25 battery boosts in 1 year

Discussion in 'Clarity' started by nrmehta, Nov 10, 2018.

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  1. nrmehta

    nrmehta New Member

    Dear friends,

    I am in deep trouble with my family for the PEV we leased - Honda Clarity - 11 months ago. Over this period of time, we have called roadside assistance to our home-based garage a couple of dozen times, including today, to get a battery boost. No one - neither dealership, nor Honda Customer Support - has been able to explain why this happens.

    Here's what is going on - if I charge my car from less than 50% full then the main 17 kW battery charges to 100% but the 12 V battery fully drains. As this always happens overnight, I dread waking up and checking if my car is dead, like what happened today. I charge from a 240 V JuiceNet charger, which works quite reliably and logs its charging behavior. Usually, this happens on the weekend, which means Honda Customer Support is not available and I am always struggling with my weekend plans.

    This happened last night. Sigh. Right now I am waiting for Honda Clarity roadside assistance to be boosted. I know a couple of things - there is no parasitic draw, the battery is healthy, and my EV JuiceNet never had a problem with my previous EV (Mercedes B-Series). The usual experts can't seem to find any help for me and that brought me here. Is there a problem during the charging process that drains the battery, something like a computer that is monitoring the charging? Sometimes the car will beep three times when I lock it as it starts to charge and I can't see any problems in the car, like light left on, car not turned off, etc. That is the sound I dread because I know that the next morning I will wake up waiting for roadside assistance but I don't know what to do. [​IMG]

    Sorrowfully yours,
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  3. Richard_arch74

    Richard_arch74 Active Member

    @nrmehta, do you have your 12V battery problem when you charge with the L1 charger? Since the 12V battery is dead in the morning have you tried a battery tender over night? Does your Honda link app on your phone confirm that you are receiving a charge from your JuiceBox L2 charger? Have you researched your lemon laws for your state? Absolutely document all of your service calls.
    Sorry to hear about your problems, it must be very stressfull.

    Sent from my SM-G955U using Inside EVs mobile app
  4. petteyg359

    petteyg359 Well-Known Member

    If it's really been 25 times, you really need to take it back to the dealer service center and demand they look at it. "Lemon laws" might get you a whole new car, but you actually need to have them fail to fix it on multiple visits.
  5. Electra

    Electra Active Member

    How sure are you that there's no parasitic draw? I'm surprised you waited this long. I would have been mad after 3 times. Try to have the dealer replace the 12V battery first to see if that helps.
    Mayjend and chris5168 like this.
  6. V8Power

    V8Power Active Member

    Wondering how you ruled out parasitic draw? If the 12V battery dies that quick, either it is not being charged, the battery is faulty, or there is some kind of load on it when the car is turned off to totally drain it. My in-law's used Lexus had this kind of problem and the dealer could not figure it out after many visits. It was a certified pre-owned car. I recommended them to my trusted independent mechanic who is a great problem solver, true repairman (not a code monkey) and he suspected some device was draining the battery like a Lojack always on car locating security device and he was right. He found it hidden and cut the wire, problem solved. You can isolate and prove to yourself what loads are presented to your 12V battery with ammeter and start pulling fuses. I am not impressed with dealers' problem solving skills these days.

    chris5168 likes this.
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  8. chris5168

    chris5168 Member

    Sorry for your challenges, my family would be super frustrated as well.

    Interested too if the OEM L1 Charger produces the same results as your current L2 EVSE. It sounds like it was checked, but if Clarity is left ‘On’ or in Accessory mode, this would produce extra beeps when exiting but not necessarily when you are exactly charging. You may want to restart the Clarity and shut it down again when you hear extra beeps.

    Clarity factoid: For the EV battery to charge, it absolutely needs the 12V.

    Is there any electrical reading from the dead battery? What comes ‘on’ when external 12V power source is connected to jump/boost your battery?

    Also what happens when the Honda Link or JuiceNet app alerts you that battery is fully charged, are you able to run out and unplug?

    The “if I charge my car with less than 50%” is an interesting observation too.

    Good luck and keep us posted.
  9. Viking79

    Viking79 Well-Known Member

    This needs to be fixed by the shop. I have never needed any sort of jump start of my 12 V in 25,000 miles.

    I would make sure you don't have something draining the battery though, any after market add on or anything?

    If the dealer is unable to fix it, contact a lawyer and see if your state has a lemon law. Most likely it is a bad 12 V or something draining it, or possibly the DC to DC converterthe car uses to charge the 12 V from the higher voltage battery.
    Domenick and DaleL like this.
  10. PHEV Newbie

    PHEV Newbie Well-Known Member

    Agree that Honda must fix this. Until that happens, purchase an inexpensive 12v powerpack starter. Many of these are about the size of an external battery that charges phones. These have enough power to crank a full sized ICE engine with a dead battery so they have ample power to turn on the electronics in the Clarity to get you on your way when you're away from home and save you valuable time when you are at home. Good luck! BTW, my 12 volt battery has never failed after nearly a year of ownership and that's including leaving the car in an airport long term parking lot for a couple of weeks (during that time, my Clarity continued to communicate with the Honda App server because I could get updates on its condition by checking the app on my phone).
  11. ab13

    ab13 Active Member

    You say the car may beep three time when you lock it. Did the dealer install an aftermarket alarm system on this car?
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  13. V8Power

    V8Power Active Member

    If I had to guess, some aftermarket device was added always on that is tapping it. Maybe a dashcam or something?
  14. jorgie393

    jorgie393 Well-Known Member

    Wow, this is a big problem and 100% up to the dealer to fix or replace (whether or not they know what it is).

    Though I agree with most that thus sounds like parasitic draw at first glance, regular parasitic draw would affect the car any time it is left overnight—not just when charging. The report that only after charging is the real mystery. Could be that a relay, engaged when charging, is not releasing afterwards. The way to check this overall would be to measure volts and amps out of the 12V when car is off (to look for general parasitic drain) and again after car has just finished charging (to look for parasitic drain that only happens after charge). This may or may not be in the OPs comfort zone: needs a voltmeter and ideally clamp dc ammeter.

    The beep three times relates to the car thinking keys are inside, door is open, etc. That can be as simple as nearby reflecting surfaces increasing the signal from the key so it seems closer than it is. I press again and it’s always ok: if OP finds that it happens all the time, that is different story.

    Sent from my iPhone using Inside EVs
  15. SkipperT

    SkipperT Member

    We need more info from the OP.

    Also I’m fairly certain that there’s an inverter or some other box that is responsible for allowing the flow of juice to and from the 12v battery from the traction battery. Maybe that’s faulty and not allowing current to go from the traction to the 12v system under certain circumstances?

    Parasitic drain a simple test that anyone with a VOM can perform.

    Also would like to know about ALL mods and installed accessories.

    Random thoughts...


    Sent from my iPhone using Tapatalk
  16. petteyg359

    petteyg359 Well-Known Member

    That's a transformer. The inverter is what powers the motors (which use AC instead of DC).
    Domenick and KentuckyKen like this.
  17. Sandroad

    Sandroad Well-Known Member

    I'm not familiar enough yet with Insideevs to know for sure, but if a post like the OP popped up on either of the other 2 forums I participate in, it would be considered a troll.
  18. SkipperT

    SkipperT Member


    This is an automotive application. I’m no engineer, but my understanding is that transformers are more common on a utility pole. Maybe the Honda engineers stuck one in a box under the hood somewhere...


    Scroll down to “input and output”.

    I’m assuming the battery pack is also DC.
    The inverter can’t power the motors, it simply changes DC current to AC current so the electric motor can use it.


    Sent from my iPhone using Tapatalk
    Last edited: Nov 11, 2018
  19. Garry2

    Garry2 New Member

    The Honda Clarity uses a DC-DC buck converter to step down the traction battery voltage to ~14v to charge the 12v battery and run accessories. To the OP, if you have a multi-meter, during charging check the 12v battery voltage. It should read higher then 12.5v. The DC-DC converter should be supplying power to the 12v system during charging to power the coolant pump and the fans occasionally to keep the on board charger cool. It sounds like this may not be occurring during charging and runs the 12v battery down even though the traction battery is full.
  20. insightman

    insightman Well-Known Member Subscriber

    I hope the Original Poster hasn't abandoned us! This problem is so fascinating and there's so much brain power on this forum that the collective can certainly help get it solved. If the dealer has a fit of brilliance and figures out the problem, we want to know how it was resolved!
    Domenick and Phunny like this.
  21. petteyg359

    petteyg359 Well-Known Member

    DC-to-DC or AC-to-AC are by definition transformers. It's only a converter if it is going AC-to-DC, and vice-versa for an inverter.
    KentuckyKen likes this.
  22. Sandroad

    Sandroad Well-Known Member

    Hmmm, see my post above about trolling. That OP's first post was an only post and had lots of oddities.....we'll see.
    vicw, Candice, ClarityDoc and 3 others like this.

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