.5L DOHC

  • Even though I specified my specific car, Pep Boy seems to put "This product may not be compatible with your 2019 HONDA CIVIC" for its Bosch Batteries.
  • The reason this one is a lot more expensive compared to the NAPA one is that it is designed for extreme weather. So, if you don't live in California/Texas or very cold places like Minnesota, the NAPA one will work fine (& a LOT Longer than the Factory Battery).
 

Dario1101

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What people are having problems with is the Factory Battery the car came with new.
These are really bad batteries that drain way too fast with light usage, like in Accessory Mode just using the radio.
1.5+ Hours or more just using the Radio in Accessory Mode will drain the Battery too low to start the car.

The Screenshot you provided are just for Honda Batteries bought at dealerships.

Also, these replacements are NOT free. It will still cost you $$ even if it fails in the first month.
"You are responsible for the labor or installation charges."

For $109.99, you can get NAPA battery that has 40 Amp Hours.
https://www.napaonline.com/en/p/NBP6551R?partTypeName=Battery+-+Automotive&keywordInput=si+battery

My Factory Battery was checked by the dealership, & according to their equipment, it is only a 2.1 Amp Hour Battery.

Pep Boys has a Bosch Battery that costs $194.99 & has 45 Amp Hours (see label on the Battery).
https://www.pepboys.com/bosch-platinum-series-agm-battery-group-size-51r/product/844473/2019/HONDA/CIVIC/4-1498 1.5L DOHC

  • Even though I specified my specific car, Pep Boy seems to put "This product may not be compatible with your 2019 HONDA CIVIC" for its Bosch Batteries.
  • The reason this one is a lot more expensive compared to the NAPA one is that it is designed for extreme weather. So, if you don't live in California/Texas or very cold places like Minnesota, the NAPA one will work fine (& a LOT Longer than the Factory Battery).
Hmm... I just got my battery replaced under warranty because I love to run the car just from the battery during driveway moments or to charge my phone or something. I mean yeah the battery could be better but I'm just used to how it operates. That being said, I am definitely open to new batteries like the NAPA battery you mentioned. Is there a place that does battery comparisons or something where I can compare the two batteries?
 

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Hmm... I just got my battery replaced under warranty because I love to run the car just from the battery during driveway moments or to charge my phone or something. I mean yeah the battery could be better but I'm just used to how it operates. That being said, I am definitely open to new batteries like the NAPA battery you mentioned. Is there a place that does battery comparisons or something where I can compare the two batteries?
There are a couple of sites I found, but have never used.

This one requires you to make an account to view the ratings. I did not make an account, so I don't know what it will show.
https://www.consumerreports.org/products/car-battery/ratings-overview

Here is another site I just glanced through. The "Shop Now" button for each one points to an Amazon site (I did not look at all of them):
https://www.autoguide.com/top-10-best-replacement-car-batteries#mm-section-0

BTW ~ I just called my local Honda dealership's Parts Department & they said the one they have would be the same as the factory. But, when I asked him the Amp Hours, he said it is rated at 45 Ah.

I just rechecked the printout the dealership gave me when I had it checked 2 weeks ago & it does say "2.1".

They can't be the same as the factory one. Too many people are having the same problem with the Factory one.

I also found a really cheap new battery for the 10th Gen Civic's. It was around $33 & even this has 6 Ah. Almost triple what mine is, according to Honda's own measuring devices.
 

Benster

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it's most likely a 45 Ah, no way a car battery only has 2.1 Ah brand new, you wouldn't evne run the radio on that. You need to look at the reserve capacity of the batteries. Similar size batteries will be similar in capacities unfortunately so if you want a better battery you'll have to settle for some weight gain too. Make sure you measure your battery tray and don't buy one bigger than you can secure.
 

ManualOnly

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it's most likely a 45 Ah, no way a car battery only has 2.1 Ah brand new, you wouldn't evne run the radio on that. You need to look at the reserve capacity of the batteries. Similar size batteries will be similar in capacities unfortunately so if you want a better battery you'll have to settle for some weight gain too. Make sure you measure your battery tray and don't buy one bigger than you can secure.
Reserve Capacity is basically the same as Amp Hours (if the battery does not list Amp Hours, there is a calculation you can use on the Reserve Capacity to get the Amp Hours).

The battery is not new. It's a Factory Battery that came with the car. The car is a little over 1 year old.

According to the dealership's equipment, my car's battery is 2.1 Amp Hours. This is the actual printout from their equipment:
1591918475198.png


Amp Hour:
"An ampere hour (abbreviated Ah, or sometimes amp hour) is the amount of energy charge in a battery that will allow one ampere of current to flow for one hour."​

If you have a 45 Amp Hour Battery, if you run something that uses 1 Amp to run, it will run 45 Hours.

If 5 Amps are used, it will run 9 Hours.

If 10 Amps are used, it will run 4.5 Hours.

Updating my reply as I did not know what an energy hog Honda's Radio (Audio System) is in the Civic Si.

The calculation is:
Watts = Amps x Volts​
Examples: 10 Amps x 120 Volts = 1200 Watts.​

For a 12 Volt Car Battery (they aren't exactly 12, but close enough):
10 Amps x 12 Volts = 120 Watts​

According to the 2020 Civic Si Specs:
https://automobiles.honda.com/civic-si-coupe/specs-features-trim-comparison

The Audio is a "450-Watt Premium Audio System with 10 Speakers, Including Subwoofer".
But, I would expect that to be at top volume. At a lower volume, it should be a lot less.

Taking the top power consumption from Honda for its Civic Si Radio, it would come out to "37.5 Amps" (37.5 Amps x 12 Volts = 450 Watts).

According to Honda's generators, they list radios "Running Wattage" as "50 to 200".
https://powerequipment.honda.com/generators/generator-wattage-estimation-guide

450 Watts seems excessive when the radio is only set to 12-18 level.

I just checked my 2019 & the volume goes up to "40", so running it below half its max level should take far less than 450 Watts.
200 Watts or less is more accurate.
 
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Dario1101

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Reserve Capacity is basically the same as Amp Hours (if the battery does not list Amp Hours, there is a calculation you can use on the Reserve Capacity to get the Amp Hours).

The battery is not new. It's a Factory Battery that came with the car. The car is a little over 1 year old.

According to the dealership's equipment, my car's battery is 2.1 Amp Hours. This is the actual printout from their equipment:
1591918475198.png


Amp Hour:
"An ampere hour (abbreviated Ah, or sometimes amp hour) is the amount of energy charge in a battery that will allow one ampere of current to flow for one hour."​

If you have a 45 Amp Hour Battery, if you run something that uses 1 Amp to run, it will run 45 Hours.

If 5 Amps are used, it will run 9 Hours.

If 10 Amps are used, it will run 4.5 Hours.

If the Factory Radio is on in Accessory Mode & NO other user attached accessory/accesories are attached/running, Honda's Accessory Mode should NOT consume 10 Amps.

If it is, there is a defective component(s) or it is an inexcusably bad design by Honda.

ON mode is a different story. Everything is turned on, including the Engine Management System.
I like to run my car in the ON position often. I note that around 30-40 minutes, with my phone plugged in, the car will then lose the charge on the battery enough to not turn over the engine anymore.
 

ManualOnly

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I like to run my car in the ON position often. I note that around 30-40 minutes, with my phone plugged in, the car will then lose the charge on the battery enough to not turn over the engine anymore.
I updated my response in the last post you quoted.

If the engine is not running, I would recommend using just the Accessory Mode.

There is no need to power other high-power consumption things on the car if they aren't being used.

For the 2020 Civic Si, Honda also lists: "1.5-Amp USB Smartphone/Audio Interface".
 

Dario1101

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I updated my response in the last post you quoted.

If the engine is not running, I would recommend using just the Accessory Mode.

There is no need to power other high-power consumption things on the car if they aren't being used.

For the 2020 Civic Si, Honda also lists: "1.5-Amp USB Smartphone/Audio Interface".
I would leave it on accessory mode but it doesn't activate my phone's quick charge capability haha.
 

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Im currently having the same issue after about 2 years of owning my 2018 Civic Si sedan. First time the car died on an indoor parking lot after just about 15 minutes of charging my phone and leaving my headlights on by accident due to the "auto" feature. This last time it died I was listening to music while charging my phone. I made sure to turn off my headlights and touch screen to try to save energy but it still died. I called Honda and will be taking it tomorrow for service and a battery test. Lets see what they tell me.
 

the27thaxe

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So I work at an auto parts store and We typically see Honda's (civics in particular) killing batteries right around that three year mark. Not to try to sell you guys anything, but in the future, it would be worth while to look into an AGM battery. Absorbed Glass Matt Batteries are far more resistant to draw.

The problem we run into is 51R's which in my experience are the more common option (some do use a 35) don't pack a lot of power. 1.5t's don't need a lot of power to crank compared to some other cars and trucks so it makes sense to use a smaller battery to save weight even at the cost of power.

I should have a few more years out of my battery but I'm planning on replacing mine with an AGM when the time comes.
 

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