Last Modified: July 23, 2011
Contents:Basics; Buying Advice; A Concern; Odds & Ends;
The term Hybrid in this context includes any vehicle which uses battery power for propulsion, whether fully, or in part. This includes, but is not limited to, the Prius®, shown here, the Chevrolet Volt®, or Nissan's All-electric Leaf®. The Prius® has evolved since its introduction to its current Generation III. The Prius®, and other models that use the Synergy® drive system, are true hybrids, in that the ICE (Internal Combustion Engine) is fully integrated with the electric propulsion motor. Depending on driving conditions, one or both propel the vehicle. The latest offering from Toyota, is a plug-in version, with a larger capacity battery.
The Volt® is a new offering from GM, and is primarily an electric vehicle, with a back up 1.4L, I4 ICE. It is currently (Summer 2011) the highest mileage rated vehicle on the planet (≈96 m.p.g.). Real-world mileage is somewhat (some say considerably) less according to owners. The Leaf® is also new, and is a full battery powered vehicle with no ICE. Both are plug in vehicles, although the Volt® can partially charge its own battery.
Hybrids share a lot of the same features. For example, regenerative braking which puts back some of the power used to accelerate the vehicle in the first place. Most use electric motors not only to power the vehicle, but to run water pumps, power steering, and even the HVAC! A few use switching power supplies to power the lighting, radios, navi systems, etc., but others do have 12 volt, standard lead-acid vehicle batteries on board for that purpose.
Propulsion batteries are universally NiMH (nickel-metal-hydride), although Mercedes Benz's model uses a Li-ion (lithium ion), as does the Leaf®. Nominal battery voltages range from 36 volts, to 440 volts. All of this power does generate some concern for both owners, and emergency-responders in case of a vehicle crash (see below).
Quite obviously, all of this electrification requires some sophisticated electronics, as evidenced by this white paper. The main reason is, the propulsion motor (at least) is a three-phase, AC motor. Those electronics are used to generate the requisite three-phase current, but that's not all. The frequency, voltage, current draw, pulse width (in some cases), regeneration, and many more parameters are controlled by digital electronics. Read into this, harmonic-generating, square-wave, switching circuitry!
Unless you live under a rock, you know that RF filtering a nominal 12 volt DC switching power supplies is a mixed bag of tricks. A few don't generate a significant amount of hash, while others sound like white-noise generators! Part of the issue is the amount of current being switched. In a hybrid, not only is the voltage considerably higher, so is the current. Thus, the amount of RFI they generate is rather copious in nature irrespective of the manufacturer's efforts to quell it. We should be protected to some extent by Part 15 of the FCC rules, and regulations, however, vehicle manufacturers are exempt (Section 15.103)!
The question remains, just how RF noisy are they? Although the level of RF emitted varies considerably from model to model, none of them are what amateurs would call quiet! In fact, some are so bad, they can be heard from several blocks away, and the year of manufacture has little to do with the level! The next question is, can it be tamed? Based on my e-mail correspondence with John Pavelich, VE3XKD, and others, it appears to be a herculean task requiring countless hours, and hundreds of dollars spent reducing the RFI to a level compatible with HF operation. This is on top of the premium price most hybrids demand (≈$4,500 to $6,000).
A recent study by an independent research company, proved that the average hybrid owner will never amortize the additional cost of procurement, and maintenance costs regardless of the mileage driven.
If you're thinking about buying a hybrid vehicle, read all of the data on the particular model you can, as some of the data is purposely misleading no matter the manufacturer! This includes, but is not limited to, the application of included warranties, extended warranties, and assumed warranties especially with respect to the requisite assist batteries all hybrids require. While this may sound off the subject, it isn't. In a recent California Supreme Court decision, it was ruled that extended warranties cannot be considered an assumed warranty. By all means, read the fine print carefully, and ask questions even if the wording appears non misleading.
Here are a few things a potential buyer (read that amateur radio operator) should consider when purchasing a hybrid vehicle:
1). What size SLI battery (if any) is used? The SLI is usually quite small, and in most cases is not used to start the engine unless the assist battery is discharged for whatever reason. The other SLI issue is its voltage. When the engine isn't running, the battery is not being charged, and the voltage drops to resting, or below depending on the load. In fact, if it gets low enough, below 11.6 vdc, some radios will just turn themselves off.
2). Does the vehicle have a standard alternator to charge the SLI? If it does, what is its rating? I should point out here that unlike a non-hybrid vehicle, accessory loads like a rear window defroster may not indicate a reserve large enough to operate a mobile transceiver. It depends on the system strategies being used.
3). What if the accessory voltage (nominal 12 volts) is generated from the propulsion battery by a switching power supply? Universally, this negates just about any kind of amateur activity.
4). How good is the RFI suppression? One way to tell is take along an AM radio (short wave if you have one), and listen on an unused frequency. This method isn't fool proof, but it is a start. Don't plan on using the OEM AM radio, as a lot of hybrids don't have them (makes you wonder doesn't it?).
5). If you can, talk to the Service Manager, and ask specific questions about RFI. Most of the ones I've talked to have been rather evasive as if they know more than they want to admit. That wasn't the case at my local Toyota dealer here in Roswell, NM. They were very helpful, and even gave me the name and number of their local Toyota representative. The local Honda dealership (owned by the same folks), were equally helpful. Lets hope yours are too.
If you already own a hybrid vehicle, and are planning on installing amateur radio equipment, I wish you a lot of luck, and hope you have the patience of St. Job!
The National Fire Protection Association recently released a report entitled Fire Fighter Safety and Emergency Response for Electric Drive and Hybrid Electric Vehicles. It's a 5 Mb pdf document outlining the procedures for proper emergency response to hybrid vehicle fires, and crashes. If you own any hybrid, it is worth taking the time to read it. It also contains a list of all current (circa 2009), and near future models of alternate-fuel vehicles. These include all electric, hybrid electric, hydrogen, CNG, and the various combinations. Here's an excerpt from the document:
Electric propulsion systems introduce new and possibly unanticipated hazards to emergency responders, although these do not include anything that members of the fire service would consider particularly challenging. For example, EVs and HEVs utilize high voltage power used for propulsion in conjunction with their low voltage electrical systems used for accessory lighting. The cabling for these high voltage systems were voluntarily colored bright orange for easy and consistent identification. In certain recent models cabling has appeared that, although it does not carry high voltage, still presents an appreciable and dangerous shock hazard, and these are identified using blue and yellow to color-code cables. In the meantime, additional shock hazards exist in all vehicles from certain features of the low voltage electrical system, such as, for example, the use of special high intensity discharge headlights.
While the NFPA is concerned with emergency response, potential mobile operators of these vehicles should also be concerned for obvious reasons. Considering the aforementioned, there might not be many mobile operators opting for alternate power vehicles. In any case, it pays to be informed.
Plug in cars like the aforementioned Leaf®, are not as environmentally clean as pundits claim they are. Just ask yourself where the power to charge them up comes from. Here in the US, that's predominately a coal-fed power plant. Oh! But! You can charge them with solar panels! The truth is, the cost of enough solar panels to charge the Leaf® in the same time frame (≈8 hours) as 240 volt mains, would cost almost twice the Leaf's® ≈$40,000 MSLP. Using solar also negates charging the vehicle overnight!
Everyone I have ever met (including my brother Evan, KØHYG, sk, a Prius owner) bragged about the mileage they were getting. What they didn't tell you about, was all of the trips back to the dealer to adjust or fix something that quit working. And, if they installed HF amateur radio equipment (as my brother did), they don't tell you they have to pull over to use HF radio.
Manufacturers of hybrid vehicles go to great lengths to increase the overall mileage (bragging rights, don't you know?). One of the strategies is to employ small diameter, low rolling resistance tires. Since they have to carry a lot of battery weight (up to 1,000 pounds), they require high inflation pressures (≈40 psi). Add in the requisite stiff suspension, and the ride isn't what one could call cushy! It's best if you have a cushy bombosity.
Another strategy to increase fuel mileage is to essentially enclose the bottom of the vehicle in an effort to decrease its Coefficient of friction (CF). It does work by the way, but there is a drawback. Remember, those skinny little tires aren't very good in the snow. So, skidding off into the ditch on a snow-packed street is enough to do great damage to the underside, and it is very expensive to fix the damage. This is how my brother's Prius ended up on the scrap heap.
Hybrid vehicles tend to be sub compacts (although some are mid, and some are large sized). Sub compacts typically are four passenger vehicles, with an occasional 5 passenger if you don't mind using Right Guard®, or Secret® deodorant. Add the requisite battery space, and the trunk tends to be miniscule. They are not long-vacation-travel vehicles, unless you have a very good relationship with your travel partner. By the way, if you're a golfer you'll have to put the clubs in the back seat as hybrid vehicle trunks are typically too small. After all, they've got to put those batteries someplace.
I cannot speak for anyone, but myself. I believe hybrids vehicles are like compact florescent bulbs. The idea seems like a very smart, environmental-friendly, form of transportation. But the fact is, their overall cost to manufacture, distribute, and recycle, far exceeds any real-world benefit they may appear to have. Especially if you're an amateur operator. Caveat Emptor!