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Discussion Starter #1
I am not an alarmist about things like EMFs, and found the claim of one Insight driver in a previous discussion that the magnetic fields in his vehicle were giving him headaches somewhat over-the-top.

Anyway, before graduating to my 2000 5-spd Insight, I owned two CRX-HFs, and averaged 64 MPG combined for the lifetimes of both. I've been an eco-driver for a long time, and hit 70 mpg on a few long trips in the CRXs. But that seemed to be the ceiling--there was no way to stretch the figure beyond that shy of trailing the car behind a U-Haul. (Actually I once drove in the slipstream behind my girlfriend who was in a U-Haul and got 90 MPG from NH to NY)

Not so in the Insight. Using the same driving tricks, and adding regenerative downshifting, which of course the CRX didn't offer, I averaged 94 MPG on a recent 2000-mile trip from Santa Fe to Wyoming and back at an average altitude of about 6500 feet. I have gotten 128 MPG on the 60-mile trip from Santa Fe to Albuquerque. So there is a big difference in the mileage ceiling, mostly on the highway (in the city the two are very close, at least with me as conductor).

But I've always been curious: What if one turned the Insight into a more aerodynamic CRX-HF (which it is) with an aluminum body (which it has), alloy wheels with low-resistance tires running 58 psi (the pressure I maintain with no apparent ill wear effect), and a higher-tech, lower-powered, cleaner-burning engine (which it has). After all, the consensus among us seems to be that the best fuel economy in the Insight is achieved when the IMA is used the least.

So with that in mind, what happens when you use the IMA and its battery not at all by removing or disabling them? Has anyone tried this? (Forgive me if I've overlooked previous postings on this subject--I'm a newcomer to the site.) I know you can flip the switch on the battery pack and take it out of the loop, but as I understand it, that prevents the 12V battery from being recharged, right? If that's the hitch, has anyone hooked up a conventional alternator on its own circuit to the 12V battery or found a way to use the existing alternator to generate/regenerate just for the 12V battery with the high-voltage battery pack disconnected? Or are the two motors simply too integrated by computer and circuitry and controllers to do this in any simple, easy way?

If it's reasonably possible, how do I do it? And if, for starters, I switch off the rear battery and drive, how far (long) can I go before the 12V battery dies (daytime)? Is it harmful to the car to do this? Would the car still go into lean-burn mode on the highway and are mixture/valve setting/combustion functions still intact?

Many, many thanks to any technical person with the patience to read this and answer any or all of the questions. I miss my old pre-EMF self.
 

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Been extensively discussed. I'd recomend using the forum search feature. :)

Here's one recent that I remember:

http://www.insightcentral.net/forum/vie ... php?t=3191

And AFAIK no its not been done. You'd need and alternator to maintain the 12v system (I believe the link to that old thread is embeded in the thread in the link above).

HTH! :)
 

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Mounting an alternator is going to be a problem. Maybe you could use the A/C compressor mount, and then use an electric A/C compressor from a Prius. If you need A/C.
 

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Trekker wrote:
And AFAIK no its not been done. You'd need and alternator to maintain the 12v system
Yes, it has been done, it's called MIMA, you can totally disable the IMA, and the car feels different, if you take your foot off the gas it feels like you are going in neutral, there is very little engine resistance, the IMA really slows down the engine, I think this mode (turning IMA off) has the most potential for mileage, you'll spend a lot more time in leanburn, then you can just recharge the battery on the downhills or as needed.
 

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Calpod said:
Trekker wrote:
And AFAIK no its not been done. You'd need and alternator to maintain the 12v system
Yes, it has been done, it's called MIMA, ...
While I _really_ appreciate a MIMAist's enthusiam PLEASE let's not go back to all the fragmented threads about MIMA. I am NOT "picking" on you Calipod and this is NOT the first reply like this. There have been several by various members.

Post the same message as above sure :!: BUT ADD a link to the MIMA thread. And _specifically_ invite further MIMA discussion to continue "over there".

But you really need to re-read the question. He wants _all_ gas, no electric. :p

Sincerely,
 

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Discussion Starter #6
Thanks very much to all of you for the help so far. From reading previous posts, I realize what I'm asking is not the same as MIMA.

I tried a brief gas-only test myself yesterday. Drove for a few miles in city, then on highway for a total of 48 miles at average of 6500 feet elevation with 1500-foot elevation change. I did this with the battery pack switched off, air blower motor on third speed, headlights on, and radio on for heavy draw. Back at home after an hour, the little battery still had enough juice to restart the car on 12V. The car had perfectly adequate power for me under all circumstances and I did not need to slip the clutch (or even come close) during first-gear engagement. I'd drive the car this way happily and comfortably all the time--if the battery wouldn't go dead.

Mileage for that 48-mile, one-hour trip at high elevation with severe hills: 91.8. Highway speed: 55-60 mph.

This is certainly no worse and perhaps a tad better than I would have done on the same trip with IMA on. That suggests that as an eco-driver who doesn't need much jackrabbit or passing power, I'd rather buy this car 150 lbs lighter (even better gas mileage) and cheaper without IMA (with the small modifications of a slightly less tall first gear and stouter 12V starter). No IMA means no battery replacement, no nickel/metal hydride for the landfills, and no less gas/more gauss dilemma. I wish they sold the car both ways. Why make a hybrid if all-gas does a little better?

That said, anyone have some ''insight'' or experience (1) mounting, say, a CRX alternator, which has voltage regulator built in if I'm not mistaken, to the compressor bracket and running a line to the battery, (2) substituting a higher-capacity marine-grade battery for the dinky one, and (3) switching the IMA back on ''on the fly,'' meaning while running, when the 12V low battery light comes on (I could do this from the driver's seat, but won't risk frying the electronics unless I have info that it's safe).

It also occurs to me that if installing a high-capacity 12V battery (the space is there) is do-able, a simpler option, based on my experiment, is to run the car 90 percent of the time IMA-off (the heavy duty battery could last hours), then switch IMA on long enough to recharge both batteries, then repeat. This preserves both options, gas only and IMA, and keeps the IMA battery healthy. Ideas on this as an option over the long haul?

Thanks again for all your thoughts.
 

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I suspect that you are still getting 12V charging when the main switch is turned off. The switch basically disables the battery. The rest of the system should be ok. You can verify this by simply measuring the voltage of the 12V system (Lead-acid is nice in that the SOC is directly reflected in the current voltage), while the IMA battery switched off. A better test would be to use a clamp-on ampmeter on a battery lead.

BTW. The reason you get the best MPG when IMA is used the least is because you are using less gas pedal, not because IMA hurts MPG.

IMHO, Driving around with the IMA battery switched off is not going to help MPG. But, removing the entire IMA system and adding an alternator may help MPG because of the weight savings. To each, his own.
 

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Discussion Starter #8
Regarding the last post, I didn't mean to imply that IMA hurts mileage (although its added weight could, slightly). But I think most of the public would be rather surprised to learn that the electric side of this hybrid helps performance (read ''pep'') more than MPG or cleanliness of burn. They think it's the reason for the great MPG and clean burn when the real reason is a super-light, highly engineered car with special tires and a beautifully designed clean and efficient 1-L engine. There is still a large segment of the public that is frightened by new technology. So why not increase buyership and help the environment by selling a gas-only Insight to the less adventurous?

Back to topic, I was wondering the same myself about a possible continued 12V charge to the small battery with the large one disconnected. There are many stories in previous posts of cars going dead when driven too long in this mode, so I assumed that to be the case. To double-check, however, I'll keep driving mine with IMA off until if and if and when it quits, and that will settle that.

There is a redundancy of starter but not of alternator. So for what you're suggesting to be true, the charge controller must remain powered up even when the big battery is cut out. That seems probable. But is it still governing what now serves solely as alternator so it feeds 12 (or 14) volts to the battery?

If the other reports are correct, no. I didn't feel any drag while driving yesterday (but you generally don't feel drag from an alternator), so that may not mean anything. If my car dies in the road and I have to switch the IMA back on, that will end the speculation. I'll let you know.

Bottom line: If what you say is true, then these cars can be converted to all-gas non-hybrids with the flip of a switch, and you'd think that's something Honda would mention in the manual if it were true.
 

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gausshaus
I don't know if this is helpful or not to you ...but I actually *lost* the battery connection for some reason and am driving currently on the engine alone. Under normal driving conditions, mileage has dropped about 10% (I was about a 60mgger before ...now it is reflecting about 54mpg on average). Of course the longer trips (highway) are closer to the 60mpg I used to get - which is when the assist is not being used much anyway. For some reason I have a hard time believing that you can get better mileage with the electric off. (The energy addtiion from the RGB must be worth *something*). Sorry I am not a techie - or I might try to answer some of your other questions.
Phil
 

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Discussion Starter #10
Phil: I'm wondering if you've truly ''lost'' the connection to your battery, which would involve a physical or electronic disconnect. You may have a battery that is still connected but very weak. Just because the IMA light is on (I'm presuming it is) doesn't mean the battery is disconnected. If the battery is getting weak or nearing the end of its life and the gas engine is working harder than usual to recharge it, your mileage will be worse than before with the extra drag, as you report. If you switched the big battery off as I have, that problem would be solved; however your small 12V battery might soon go dead, too, leaving you stranded. I'll explore whether that's what happens on my next drive.
 

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Trekker wrote:
But you really need to re-read the question. He wants _all_ gas, no electric.
I will drive a couple lf days next week with no electric to see if there is any difference without MIM.. opps, I almost did it again. :twisted:

And please the name is CALPOD.
 

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A lot of people say you get the best mileage by not using the hybrid system, but I tend to doubt that. I think maybe people get better mileage that way, because they tend to drive slower and accelerate less as they try to avoid using the battery. In other words, they are just getting better mileage because they are driving slower.

I dunno. That's just my hunch. I could be wrong. There are so many variables involved here that I don't think the answer can be derived on paper. The only way to really find out is to get two Insights, one with the hybrid system enabled, and the other with gas only. Then drive them under identical conditions, and with the same speed and acceleration.

Wha'd'ya think?
 

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This idea ("gas only") is a first step, but the second step would be to retain the hybrid system and use a smaller internal combustion engine.

The whole point of the hybrid concept is to size the ICE for the average power requirement, and then fill in the times you need more power with the electric motor.

So if you're happy with the performance of your ICE-only Insight, and don't need the electric supplement, then you have too powerfulf an ICE.

The thing to do is find an even smaller ICE, something like 750cc. Perhaps you could adapt a small motorcycle engine for this purpose. It might require detuning: The goal would be a high efficiency motor with around 50 HP.
 
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Hi Dougie:

___You just made a good point … The only time I used more then 2,300 RPM’s was one time when seeing what the Insight was worth at 80 mpg and when I was using ~ 2,650 RPM in second gear when climbing 5 + degree slopes on my last day with the Little Beauty. Both without IMA! I just looked at some older Insight performance curves and I’ll be damned if I was ever using more then 25 HP! If I can get by with just 25 of the 1.0 L’s 67 - 68 Horses through Chicago’s nightmare for a year, imagine a .66 L ICE w/ maybe 50 HP and the HCH-II’s IMA setup in a stripped down Honda Fit? 0 - 60 in 14 + seconds sure but the FE … Oh My God!

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___[email:1zj2gbu9][email protected][/email:1zj2gbu9]
 

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You could also put together a de-stroker kit (new crank and rods), which would allow you to keep pretty much everything else the same. Big bucks, though, and all you would be saving is a bit of engine drag...
 

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back from the dead, sorry

What other issues would there be, with taking the batteries out other than getting the IMA light? Would emissions be increased? Would the ECU detect it and throw the tune into safemode?
 

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The IMA is used to help balance the engine without adding much rotating mass. So removing the system will likely cause the engine to vibrate alot at idle and while driving.
 
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