Honda CR-V Owners Club Forums banner
  • Hey everyone! Enter your ride HERE to be a part of December's Ride of the Month Challenge!
1 - 16 of 16 Posts

·
Registered
Joined
·
24 Posts
Discussion Starter · #1 ·
Hello,
My 2015 has a curious problem that I can only guess is a SW issue. If I run my car without the headlights on the alternator is not producing little pixies to put back in the battery. But click the headlights on an voila pixies galore. She then shows a rock steady 13.9 Vdc on my ScanGauge which is always attached.
But turn the lights off and sad face, 13.3, 12.9, 12.6, 11.8....Oh shit lights on Scotty!!!!!!!
This is not a major issue as I tend to always drive with lights on. Unfortunately my dear wife isn't as diligent but luckily that tiny battery has enough juice for one trip to town and back.
Anyone know if there is a TSB? Or a DIY fix?
Thanks
 

·
Registered
2010 EX-L (AWD, non-Nav)
Joined
·
565 Posts
It's mostly Honda's strange charging system. The system has an electrical load detector, and that communicates with the alternator, which is a variable-output design. No/low load? Little coming out of the alternator. Major load detected (headlights, rear window defroster, etc) = big-time output from the alt.

I know some Accords had a TSB or recall issued for the ELD being defective. I don't know what year(s).

 

·
Registered
Joined
·
1,931 Posts
Not just Honda. My Ford does the same. In normal conditions the charging system may fluctuate between 9..12V. It's normal.

Here's just a random screenshot I made:

138510
 

·
Registered
Joined
·
148 Posts
BMW does the same thing and then some:)) - it charges the AGM battery but never to full capacity (full capacity=bad for AGM)
also charges only when you are decelerating (i.e. not stepping on the gas pedal)...so trickle chargers are very popular in the bimmer community🤪
 

·
Everything in Moderation
2006 CR-V EX, 5MT
Joined
·
12,154 Posts
If your battery is going down to 11.8VDC when the system isn't charging, it is weak. Ours stays in the mid to low 12V range.

In any case, after a start, the voltage SHOULD be higher to replenish the battery. Ours needs to be fairly warmed up (5 - 10 minutes of driving) to drop back to the 'energy saving mode'.
 

·
Registered
Joined
·
439 Posts
Welcome to the modern world of computer-controlled charging systems. When my 2012 CRV was new, it was driven mostly by my wife on her short commutes, and with the headlights on Auto. After having to jump-start it 5-6 times, changing the battery, and Honda doing 2 or 3 software updates, none of which solved the issue, I told her to just start turning the headlights on and off like we did in the Stone Age before Auto was a thing. For the last 7 years the battery has remained adequately charged and we've had zero no-start issues (yes, the battery is 7 years old!). My research before buying our 2016 Subaru Outback revealed it's notorious for the same battery charging issue, so we've never run the headlights in Auto and have had no issues.
 
  • Like
Reactions: 8dragon

·
Registered
Joined
·
222 Posts
that's weird, i've run auto headlights on my 2015 since the day after i bought in Nov of 15 and i've never had any issues with the battery except once when i was out of the country well coming home. My mother and sister had borrowed it and then went to a local carwash to clean it and left all the doors opens; well it didn't start back up. About a two months later i just went ahead and replaced it along with my sister's HRV's battery.
 

·
Super Moderator
2017 CRV Touring - Pearl White w Black Interior
Joined
·
7,554 Posts
If your battery is going down to 11.8VDC when the system isn't charging, it is weak. Ours stays in the mid to low 12V range.

In any case, after a start, the voltage SHOULD be higher to replenish the battery. Ours needs to be fairly warmed up (5 - 10 minutes of driving) to drop back to the 'energy saving mode'.
(y) (y) yep.. I would go get that battery properly tested asap.. because you should never see below 12.4 vdc on a Honda with a good battery and a properly working charging system.

For those that are not aware, normal for Honda charging systems are as follows:

1) Honda's charging system uses a ground side sensing circuit to detect if the battery if fully charged or not.
2) If the charging system detects the battery not fully charged, you should see it set the charging voltage to 14.4-14.6 vdc
3) If the charging system detects the battery is fully charged, it downshifts the charging voltage to 12.4-12.6 vdc
4) The charging system is dynamic and will continue to check the battery charge and will cycle periodically between 12.4 and 14.6 as you drive.
5) Driving with your headlights on forces the charging system to stay in the high charge state. So does setting your internal cabin blower fan on high.

If you are a short trip driver, doing mostly in town short trip driving... do like I do... train yourself to drive with the headlights on (AND.. remember to turn them off when you stop the engine). :)
 

·
Registered
Joined
·
24 Posts
Discussion Starter · #9 ·
Thank you all for the replies. I suspected this was some overly complex "How cool, we've got computer control of the alternator, lets dick around and see if we can save a tenth of a gallon of gas over 10,000 miles!!!! YEAH WE ARE BEING GREEN!!!!!". I played at being a CS for years I know how those pea brains think. Anybody remember that phalic scene on old Windows NT, was it the start screen? Oh hell maybe it was on those Apple Quadras we started screwing with. Can't remember which screen exactly too many hours and too much caffeine.

Yes the battery is weak, and tiny. 5 years old, but I stick it on a trickle to keep a float charge since there appears to be about 150mA load keeping the clock, video games etc running when turned off. And it's been sitting a lot since our Dear Leader shut down the state. But the good news is we're beyond our negative degF temperatures so I should be able to get it through until there is a spring sale :)
Take care all and thanks again
 

·
Registered
Joined
·
173 Posts
Never underestimate the value of an old car. If it was designed well, it's simplicity make it a joy to work on. Wait until they develop a weapon to knock out computers (or start using the one the military probably already has). That old guy down the block with his 30 year old car will toot his horn as he drives by your stranded vehicle!
 

·
Registered
Joined
·
1 Posts
Hello,
My 2015 has a curious problem that I can only guess is a SW issue. If I run my car without the headlights on the alternator is not producing little pixies to put back in the battery. But click the headlights on an voila pixies galore. She then shows a rock steady 13.9 Vdc on my ScanGauge which is always attached.
But turn the lights off and sad face, 13.3, 12.9, 12.6, 11.8....Oh shit lights on Scotty!!!!!!!
This is not a major issue as I tend to always drive with lights on. Unfortunately my dear wife isn't as diligent but luckily that tiny battery has enough juice for one trip to town and back.
Anyone know if there is a TSB? Or a DIY fix?
Thanks
Had the same problem with my 2016 CR-V, no TSB that I could find. Read somewhere about the issue with the variable alternator output and the writer recommended driving with the headlights on. Started doing that religiously and did not have any more problems with the battery running down. After four years I was ready to buy a new battery and got one with about 50% more CCA than the Honda original. I don't drive with the headlights on any more and have not had one problem.
 

·
Registered
Joined
·
24 Posts
Our CRV sits for months in winter cold weather without being used or charged and it starts right up in the spring. The point being the static drain has to be low or it would not start like that. If you have to use a trickle charger routinely either there is a battery problem or something is draining it. When the CRV is first started, it has voltage readings in the 14.4 range. I never checked it after running and warm up. We do use the auto light mode most all of the time. YMMV
 

·
Super Moderator
2017 CRV Touring - Pearl White w Black Interior
Joined
·
7,554 Posts
Our CRV sits for months in winter cold weather without being used or charged and it starts right up in the spring. The point being the static drain has to be low or it would not start like that. If you have to use a trickle charger routinely either there is a battery problem or something is draining it. When the CRV is first started, it has voltage readings in the 14.4 range. I never checked it after running and warm up. We do use the auto light mode most all of the time. YMMV
What year CRV? I ask because the level of normal parasitic drain depends on the year of the CRV.

The gen5 CRVs have higher normal static drain than prior generations. Normal for a gen5 is 35-50ma. For the gen4s I believe it is around 15 ma, and for earlier generations, before all the smart goodies were designed in... probably little or no parasitic drain when turned off.

A general area of improvement needed in these modern vehicles, regardless of manufacturer, is lower parasitic drains from all of the different electronics systems when the vehicle is in low power state after being turned off. There really is no reason for these various electronic systems to be drawing more than 50 micro amps each when powered down. But with so many electronic systems outsourced to non Honda suppliers now days... I imagine Honda has difficulty holding the suppliers to really tight power down current specs since tighter spec limits generally mean more expensive prices from the supplier and Hondas are in very price sensitive market segments.
 

·
Registered
Joined
·
173 Posts
So, since Honda didn't do it's due diligence on it's controllers/processors current draw when the car is shut off, we are left with either having to trickle charge the car or drive it more often?
 
1 - 16 of 16 Posts
Top