Comments

Episode-1530- David Haight on Alternative Fuel Vehicles — 39 Comments

  1. The current dual motor Tesla Model S and the upcoming Model X SUV have all wheel drive. Granted not in the budget for most people.

  2. In some defense of ethanol, there is a byproduct that is a great animal feed called DDG or DDGS. The ethanol process itself only uses up the starch in the corn leaving a product that is high in protein and oil. And it so happens that cattle really can’t utilize the starch in the corn anyway. Now I know Jack and others prefer grass feed cattle and that’s a whole nother argument. But I just wanted to point out that the ethanol process isn’t a one trick pony. Btw, I know this because I worked as an enigneer for a while in an ethanol production plant.

    Now are there other ways to make ethanol that would work better and other ways to utilize corn fields for better alternative crops? Sure. But there is this big misconception and food OR fuel with corn ethanol that I wanted to point out.

  3. Great episode covering “alternative” transportation. I commute with an electric motorcycle 52 miles each day year round in Virginia at highway speeds. I can do it on one charge (10kW nominal) and still have some left over when I get home depending how aggressive I am with the throttle.

    The bike is a blast to ride, 0-60 in 3.3 seconds without shifting — you just twist and go. The whole bike can be controlled with one hand. At 70mph you can go about 70 miles when the weather is nice; at 55 you’re looking at 90 miles. If you streamline the cowl you can go nearly double that.

    Running the numbers my bike will pay for itself in 5 years over a typical ICE (internal combustion engine) bike at which point I would be “saving” money. Most of this savings is from maintenance cost, not gas savings over electric.

    The batteries last 300,000k miles before the charge provided is 80% of what the original range was. In my State it cost less than a dollar to charge my bike up 100% at home, and many stations on the road are free.

    The more I ride it the less I want to ride anything else.

      • Zero Motorcycle S ZF11.4 2013

        It was previously modified by Electric Cowboy (aka Brandon Nozaki Miller) for racing so it is as fast if not faster than the 2014 / 15 SR models.

        You can test ride these bikes for free at any dealer who sells them, or set up a test ride on zero’s page http://www.zeromotorcycles.com

        A used 2013 11.4 is currently about 10-12k used.

  4. The locomotives you see going across the country are hybrids, burning diesel to drive generators which run the electric motors. So you could make diesel trucks that are hybrids like the locomotives. Some new sports cars like the Acura NSX have electric motors on the front tires to go along with the gas motor.

    • I could be wrong, but I think they were mainly talking about all-electric trains in Europe or Japan that have wires running above the tracks.

        • You are correct that when Jack asked if I ever saw the vehicles being as “powerful” (aka produce as much torque) as an F-350, I was referring to diesel electric hybrid locomotives already in use today. I later pointed out that to get to the same energy density as a tank of diesel we need batteries that are about 10x the energy density of ones used in production EVs today. I hope that clears that up.

  5. I realize that we can all have differing opinions, and I welcome this ordinarily, but some of the statements made here directly conflict with advice made by Steven Harris, specifically with the ethanol issue.

    I’m not really sure what to believe now, it would be nice to have this guest and Steven on the show to discuss these questions, in a respectful way, to clear up some of the confusion this may have caused.

    Thanks for doing this Jack.

    • With due respect to the guest when asked to back his claim up he didn’t state any specific facts but rather externalized using terms like “there is debate …” and citied arguments Harris has already shown to be fallacious.

      In contrast Harris is very exact in the evidence he provides for his reasoning, and has examples of what he is claiming works to back him up.

      I would like to hear Harris address bio butanol as a energy source and if it would have to be “mixed” like gasoline is mixed per region. From what I understand the current yield from algae or diatoms is too low for easy mass production.

      Also it would be interesting to hear what would be required to turn a EV, like my motorcycle, into a moveable power source. (nominal 102vDC). And if old lithium packs from wrecked cars would make sense for a battery backup source in place of traditional lead acid batteries.

      • Like anyone, Mr. Harris has his own agendas when he is backing his claims. Although exact in his evidence, he doesn’t provide the opposing evidence, to which there is quite a bit that shows ethanol to be harmful in some regards to engines at certain levels. There is plenty of evidence to show, for example, that running E-85 in a non-E-85 vehicle can over time degrade fuel lines and seals of the fuel system. There’s a very particular concern in the aircraft industry where they are considering introducing E-85 and how they can present water from getting into the fuel and cause icing.

        Being into older cars and motorcycles, the effects of ethanol are well known and documented in these circles. So Mr. Harris may be spot on when it comes to newer cars, but not so with the older stuff.

      • To turn an EV into a moveable power source:

        1. If the (PH)EV has an existing Low-Voltage (i.e. 12V) system, use commercial off the shelf inverters to turn this 12V to 120VAC. I have done this myself with my Volt during a power outage, and it works exactly the same as Steven Harris’s “power your house from your car” would, with one major difference: my Plug-In Hybrid Volt takes care of deciding when to turn the engine on automatically (as long as the Volt is left powered on). I would not need to go out and start up the car periodically to prevent a dead 12V battery. The size of the inverter should be less than the size of the existing DC-DC converter that takes the EV’s high voltage down to 12V. In the case of my Volt, this limits me to inverters in the 1500W category.

        2. If the EV does not have an existing low voltage system, it would be possible to add a properly sized DC-DC converter down to 48V or less, with appropriate disconnects and fuses. Then use off the shelf inverters from this lowered DC voltage. If you need instructions on how to do this, you should leave the high voltage well enough alone…

        3. It is possible to obtain inverters that will accept the high voltage from the traction battery pack. However, this is more dangerous and will require much more accurate electrical engineering. Again, if you need instructions this is not a DIY project for you.

        I had looked for a good source of “salvage” lithium batteries from EVs awhile back. All I could find was buying the entire wrecked car as is, and all of those had the high value battery already scavenged before they were put up for sale. I should probably look again now that a few years have passed.

    • I agree that Steven Harris and I hold different opinions about ethanol’s suitability in ICEs of various sizes and configurations. Steven and I respectfully disagree about other topics as well, that is certainly fine. I openly acknowledge that I have not run more than E10 in any engine, and tried to make it clear that I was echoing research, not direct experience. If Steven Harris has direct experience running E85 or E100 in engines, then of course his opinion would carry more weight.

      I think the most interesting argument against using ethanol+gas blends is the fact that they are not pre-mixed at the refinery, but kept separate until the time of dispensing at a gas station. The “blender pump” is not the most logistically simple way of going about it, so why would the fuel industry set it up like this if there was not some concern about storing blends of gas and ethanol?

      What I think we need to be the most careful about is lumping all engines together. A low compression air cooled Briggs and Stratton is going to operate very differently than a high compression Indycar engine that is designed to run E100. I do not think there is enough specificity provided by either the pro-ethanol and anti-ethanol camps to say, do use it in this type of engine, or do not use it in this type of engine, etc.

  6. Likely a Briggs & Stratton motor on Jack’s tiller, hence the warning

    “Ethanol has inherent properties that can cause corrosion of metal parts, including carburetors, degradation of plastic and rubber components, harder starting, and reduced engine life,” says Marv Klowak, global vice president of research and development for Briggs & Stratton, the largest manufacturer of small engines. “The higher the ethanol content, the more acute the effects.”

    • This is exactly my point. EVERYONE warns of the dangers of ethanol use, but Steven Harris is adamant that it is a non issue. In fact I have purchased small engine products over the last few years that warns if a fuel stabilizer is not used, then the warranty will be void because of the problems associated with ethanol.

      In all fairness I have been treating all of my stored fuel with PRI-G and D, and have not had any trouble thus far where as I have had issues prior to that. Stevens recommendations for the PRI- products appear to be a good one, but I have not been using it enough to give first hand accounts of this.

      I am skeptical of his recommendations that the ethanol issues are not valid. I would like to hear his rebuttal to this podcast.

  7. I really enjoyed the episode. Especially the part on the plug in hybrids. I learned a lot in that venue.

    For more information on ethanol check out ‘Alcohol can be a gas’ by David Blume. http://alcoholcanbeagas.com/ and a video https://www.youtube.com/watch?v=Jew3ah24Zj4

    If you frame ethanol with permaculture many potentials surface.

    Food vs fuel is a catch phrase, but looking a bit deeper it’s not that simple. 90% of the corn grown in the US is feed to cattle. Cattle are rumens and can’t digest sugars. Yeast only eats sugar so the byproduct of producing ethanol is improved cattle feed. David Blume cites studies that cows gain about 18% more weight on the dried distillers grains than they do on the corn alone. The distillers grains only weigh 1/3 what the corn did so shipping costs drop with the weight. Corn is one of the least efficient feedstock’s for making alcohol. Sugar beets, Jerusalem artichokes, mesquite pods, there are many options depending upon your climate.

    David describes some beautiful systems based around a still.
    1) Fermentation of your feedstock produces CO2 and alcohol.
    a. CO2
    i. Feed into a greenhouse it increase plant growth.
    ii. At high concentrations in a greenhouse it kills bugs – so keep people and animals out during these times.
    iii. Dissolved in water it increase algae growth. Algae has many uses….
    b. Alcohol
    i. Drinking at this point @ around 15-20% concentration.

    2) Distillation byproducts:
    a. Alcohol….concentrated. Drinking, cooking fuel, heating fuel, car fuel. Some of the first cars ran on alcohol. It’s 106 octane. There’s oxygen in the molecule so you need less air in the mixture which means you can get a much greater compression ratio in an alcohol only ICE (14 to 1 in lieu of 6 to 1 for gasoline). It burns clean – the emissions are CO2 and water.
    b. Hot mash can be used to sterilize and feed straw bales for mushroom production. The spent straw bales are good compost and may be able to be uses a silage.
    c. Mash can be put into a methane digester producing methane, CO2 and fertilizer. There’s enough methane to run the still the next time. The CO2 can again be removed with water and you can do the algae thing. The byproduct of a methane digester is fantastic fertilizer. The yeast ate the sugar, the methane digester eats the fats and protein – all of the minerals remain. Grow some more crops and keep on cycling while building fertility.
    d. Mash can be feed to animals.

    • I like the permaculture thinking and material cycling thought process in your comment. I would love to see more of it done on both the backyard scale and on the industrial scale.

  8. The only data I have are my own engines that have been sent to that great scrapyard in another dimension, my own experience validates that ethanol does indeed kill small air cooled engines. (Especially Briggs &Stratton and whatever brand Black & Decker uses)

  9. While I very much want some kind of EV I cannot make the math work over a small ICE car. In the interview David said he saves $4.50 a day on his commute to work. That is $22.50 a week or about $1,000 a year (assuming some vacation time).

    To put it another way, in 2002 I bought as a “go to work car” a small Saturn that was $10,000 brand new. I now have a little over 100,000 miles on it. Assuming an average of $3.00/gallon for gas over this time (which is on the upper end) I’ve only put about $10,000 in gas through the car. So for 12 years it cost me $20,000, this is quite a bit less than just the purchase price of any of the electric or hybrid cars, let alone the low, but not zero cost of electricity.

    Don’t get me wrong I feel this is the right way going forward, but until we get some cost savings based on production volume I just cannot justify the expense in my life. On the other hand once I get my house paid off a Tesla becomes a real option, but that is many years away.

    • You are correct that purchasing a new electric or plug in hybrid can have a very high price tag. It was important to me personally to have a very high quality and low maintenance vehicle. I see my choice of a plug in hybrid as allowing that high quality that I was looking for with a lower 10 year life cycle cost than equivalent high quality cars that also have a high cost to purchase new.

      With so many more used plug in hybrids on the market now, and the recent low in gas prices, it should be very possible to avoid the cost and depreciation of the new car.

      You are exactly right about the cost savings from higher volume… and also from more different chassis being released with similar drive trains. I expect a lot more action from a lot more manufacturers in the next 5 years along these lines.

  10. Dude never said thank-you for having him on… I try to not let it annoy me too much. Thanks for the service Jack.

    • Joe –

      I thought of that, and about a hundred other things, I wish I had said during the interview. So, I will C my A now and say, “Thanks, Jack!” I do very much value what he does and especially what the TSP community does…

  11. I was very surprised CNG powered cars were never covered. They are getting fairly popular here in California with more and more stations popping up (some standard gas stations are starting to retrofit pumps for CNG). I don’t see why CNG wouldn’t work in large pick-ups/4×4’s because they are using it to replace diesel in most busses and delivery trucks.

    • CNG was on my outline to talk about, but we did not get around to it in the show.

      A couple of things to consider about CNG: in order to repressurize the natural gas from the <10psi (usually <1psi) delivered to a home, you will need a pump like the "Phil" that will use ~800W of electricity to do the pumping. So therefore you need both the methane and electricity delivered at the same time and place. FWIW, I charge my electric car on only ~1400W from the wall socket. Yes a CNG tank can store more miles then most batteries when full, but the energy audit has to account for the energy used in recompressing the gas.

      CNG works better in higher compression ratio engines. IIRC, you can expect a loss of somewhere between 20 and 40% for the torque figure of a typical low to moderate compression vehicle engine if switched to CNG with no other modifications

  12. One point of ethanol not covered was when the price of corn was pushed to over $7/bushel five years ago the cries of food price increase, etc were at a fevered pitch. This past harvest, and the previous two years corn was around $3/bushel. Hmmm….so how far did food prices drop? Cattails are a better solution to corn, as you can about double your starch per acre, and use less water. Could raise tilapia in the reeds, too. I’m in the Midwest, and the ethanol industry has provided some decent jobs for a farming community that wasn’t doing well. I’m on Jacks side when it comes to getting people out of mono-cropping, but if you put three farmers together they couldn’t agree on the time of day. Not sure what it would take to convince them they could make as much or more on less land. I asked one farmer about raising organic soybeans. I told him you get three times the price of non-organic. His reply was “but Ill only get half the yield.”. Sigh. The water usage to make ethanol is dubious, as it takes over 20 gallons of water to get oil out of the ground and process it to a gallon of gasoline. Ethanol plants recycle their water now, and use far less than refineries.
    . Navistar and Peterbilt have been experimenting with diesel/electric hybrids, in smaller trucks. If trains can do it, so could a semi?

    Great show again!

  13. It is easy to tell Mr. Haight is from a warm climate. It is then quite easy to excuse is answer to the cabin heating issue. Heating the air in the cabin of a vehicle in cold weather is less about keeping the people warm and more about keeping the windows defrosted. The reason for the rear window defrosters (those lines across the back windows for anyone who has never had to use them, that work like an electric blanket) is because the cabins are rarely warm enough at the back to keep it defrosted. However, trying to use those types of defrosters on the windshield and side windows would not be possible, too much obstruction of view. If at all possible hearing from someone with an EV in the northern climes would be helpful.

    From what I understand, during the winter months, up here in “tundra-country” (north of Nebraska) one can expect about 80% of rated capacity (which would be in line with what I have seen from other battery usage in cold weather).

    • There are two ways to defog a window… heat it up, or reduce the humidity in the air. In order to de-fog my windows (in the rare case the humidity gets high enough here in Colorado), here are my strategies:

      1. Clean the window well
      2. Apply the product “Fug” by the makers of Rain-X
      3. Turn off the air recirculation
      4. Use the air conditioner directed against the glass for 30-60 seconds, which uses 1.5 to 2kW, even if the cabin is cooler than I would like. Manually cycle as needed to keep a safe level of visibility. Add seat heat if necessary to keep me comfortable
      5. Use the “defog” setting that runs both the air conditioner and heater simultanously, using up to 6kW of power. Manually cycle as needed.

  14. With electric vehicles, is it possible to put solar panels on the roof of the cab or use the fan in the front of the vehicle to charge emergency batteries when the vehicle is running or to charge the regular batteries when parked?
    I have seen videos of solar panels that you can wrap around a pop bottle, this would be perfect to use on a vehicle for this application.

    • At the sizes/surface areas of typical vehicles, and the efficiencies of todays solar panels, and the amount of energy used in an EV, the panel would do fairly little to add to the range of the car. Wrapping the car in the panels would take the total price tag of the car and send it way higher.

      I think Jack had it right when he was talking about solar panel covered parking lots. Or covering the entire roof area of commercial buildings for this purpose (I look down on acres of underutilized roof space all the time!). I think the Hyperloop project also has it right by covering the entire length of the tube/track with solar panels to generate the energy necessary to operate the Hyperloop. Finally, I would love to see more effort to combine roads and the electrical grid, to either allow for in motion charging and/or greatly increasing the density of charging stations…

      I am sorry to say that your fan idea would also not net enough energy to be worthwhile. We do use “Ram Air Turbines” as an emergency electrical source on some models of airplane, and it is a very inefficient way to gain that benefit.

  15. You can build an ICE vehicle. If something blows up, you can “easily” go buy parts and repair it. (yes, I know, easily is relative).

    I converted an old pickup to electric, so now I have an EV. Great, right? Not so fast. At the time that I converted it, Li-Magic batteries were astronomical (I could buy 3 used Geo Metros for that price, in 2007). So, batteries are cheaper now, right? Sure. If you can find *anyone* to sell them to you. Well, you can, just no US manufacturer will sell to an individual. You have to buy Chinese Li-Magicum batteries.

    Repair: Simple, right? Drop in a new armature, drop in a new controller. Great, except a new electric motor is $1800 plus (for a DC motor) – and a controller (even a cheap Curtis model) starts at $1500. You want a Zilla controller? Start at $1900-2100. So, I’ve built an EV, and I had to repair a controller (motor is still fine). Where do you get controllers? Hmmm… New (been there) Repaired – starts at $600. That’s the price of a nice used engine in an ICE vehicle. No, I didn’t screw up. I had over 2000 miles on the vehicle when the controller smoked. Left me stranded, and I had to have it flat-bed carried. What non-dealer mechanic can fix a when the controller or batteries on it goes? So, I shipped my controller off, the guy said it was a manufacturing defect. He fixed it, it still works.

    Don’t forget, DC armatures are wound armatures (mine is, anyway). They tend to blow up above 5000 rpm. So, don’t “rev” the “engine” – besides, you won’t hear it (at least until the bang, or whatever sound it makes when the armature comes apart).

    AC armatures are much simpler, but their controllers are an order of magnitude more complicated (and a grand or so more expensive – probably. I’ve never priced one, or the AC motor to go with it).

    Regenerative controllers are more expensive too – you dump 600 amps into your heavy foot acceleration (or more). Pb batteries can’t take that back (with regen braking, so what’s the point? Lithium Magicum batteries *could* handle it though, probably).

    Lead Acid batteries SUUUUUUUUUCK at storing or retrieving energy, and I can’t afford to spend another 6 Thousand on a 20 year old vehicle with no heat or AC to put batteries in it (I’m not even considering Pb again).

    Guess what happens in the winter? Chemical reactions are cut in half in cold areas. Meaning, Pb batteries give you 1/2 the range (and friends say their Prius doesn’t perform as well either – I have no data on the Leaf’s performance).

    My conclusion: When the tech is ubiquitous, I can go to any salvage yard and buy a motor or controller, or charger, or DC-DC converter, or PB-6 Throttle, and/or I can get new batteries without selling my and my children’s souls, THEN I’ll consider EVs ready. They’re working on it, but for the hobbyist, I don’t recommend it. I spent 8 grand converting an old mazda, and I have an 8-grand albatross in my front yard sitting there.
    2007 prices:
    Controller $1500
    Motor $1500
    Motor overspeed detector/switch $150
    Charger $700 (fancy electronic ones are $1500 or more)
    Adaptor Plate (connect motor to standard transmission) $700
    DC-DC (convert pack voltage down to 12-volts to run turn signals) $250
    24x 6-volt golf-cart batteries $2200
    Welding and whatnot (to carry around 1500 -2000 pounds of batteries) – varies depending on the welder.
    Other parts
    main contactor $120
    PB-6 Throttle $65 (they’re cheaper now)
    2ft x 1ft aluminum Heat Sink (for the controller) $100
    70 feet of 2/0 wire $280
    Connectors (once wire is cut up) $150
    Crimpers (to crimp the connectors) $290 (I could have gotten something smaller that involved a hammer, but those did a horrible job; and I could still sell the crimper).
    Scrap Truck: $250
    Dental Aspirator (to provide vacuum for the brake vacuum boost) $40
    Vacuum Tank (to hold extra vacuum) $20
    New brakes for really old truck (well, now we’re not taking strictly EV stuff, so never mind)
    Tires for old truck: $300

    There are neat ideas out there about how to store energy locally (18-wheeler trailer with flywheels, spun up while we’re all asleep, could dump energy fast into a ‘fast-charge EV’) at a ‘filling’ station.

    How far can I go? 45 miles. How long to recharge? 8 hours on 110 volts.
    How fast can I go? I’ve had it up to 70mph, but lead acid chemical reaction can’t keep up, so you eventually go slower… and slower… until you pull over and let the chemical reaction catch up. The best speed for a “lead sled” is about 45mph. The noisiest things on the truck? The dental aspirator and the transmission (those 3rd gear bull gears whine loudly at 45-50mph). 4th and 5th are very quiet, but the motor doesn’t have the torque to run it in 5th gear well.

    One last comment. My truck is WAAY out of balance. When I slam on the brakes, the front wheels lock up – because I have too much weight behind the axle (remember those really heavy batteries? Pb batteries SUCK).

  16. I forgot. You’ll need at least 1 12v battery to ‘start’ the contactor. My DC-DC converter doesn’t run all the time, but if it were a daily driver, you could do it that way.

    If I had the money back, I’d research the following:
    Earnie Parker (see Mother Earth News) Hydraulic Hybrid.
    Look up UPS Hydraulic Hybrid on YouTube for a cool video.
    Earnie’s son (I forget his name) made a Diesel Hydraulic Hybrid Motorcycle.
    They used to have a website called ‘hydraullicinnovations’ but they’ve let the domain lapse.

    I wanted to take Robert Q Riley’s (rqriley.com) 3-wheeler XR3 to convert to Hydraulic Hybrid, and use Josh Wolf’s Algae method to make diesel (Oh, that’s another thing – you CAN make your own diesel, if a 16 year old genius can do it, he can license it out to the average Joe to do it to in their back yard, with a 700 gallon homemade fishtank).

    Jack interviewed him once. Look him up. I think he’s approaching 20 now.

    I had more thoughts on the topic, and there are smarter people than me out there doing cool stuff. Look for EV forums (David – somebody out of Ohio runs it, or at least he used to. http://www.diyelectriccar.com) for more information.

    There are tons of converted EVs out there for sale, and folks are converting old Chevy S10s (they’re the easiest and lightest to convert) all over, and YouTube videos. Try NOT to fall out of your chair when you see the prices for a 20 year old EV in working condition, since now you might have a better understanding of the costs of parts.

    Finally, EVs (in a drag strip) will leave ICE racers in the dust – but can’t compete in the long range races. Electric motors have all their torque available at 0 rpm, whereas gasoline ICEs have to run up to 4000+ rpm to get their best torque.

  17. I have been to Washington state which is a pump your own gas state. The price of gas in Washington is not any lower than it is here in Oregon. Pump your own gas just means the loss of the service station attendant jobs. Who told you your gas is cheaper because you pump it yourself? Do you really think the gas station is passing that cost savings on to you?
    Peace in Christ
    Jeff

    • Okay you are delisiounal on multiple levels.

      1. Don’t eliminate a job that isn’t necessary so people can keep minimum wage jobs. Well shit let’s bring back all those elevator operators, phone operators, the 411 service, yellow pages delivery, the milk man, etc. all in the name of jobs then, oh and let us expect the cost of all said things to not go up.

      2. Forcing labor into an equation doesn’t add cost, wow, and where does the money to pay the guy come from, rainbow farting unicorns? Do you even understand that the average gas station makes about 2-3 CENTS a gallon on gas? Why do you think there are no gas stations that only sell gas? Why do you think they all sell shitty food and squishies? And say “thank you, come again”.

      3. So gas in Oregon and Washington is the same? Really? Well, that just might be because gas in Washington is 38 cents above the national average! So what does that tell you. It tells me the theives in Washington steal money directly and the thieves in Oregon steal it Robin Hood style though the phoney need for a person to pump my gas. The net effect is the same.

      4. The reality is some states jack up cost with state/local taxes and some with phoney baloney jobs. But the cost is still a cost of being stolen from by the state. Right now you guys are paying about 4 dollars a gallon in those two states, guess what a gallon of gas costs me where I fill up in Texas? About 2 dollars. Perhaps if you ventured outside of the tax the shit out of you left coast for a few days you’d get a better view into reality?

  18. David,

    Do you have any experience with the older Hybrid cars/suvs? Let’s say 2006-2008 Mercury Mariner Hybrids? Just looking at something for a 2nd vehicle to drive around town and on short 40-60 mile trips a few times per week. My biggest concern is how long do those batteries last.

    thanks,

    Clyde

    • Clyde –

      I have little personal experience with straight hybrids such as the Prius, Mariner Hybrid, etc. All of the energy used to move the vehicle comes from gasoline, none from the electrical grid. Mild hybrids will reward someone who already drives with an efficient style, but cannot solve the inefficiency of a lead foot.

      According to Wikipedia, the Mariner Hybrid uses ni-mh batteries. In the Prius, these typically get changed out between 200,000 and 300,000 miles. Your mileage may vary though.

      I personally would still choose a plug in hybrid for the use pattern you are talking about. Look for used ones coming back from lease (no fed income tax credit) or dealer demos being sold at a deep discount (with fed income tax credit if new/untitled prior to you). I would definitely choose a pure hybrid over a straight gasoline car, if for no other reason than a hybrid is going to be an even better source for emergency power than a regular car.