Jeep Patriot 4x4 Off-Road: High Value, High MPG ...

Work-in-Progress (WIP)

Quick Pictures (taken at the WORST time-of-day)

I've gotta get to work at my current client in Fairfield (CT), of which I will be doing all weekend as my last day is 7/13 before heading out to my new employer a couple of states away. I recently drove my "temporary car" up from Florida, a 2006 Chrysler PT/Crusier and due to "certain circumstances" I decided to finally get rid of it this week and purchase a 2007 Jeep Patriot (temporary Flickr set). I had previously had a 1996 Mazda B2300 (actually a Ford Ranger SE, right down to the VIN, except for the Mazda trim) but it broke down on my in january after 11 years and 165,000 miles. I wanted the Jeep Patriot at the time, but they did not come out until March (and not much beyond the initial 800 run until really April).

This is the Jeep Patriot 2007 in the Sport "E" package with the 4x4 Off-Road ("Freedom Drive II") configuration. Not too much is added beyond the "E" package other than the 458W 9-speaker Boston Acoustics speaker system. I don't recommend people getting this configuration if they want cruise control and other goodies, and either get the Sport "E" package without 4x4 Off-Road if they don't need it (keeping the price down), or just going for the "Limited" (as much of the electronics becomes standard in the Limited) if you want all-the-goods including the 4x4 Off-Road (plus some options that are only on the Limited, like a sunroof).

The Jeep Patriot 2007 dwarfs is "chick" counterpart, the Jeep Compass also sold as the Dodge Calibre, in size (read up on the Patriot's development if you want to know more about how it split into 2 models after the results of focus groups). But they are the same engine, frame, roughly weight (except for the 4x4 Off-Road version, although it's not much more), transmission (again, except for the 4x4 Off-Road version), etc... I like both the headroom and the some 2+ extra feet in the cargo area of the Patriot over the Compass/Calibre, which has more of a "cab forward" design that cuts into both cargo and height.

As far as everything else, for now, here is the review I submitted Consumer Reports (subscription may or may not be requried), based on my first 100 miles ...

Outstanding Value, MPG in 4x4 Off-Road

Pros: Inexpensive, Trail Rated 4x4 Option, Always well above 20mpg (even in city), 172hp 4-cylinder is "good enough," good cargo capacity/folding front seat and will fit 6'4" drivers, CVT2 with 19:1 low-speed option in 4x4/Off-Road

Cons: CVT advantage ends at 55mph, Chrysler needs to update Radio with text, poor towing capacity

Driving experience

If you want a SUV with pick-up, look elsewhere. The 172-hp 4-cylinder is "good enough" and will let you pull out in traffic, but don't expect it to be as fast as the same in Chrysler's smaller, lighter vehicles with the 2.4L, or your typical, 6+ cylinder mid-sized SUV. The CVT makes driving fun again, and allows you to get as good or as poor gas mileage as you wish. It's nice to slowly accelerate at 1500rpm saving on gas, and you can peg the engine at a consistent 5,000rpm+ when you need to move.

Definitely low road noise compared to other Chryslers and even other, smaller SUV/economy cross-overs. Engine purs at only sub-700rpm idle. Just feels good, "big enough without being
too big," enough that my wife (who dislikes standard-size cars and bigger minivans) loves it too.

My only complaint is that the CVT seems to lose any advantage after 55mph, and 65mph will peg the engine at 2750rpm, 70mph at 2900rpm, due to no higher gear ratio possible. I'm not a mechanical engineer (an electrical engineer actually), but either I'm not understanding something about gear ratios and torque at those speeds or Chrysler-Jeep still designs for only 55mph and no faster.

I paid the extra $2K for the 4x4 Off-Road model, with the upgraded CVT2 "Freedom Drive II," 19:1 gear ratio "low" gear, skid and other undercarrage improvements, and heavy duty electronics/components. Haven't extensively tested the 4x4 Off-Road mode but it's quick to put into L and 4WD and get a 19:1 gear ratio that keeps you from spinning in mud as well as not tearing up grass when it's wet. It's not the Jeep Wrangler's 38:1, but it can take almost as deep of water (19" v. 20"), is "Trail Rated" and Rubicon tested and you definitely won't have issues with road hazards in this model.

Definitely a great vehicle for city driving, including well over 20mpg in a SUV/4x4 Off-road -- Unheard of! Great turn radius for a SUV, better than some cars! I just wish the CVT/CVT2 had better, higher gear ratios so the engine isn't going past 2000rpm above 55mph. That 172hp is definitely able to at least cruise or give a little pick-up at 65-70mph with a better, more efficient gear ratio and should have offered it.

Several people have mentioned there is a "blind spot" near the left (driver) back -- well, it's worse on the Calibre/Compass versions! And I've run into the same with most newer cars as well. The nice thing about the Patriot are the huge side mirrors, at least on my 4x4 Off-Road -- Wow! Can definitely see everything on the sides, removing my worries about a "blind spot."

Comfort & convenience

It's a smaller SUV, but it definitely gives you space! Like one other reviewer, I have driven a PT/Crusier (which has a bigger, rather pathetic for a smaller vehicle, turn radius than the Patriot if you can believe that!), and while the PT's chassis makes it very low-loading for slightly more height (one of the reasons I prefer the PT over the Pontiac Vibe/Toyota Matrix, let alone the engine size difference), the Patriot has far more depth and volume -- especially if you don't remove the seats in the PT, which take up a lot of room. I'll take the convenience of "flat folding" any day over having to remove the seats when I get more capacity at the expensive of a little height. In fact, speaking on cargo capacity, I was going to buy a Honda CR-V a few years ago, but Honda has utterly destroyed that capacity in newer models, while offering absolutely nothing (not MPG or anything else, let alone no 4x4/Off-Road option) over the cheaper Patriot.

My 6'4" brother-in-law (who is a mechanical engineer with GM no less) would probably like riding in this more than GM's Equinox -- definitely more headroom over the same frame in the Compass/Calibre body. Not only do the back seats fold flat, but the front passenger seat folds flat as well, giving the ability to carry 4x2s internally, or just a lot of boxes.

I happen to like Chrysler's console overall, and the new Patriot and other designs clearly design a fold-out to hold an Apple iPod/Mini in the center console. The Compass/Calibre has a top compartment above the Glove compartment, the Patriot just has a smaller, "open" storage area -- probably due to the lack of as much depth before the windshield in comparison. But that's also the same reason you get another 2' (AFAICT) in the storage area (as well as the increased height).

The only negative on the Patriot is the towing capacity, a measly 1,000lbs. I think the 4x4 Off-Road version may increase that, but it's still well under most other SUVs, even small ones, that sport a 6+ cylinder. Case-in-point: If you want to tow 2,000lbs.+, you need a 6-cylinder, the Patriot is not going to satisfy, so you need to look elsewhere.

Comments

I skipped on the "Limited" and some $1,200-1,500 electronics extras, buying the Sport "E" package (up from the "D") which kept the price just above $22,000 for the 4x4 Off-road version, with the upgraded stereo system and a few, other extras (you could get the 4x4 Off-Road CVT2 "Freedom Drive II" for $20K if you skip the "E" package and these extras). If you want all the electronic extras, don't bother with the Sport as you'll hit or pass $25K and you'd be better off just getting the "Limited" package for a little more. At $22K for a solid, entry-level 4x4 Off-Road in the Sport "E" package, the Jeep Patriot is an outstanding buy. I just hope the resale holds well like other Jeeps, at least for an American car, if I ever decide to sell it (although I'm not planning to before it's death comes).

My package came with Sirrus Satellite radio, although not the upgraded 6-disc MP3 player, which I did want, but couldn't find within 150 miles without hitting a $25K configuration. The power the standard Chrysler radio (which has AUX IN as a standard -- thank you Chrysler!) can deliver the 458W, nine (9) speaker Boston Acoustics is definitely adequate, although I'll probably upgrade the radio at some point in the future. My biggest complaint about the radio is that it doesn't display anything about the Satellite but the channel -- no artist/title/etc... info like just about every other satellite receiver sold period. Don't know if the 6-disc MP3 version does, but Chrysler-Jeep shouldn't be selling satellite without upgrading that detail in its radios -- which look like they are from the '70s with that bright green, almost "calculator LED." Although I do want to point out the 2-speakers on the gate in the 9-speaker system is a nice touch, and great for tailgating at my Alma Mater's home and away games (Go UCF! Go Knights! -- now if they would only offer the Patriot in Gold! ;).

I owned a 1996 Mazda B-series (Ford Ranger, even Ford VIN) for 11 years, 165K miles -- no unscheduled maintenance (until that 165K), never even replaced the clutch (and I'm hard on clutches). I'm hoping this 2007 Patriot gets me at least 8 years, 120K miles, if not close to the same. I bought the extended 5-year/70,000 mile warranty. I'm hoping the Off-Road upgrades and the CVT2/Freedom Drive II are heavier duty than typical Chrysler transmissions (the CVT2 is still made in Mexico), and that's the only major item that I'm afraid won't last until at least 120k. We'll see, these CVTs -- at least the CVT2 -- are supposed to be as good as a manual in lifespan. By then I will be in my mid-40s, hopefully making even more money, and will probably revert (even if temporarily) back to being a child with a mid-life crisis that forces an impulse buy into a Chevy Corvette convertible (I hope I'm still practical when I reach that age, we'll see).

Rechargeable Li-Ion is not Non-Rechargeable Lithium (e.g., Li-Mn, Li-Fe)

Additives 2007 July

Preface: I was very forward after writing this article and solicited input from any EEs that may be on various forums. I am an EE with computer option, a dozen years removed from school and far too focused on microelectronics in my career. I am not a power expert nor have I designed filters, regulators, etc..., but I do know what over-volting does to microelectronics as well as what happens to microelectronics when you throw voltage outside of that supported by the regulator feeding it. Thanx to JensR (a German Mechanical Engineer), SteveB (a British Electrical Engineer), CurtisR (an American) at the forums at DPReview and Wayne at PentaxForums (post 2) (an engineer with 20 years in the power conversion controller/power supply industry) for helping me address many details in this entry, and I will continue to do so as others provide such information.

After recently acquiring a Pentax K100D, I have run into no shortage of individuals tell me that it's safe to use Lithium Ion (Li-Ion) Rechargeable CR-V3 (RCR-V3) as replacements for Lithium Manganese (Li-Mn) [non-rechargeable] CR-V3 batteries, despite Pentax's (among other vendors') stern warnings on not doing so. It's not that rechargeable Li-Ion (or Lithium-Polymer, Li-Poly) is a poor choice for a battery in general, quite the opposite, Lithium is lighter and better in many ways than the heavier metal rechargeabales approved for use in the K100D. But it is the fact that the chemistry and nominal voltage in RCR-V3s are completely different than what Pentax designed the K100D for. Many of these proponents speak of the improved motor and auto-focus performance, and while I agree that not only will you will see better auto-focus, I'll even agree you won't damage your motors or auto-focus either. That has nothing to do with my concern, but the nominal, operational voltage provided.

If you have a Pentax K100D, there are some sound, quality approaches to getting solid performance with simple NiMH battery rotation and Li-Fe as a backup. This approach will not damage your K100D's sensitive, internal voltage regulators and microelectronics -- which do not handle over-voltage like motors, TTL and other, 5V+ electronics do. If it doesn't work for you, then you may have a rare, but possibly defective K100D with a voltage regulator that has a cut-out voltage set too high.

Overview ...

• Of Voltage, Current, Current-Time (Charge) and Various Effects on Life
• Commodity, AA Line-up: Alkaline, NiCd, NiMH and Li-Fe
• Non-AA, Commodity Lithium: Li-Mn and Li-Ion
  
• A Tale Of Two Impedances: Of Motors and Microelectronics
  
• Best Practices for the Pentax K100D

Of Voltage, Current, Current-Time (Charge) and Various Effects on Life

Voltage is not what drives electronics. Voltage is merely the electric potential. And while there must be enough electric potential to cause motors to spin or transistor gates to change state -- overcoming the electrical impedance ala the resistance -- it is the electric current that provides the actual work and resulting power. Hence the common saying, "it's not the volts that kill you, but the amps (current)." The electric potential multiplied by the electric current working is the power utilized.

The Voltage of chemistry

Different cell chemistry types provide a range, although sometimes fixed, nominal operating voltage. Battery cells are used in series, a series circuit (one behind another, positive to negative, positive to negative, etc...), in order to provide a higher, nominal voltage. There must be enough electric potential to overcome the impedance to current flow. When a voltage is insufficient, the motor will not spin, the gate will not fire.

SIDE NOTE: Do not confuse "nominal operating voltage" with "open voltage." There are charging and select other advantages to a device which has a higher "open voltage" than its "nominal operating voltage" with load. For all intents and purposes in nominal usage, ignore "open voltage" or only compare "nominal operating voltage" to "nominal operating voltage" (and not "nominal operating voltage" to "open voltage" -- apples to oranges). The rare case of concern is when a chemistry can be charged to the point that it will provide the full, open voltage under a load.

The Amps of chemistry

Like voltage, some chemistries are able to provide varying limits of current, rated in Amps (A). Some batteries provide more real-time current than others, and will last longer (or will even be useful or not useful) at higher real-time currents than others. If a battery is unable to provide sufficient current at its voltage, total power drops, which brings down voltage as the current continues to try to flow through the device. There is a point where the voltage will drop enough that no current will flow at all. In a battery, there is a threshold where the real-time current provided will be insufficient due to the charge left (or even beginning if the battery is insufficient for the application), even though the battery will work in another device that draws less current.

In a series of batteries, the current remains the same, but power is increased as voltage is increased. And again, this has many advantages such as allowing chemicals with lower voltages, in common, easy-to-port sizes, to provide sufficient power to a device. Unfortunately, the great disadvantage is that when one battery is unable to provide sufficient current, voltage drops, so the entire voltage of the circuit drops, possibly rendering the battery pack useless.

Batteries can be put in parallel, including parallel banks of series circuits, in a battery pack. The advantage of this is that current can be multiplied. The disadvantage is that you quickly start needing more batteries and take up more space. Hence you will rarely see a portable device purposely designed with parallel battery circuits, just enough batteries delivering enough voltage to push the device, as batteries can always be replaced. Nearly all exceptions to this rule are added and external battery pack "options" which are purposely and are knowingly large and inconvenient (hence the "option," not the "standard" in the device).

Current-time is in-charge

The amount of overall "charge" in a battery is current-time, rated in Amps per hour (Ah). Milliamps are the metric prefix of 1/1,000 of Amps, and commonly used -- e.g., 1A = 1000mA. So it is not common to see a battery's charge rating in mAh, such as 2500mAh. Which is less commonly understood is how that number translates into something useful.

While you can measure current, there is no way to "measure" current-time other than full depletion of the battery. Likewise, in rechargeables, a "good charge" cannot be measured other than the full depletion and recharge of the battery. A simplistic "measure" of the "charge left" is often attempted by looking at the voltage output under load of a device. Hence the simple "full-half-none" battery indictor ...

• Full = "I'm getting sufficient voltage and current"
• Half = "I'm not getting sufficient current, so voltage has dropped"
• None = "Voltage has dropped below minimum, so current is no longer flowing or effective"
  

The effects of memory and life

On the caveat of rechargeables, understand there are issues. Rechargeable alkalines tend to be good at holding their charge and don't have what's known as a "memory effect." The "memory effect" is when a rechargeable battery is not fully discharged, typically far from fully discharged, and tends to think the point where it is recharged is its new "empty" point (yes, that's over-simplified). The "fix" for "memory effect" is a "deep cycle" -- many full discharge and charge cycles, very time consuming.

Another issue to all batteries is "shelf-life" -- of both charge and lifetime of rechargeable. Some batteries last a long time and lose no charge. Others, select rechargeables, lose their charge within weeks ("leaky"). Some batteries last varying amounts of time based on the voltage contained during storage. I.e., some rechargeables will have their cells damaged faster when they are stored with a full charge.

I call this part of my batteries' life "being stupid" ...

They say you shouldn't mix battery types. Why is that? Well, potential in a series circuit changes, possibly drastically. Furthermore, the current also varies, especially under different loads. What does that mean?

Well, you get all sorts of interesting electrical effects, even if the different chemicals themselves never meet (which always provides interesting, pure chemical effects). A battery with higher electrical potential may attempt to increase the electrical potential of the other battery. Different batteries have different results when overcharged. Some heat up and melt, like alkaline or NiMH. And in extremely rare cases, some can catch on-fire (e.g., Lithium).

Another issue that can occur is select transient states and a cause-effect of one type of battery being destroyed. Some of these transients may just cause the circuit to stop functioning. Others may result in not merely a drop in any polarity, but a reversal of it. If you take common alkaline or NiMH batteries and reverse their polarity (put positive to positive), they'll heat up and melt. For lithium, a quick polarity reversal results in fire. It's one of the reasons why the FAA officially states that notebook computers should have their Lithium batteries removed when on airplane power, as most "explosions" (not really "explosions," but they are rather "intensively fed fires") of notebook computers are a result of an unforeseen and unexpected transient and polarity reversal when plugged in.

Commodity AA Line-up: Alkaline, NiCd, NiMH and Li-Fe

The AA battery is a cell type of a nominal voltage output of 1.2-1.5V.

The alkaline battery typically provides a nominal voltage of 1.5V or even 1.6V in some cases, including alkaline rechargeables. Rechargeable batteries, such as Nickel-Cadmium (NiCd) and Nickel-Metal-Hydride (NiMH) provide a nominal voltage output of 1.2V or 1.3V in some cases. Newer AA batteries use Lithium, although the only AA "voltage compatible" Lithium technology is Everyready's (Energizer's) non-rechargeable Lithium Iron (Li-Fe) that provides a 1.2-1.5V nominal (a few other Li-Fe technologies, some even rechargeable, provide 1.4-1.6V and are not "voltage compatible").

Real-time current affects current time, memory effects current time

While some alkalines claim a capacity of 1,000mAh (1Ah) or even double that, that rating is based on a minimal 100mA (0.1A) draw. When increased to 500mA (0.5A) or higher, the total current-time charge deliverable can drop immensely, sometimes to 1/2 or 1/3rd actual time. At some point, such as a 1A or higher draw, even fully unused and fully charged Alkaline batteries will fail to provide a minimum 1.2V. Rechargeable NiCd can provide its full current-time charge in up to 5,000mA (5A) of real-time current. Rechargeable NiMH quality varies, with some only providing its full current-time at 1A, others at up to 2.8V+. Non-rechargable Li-Fe of 1.2-1.5V nominal voltage seems to be able to provide a solid 3A+ and deliver its full range of current-time.

SIDE NOTE: Energizer has some most excellent specification sheets with graphs of current-time (charge) against real-time current application for its current NH15-2500 Rechargeable (NiMH), E91 Alkaline (Zn-Mn) and L91 Lithium (Li-Fe) batteries.

NiCd has horrendous issues with memory effect, and you should never charge a NiCd cell that hasn't been fully depleted, although the "shelf-life" is not good, but not bad. Always use a recharger that can fully discharge NiCd cells. NiMH still has "memory effect" issue, but it's far removed from NiCd in that regard, and the regular quick charge (without discharge) can be done. Of course, NiMH cells are "very leaky," and can lose their charge in weeks.

The best of the best isn't always best because there is no best

What battery is best? On low-current draws, say 100mA (0.1A), the nominal voltage of 1.5V Alkaline, including rechargeable Alkaline (which don't have many "memory effect" issues, fair shelf-life), gives the best performance. On higher current draws, typically 1A, any NiMH will give you at least a solid 1.2V throughout its full current-time where most Alkalines will drop below 1.2V immediately. Between 100mA and 1A (1,000mA), it's a toss up. Beyond 1A is where you either need rechargeable NiCd (high "memory effect") or newer, higher-current NiMH (less "memory effect", although very leaky), or you may want to possibly look at the new, non-rechargeable Li-Fe (very long shelf life) which provide a solid 1.5V throughout their life.

Quick summary ...

• AA batteries are 1.2-1.5V nominal operating voltage, no more
• Alkaline (rechargeable/non-rechargeable) is 1.5V nominal, have good lifespan, but is for sub-1A applications, current-charge is 1000mAh and drops with high current
  
• NiCd (rechargeable) is 1.2V nominal, tolerable lifespan, great for multi-amp applications to provide current-charge of 2000mAh+
  
• NiMH (rechargeable) is 1.2V nominal, poor lifespan (leaky), great for 1A or even 2-3A (newer types) applications to provide a current-charge of 2000mAh+
• Li-Fe (non-rechargeable) is 1.5V nominal, outstanding lifespan (decades) great for 3A+ applications to provide a current-charge of 1500mAh+ (typically 2x "effective" of NiMH at 2A+ applications)
  

Non-AA, Commodity Lithium: Li-Mn and Li-Ion

There are literally dozens of Lithium battery chemistries, with more are being discovered monthly. We already exposed just one implementation of just one chemical type in the AA section. We will cover the two most popular types, one non-rechargeable, and one rechargeable.

Li-Mn: CR-V3 is not double-double-A (2x AA)

The first mistake new owners make of CR-V3 (RCR-V3) batteries is that they believe they are two (2) AA cells. They are one, single Lithium Manganese (Li-Mn) cell of 3.0V nominal output packaged in a form that looks like two (2) AAs side-by-side. Likewise, the package is a purposely rectangle with round ends, and will purposely not fit a typical 2x AA battery compartment that is molded around each, individual AA battery.

"CR" Li-Mn batteries are the most popular type of Lithium on the market. Depending on the type, some are designed for low-current (sub-1A) applications but last much longer than Alkaline. Others are designed for higher current (2-3A) applications and last much longer than most 2x AA applications. The tolerances required for CR-V3 over 2x AA are minimal, since CR-V3 was designed for a nominal 3.0V. Voltage will drop as the non-rechargeable is in use.

Li-Ion: It's what's for your notebook's dinner

Increasingly, the Lithium Ion (Li-Ion) or its more solid and stable, but not quite as long (lifetime-wise) Lithium Polymer (Li-Poly), battery has found a home in all popular, higher current electronics. Li-Ion has a nominal operating voltage of 3.6-3.7, although its output varies more widely. Its open and charge voltage of 4.2V+. Indeed, most Li-Ion batteries have a "90-100% full" indicator for when it's providing at least 4V. I really and truly appreciate a vendor who designs its products with a Li-Ion or, better yet, Li-Poly battery, and no one should demonize a vendor who sells a proprietary Li-Ion battery pack for its products, it's just a sound, solid decision. Pentax did such for its newer K10D, but it did not for the K100D, which shares the CCD and other microelectronics with older models that used 4xAA or 2xCR-V3 batteries.

Unlike other, heavier metal rechargeable battery cells, there is a voltage "point of death" for Li-Ion (Li-Poly). This is below 3.0V, typically and always by 2.7-2.8V you can assume nothing in the cell will be usable. Many common Li-Ion battery packs (of 7.2/7.4-14.4/14.8V+ variety) contain cell protection logic to ensure Li-Ions do not reach this point, among other regulatory attributes. As such, Li-Ion batteries will typically "shut off" to protect themselves when voltage drops below 3.3V, especially since the regulator logic itself needs power to maintain the state over time. In fact, this is another area where common Li-Ion batteries have a "less than 25%," where it's moving into its "do not store me at this charge or I might not come back alive" aspect. Recommended storage is at 40% -- enough to maintain a long store, but not too much to degrade the cells. Storage at greater charges is not recommended because Li-Ion degrades faster with a greater, stored charge.

SIDE NOTE: Minimum voltage and the degradation of the cells over a full cycle is why you never deep-cycle Li-Ion. As long as you're using your Li-Ion battery, unlike NiCd/NiMH, it not only okay but actually good to "top off" regularly (the less full cycle, the better). When you're not going to use it for awhile, let it drain down to under half life.

Li-Ion RCR-V3: The largely "non-option" CR-V3 option

A new crop of "Rechargeable" CR-V3 (RCR-V3) batteries have started to hit many shelves. These are all Lithium Ion (Li-Ion) based. Although any Lithium battery is, chemically speaking, a "Lithium Ion," the term is used to cover the broad, non-standard variations of rechargeable Li-Ion batteries on the market. Unlike most other, non-Lithium chemistry rechargeables, there is absolutely no standard to Li-Ion, much less in the RCR-V3 space. That includes RCR-V3, you can often not use one vendor's charger with another -- especially since RCR-V3 itself is really a non-standard from the chemically different Li-Mn CR-V3, and different vendors try to use different terminals, voltages, regulators, etc... in ways that do not work with one another.

Some vendors are honest, and label them the true, nominal voltage of Li-Ion 3.6 or 3.7V. Others are not honest, and label them 3.0V to match Li-Mn. Some vendors market their RCR-V3 batteries as "regulated," which can mean many things. For some, that means they will not drop below the "point'o death" and "cut out" before then. For others, it means they will not charge to the "last 90-100%" and have a potential of 4V+ for a period.

Probably the most telling of RCR-V3 is how no vendor uses or supports them in their devices, and they create their own "battery packs" of 7.2/7.4V, 10.8/11.1V and 14.4/14.8V instead of using two (2), three (3) or four (4) RCR-V3s, respectively. That's not because they want to sell you a costly, proprietary battery. That's because they want to regulate the entire series of Li-Ion cells. The variance in multiple Li-Ion cells can be better regulated as a single unit than separate Li-Ion devices with their own, independent regulation -- as multiple units can quickly and exponentially result in greater variance than a single pack regulated as one.

There are a few "under-charged" RCR-V3 products on the market that keep the voltage purposely to 3.5V or less. But what does this mean? Instead of starting at over 4V or even achieving the nominal 3.6-3.7V for Li-Ion's physical properties, it's already "drained" (i.e., the Li-Ion capacity is not charge to anywhere near capability) to the point where it's providing only 3.5V maximum. So it doesn't even last as long as much cheaper NiMH! I have confirmed this with several K100D users now, and you'll note several that post on boards.

Side Note: To be fair, there are several individuals who have been using select Li-Ion RCR-V3 batteries in the K100D and earlier Pentax dSLRs that take CR-V3. These RCR-V3 designs typically use a 3rd connector for charging, away from the regulated output. MobyPower RCR-V3 and Delkin RCR-V3 are two vendors' products to consider, as they regulate their nominal power under 3.5V and possibly as low as 3.2V. So if you are absolutely determined to use Li-Ion RCR-V3 products in the K100D or earlier devices, please consider these vendors first, or anyone else who has a known track record of actually providing reduced output (and not merely their marketing). Unfortunately, several people have also reported MobyPower and Delkin units producing more than 3.5V with load, and over 4V with open voltage -- so test each and every unit several times! As such, if you're not willing to test (and even if you do), I cannot condone using RCR-V3 batteries with the K100D, as not only does Pentax not support it (and you will possibly void your warranty, as at least one person has documented), but I've seen what happens to microelectronics when you input voltage outside the range of its regulator -- especially the "hidden" effects to the logic (especially over time).

Summary ...

• Non-rechargeable Li-Mn has a nominal operating voltage of 3.0V
  
• Rechargeable Li-Ion/Li-Poly has a nominal operating voltage of 3.6-3.7V
• It is not uncommon for Li-Ion/Li-Poly to discharge over 4V after a full charge (the "90-100%" charge)
  
• Li-Ion requires regulation to avoid dropping near 3V and destruction of the cell
• Li-Ion batteries never operate at 3V or below and cannot replace 2x AA, nominal operating at least 20% higher (and can be 40% higher)
• Li-Ion batteries that provide less than their nominal 3.6-3.7V do not last long, and are still well over 3V
  

Being stupid ... revisited ... taunting super-happy fun battery ...

Some individuals have stated they mix 2x AA NiMH batteries with 1x RCR-V3 battery in a 4x AA product to "average out" voltage to 6V. Let's see here, 2.4V nominal on the one side, 3.6V nominal on the other side. In the "common case" scenario, delivering a 1.8V effective potential, the NiMHs heat up and melt over time. In the "worse case" scenario, let's say the NiMHs melt, whether they are conducting (a fully charged, thanks to the potential difference) or now delivering near absolute 0 current, and some sort of transient occurs. Li-Ion is bad enough on the table or even your lap when it catches on fire, consider what it might do if it's an even smaller device that you put up to your eye?

Sorry, I'm not stupid enough to save a few bucks and charge frustrations to tempt "super happy fun battery" up against my eye.

A Tale Of Two Impedances: Of Motors and Microelectronics

Unless an electrical device is completely solid state, there are typically two common types of impedances which require a minimum electric potential to overcome and will constantly take electrical current. One are motors, the other is microelectronics.

Steppenpot[ential]: Get your motor running ...

Most small motors require a nominal voltage of 5V or 12V today.

Motors are tough beasts with high gage (thick) wires and various, large relays and other circuit components. They can often take voltages far in excess of their design, and some will even run better so "over-volted." It is not uncommon for most 5V motors to run better without issue at 6V, and be tolerable up to 9V. After all, with increased potential with the same amount of electrical current more power and work can be done.

The speed of light is just too slow for CMOS

Most microelectronics are now CMOS (complementary metal-oxide semiconductor), and require nominal voltages of 3.3V to as low as 0.8V (just above the diode gate of 0.7V, long story).

Microelectronics aren't so tolerant of over-volting. Well beyond the vacuum tube, logic left the printed circuit board (PCB) long ago and today's CMOS transistor logic uses lithography to create multiple layers of silicon wafers with up to and beyond a billion transistor gates in the size and thickness of a fingernail now. As such, as CMOS has become exponentially smaller and smaller over time, with the traces are far smaller than a human hair -- closing in on merely a dozen atoms wide -- there is little left for tolerance.

Because they are so close, the constraints of voltage, timing and other details are exacting in microelectronics. The speed of light is too slow -- actually over 100x to slow -- to travel from one edge of your fingernail to the other in a single clock cycle. And because the traces are so close together, the smallest increase in electric potential can cause "transconductance," whereby the current "jumps tracks" inside a semiconductor. Over time, this transconductance can fuse traces, reducing precision of logic, causing glitches, hangs and, eventually, death.

Regulation to the rescue!

Since a lot of people are self-educated PC Tech's these days, if you've seen a computer hard drive, you've noticed it takes multiple lines of voltage -- e.g., +5V and +12V wires (plus ground) in the typical 4-pin Molex, or even +3.3V, +5V and +12V wires in the newer, 15-pin SATA/SAS standards. So, how do we deal with a device that is being delivering only one voltage? We regulate! Now without dipping into the countless of factors and options of regulation, just know a lot of it comes down to cost and, even more so in portable devices, size.

A common and size efficient approach to voltage regulation in portables is to deliver the electrical potential required to move the motors, and then divide or otherwise transform the voltage to run the microelectronics. While diodes, light emitting diodes (LEDs), simple ASIC (application specific integrated circuits) and other devices can run on as low as 1.2-1.5V (single AA), and other solid state devices with fairly complex microcontrollers run on 2.4-3.0V (2x AA) or more simple, 5V tolerant 3.3V CMOS integrated circuits (IC) go for 3.6-5V (3x AA), motors typically need at least 5V, so 4.8-6V (4x AA) is common place.

Dividing is tolerable with more simplistic microelectronics. But that still leaves a lot of variance. With today's complex CMOS and Charge Coupled Devices (CCDs), the difference of a single tenth of a volt can mean operation or increase transconductance. Most regulators are designed to provide an exact voltage, or minimize variation, based on input voltage. That costs in size. But in all cases of regulation, there is a range limit outside where regulation does not work, causes damage or otherwise abnormal operation, or just passes those variations beyond its limits on to the devices it regulates potential for.

And if the voltage regulator itself goes, well, it's just as bad. Same goes for the capacitors and other support electronics.

Over-volting is common, massive over-volting is not ...

Going back to PC Tech analogies, take a CPU designed for 1.2V as an example. You can probably get away with varying voltage to 1.5V or even 1.6V. But start to throw 1.8V or greater at it and you'll get noticeable and immediate transconductance (unlike heat, which takes time to "build up") and hangs, crashes or even a failure to start. Throw over 2.0V or 2.1V, and it's likely the transconductance will turn the CMOS layer's lithography into its own, imperfect matrix of new traces in a nanosecond -- permanent, done, buy another.

Now consider a 4.8-6V circuit divided into 1.2-1.5V, typical 4x AA, or even 2x CR-V3 (Li-Mn). You'll probably be fine with slight variances in your AA like 1.6V that even push it up to 6.4V total. Now consider using 2x RCR-V3 (Li-Ion), which is chemically impossible of delivering anything less than 6V, and has a nominal operation of 7.2V! That's 1.8V. And if you take it off the charger, and it's not clamped, it could be as over 8V high as 8.4V total, a whopping 2.1V divided!

Now these are simple examples using a simple divider, and a very complex (and larger and costly, especially if and as size is maintained as small as possible) regulator could possibly handle such within its nominal input. Of course, look at the regulators that are typical in a PC mainboard and you'll quickly realize that there's a lot of space to just support a device that uses 30-60W. Size that down to 10W and maybe just 2W actually being delivered to the microelectronics, it's still sizable and, even more so, cost to size.

When the vendor says it does not support a battery type, there's a reason, voltage and variance. It's not operational profit (maybe the reduced manufacturing cost for the regulator choice, but not support/operational/consumable sales). It's not to sell you more batteries when they support standard, generic 4x AA. It's to keep you from damaging your electronics or, worse yet, being stupid.

Best Practices for the Pentax K100D

Okay, with all that said, and assuming I've convinced you RCR-V3s aren't worth the bother, what should you use? It really all depends on what you're willing to deal with, both fuss and monetary-wise.

By battery (chemical) type ...

• Non-rechargeable 2xCR-V3 (Li-Mn): Ideal. Maximum 6.0V delivery, minimal lithium variance (2 units). Sold at all battery shops, some other stores, for $20/set (2). Keep one (1) set of two (2) CR-V3 as your "backup." The charge will not "drain" after use, just as you actually use them.
• Non-rechargeable 4xAA (Li-Fe): Eveready L91 (Energizer e2 Lithium) -- the ultimate backup. Maximum 6.0V delivery, tolerable lithium variance (4 units). Sold at virtually all stores for $10/set, buy them if and when you're dead-in-the-water. Keep one (1) set of four (4) as your "backup" in lieu of CR-V3.
• Rechargeable 4xAA (NiCd): You don't need it, the fuss, the pain. The K100D pulls up to 2A, not 4-5A. At higher voltage applications (e.g., 14.4V notebook batteries), has utterly been replaced by Li-Ion for a reason.
  
• Rechargeable 4xAA (NiMH): Get quality NiMH batteries designed for 2A+, not merely 1A (which will be "half" battery fully charged). Will run $10/set. Get at least four (4) sets (if not five, see below) and rotate (again, see below). Get yourself a charger than can fully charge and discharge. You can use a quick charger "on-the-road."
  

The bother of minimizing costs with NiMH ...

With that all said, if you want to minimize costs, you want to stick with rechargeables. And here, there is only NiMH, which has another "cost" -- your time and focus.

First off, it's not just any NiMH, quality NiMH batteries designed for 2A+ discharge. The overwhelming majority of "cheap" NiMH 2000-2600mAh batteries are rated at 1A, and won't deliver sufficient current in a device that closes in on 2A like the K100D. They will show up as "half full." The Sanyo Enelope 2000mAh and Energizer Rechargeable 2500mAh batteries can deliver the current the K100D needs. I have personally found the All-Battery.COM (Tenergy) NiMH 2600mAh not only incapable of such, but they don't even charge to 2600mAh (more like 2000-2100mAh).

Secondly, you must consider rotation. Keep two (2) to three (3) sets of NiMH batteries charged every few weeks and in your camera and bag -- which should give you 750-1,500 shots (flash to no flash). I keep one (1) set in the camera if I plan on using it in a few days, and two (2) sets ready-to-go. It's good to have at least four (4) sets so you're always charging one set. Charge one (1) set every week, so none of the three (3) sets between your bag and camera is older than three (3) weeks. It's also important to have "spares" if one (1) doesn't fully discharge and has to go through another cycle -- this will happen in one (1) out of ten (10) on average. That's a reason to actually have five (5) sets, one to cannibalize into the other four. It's also another reason to get a charger with a LCD or at least an indicator that a NiMH failed to fully discharge then recharge adequately.

Third, while you can use a "quick charger" on the road, you need to do full discharge/charge cycles. On-the-cheap, I have a $40 LaCrosse 900 series, but there are better for $100+, and non-display units for $20 or less (but still do a full discharge, possibly have a LED for a failed/incomplete cycle). It has LCD display to show you the exact discharge/charge. There is no reason why a NiMH battery should not have a full, 2500mAh (or whatever rating) at the end of the cycle -- unless it has some memory and failed to completely discharge. The kicker on the LaCrosse 900 series is that it has a default (you should change it) slow discharge/charge mode of 100/200mA (although it does give you better charges and longer battery life, it's not worth the issue). At such a low setting with today's 2500mAh+ batteries, it can fail to detect the DeltaV that the NiMH is fully charged and over-charge, melting the battery. Stick with 250/500mAh or higher and you'll never, ever see this -- or just get a better charger.

1. Get quality, 2A capable NiMH
2. Use a weekly rotation between four (4) NiMH sets, one (1) in camera, two (2) in bag
3. Get a full discharge/charge battery charger

Remember your backup ... carry 2x CR-V3 or 4xAA L91

You're going to forget at least once to do your NiMH battery rotation. And it'll be at a moment where you can't rush to the store. That's where having at least one (1) set of 2x CR-V3 or 4xAA L91 will save you. You can use and remove these sets as much as you want. They will keep their charge regardless of how often or infrequent you use them with your K100D, delivering the same, resulting total net current-charge. If and when you feel you've used them enough -- say 350-700 shots (flash to no flash), then make sure you have another set because you're only 50-100 shots away from replacing them.

When not to even bother with NiMH?

Of course, if you're finding that the catering to and nursing of NiMH sets is too much to deal with, you can always just buy CR-V3 or AA L91 batteries instead of dealing with NiMH. If time is your money, it's not a bad avenue -- especially if you use your Pentax K100D very infrequently, and you're spending more time managing your charge rotation than actually using the camera! ;) NOTE: I recently noted that Sams' Club carries the 12 pack (3x4AA sets) of the Energizer L91 for $19, making it just over $6/set to get a solid 500+ shots (possibly 1,000 without flash). Just a consideration.

Lastly, if a solid NiMH charge and rotation doesn't work for you, then you might have a rare, but possibly defective Pentax K100D. Some Pentax K100Ds seem to have a voltage cut-off that is way too high. It should not be 5V or higher, it should be around 4.5-4.7V, and otherwise would indicate a defective voltage regulator (or possibly one abused by high Li-Ion voltages -- another reason not to use RCR-V3!). If non-recharageable Li-Fe batteries, like the Energizer e2 Photo work, but every set of Energizer Rechargeable NiMH2500 or Sanyo Enelope (after ensuring they are fully charged) do not give you a full charge indicator on the LCD, you should bring this to the attention of Pentax.