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Discussion Starter #1
I read on here yesterday that turning on the headlights can change to a more aggressive charging program. So today I turned on my headlights, and my battery stayed closer to the top of the charge guage regardless of how I drove. No longer worried about draining the battery, I revved the engine more aggressively and used assist more often and at higher levels. The thing is, my mileage did not go down at all. I am still at 62 mpg, and the Insight is a lot more fun to drive. Granted, if I was shooting for 80 mpg I doubt I could pull it off driving like this, but I think I could at least maintain my solid lo 60's because I get into lean burn a LOT sooner. Any advice?
 

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It has to do with the infamious ELD. :)

Having a few thousand watts of audio equipment drawing power from the electrical system has the same effect, but you cant see out of your mirrors. :D
 

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I don't believe that's true. Having the headlights on doesn't change the way the car charges the battery. In fact, it can deplete your battery very slightly as the DC-DC converter draws [more] power from the battery instead of the IMA motor while you're decelerating or in auto-stop.
 

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Discussion Starter #4
I'm not saying you are wrong because I don't truly know. However, my own experiences tell me differently. I use a lot more assist with the lights on, yet it is much harder to drain the battery. I am also planning on modding my driving style a bit in that when I am lean burning, it is difficult to maintain speed so I end up driving in a pulse and lean style. Or, I can shut off the lights and I can maintain speed and lean burn. This is more evidence to me that there is some charging boost going on when the lights are on.
 

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Mine also changes charging if the headlights are on. It will try to keep the battery at 18 bars SOC. If lower than that with the headlights on, it will background charge until 18 bars. With headlights off, it does not exhibit this behaviour.

Mine also does the same thing with AC on, but the AC is a MPG killer.

This behaviour may be unrelated to headlights, but may be related to high usage of the DC - DC convertor.
 

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Hmm. Interesting.

While doing a discharge test, I noticed behavior contradictory to this as well. When the radiator fan would come on, my charge amperage would drop by 1 - 1.5A because the DC-DC converter was taking this power off the top, so to speak. This had the effect of prolonging how long it took for me to charge the battery up.

I'll have to do some more tests. I've never found it a problem to run my battery to empty with the headlights on.. lol.
 

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I have found that if my IMA battery is showing a little low after a few hill climbs if I turn on the lights it does charge up faster.If I just leave it to charge normally it takes a long time to reach 18 bars.The battery is almost new.I have two Insights and it works on both.Strange but true.
 

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Hows your mpg during this experience?

I notice when I push my phev kit to higher voltages and amp settings than before it wont throw a code if I have a substancial 12 volt load on. It seems Honda uses something called an ELD that turns the alternator or dc-dc converter off and on as needed vs constanly charging the battery of their cars depending on the needs of the 12 volt side.

I posted for more in another thread, but didnt get that many responses. I may doa hack I see in an audio forum to keep the ELD off so there is always a charge taking place, further allowing me to power up the IMA system for more MPG and abuse of EV mode without throwing a code.
 

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Its very hilly around the top of the South Island and I notice on a 100km trip to Nelson with the CVT I get 24k's/L on the return in the dark with lights and radio on its the same but I notice the IMA batt recharge quicker on the return.So far no difference in fuel used.??
 

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So I just took a 50mi drive with my headlights on. Same as my past experiences, the DC-DC uses energy from the battery very slowly, 0.1% at a time and the only way I get it back is by actual regenerative braking. At around 68% SoC, the background charge came on. I'm not sure if this was because of the headlights on or not, but it seemed odd for it to come on so high. So maybe that's what you're experiencing, but this certainly isn't "free" charge, it will affect MPG just like the automatic background charge always does.

One thing I've learned with this car is that it's very easy for your perception to be way off. Without knowing how many amps are coming in and going out and also the time frame, it's just a pure guess. That's why the data logging with the BCM Gauge is so invaluable.
 

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Eli, that was very early for your background charge to start.

DRL is mandatory here, so i always drive with the headlights on, and in
my car the background charge starts at 65-66% SOC charging at 6-6.5A
back up to 70% SOC.

When i have finished the clips & molding job, i will go for a drive without
headlights on, and see if that makes any difference.
 

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Interesting behaviour. I switch to having no lights during daylight and this could explain a raise of mpg as the background charge is said to be less 'aggressive'.
 

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It seems Honda uses something called an ELD that turns the alternator or dc-dc converter off and on as needed vs constanly charging the battery of their cars depending on the needs of the 12 volt side.

I posted for more in another thread, but didnt get that many responses. I may doa hack I see in an audio forum to keep the ELD off so there is always a charge taking place, further allowing me to power up the IMA system for more MPG and abuse of EV mode without throwing a code.
The ELD data is available on the OBDII K line.
 

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Discussion Starter #14
After further driving, I agree. Nothing is free. My long-term fuel mileage is dropping slightly. I think the background charging is probably slightly more aggressive. Unfortunately, the byproduct is that maintaining speed and lean burn is an either/or choice. Now the tough choice comes in to play. I can drive for maximum economy or I can make it more enjoyable to drive.
 

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I do both. :) I drive like a bat out of hell in the city, and hypermile out on the open road.
 

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Just thought I would drop in.

Some things are just better left unsaid. Old age I guess.

Jim.
 

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Jim, I have no problems with what you originally said. You're right, I didn't word myself correctly in my initial post. I started out on the right track by saying "I don't believe..", but then I made a statement that could be taken as fact, when it should have been part of the original sentence.

Obviously if the DC-DC is ticking down the SoC, the background charge will come on eventually. I had never studied when this occurs, and it appears to be in the 65-68% SoC range, which is interesting, but makes sense - it would be alarming and frustrating if your battery ticked down to 10 bars of SoC just because the headlights are on, only to have the background charge come on and lower your MPG for a long period of time while it charges back up. Amongst other undesirable scenarios.
 

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Perhaps as in maintaining lean burn, where the rate of throttle position change [deltaThrottle] vs. the throttle position itself determines if the car will remain in lean burn or not, then perhaps if so, could it be that the recharging rate of the IMA battery is regulated by the rate of amps drawn vs. an actual SoC point for the IMA battery?
Just wondering if they may have done that using similar logic to apprehend the SoC outcome in advance.
 
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