I got a new napa power 12v battery in December 2019 and it ended up disabling the auto-stop feature in my vehicle for a good 4-5 months, not sure why. Because of Covid, I drive a lot less and the battery ends up discharging really quickly, is this normal? Would getting a 12v battery with higher CCA be helpful? If I don't drive the car for around a month it always requires a jump start...

Here's a link to the new battery: link

And here's the old one: link

 

It's possible you got a bad/weak 12V battery. Just because it's new doesn't mean it's good.

It's possible you have a heavy parasitic drain cause by a malfunction or some aftermarket electronics.

Please refer to your quoted text above:
(0) No it didn't. Something else is wrong.
(1) This is really bad. If you let hybrids sit, it's dramatically worse for them than it is for regular cars.
(2) Generally no. It really depends on how much you're driving. If you're driving less than 3 times a week for a total of 50-100 miles, then you might not be driving it enough to keep the battery charged.
(3) Generally, no. It might mean you need to jump it 5 weeks instead of a month. You don't have a lot of options, but I recommend a 51R vs. the stock 151R. You have to remove the plastic shroud and be careful about how you orient it when you bolt it down, but it will fit. Ithas about 40% more capacity.
(4) How much are you driving?

I have the following additional questions.

When you turn the key to the ON position, but you do not start the vehicle,
(1) Do you see the IMA light illuminate?
(2) Do you see the check engine light illuminate (picture of an engine)?
(3) Do you see the Red 12V battery light illuminate?

Lastly,
(X) What instrument cluster lights are on when you're diriving?

I suspect you may have lights that are burned out concealing that you have a problem. My gut says that your IMA battery is bad, or your DC-DC converter is malfunctioning, and you are not getting proper 12V charging where it only charges between about 1600 and 3500 rpm.

Probably worth conducting this test:

 

Thanks for your reply Keith. I'm taking the car to NAPA tomorrow to get the battery tested, I already got a battery test and oil change done at Pep Boys a month or so ago but everything came back normal. The mechanic at Pep Boys informed me about the possibility of parasitic draw and suggested I disconnect all the peripherals from my car when not in use (like the dashcam and phone chargers), but that didn't seem to help since the battery ended up dying again a few weeks after.

Before the oil change, the only light that was on was the maintenance minder light and the oil level indicator at 10%. After getting the car serviced, there are no warning lights or error codes displayed once I start the car. The IMA, 12V battery, and check engine lights are not illuminated either. However I'll try running the gauge cluster test and report back.

I do have to note though, I'm not driving the car nearly as much as you indicated. Because of the outbreak, I only use the car once or twice a month max to run a few errands. I've been working from home most of the time, and only drive *20-40 miles max per month. As far as I can tell, the IMA battery does retain its charge but once the 12V battery dies (after about 3-4 weeks of no use) I need to jump start the vehicle and the IMA battery indicator displays as nearly depleted (only 2 bars).

The mechanic I spoke to before said that car batteries don't usually die so quickly, and typically even if you don't use a car for months on end it should still start up just fine - especially with a new battery. However if the IMA battery is going bad or the DC-DC converter is malfunctioning, I might just take it to a Honda service center and have them run a full battery diagnostic. If the problem can be solved by simply using the car more, then I might just have to do that instead. I don't know if replacing the current battery with a 51R is worth the risk of continuing to not drive the car though, otherwise that seems like the most convenient fix.

 

Pep Boys is not giving you the best information.

Please note that I have owned 2X '06 HCHII, which are identical to yours, and I am reasonably knowledgeable about your exact car and hybrids in general.

It's not clear to me in your response if the IMA, CEL and 12V lights are ON when you turn the ignition on but prior to start, and then extinguish after you start the car. PLEASE CLARIFY.

If you don't have a system fault, your behavior is why the 12V is dying. You can't let a 12V sit for weeks and expect it to retain charge. A 12V loses about 30% of its charge in the first month WITH NO LOAD. When connected to a car, a very small current is being pulled from the battery, which will flatten it. Additionally, the Honda charging algorithm kinda sucks. It's never actually fully charged, and it's allowed to run at lower voltages for very small gains in fuel efficiency. I have the following recommendations:

Given the description of your driving, I am concerned that short trips to the neighborhood grocery store, or "around the corner" do almost nothing to keep the 12V and hybrid battery charged.

If you want to continue doing what you're doing with some modifications:
1) Disconnect the 12V (-) terminal from the battery if you plan to leave it parked for more than a week.
2) When reconnecting the (-) terminal and starting the car, allow it to idle for 30 seconds before driving.
3) or attach a "battery tender" or other device that helps maintain the charge of the 12V while parked.

Best:
Come up with an excuse to take the car for a 10 mile drive at least twice a week. The next thing to fail is your IMA battery (It's a matter of WHEN, not IF). The more you DON'T drive it, the greater the chances of failure.

Hybrids are meant to be driven. Parking them for extended periods leads to problems. Period.

 

Wow that was a blazing quick response! I believe the IMA, CEL and 12V lights (ie. the entire dashboard) lights up when I turn the car on, but they all extinguish after I start the ignition and no warning lights are displayed while driving.

I was just going to ask you about disconnecting the negative terminal as well! Funny enough, the Pep Boys mechanic suggested the same thing since they've been kind enough to help me out every time my battery dies (far too many times haha). I'll definitely keep that in mind going forward, I wasn't aware the 12V keeps pulling a small current even when the car is completely off. However if this still leaves the IMA battery at risk of failure, then I will most definitely prioritize driving the car around more.

I really do appreciate your invaluable advice on this matter, I didn't mean to come across as doubtful in any way I was just trying to reiterate what I heard. Based on how much you've helped everyone in this forum you certainly are THE best expert, thank you so much!

 

Thank you for clarifying. You're welcome. You didn't come across as doubtful. I was just elevating myself above a Pep Boys mechanic in terms of qualifications...

The clock, radio (station programming) and the multitude of computers require power to retain their settings. It's not a lot of current, but when you consider the draw over weeks, AND the fact that the Honda charging algorithm rarely takes the battery to > 80% charged, a few weeks of sitting can flatten a battery.

EDIT: One additional thing... EVERY time you drive, even in daylight, turn your headlights on. This defeats the default charging algorithm and forces the charging system to drive the battery to higher voltages more typical of traditional charging systems imparting greater charge to the battery.

 

Hi guys,

Just wanted to provide a quick follow-up. NAPA Auto told me that the battery they initially sold me was bad, so I spent $30 getting a replacement battery installed only for them to tell me the first one wasn't actually bad it was just running a little low and they 'didn't calibrate the battery tester correctly' (???). So I spent all day yesterday doing that, but hopefully the new battery runs a little better now. I'm still going to heed your advice Steve and try to use the car 1-2 times a week at the very least. God forbid the hybrid battery starts throwing a temper tantrum because I'm not giving it enough attention!

 

Thanks for the follow up. The battery was likely in a lower state of charge when tested. They need to be tested at full or near full charge. They probably weren't paying attention to the distinction between "bad" and "recharge and retest" outputs on the tester.

Again, hybrids are meant to be driven. If you're not putting average mileage on them, you're taunting a very high maintenance risk for little to no financial reward from fuel savings.

Please note that I didn't say 1-2 times/week. I said at least 2 times per week for 10 miles. And to clarify, that's 10 miles non-stop, i.e., not 5X 2 mile drives running a bunch of errands - that's almost worst than not driving it. Sure, you can stop at lights and stop signs, but the vehicle needs to be operated for at least 10 miles to ensure all systems reach operating temperature and the hybrid battery cells experience at least light cycling. Honestly, that's probably not enough, but hopefully it is. Consider... 20 miles per week, 52 weeks per year... that's only 1040 miles/year - about 10% of the low end of what it should be driven.

In short, you will likely eliminate the problem you posted about as well as others that may be looming simply by driving the car enough to make sure it goes through at least 2-3 gas tanks per year. That's it.

Lastly, seriously, always drive with your headlamps on to ensure you defeat the silly Honda charging algorithm and ensure you get better 12V charging.