Bad 12V battery??

Discussion in 'Honda Hybrids' started by greenrider, Jun 10, 2009.

  1. greenrider

    greenrider Well-Known Member

    At the beginning of the last winter, the 12 volt battery in the HCH II was unfortunately completely drained by a done light that was left on. After charging it up again, the indicator has consistently shown a good battery and there have been no obvious issues with it. I've had a drop in mpg to the low 40s consistently, and the IMA battery is having increased fluctuations, with crashes even in cool weather when half to almost fully charged (no codes yet).
    Could a dying 12 volt battery be putting a load on the DC-DC and the IMA battery, causing the lower charge state and lower mileage? Or is my IMA battery going at only 41K?
  2. msantos

    msantos Eco Accelerometrist

    Hi Mike

    Your diagnosis of the 12V battery as the cause is dead on. I've literally lost count of the number of cases similar to yours and in each one of them the replacement of the 12V battery was the solution. ;)

  3. greenrider

    greenrider Well-Known Member

    Manuel, you just made my day :woot: Thank goodness I won't have to battle it out for a new IMA battery.

    Now, if I remember correctly, the HCH has a specific battery that really can't be purchased in the aftermarket, correct?

    Is there any place cheaper than the dealer to replace it?

  4. msantos

    msantos Eco Accelerometrist

    Hi Mike;

    This is a touchy area and others will certainly have a different opinion.

    I in the other hand, prefer getting a direct replacement either from the local dealer or an online Honda dealer/retailer if at all possible.

    The primary reason I would do so is because the OEM 12V battery has very unique load characteristics and plays such an important role in the overall energy equilibrium of the car that a slight difference in the specs will make itself noticed. Maybe not noticed by many people, but I will tell you that some of us would notice it anyway.

    With this said, you can get third party replacements elsewhere. Autozone, walmart, pepboys and the rest provide "direct equivalents" that appear to do the job well and come with good warranties at least as far as the battery is concerned.
    And depending on how well you are tuned into it, your mileage and results may or may not not fall under the same garantee. ;)


  5. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member

    Mike, our '06's 12 volt battery had a couple of close calls, once due to the 2 map lights being left on overnight, and another time with the headlights left on for about one hour. In both cases I was able to restore the battery with a charger I have, and the indicator window shows the battery as ok.

    Anyway, I'm thinking the 12 volt battery may or may not be the source of your problems. I would go through the dealership, and ask them to verify it's condition first.

    I just happened to do a maintenance on our daughter and son-in-law's 12 volt battery last night. It's a non-hybrid vehicle that's been back east up to now, maybe 4 years old. They're not sure if it's the original battery. Corrosion on all the fasteners, coupled with the white stuff around the battery terminals made it very tough to extract from the car.

    The positive terminal lead in particular was very difficult to work loose, and I wished I'd had the proper battery cable puller. I managed to pop it loose gently, though.

    Our car is maybe 1 year younger, but the 12 volt battery looks as-new. Maybe in part due to west coast environment, but could it also be due to reduced load, since the IMA battery typically does the engine start-up?
    Last edited: Jun 12, 2009
  6. psyshack

    psyshack He who posts articles

    Just take the batt in to a local parts house and have them check it. If you have a dead cell you found the problem....
  7. armadaman

    armadaman Active Member

    Just replaced my 12V in my 2000 Insight this past Saturday as the electric windows were moving slowly and the voltage on scangauge was reading a lower than normal value.Had the battery checked and it had a dead cell.Replaced and one of the first things I noticed is the car ran better.Wasn't assisting as much.Now the HV battery is staying topped off longer and my MPG is better.
  8. greenrider

    greenrider Well-Known Member

    I put in on a trickle charger after leaving it in the garage for 5 days while away. It took a few hours to charge back up. I think I'll bite the bullet and make a trip to the dealer for a batt check.
  9. hunter44102

    hunter44102 Well-Known Member

    If you have a Harbor Freight nearby, you can get their 50A or 100A battery tester. It basically puts the 100A load on the battery while measuring the voltage, and it should stay in the green region if its good. (should not drop too much voltage).

    They are like $20
  10. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member

    Verbatum from the HCHII Service Manual:

    (I'll skip the first few steps, which basically say to check the case for cracks, and the status window colors)

    4. Apply a 300 amp load for 15 seconds to remove the surface charge.

    5. Wait 15 seconds, then apply a test load of 280 amps for 15 seconds.

    6. Record battery voltage.

    * If voltage is above 9.6 volts, the battery is OK.

    * If voltage is below 9.6 volts, go to step 7.

    7. Charge the battery on High (40 amps) until the test indicator window shows the battery is charged, plus an additional 30 minutes. If the battery charge is very low, it may be necessary to bypass the charger's polarity protection circuitry.

    * If the test indicatory window indicates the battery is charged within three hours, the battery is OK.

    * If the test indicator window indicates the battery is not charged within three hours, replace the battery.
    Last edited: Jun 22, 2009
  11. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member


    I'm thinking it might be time for a replacement 12 volt battery for our '06. The 4th "anniversary" date of the car is in December, and it's still the original battery in there.

    In addition to the two close calls I outlined above, we recently got the car back after nearly a month in the body shop. While the car starts ok and behaves normally, the 12 volt battery's status window was showing red dot with clear surrounding ring (indicates charging needed).

    I charged for two evening/overnight sessions, with a 6 amp charger with auto overcharge protection. By the second morning it continued to show clear ring, but by the end of the second day when I checked, it had gone back to blue. I guess a full day driving around helped.

    Still, 3 close calls: I'm wondering if it's time for a premptive change. I do notice the mileage seems to have worsened in the few days we've had it, not a big sample though. I filled the tank and reset the odometer the night we got the car back.

    A possible clue to the depleted battery: the Trip A mileage (which had been under 6 l/100km pre-accident) was at...:

    29.something per 100/km.

    I didn't think that was possible. I'd gone to air up the tires at our usual station (one of the rims sustained damage in the accident, was re-machined, and consequently had pressure lower than the others, being filled by the body shop or sub.). Anyway, when I saw that fuel consumption I decided to refuel and reset the Trip A (and B), couldn't stand to look at it ;(

    Questions if you please, and please excuse the preamble:

    Considering the age and history of the battery: time to swap it out?

    Also, any tips on correct battery number? I've checked with our (Canadian, west coast) parts department, and they say they are seeing a distinct part no for the civic hybrid, different than the regular civic battery. They have one in stock, asking $133.

    According to them, the batteries are full charged when you pick them up, no need to top up. Does that make sense? Any likelyhood of getting a "lemon" battery, ie: one that's been sitting around too long?

    Thanks in advance for any light you can shed ;)

    Addendum: I might have actually answered my own question. I think my situation is similar, or worse, than the OP. Anyway, typing has helped me sort this out. Any comments still much appreciated ;)
    Last edited: Oct 9, 2009
  12. Taliesin

    Taliesin Well-Known Member

    I know it is definately time to replace my Ranger's battery.

    It's still original and I bought it in July '02.
  13. msantos

    msantos Eco Accelerometrist

    Hi Mendel;

    The battery part reference I have is "44B19L-S" and yes, it is definitely different from that of a typical/regular Civic "51R/500AMP85".

    In retrospect, I have literally lost count of how many folks chose to get a different spec'd battery only to regret the lower mileage they got afterward... so on that note, I would not take anything other than the recommended OEM even if the alternative was free.

    Of course, I would reconsider this position "if and only if" an alternate battery source can match the original specifications. if they can't match it, then its a no-go for me. ;)

    In any case, given the circumstances and history perhaps your battery has had better days and maybe a replacement will be key. Did you have a chance of load testing it?

    Also, age is a factor in most cases, but curiously the battery on my 2006 is still as good as new and I suspect it will go far beyond 5-6 years. Sure, I have a full time enhancement (solar panels) installed and that may be mitigating factor in extending its life beyond the regular 3-4 years these cars seem to exhibit. Oh well.


  14. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member

    Hi MSantos,

    Thanks for all the info. I have seen both those numbers, when I looked at a US Honda site, for the hybrid and regular civic respectively. And the top of my battery's case (raised letters) is "38B19L(S) - MF". It's also indicated as "Furukawa HiDash". Regarding the slight difference I would speculate since 4 years back the battery manufacturer revised the design, and bumped the number 38 to 44. I think ultimately I have to rely on the parts department judgement, but I will check the manufacturer and his part no as well. And for good measure: I'll check dimensions. Still, Honda might switch suppliers.

    I haven't got a load tester, that is something new for me. I gather regardless of the battery's status window appearance, the load test is a better assesment of the battery's "health". I've read through the shop manual regarding load test, and just did a quick look for load testers online. Locally, Princess Auto has only a 100 amp model, for just under $100. From the Service Manual I believe I need a 300 amp tester, minimum. I only found higher amp models on US sites, so far. They're also around $100, and are dollars are close to par, but I'm leary of shipping, think I'll check a bit more locally.

    So, in my current situation, I can:

    1. Hand it over to the service department for load test and assesment. This is likely the smartest choice (especially considering my lack of load tester), except they are not necessarily the "smartest" bunch. I talked to service prior to parts yesterday, and the service rep was saying there was no difference: reg vs hybrid 12 volt batteries. I put this down to Service Rep "bluff", and would hope they would sort out with Parts as to what the correct replacement battery is, along the way.

    2. Forget about load test, consider the battery's "checkered" past, go straight to parts department and swap it myself.

    3. Wait a while and keep an eye on it. My only concern with this option, and I think this goes back to the OP's concern: is a "borderline" battery detrimental, ie: could it be degrading your mileage somehow, by burdening other systems, or accelerating wear-and-tear on other systems.

    Not sure, will wait-and-see and think on it for a few days. Maybe I can even find a better source/price on load testers, and see for myself.
    Last edited: Oct 10, 2009
  15. msantos

    msantos Eco Accelerometrist

    Hi Mendel;

    I would pick your option #2.

    The part numbers I listed are from the Honda Canada parts list. However, just like yours, my 2006 HCH is shown with a 38B19. Here's a quick pic I snapped in the garage a few moments ago.

    Oh I should note that the "44B19L-S" is the formal designation for the 2006-2008 models. The 2009 model had some hardware revisions and the battery specs were therefore revised up. This means that the 2009 HCH now shares the same battery model as the regular gas only Civic. So I guess the service person you spoke with was not "totally" wrong. They just ignored the differences between the two distinct HCH-II baselines.


    Yes, when the battery is just so-so on the borderline, you also run the risk of not only not starting correctly (flashing dash syndrome) but you'll also see odd things happening until it totally fails. Erratic FE and coarse power train control are just some of the most common symptoms.

    Whether on the Low or the High end of capacity, extra load and stress is always placed on the other systems with the Low end of battery capacity being the most harmful.


    Last edited: Oct 10, 2009
  16. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member

    I agree about #2. No muss/fuss.

  17. Jess

    Jess Well-Known Member

    MSantos, can you elaborate on the "course power train control?" How would one know if that were occurring?

    I'm coming up on 3yrs with mine and I want to be aware of anything that might point to the battery failing. I've never had an issue with it and I can still see the blue ring w/ the red dot.

  18. msantos

    msantos Eco Accelerometrist

    Hi Jess;

    Faulty 12V batteries have also been found to be the cause of coarse power control and delivery. For instance, deficient power levels can cause slow and delayed responses of the solenoids and valve activations in the CVT and that can make the transmission seem rough and seemingly uncoordinated.

    Of course, there is so much more that also gets affected by a 12V power deficit but the transmission and steering are the next domino pieces in line right after your fuel economy begins to take a serious dive. The other thing to remember is that the IMA DC-DC controller is designed to provide steady power that profiles at much lower power levels than the peak power demand exposed by a weak 12V battery. The idea is that a normal operating regimen includes a healthy 12V battery ALONG with the somewhat leisured contribution from the DC-DC controller. ;)

    Anyway, while I would not lose too much sleep over this, I would still keep an eye on your FE... and as soon as you notice a change (and it is VERY noticeable) then have a closer look at your 12V battery.


  19. Jess

    Jess Well-Known Member

    Cool, sounds good. Thanks again!

  20. ematzen

    ematzen Well-Known Member

    Ok gang - any help? My battery on my 06 hch2 is labeled: 31500-SR1-100M

    Is this correct? I think it might be the standard civic battery, not the hybrid battery, but I am having trouble tracking it down.

    In the U.S., if that matters.



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