12v Battery Replacement

Discussion in 'Clarity' started by Dan Albrich, Sep 13, 2021.

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  1. Dan Albrich

    Dan Albrich Well-Known Member

    I have a 2018 Clarity with the original 12v battery working fine. From reading online some websites recommend 3-5 year replacement. I also read that cooler climates (well typically anyway) like Oregon the battery may last longer. I recently replaced a 12v in my 2004 Tundra that was 11 years old (no not kidding or exaggerating). It still worked, but didn't want to find out the hard way when it fails, so replaced it even though it still passed tests.

    So with Clarity, we don't need cranking amps, but there's been some weird failure modes for folks who had problems with their 12v battery. I also wonder if it would be crazy to replace with a smaller 12v AGM sealed battery given that we don't need cranking amps. (I likely won't do that, afraid of doing anything to violate extended warranty).

    Anyway, curious about your thoughts on when you plan to replace the 12v battery.
    i.e. When it dies, In X years whether it needs it or not, etc.
     
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  3. MrFixit

    MrFixit Well-Known Member

    I have never replaced a battery preemptively. Often there are some warning signs before failure (but that logic probably applies more to a conventional vehicle because of cranking), and a failed battery has never posed a serious hardship for me. But you don't need to be especially brave to do this. Just purchase and carry one of the simple jump starter units. The Clarity does not need a complicated one. Mine was about $40.

    My plan - run it until it dies. Use the jump starter as piece of mind.
     
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  4. petteyg359

    petteyg359 Well-Known Member

    You might need cranking amps if you ever intend to help somebody with a jump start. IMNSHO regular old jumper cables are much simpler to carry around and use than yet another gizmo.
     
  5. MrFixit

    MrFixit Well-Known Member

    Even the simplest ones are quite capable of cranking a conventional car, but...

    I completely agree that it is another gizmo. Most people will throw it in the trunk and not think about it for a year or-two, only to find out that it is dead when they need it the most.

    From a practical standpoint, you really have to check it / charge it 2-3 times per year. It is trivially easy to check it's charge status, but many (most?) would forget and it will become useless. Jumper cables become useless too if there is not another vehicle to assist you, but it is rare to be completely alone in this world !
     
    sabasc likes this.
  6. I’ll replace it when it dies. The replacement will be the Honda battery as it carries a 100 month warranty and I intend to keep the car for many years.
     
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  8. PHEV Newbie

    PHEV Newbie Well-Known Member

    Lead acid batteries are very different from lithium ion batteries. Whereas lithium batteries last longest if kept at 50% state of charge as much as possible and to have a low level of electrons always flowing through, lead acid batteries last longest when kept fully charged. That's why ICE cars that are take a lot of short trips that don't allow time for fully recharging will see their batteries failing prematurely. I replaced my Clarity 12 v battery at 4 years and it was in excellent condition (just paranoid because my Subaru batteries kept failing prematurely). I think the Clarity only uses the 12v battery for the electronics to fire up and to activate the big switch that connects the traction battery to the system. Once on, the traction battery will recharge the 12v battery but there wasn't much drain so that won't take long. I suspect people who had their batteries failing prematurely either had defective batteries or regularly had their cars in accessory mode and using 12 v components on like the infotainment, lights, windshield wipers, etc. Regularly draining, even partially, the 12 v battery will cause it to fail prematurely for any reason. BTW, the 12v battery is the same one used in the Civic and it's very easy to replace.
     
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  9. fotomoto

    fotomoto Active Member

    I’m in the deep southern USA (near space X) and my lead-acid batts last about 4-5 years regardless if the vehicle primarily makes short or long trips (commuter). Temp is a big factor in the life of lead-acid chemistry battery:

    95E6DFB5-3791-40CD-A6D9-666A22F0803C.jpeg
    I really like the fact that the Clarity 12v is under the hood so most 12v batts around that size will work in an emergency out in the middle of nowhere because with my luck that’s where it will fail.
     
    sabasc likes this.
  10. The 12V battery powers all 12V systems in the car. In most cases, while the car is in “On/Ready” mode the DC/DC converter will hit the battery with ~14.x volts in much the same way as an alternator on a conventional car. It has been reported that under a certain set of conditions, if I recall correctly it is car in EV with headlights on Auto, the DC/DC converter does not send the ~14.x volts to the 12V battery.

    Voltage under those conditions reportedly sits at 12.6-12.7V. I do not know if observations have been made which show the voltage dropping below that point. Or, if the voltage does drop to say, 12.2V if the converter activates to begin charging. Or, if the converter is only supplying 12.7V under those conditions.

    It is yet another peculiar decision on Honda’s part and one that could lead to less than ideal conditions for a battery that an owner would never suspect.
     
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  11. bpratt

    bpratt Active Member

    How could it have been 4 years? The PHEV Clarity was not being sold until December 2017 when I purchased mine. My battery fail and the car would not start at 3 years 2 months.
     
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  13. Annwn

    Annwn Member

    The Clarity seems to regularly draw on the 12v battery when just sitting. Plenty of posts about that scattered around. I'm partial to AGM batteries anyways to help prevent some issues like this (& also running various in-car electronics), but haven't decided on what to replace my original battery with yet. The Clarity is one car though that I will keep jumper cables in no matter what for that reason. Already had a situation where it had to be jumped in my driveway.

    If you want a jump assist device that isn't jumper cables or one of the li-ion jumper batteries, check out something like this - https://www.amazon.com/gp/product/B086L29DL9/ref=ox_sc_saved_title_6?smid=A2HH6L22S81Q7B&psc=1 It's a capacitor based device, interesting how it works. It obviously won't help with a truly dead battery, but is a pretty decent device for it's use case and doesn't rely on keeping anything charged.

    I'd recommend a battery tender of some sort (Battery Tender Jr for example) - they're pretty cheap. Useful thing to have around the house. I typically put it in our batteries at least 2 times a year - when it starts getting cold out, and in the spring. If there's a forecast for a deep cold spell, I'll also put it on all our vehicles before that. Also if I let a car sit for awhile. Easy enough to put it on overnight or such - but it can take longer if the battery is particularly weak. After having to jump the aforementioned Clarity battery last week, it took a solid 2 days for the tender to finish it's job though. I've easily gotten 7-8yrs+ on all sorts of batteries doing this routine (not just auto - works well for lawnmowers too). Last winter I replaced an 8 year old battery (it was a bit weak, but mainly replaced because I'm driving that car alot less - need to sell it) and another is still going and will be 9 this winter (I'm selling it soon, otherwise would replace this winter). Had it grumble a tad last winter, but only during a particular cold snap and putting the tender on it led to no further issues the last week of that stretch (or since).

    As for actual batteries, some tips -
    - There are only like 2 major battery manufacturers in the US (+a 3rd smaller company if I recall). All of the brands are just relabeled typically. You can look up who makes what, but a $180 battery at one store is often just the same as a $80 battery at another place. You're just paying for a sticker, and maybe a bit of a warranty.
    - The main choice is probably going to involve deciding if you want an AGM battery, and then looking at warranties & prices.
    - For warranty considerations, the Honda battery as mentioned above is pretty decent. It's actually more of a 95 month battery warranty since I believe the last 4 months are 0% pro-rated (but I believe still covers any potential install costs). It's got 3yrs free then is pro-rated.
    - For price or price/warranty, hard to beat a Rural King battery (made by Exide) if you have a Rural King around. I believe they stopped carrying AGM, but the EFB's aren't a bad alternative. Warranties aren't bad - the higher tier ones have longer warranties at very competitive prices. They always have a storewide 10% off on Thanksgiving & Black Friday FYI. Also, if they have an employee on duty who can do it, they'll swap the battery for you. Bonus - no hassle returns. They don't even test batteries you bring in for warranty purposes at our local stores - they just scan them on the computer and pull up your warranty info for the exchange. No hassle at all when I had an early failure on an AGM in our SUV.
    - Wal-Mart batteries have a decent rep as a value buy other than that and there is a walmart everywhere. Sam's Club for AGM's isn't horrid (Duracell I think? made by East Penn) - they will sometimes run ~$25 or so off on them, I've seen it around Thanksgiving, but haven't paid close attention since we started shopping Rural King batteries.
     
    Last edited: Sep 14, 2021
  14. The Gadgeteer

    The Gadgeteer Active Member

    When the traction battery is charging via the EVSE input, the 12 battery also receives a little bit of a charge. Once charging of the traction battery stops so does the trickle charge to the 12v battery. You can do a simple check to confirm this by watching the voltage on the 12 volt battery with a volt meter.

    I have a 2018 Clarity on the original battery so far. I carry both a jump pack and jumper cables.
     
    Last edited: Sep 14, 2021
  15. MrFixit

    MrFixit Well-Known Member

    This is an interesting idea. As you say, useless with a truly dead battery.

    What bothers me about this kind of device is the lack of detailed specifications.
    You can't really compare options with what is given. Being a capacitor, they should at least tell you the number of Farads !

    If you make an assumption that starting a conventional car would require 100 Amps for 5 seconds, then the Super Capacitor will need to be around 120 Farads (the voltage will drop from 12 to around 8 during those 5 seconds). Charging a 120F capacitor requires 2.4 Watt Hours. They claim 3 minutes to charge, so it would have to be drawing ~4 amps. Will a mostly dead battery be able to provide 4 amps for 3 minutes? Maybe... If you want to charge it with a 2A USB charger, then it will take 50 minutes (they advertise 45, so the initial assumption I made seems close).

    Conventional jump starters (with Lithium Ion batteries) have a capacity of at least 50 Watt Hours (20X what this capacitor unit has), but if you can get the car started in 5 seconds, that's all you need.

    With the Clarity however, I presume it needs nowhere near 100 amps to 'start'. Maybe it takes more than 5 seconds to boot and engage chargng from the HV battery. The trouble is this - If your battery is low enough so it cant even "start" the Clarity, then it seems unlikely that it can charge the jump capacitor either. It is kind of a catch-22 because the battery has to be very dead to not start the Clarity. In which case, it is likely too dead to charge the Jump Capacitor.
     
  16. The same conditions that prematurely kill a $100 FLA battery will also prematurely kill a $200-300 AGM battery. Choose wisely.
     
  17. PHEV Newbie

    PHEV Newbie Well-Known Member

    My mistake. Can't keep the years straight. It was at 3 years and a bit. Didn't have any problems with the original battery but took advantage of a rare battery sale that had the right size. We did purchase our Clarity in Dec. 2017 though. It was the first one that appeared at my dealer.
     
  18. Annwn

    Annwn Member

    For anyone not following, some details - from the manual on that capacitor (mine arrived today) - 800a peak current
    For a totally dead battery, these are your options - 1) use another car battery (<3min), 2) from a USB power bank (<30min), or 3) another car 12v.

    Has a nice carrying case. Gonna be handy even just for a riding lawnmower or the occasional co-worker who has a dead battery. Cables can be a pain.
     
  19. PriusGeek

    PriusGeek Member

    My experience with a failing 12V battery in my 2018 Touring was my instrument panel lighting up like a Christmas tree while I was driving down an interstate on a road trip. All of the "advanced" features, like LKAS, cruise control, brake hold, etc failed with warning indicators. There were 6 or 7. However, the car continued to run, the brakes worked and was otherwise OK. After a restart, everything came back for a while except the lane departure and cruise control. Anyway, I drove it in this condition for a couple of weeks while I waited for my Honda service appointment. The car always started, and there was nothing that told me the 12V battery was bad. So, in my case, the battery failing was not like my experience with other cars, including several Priuses which are notorious for their expensive little 12V batteries failing. Honda replaced the battery, and all is now well as far as I can tell. It would be nice if there was some kind of 12V battery failure indicator other than scaring the crap out of the driver in traffic!
     
    Dan Albrich likes this.
  20. MrFixit

    MrFixit Well-Known Member

    I would not have expected that a battery failure would show up like yours while driving...
    When actively in RUN mode, the HV battery charges the 12V. I suppose the charging process will cycle on and off, and with a bad battery, maybe you effectively get a drop-out at the moment the charging process cycles off, triggering the dreaded Christmas Tree on the dash.
     
  21. fotomoto

    fotomoto Active Member

    Yes, on the OEM 12v battery there’s a charge level (good/bad/needs charge) indicator on the battery itself, just got to pop open the hood to see it. As others have said, a plug-in voltage monitor is better. The data is also on the OBD port that can be access with a WiFi reader + app.
     
    DaleL likes this.
  22. Clarity_Newbie

    Clarity_Newbie Active Member

    A couple years ago there was a spate of folks complaining about bad batteries...primarily on the 2018 model after ~18 months. Symptoms ranged from battery icon would illuminate slightly on the dash to a rash of warning lights. Some opted to replaced with another OEM battery whilst some went third party.

    I chose the Optima yellow top AGM. Data collected indicates the Optima and the OEM battery operate in identical fashion as far as volt ranges at resting and when the car is in operation. I was fortunate enough to catch it on sale plus a $50 coupon so cost was negligible.

    Once again this subject evokes the ire of some but it does come down to choice and preference. I choose to avoid Honda dealerships at all cost hence my decision. Choice is a wonderful thing.
     
  23. Was the original battery ever load tested?

    What you’ve described is not consistent with a failed 12V battery. The car will not power up if the 12V battery is dead. It is possible that the “hard reset” (disconnecting the negative battery cable for ~30 seconds) may have solved the problem.

    FWIW: I’ve left the car to sit for 4+ weeks with no battery issues. It also once sat for 6 months and in that case the 12V was dead. I jumped it with a NOCO GB40 or GB70, drive it for 10-15 minutes, and have had no issues with the 12V since. It has been 12 months since I had the dead battery.
     
  24. My 2018 is coming up on 3 years old. I plan on replacing the 12v battery right about then. It just seems like $100 or a bit more for a fresh battery is cheap insurance against the inconvenience of a possible battery failure on the road. Plus, if removed from service while its still working, it can be useful to have around as a spare 12v source.

    However, to be honest, I don't tend to do this on my other vehicles, and in general they usually give a head's up in sluggish cranking when they're about to go. Not sure the Clarity would give that sort of warning, hence my Most Conservative Action approach.
     

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