This always has been problem on vented Lead acid batteries. The issue is exacerbated when people over fill them but even happens on batteries without filler caps. When you open the hood for other reasons, just look at battery, If it is wet, damp, or dirty, Clean it with spray soap Like Simple Green and water. Rinse thoroughly. Baking Soda and water is only necessary if you suspect acid accumulation or are experiencing a current drain across the top of the battery. But using it also will not hurt anything and is cheap. Rinse it thoroughly and let it dry. This is something we do to lead acid aircraft batteries once every 100 hours or annually. Airplane the batteries are in a plastic box which promotes this problem due to poor air flow across them.

KEEP THE BATTERY TOP AND POSTS CLEAN. It only takes a few minutes to do it.

 

The battery on my '15 (bought CPO in '16) is original afaict, still tests fine, hasn't let me down yet, and only long distance drives it gets are the occasional vacation on the Gulf in Alabama or maybe heading out to the mountains here just to cruise....have always worked fairly close to home, car is used mostly to go to work or jet around our small city, but....it's hanging in there just fine. It IS ridiculously small, though, wonder if you could put a lawn tractor battery in a Fit??? It's be cheaper. Probably jinxing myself, here, but have never had a battery on my car let me down at any inopportune time, my wife's car has had her batteries give up the ghost a couple times, but it's 11 years old with 160,000+ miles on it, so, it happens. I just expect to need one on my Fit.....and if I'm expecting it and I DON'T need one, each day I don't need one, is a bonus....reverse psychology, or something, perhaps. Best battery I ever had was on an old Tercel we had.....car was bought new, traded in after 11 yrs, original factory battery - was a Panasonic (and that was the first time I ever saw a Panasonic battery...LOL....but it was a trooper. I figure if the battery goes in my Fit, having a MT, can always resort to push starting it.....I assume you can still do that with a manual?

 

If when it comes time to replace the Fit battery do as many others have already done and replace the stock 151 battery with the larger 51 battery. Bit of a squeeze but it works. Numerous threads on that.

151R battery 360 cold cranking amps
51R battery 500 cold cranking amps

(Capacity will vary a little bit depending on manufacturer).
From what I recall there's not much of a difference in price between the two. The price of car batteries seems to have been climbing lately I guess because the price of lead has been climbing for the last 6 months.

 

My original battery in my 2015 EX is great so far. Just had Autozone charge it for Free.

 

When I was a kid, making a trip to Sears for a $10 battery was a regular activity. Now, they often last for the ownership of the original buyer. Looking online, batteries supposedly last 3 - 5 years. That' doesn't sound realistic.

 

Way back in the 70's and 80's car batteries not only lasted alot longer than today, they also lasted for the life of the car. With today's gizmo gadgets, cell phones, kid's tablets, video games, GPS car batteries today don't last as long as back then.

 

In the early 20th century the major cause of battery failure was overcharging. Then someone invented the voltage regulator.

 

I sat in my car with the motor off and the defrosters on to keep the windows clears while I was dining Covid style in my Fit. Outdoor temp was 45 degrees and after 20 minutes I could not start the car, I had to get a jump. After driving home I checked the battery with my TopDon battery analyzer and it reported AOK.

 

Were you in accessory mode? Or were you in pre-start mode?

If you were in accessory mode you might have not drained the battery.

If you were in pre-start mode then that might account for why you couldn't start your Fit.

 

Thanks for the reply. I reviewed the manual and you are probably right. It says without pressing the brake, press the start button once for Accessory Mode and press twice for On Mode. I may have pressed it twice. I will be more mindful of that in the future! I continued to search the manual, but can't figure out what On Mode is for.

 

It's just like our dad's old cars. When you twist back the ignition key the car goes into accessory or power on mode. It's to put the car radio on without starting the engine.

To put a Fit into accessory or power on mode just tap the push start button once and let go right away. Then on the right of the gauge column. The side that shows your gas gauge it should display "Power On". Now you're in Accessory mode. You can turn on the radio without starting the engine. If all your gauges light up then you're in pre-start mode. Like you're about to start the engine.

 

I woke today after cold weather and God help me weeks of snow to find my Fit would not start (yes it was started during these snowy pandemic weeks). Well its from November 2015 and sits outside so yes its time for a new battery. The 151R battery small with a large price mostly around $169. The 51R larger and $79 with more Cold start amps etc. Read people writing here on "Fit Freak" on about enough room etc. Well it 'Fit" like a glove! Happy to have a bigger battery and capacity. Thanks for sharing the information.


Checkout the size difference

 

Thanks for the photo and price difference. I put a "51R" label on my battery so I will be sure to remember which battery to substitute when my battery dies.

 

That was a smart move. If the battery in my 2015 (bought in 2014) ever dies, I buy the larger one.

 

I live in a temperate climate zone. My 2015 Fit, manufactured in Celaya MX in 2015 Feb, and purchased in 2015 June, still has the original battery, in 2021 March. In January I connected a voltmeter to the battery and had someone start the car in -4 degree C weather (a little below freezing point) and the car started right up, but the voltage dropped down to about 9 volts. It shouldn't drop down below 10 or 11 volts. So I'll probably buy a new battery this coming fall, before the cold weather starts in 2021 November. The battery 6 years despite the fact that every once in awhile I vacuum the car with a 12-volt vacuum cleaner (about 10 amps) and fill up the tires with a 12 volt compressor (about 14 amps) and I do that without the engine running. Did it recently in 5 deg C weather and the car easily started up afterwards. But I don't think it will last through a 7th winter. This has been the story with all 3 cars I've owned the battery needs to be relpaced once every 7 years. I don't worry about listening to the radio with the engine off. The radio doesn't draw all that much power. Although I have the LX model. The radio and video screen in the EX probably draw slightly more current than the ones in the LX.

What draws the most current from the battery on the Fit? The starter. But the Fit engine is small, and has low friction. The starter is small and probably draws less current than the stater in cars with larger engines. The computer automatically adjusts things to help the engine start quickly, unlike in a car from before the computerize era, where you had to maybe step on the throttle pedal before starting to set the automatic choke, and where people sometimes either did not set the choke, or flooded the engine, causing the starter to have to work longer, to start the engine.

After the engine comes the headlights. And here, the Fit turns on the headlights when you open a door and leaves them on for awhile, after you stop the car and turn off the engine. They are on even though the alternator is not running. One of the advantages of LED headlights is they draw much less current than the incandescent lamps that the Fit comes with. I put LED headlight lamps in my Fit sometime during 2018 I think. I put in LED interior lights soon after I bought the car. I don't know if they helped the battery last 6.5 years. And yes, when I replace the battery I am going to replace it with the larger volume and larger coulomb (ampere-hour) battery.

With the engine off, I don't recommend opening and closing the power windows frequently. After the starter, and then the the headlights, this draws the next most current. That is probably why Honda engineered a time limit into your ability to open and close the windows, after you shut off the engine, and why the windows won't open and close with the ignition is accessory position.

 

The alternator should keep it charged while the engine is running. I use trickle chargers on all my batteries every so often - something like like Battery Tender.

 

Has anyone that's replaced the GK Fit battery with a 51R had any issues with charging? Honda Dual Mode charging circuitry (attached to the battery) is pre-programmed for the RC value of the original battery size/type and if you substitute a different RC battery, over/undercharging might occur.

Dual Mode - from the Service Training Manual:
The IG circuit is crucial to proper charging system operation. Turning the ignition switch to the Run position will
send source voltage to the IG terminal, which is required to energize the voltage regulator.
The C circuit is responsible for controlling the charge mode. The voltage regulator sends a voltage to the ECM
through the C circuit. Depending on the charging systems needs, the ECM either holds the voltage high to signal the
high output mode, or it pulls the voltage low to signal the low output mode. When the circuit C voltage is pulled low
by the ECM: the charging voltage at the battery will range from 12.4-12.9V. The ECM uses the low output mode
when the engine is starting or if all of the following parameters are met:
electrical Load below 15 Amps (varies with vehicle),
vehicle speed between 10-45 mph or at idle while in drive,
engine speed below 3,000 rpm,
coolant temperature above 167°F (75°C),
A/C Switch Off
intake air temperature above 68°F (20°C).
Outside of these parameters, the ECM will hold the voltage on the C circuit, which will place the charging system in
the high output mode. In this mode, the charging voltage at the battery will range from 14.4-14.9V.
The ECM uses the FR circuit for field rotor status to be able to change engine idle speed. If the alternator is under
high load, the ECM will increase idle speed. While the engine is running, the ECM sends 5V to the voltage regulator
through the FR circuit. When the field rotor is on, the voltage regulator will pull the voltage down and when the
field rotor is off it will hold the voltage high.

Reserve Capacity (RC)

RC is a general indicator of how long a new, fully charged battery can continue to operate essential accessories if the vehicle’s alternator fails. It identifies how many minutes the battery can deliver a constant current of 25 amps at 80°F without falling below the minimum voltage, 1.75 volts per cell, needed to keep your vehicle running.

 

I have not. I have been running a 51r for 2 years, I make a lot of short trips.

 

I wonder why Honda didn't restrict the battery area to the size they wanted. This looks like an example of an improvement with drawbacks. In the past, I have always used larger batteries when they would fit. Maybe more sophisticated electronics are not always good.

 

I've seen a number of posts over the last few years from people who have installed the 51R. Other than some initial minor mechanical install issues ( tray related) I don't recall a single person complaining about battery problems afterwards. Let's face it, the Fit charging system is not very sophisticated and it's simply not fussy about what size battery you put in there as long as it's a standard flooded lead type. On the other hand putting in a different technology battery like AGM, gel, or even lithium would be a big no no. I believe I've heard that German cars tend to be much fussier about batteries but German cars have that tendency of being over designed to begin with.