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MIMA users quickly learn that the more electric you use to maintain speed, the higher the MPG, and the faster the stock battery needs to be recharged. Recharging cost energy, and charging is not 100% efficient, so on a straight flat road, MIMA has only minimum effect. Better to not use the IMA as Wayne suggest.
MIMA becomes more of a factor as the terrain gets hilly, and the requirement for matching speed with the other cars on the road is maintained.
The ability to cut background charging and use assist for the small adjustments in speed that we run into, can be better accomplished using MIMA than without. Finding opportunities to recharge are more numerous, and by balancing output with input, the battery can be kept in any SOC that one desires.
MPG improvements of 10-20% are usually observed.

With a fully charged stock battery, using MIMA to maintain speed with lots of electric assist on typical New England hills, at say 65MPH, one can achieve over 100 MPG while the battery has remaining charge. In My experience this can be for 15-20 miles depending on speed and terrain.

We found that the simplest way to keep the battery charged without the need for regen was to inject a booster charge from another source. The source could be simply a higher voltage battery pack, but this presents some safety and complexity issues due to the high voltage, and the need to properly monitor the battery SOC and current.This pack is charged with solar or the power grid.

The approach I used on my Insight was to use isolated DC/DC converters to build a safe to handle 48V @ ~ 85 AH boost pack and generate a 177V @ 16.5 A boost charger. This constant replenishment of charge increases the proportion of electric that can be used by MIMA for assist without the need for parasitic charging while driving and therefore extends the > 100 MPG range to nearly 1 hour of driving.
A larger capacity pack would allow the MPG improvement for longer distances, but is not practical with heavy lead acid batteries.The insight is not designed to carry more than 300 extra lbs of batteries, and would be happier with 150.
The use of Li Ion batteries could pack nearly 200 AH @48V into 150 lbs.
of course A mix of hypermiling techniques, along with driving on roads with slower traffic, can increase the MPG advantage even more.
While the MPG numbers that can be achieved by driving slow with extreme P&G are amazing, I am working towards a system that will allow driving at normal speeds which I feel will better fit more peoples driving environment.
This thread is where we will explore this system, and explore other booster battery schemes and chemistries.
;)

Great intro. It is great you explained the philosophy behind what you want to achieve. How much do Li Ion batteries cost?

The batteries of choice, would have been the KOKAM 200AH LI PO. The owner of the small Korean company was helpful, but even with a 25% discount we would have been talking $19,000 for a 48V pack of the cells with no BCM. This would have brought the on board storage to 200AH with a weight of only 150 LBS. I am presently running with 300lbs of lead acid with a useable 85 AH that cost $800.
With present booster pack, and good driving technique, one can get over 100 MPG for possibily 50+ miles at highway speeds. The present system would be better if I could deliver 20-25A of charge instead of the 16.5A I presently am limited to.
At 65+MPH, it is easy to take it out faster than it can be put back.
I will be exploring using a HV pack approach to providing the boost in the near future, which should eliminate the charge rate limitation, and allow Prius subpacks to be used for the boost pack. Lots of Prius for each Insight, so we could have a recycle path for the Prius packs from totaled prius, so the batteries can continue to save oil even after the donor car is in the junk yard.;)
The original thread on this subject:
http://www.insightcentral.net/forum/viewtopic.php?t=3996

While I am still a long way from following Mike's Lead in a booster pack / PHEV Insight it is on my list .... Currently I also agree Li is the Ideal but $$$ is extream for that option.... so I might split the difference and do NiMH which will be less weight than Lead Acid , Less Expensive than Li even if also less Energy Than Li and more expensive the Lead.... but who knows what the market will be by the time I am ready to do my own PHEV...

An Idea I had to try to keep efficiency up and to have the nice safety of the DC-DC converters was to get one of the MPPT units to do the conversion .... MPPT is normally used in Solar Cells to squeeze the most out of the power from the cells to the batteries... and they have some that will go up into the 95+% Efficiencies... and they are output voltage and current controled.... The only problem I have seen is that from what I have seen of Mike's Booster so far it is best to try to get the charaging voltage up to about 180V and most of the comercially availible MPPT units I have seen don't go up to 180V but I might be able to put two MPPT in series to get up to the 180V... But I think useing MPPT or any DC-DC system of control will be better but will cost about $1,000 on its own and likely at least that much in batteries as well.

Does anyone know of any reason MPPT type of System could not be used? and is there a problem connecting them in Series?

Ian
The MPPT solar controllers while working well with the variable output from solar systems, would not offer much improvement with our boost system. 36-72 volts is the input range of the converters, but the 48V nominal pack will be damaged if we let the voltage drop to 44V or below.
MPPT controllers are trying to maximise the output power to the grid tied inverter or batteries that are being charged by the widely variable output power of the solar panels when a cloud goes by or it is partly cloudy, which reduces the source current. We do not have that issue with the lead acid batteries, the batteries are always gradually discharging, and provide full boost output current and voltage over the full battery charge of 51.6 to 44V. The ability to maintain full output voltage and current with the variable input voltage of the discharging batteries, is very similar to how the MPPT controllers work, so one could almost say that the DC/DC converters are operating as MPPT controllers.
Series connections could be a problem on any system that does active power balancing.
;)

Just finished replacing the charge I used on the 5th wheel test run of the other night. The SOC was down to about 45%. I charged it with my Vicor batmod DC/DC converter which was connected to the 120VAC grid via a full bridge rectifier to supply the 100-200VDC needed for input power. The batmod puts out about about 3A, and has a max voltage that can be set to the float voltage of the batteries. I needed to put 2.85 KWH into the charger to get the batteries back to full. I monitored the power from the grid with a KILL O WATT P3 watt meter.
I had driven about 24 miles in 5th wheel EV mode.
that comes out to .119 KWH per mile.
How does that compare with a full electric car?
Granted I was only averaging 28 MPH.

That's pretty decent, in fact. Most electrics I've read about
seem to do 4 - 5 miles per KWH, and I think the Prius might do
about the same if its battery would last that long. At fairly
low speeds, I would imagine..
.
_H*

I recharged yesterday with the solar array. I reconfigured it to put out 75V at ~6A, and have the control circuit connected to cut it off when charged. I also found a nice precision 200A current shunt and maching analog meter in my extensive junk supply. I did not even remember having it. I installed it on the 48V return line so that it will let me know the total draw on the 48V batteries, and when in the Ewheel mode, get a much better idea of the peak and average current that I am delivering to the wheel.
Ready for my first solar charged test ride.:) ;)
I have been thinking about Ian's suggestion of using an off the shelf PWM motor controller to charge the main pack from a higher voltage booster pack, and I am feeling that it could be a nice reasonably low cost way to accomplish the current control. It is definately worth a detailed look.

Fixed the Ewheel today, had to tighten up the key between the pulley and the motor shaft. It got loose, and was rubbing the belt guard and making a racket.

I also ran a 45 mile test run without the Ewheel but with the Eboost. This was a longer section of the same route that I got 107 MPG on on the first test run. Without the boost, I got a max of 84 MPG, but that was driving real slow, not P&G.

I got 109 mpg for the run, and still have about 45 % of the charge on the boost batteries. The average speed was 37 MPH max of 51. The net elevation change was a 300 foot climb, with lots of hills. Speed limit is average of 40 MPH, some 45.
Still was wishing for more boost amps.
I am liking Ian's idea of using a dc motor controller for a boost current control the more I think about it.
That could be the cheap reliable, safe boost controller that we need to do a HV battery boost, which will only be limited by the motor controllers max current. Lots of controllers on the market, you EV guys may be able to make some suggestions?
SpecS:
Max of say 250VDC, and a max current of say 30A, with built in current limiting to an adjustable level.
The ability to regen would be a big plus, as it would allow the whole capacity of the boost battery to be used, to climb a huge hill or mountain. The large capacity of the whole pack could then be charged on the way down to spare the brakes and recover as much as possible. The more hills the more regen will be important. In the flatlands, regen would not be needed.
Ideas?
;)

I have done a little searching... allot more to do ... I like the Idea of the motor controller as well ... so far most of the DC motor controllers I have found have not been high enough voltage... I have seen 96V up to 120V is common .... still doing searching ... will post if I find somethign that fits.... But from my understanding we want at least 190V output and up to 30A of current control ... ideally with a regenerative braking ability.... Also since most of the good DC motor Controllers today use PWM you can't just put two in series to get the voltage you want... as at a couple thousand cycles on and off per second it would be nearly impossible to match them exactly to be both turning on and off at the way time.... I think this is becuase higher voltage in a DC Motor increase the chances of Arching.... but AC motor controllers might work.... but I thought they control the motor differently than DC Motor controllers do.

I haven't found much in the way of DC motor Controllers in the over 170V range... I suspect that it has something to do with the arching that may happen in the motor if a DC motor is run at over 170V .... Any EVer's out there that know of one??? I have found AC Motor Controllers that go way up in Volts like 400V and more... but DC it seems to cap out at about 120V... Any Ideas???

on a side note... anyone know .... in a inductor type of transformer... if you add or remove / change the core that is conducting the magnetic field between the two inductors... do you just change the current? or do you also change the voltage???

Ian
Many industrial motor controllers that run on 120or 220VAC, convert that to DC in the front end of the controller. If the dc from a batterypack were connected to that point in the controller, you would have your 200V motor controller.
Check out this company:
http://www.minarik.com/regen.html
they have a bunch of different types of industrial controls to choose from.
It may be worth a call to their engineering people.;)

looking for a PWM to control the current flow from a high voltage booster pack to the stock pack.... I was wondering if something like this would work??? if not what would need to be different???

http://eportal.apexmicrotech.com/mainsite/pdf/sa12u.pdf

anyway it is PWM and can supply up to 3,000 Watts to the load.... at 10A up to 200V or 2,000Watts it is 97% Efficient ... probably a little less efficient at the upper limit of 3,000 Watts ... but even if we went to a high power version of this kind of thing.... is this the kind of thing that we would need to control the current flow from a high voltage booster battery pack to the stock battery pack???

a higher power unit of the same thing is at:
http://eportal.apexmicrotech.com/mainsite/pdf/sa08u.pdf

This one goes up to 450V and is 98% Efficient at 20A continous rate and bursts up to 30A.

I think both of them are in the $700 to $800 range when you only buy one at a time.

Hi Ian
Yep either of those may work, but the price makes it a rough decision, as the only way to know is to buy one and try it out. If you let the smoke out, there goes $700-800.
Apex tends to be pricy as they integrate the whole thing into a single rather small package.
There are a slew of PWM Ic's that with external power power fets or IGBP transistors could do the same job for a fraction of the price. The power transistors will cost maybe $50, and the driver only a few dollars. I have some 600V 75A porer block transistors that I will try when I get around to that project, I want to get the battery controller worked out first, since that will be a bigger task.
If you are a good talker, you may be able to get a sample from them. I tried that with them several years ago, but had no luck.
The device will probably not do well if the IMA starts to pump charge back into the device, so get a big power diode to use in series with the output.
Have fun

Thanks Mike.... I will look around to see what else I can find... now that I know I am on the correct general direction / path.

agreed.... battery management will be required with any system we use.... I think Li have the highest cell voltages and even those woudl need 40+ cells just to get up to voltage.... so your right that the management will be an important step and probably best to go first ....

I was thinking the other day ... I know dangerous with a little bit of knowledge.... anyway here are some of my thoughts....

1> It is said you can't combine 2 PWM controllers to increase current or voltage becuase the cycles would not be perfectly matched up.... But if the output from each of the PWM controllers was in parrelel with a capacitor the capacitor would even out the pulses... and you wouild still end up with the same current flow but it wouldn't be 100% then 0% back and forth hundereds or thousands of times per second but instead the capacitor would even it out do the current should be steady more like actual DC.... the amount of ripple still left in the voltage would depend on the size of the capacitors used.... But if you added this capacitor in parrelel to the output of the PWM controller you should be able to then wire them in series or parrellel as you normally would a DC power source.... The reason for this thought is that smaller PWM controllers are far cheaper and seem to be more mass produced.... as such... it might be cheaper to put together a few smaller PWM controllers to form a larger one..... I am not sure where the break even point is between the two approaches.... more research is in order.... but the smaller PWM controllers would be more connections and more complex which always increases the chances of failure and dufficulty of getting it to work correctly.

Charge up the booster batteries while you work.
I have built a solar charger/rear window shade for the car. The output is 150W @ 56V
http://http://www.99mpg.com/Projectcars/TheBestHybridmix/portablechargingsy/
Practicle ?????? cost effective???? fun yep;)

So far the least expensive PWM controller I have found that would handel a PHEV Booster Battery for the Insigh is.....

http://eportal.apexmicrotech.com/mainsite/pdf/msa260u.pdf

If I am reading the data sheet correctly... it will do voltage ranges from a minimum of 16V up to a Max of 450V... It can do continuous 20Amp PWM effect .... short peak currents up to 30Amps .... operates in the 90% to 95% efficiency range ..... and when ordering small amount of as little as one unit 1 unit the price is $221.25 each + Shipping.

Does anyone know of any other PWM controllers that can handel ~190V and 15+Amps that are less expensive than this one?

and of course... if I am mis-reading the data sheet please let me know... of if I am just generally missing anything I woudl rather know than not.

Ian.!

Booster batteries take their toll.
Some bad news on my car.
I have been noticing that I can't seem to get as much speed when using the E-wheel, and my un modified MPG has been suffering, more than the cold weather would account for. The brakes are freed up, so that was not it, but discovered that my rear tires are wearing on the edges.
After doing some front to rear eyeballing, it looks like the 400 lbs is begining to have it's toll. Both rear wheels are bent outwards on the bottom. I think that some of those bigger pot holes may have twisted the rear axles up.
Bummer.
I will have to start tracking down a new rear torsion arm. Anyone know where I can get one?
The 5th wheel is hanging in there, but has developed a squeak between the aluminum covers, that a file should fix.
Still getting my heating system fixed, so the car will have to wait.
Too much to do, and not enough time to do it.
;)

Hi Mike:

___Whenever I was looking for an OEM replacement part and not willing to purchase new (wife took off the drivers side mirror on her former Previa a few years back), I headed to my local body shop. They have a parts Dbase with cars and parts from all over the country. That OEM replacement mirror came off a totaled Previa out of Kansas IIRC and cost 1/3 new shipped. I had it in less then 2 days as well.

___Didn’t you have access to a rolled Insight a few months ago? Another parts mule if you still have access to it?

___I hope that helps you find your replacement HW.

___Good Luck

___Wayne

Do you have pictures of the damage? BTW, I don't think I've seen too many pictures of the workings of the 5th wheel.

Tom,Wayne,
Thanks for the help.
I have some leads to a replacement rear trailing arm assembly, there are several junkyards within a 50 mile radius that say they have one, but at a cost of $250-$400.
The rolled Insight that we were hacking up would have been an option, but is no longer available.
I will pull the 5th wheel assembly and look at the damage in more detail after Nov 9, as I have to demonstrate the car for U Con and Trinity College in Hartford on that day.
The car still drives fine, but the tire wear, visual misalignment, and reduced un assisted MPG are all clearly showing the result of the damage.
At least we now know where the weak point is.
Tom
Some photos of the 5th wheel assembly:
http://www.99mpg.com/Projectcars/mikesinsight/the5thwheel/
http://www.99mpg.com/Projectcars/TheBestHybridmix/
I will document the damage once I get into the repair.
:(

It turns out that the Rolled Insight had not been crushed yet, so I can get the rear end from that one. No telling if it got bent in the multiple roll over.

The guy walked away un harmed. The Insight is a tough little car.
;)

Less mass to stop = less force applied right? Kind of like trying to swat a fly in the air.

I can't help picturing what my car would look like after a bad front end smash. The batteries would rip out the spare tire box, spark and melt the wires, hit the gas tank, and in a huge ball of fire and sparks that would be the end of me and the Batmobile.:eek:
Now I am afraid to drive it.:rolleyes:
Just kidding, I can't let a little thing like instant death stand in the way of progress.;)

LOL. And this is why we don't have 100mpg vehicles. Stinking government safety regulations. Imagine how much safer the roads would be if every vehicle carried a bottle of nitroglycerin under the drivers seat.

Hi Tom:
LOL. And this is why we don't have 100mpg vehicles. Stinking government safety regulations. Imagine how much safer the roads would be if every vehicle carried a bottle of nitroglycerin under the drivers seat.
___That would be the “ultimate” solution in order to thin the herd a touch ;)

___Good Luck

___Wayne

Nice one guys
"hypermiler":
one who drives like they have a bottle of nitroglycerin under the drivers seat.
;)

Hi Mike:

___I think you and I need to go for a ride in the Accord sometime. Or anything else for that matter? A spontaneous Alternate has been known to take an FEH onto two wheels, the chicane w/ an unweighting just before the Apex after a blind corner and the (2) decreasing radius Clover leafs I travel almost daily might make you decide to tighten your seat belts a notch as I always warn my passengers. That or your head might hit the passenger side window and she puts a knot in your head ;)

___Nitro is for those that have accidents while pulling beyond the speed limit type maneuvers in traffic :(

___Good Luck

___Wayne

Wayne,
I would love to take a ride with you and observe your techinques first hand.
It seems that we are always too busy when we find ourselfs at the same place, to do that.
Maybe sometime next year.
;)

I met the guy who has won the Pikes Peak Marathon seven or so times. He drills holes in his running shoes to save weight. :eek:

Another seven-time winner - Lance Armstrong runs his first ever marathon in NYC November 5. If you can't qualify with a good time or get picked in the lottery (70,000 apply - 36,000 are chosen) the only way to run in NYC is to raise money for charity. Lance is running to raise money for cancer of course.

Lance with have pacer runners so he knows he will finish in no more than three hours (an elite time).

I wonder if Lance will draft behind those pacers. :D

Now back to our regularly scheduled topic....

I had an alignment check today ($33) at my tire shop.
The alignment was within the honda specs.
The worse wheel was the driver rear, which has a camber spec of -2 to 0 deg, my car was at -1.5 deg.
The passenger rear which I had thought looked the worse, was -.4 deg.
The front was .1 on the driver side and .5 on the passenger.
the toe was also well within spec on all 4 wheels.
I guess that I was worried permaturely?
I watched the guy do it, and believe the numbers.
Still a mystery as to the tire wear and lower MPG?

Hi Mike, I had an alignment done with a new set of tires, and my numbers are very simular to yours. We didn't adjust anything either.

New shoes on my Insight. (http://www.cleanmpg.com/forums/showthread.php?t=2707)

Randall

Mike, I had an idea last night... probably something you have already concidered... but thought I would say it anyway....

The thought occured to me that the lower MPG might directly be caused by the deformed wear of the tires...

the Deforemed wear pattern of the tires might be caused by the uneven rear vehicle lift produced by the 5th wheel.... When the 5th wheel presses down on the road that pushes back up against the car where it attaches... If I recall correctly the wheel is not centered in the back so the lift is being applied more to one side then the other... and since the lift is not going threw the cars normal suspension it isn't being distributed normally.... then that amount of lift shouldn't be much but over time it may be adding up, especially since the Insight is such a light car to begin with even 100Lbs of downward force is about ~5% of the total vehicles weight.... also when the car hits a pot hole... it may not have bent anything as you first feared but the 5th wheel if down at the time will not absorb that rear end lowering the same way the suspensioned rear end tires will and as such the off center upward force from it will be much great for a short period of time.... The uneven wear patteren would probably happen still if the 5th wheel was centered in the back but then it woudl be equal on both rear tires.

if this theory is true I can think of 2 ways off hand to test it .... to check the uneven wear pattern of the rear tires and see if the uneven wear patten is slightly more pronounced on one tire side than the other... this might be very hard to detect as it could be a very small difference due to the small distance from rear center that the 5th wheel lowers to... and it could be caused by other things.... the second way I can think of to test it is easier and more direct evidence but more time and cost.... put a new good set of tires on the car an drive it for several hundered maybe a few thousand miles with the 5th wheel ... if the pattern of wear repeats then change the tires out and with a new set of rear tires go another few houndered maybe a few thousand miles with out useing any of the 5th wheel and see if the odd wear pattern apears again.... if in several thousand miles it show up again you know it wasn't an isolated insident... and if in the second set of a few thousand miles it does not show up again and the only varible changed is not useing the 5th wheel at all... then the therory may be correct......

any just my 2 bits....

best of luck

Another thought I'm having while reading this is that the 5th
wheel itself might have gotten a little misaligned, and might
be trying to "crab" against the car's own tires somehow. Last
time I looked at the wheel I noticed that its little scooter
tire had *much* more wear on it than when we bolted the rig in
last summer... which I attributed to the mere fact that it's
pushing the car all by itself, but there might be more in play
than immediately meets the eye.
.
_H*

if the 5th wheel one way or the other has caused the tire wear I still like the idea of the 5th wheel and it should still be fixable ... if of course it turns out that the current form is the source of the other problems..... Mike and others who know far more than I do will no doubt figure out what the cause is and how to deal with it.... I wish Mike and his 5th wheel the best... I know Mike has more of other things to keep him buisy now and so the investigation and or solutions to it once found will be slow going and will take a while... but almost everything worth while does.... and I have enjoyed the progress so far and look forward to how things will evolve from here....

On a Side note... I got to see the movie Who Killed the Electric Car over the weekend.... I thought it was a ok movie that presented allot of the issues to those people who had not been following the events that surround Electric cars and such.... if you have followed things you probably already know most if not all of what they talk about... but for those people who haven't it is a very nice sum up.... My one freind who hadn't followed electric cars any more so than what I bring up from time to time... said it was very informative for him.... If you haven't seen it ... it might be worth a watch....

careful driving is something everyone can do... more fuel efficient cars are something we can all look to as the next car we buy weather new or used.... and Projects like MIMA , the booster charge , the 5th wheel , FAS , Hot air Mod , Pulse Glide , etc.... all these things help show us that if your willing and have the time and skills you can advance the car beyond what it was built to get MPG wise and no matter how MPG freindly the car is there is always room for improvement.... Hopefully the car companies continue to produce more HEV and PHEV and other advances.... but those of us "little guys" can still make our own improvements even if the car companies don't make them.

So best of luck to everyone... looking back on the progress of the do it yourselfers... and the little guys ... allot has been done and it is nice to think about... :woot:

Just my 2 bits...

Hi Hobbit,
You are the only person besides my self that has seen the 5th wheel up close from under the car (you helped me install it before the trip to Madison), you also saw the tire wear the last time you were down.

All good points. The problem is that the tires have been rotated during the time that the 5th wheel has been installed, which has virtually erased any relationship of the tires to their present positions. I probably have 200-400 miles on the 5th wheel since installing it, and have hit several nasty potholes with the wheel down, so it is definately possible that it has been knocked out of alignment with the other rear wheels.
I will carefully look at all 4 tires, and will again rotate them to place the best two tires on the rear,and will take some tire wear reference photos.
I will also check the 5th wheel to rear wheel relitive alignment to see if it is still as it was. You may remember that I pinned the 5th wheel mount to the mounting plate, so it could not move relitive to it, but the wheel can be shifted out of alignment with the belt tensioning jack screws, and may have moved?
The "normal" wear for the 5th wheel is unknown, but the saving grace is that the tire is only $20 to replace, so I will just get a couple of spares.
Will advise once I get some time to get back under there and play some more.
I had a nice day at Trinity college. I was again amazed by the way that little wheel was able to push the car up hills. The demo drives were on a pretty steep section of road right on the campus. I could not start up hill from a dead stop, but only a 20-30 foot run on flat ground was necessary to get to 10-12 MPH, and at that speed, the hill climb was no problem, with the speed actually increasing up the hill. I wonder how the motor brushes are holding up? I would like to use a Prius MG1 BLDC motor for my next E-wheel.
:cool: ;)
IamIan
I just saw "who Killed the electric car" last night for the first time.
It makes me wonder about my experiences with my E wheel and the press.
Tour de sol had no interview or even a photo of the car.
Hybrid fest was similar.
At alt wheels, no press were sent to see my car, but they did cover the rest of the event?
At Trinity, chan 30 (NBC) did an interview, but did not air the piece.
Channel 61 (FOX) sent a camera guy and must have did 1.5 hours of shooting.
I had sent an e-mail note to the station explaining the 5th wheel and other features, and their response was very up beat, and they indicated a strong desire to do the story.
The story was a 10-15 second refrence to my visit to Trinity, and said nothing about the 5th wheel being electric, or the MPG numbers that were achieved at Madison or Ipswich. Almost like they were trying to down play or supress the really important aspects.
Am I just being paranoid????