K100D battery pack

[dale_morton]

Hi folks, first time poster here. I've enjoyed reading all the interesting

comments & advice in this forum & wonder if anyone out there in Pentax-land has

the same thoughts as me: Has anyone built a battery pack (or acquired one) for

the K100D? I like to shoot nature shots & never seem to have enough batteries

with me to last.

[alan_chan4]

What batteries you have used? A pack of fully charged Sanyo Eneloop AA should last about 500 shots.

[matthew miller]

Alternately, a set of non-rechargeable CRV3s should last for 2000+ shots. That's a lot of nature.

[thebs]

<p>Over on another forum, there was a post of a forthcoming, after-market, 12xAA battery back for the K100D. It sits under the unit and should give you 3x the normal duration (obviously). It does <b>not</b>, however, use Lithium Ion (Li-Ion) or Lithium Polymer (Li-Poly) at all (<b>never use Rechargable CR-V3, RCR-V3</b>), as the K100D wasn't designed for the voltage differences of Li-Ion/Li-Poly cells (which don't operate below 3V, but often 3.6V -- the K100D wants 4.8-6V, not 6-7.2V, and you can blow microelectronics, even if the motors will take the higher voltage). See the end of this prior thread on <a href="http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00L5hX">why you should never use Li-Ion in the K100D</a>.</p>

<p>There is also many other, good suggestions in there, including ...</p>

<ul>

<li>Always carry at least one set of Lithium AA (4) or CR-V3 (2) non-rechargables as your "backup." Unlike NiMH (let alone NiCD), <b>Lithium holds its charges for decades</b>. Lithium also functions at 1.2-1.5V like "standard" AA batteries (unlike rechargable Li-Ion/Li-Poly that doesn't operate below 3V). So you can <b>safely buy 1 set of Lithium AA (4) or CR-V3 (2) and just keep them until you need them, and use them again and again until depleted.</b> I'm personally still running with a Lithium set I've had since I bought my K100D, and I fired off 200, then another 100 weeks later, and I'm still getting a full charge indicator.</li>

<li>Always use select, proven NiMH rechargable AA battery models. The Pentax K100D <b>pulls a lot of current</b> and once your batteries hit sub-1000mAh (in a good set), expect to see no charge in the LCD (even though they will work in other devices without issues). There is <b>no way</b> to "test" for total current-time ("charge") on a battery <b>except</b> with a full discharge-charge. You can only tell the "current" (mA) delivered in real-time, not over entire time (again, current-time like mA-hour, mAh), at any point in time. <b>A single, NiMH AA battery</b> delivering insufficient current <b>brings down the entire voltage</b> in the series circuit (delivering the 4.8-6V required by the K100D).</li>

<ul>

<li>Sanyo Eneloop 2000mAh are well regarded by many here. I've had excellent results with even Energizer NiMH 2500mAh. I see 2700mAh fully discharged-charged with any Energizer NiMH 2500mAh I've purchased this year -- getting between 200-400+, depending on my flash usage (always 300+ without flash).</li>

<li>Avoid a number of products out there, including generic 2600-2700mAh Tenergy (All-battery.COM) and similar "budget" batteries. I'm consistently at "half" when I put these batteries in, fully charged, although they only give me 2000-2100mAh. They clearly aren't delivering enough current, even when fully charged, and that clearly affects the AF motor from the get-go.</li>

</ul>

<li>Always do a full discharge-recharge of NiMH batteries. If your recharger doesn't offer that, get one. Even a few of the newer NiCD/NiMH "quick-chargers" seem to do this as standard now. While not nearly as bad NiCD batteries were with "memory" issues, they still have them (unlike Li-Ion/Li-Poly, which doesn't have memory issues).</li>

<li>Don't let your NiMH rechargables sit more than a month (if not 2 weeks) without either using them or doing the discharge-recharge cycle again. NiMH "loses" charge (generics are far worse than the good ones). Get in the habit of doing a full discharge-charge on at least two (2) sets (eight, 8, NiMH AA batteries) before going on a trip. Carry a quick-charger if you want to go longer, although sometimes it's just better to buy an extra Lithium set "to be sure."</li>

</ul>

[josphy]

Bryan -- do you have a link to where you saw that 3rd party battery pack referenced?

[thebs]

<p>Nope. It was in Chinese, and someone used a translator on it. I think I might have found it somewhere on the dpreview.com forum, maybe pentaxforums.com.</p>

<p>It was clearly for the K100D. It said it's not for use with RCR-V3s, only 12x NiMH AA, 12x Lithium or 6x CR-V3. It was after-market and I don't know how good it would be.</p>

[thebs]

<p>I think I found it: <a href="http://translate.google.com/translate?u=http%3A%2F%2Fownuser.com.tw%2Fn_K100D_1.htm&langpair=zh%7Cen&hl=en&ie=UTF-8&oe=UTF-8&prev=%2Flanguage_tools">DX-FBH hand for long battery Pentax K100D</a></p>

[azemerov]

As backup I use 6V Heavy-Duty Lantern Battery. I keep it in my bag and use 1 meter cable to connect it to my K100D camera. Not the best solution, but it works fine if you carry the bag.

[thebs]

<p>Well, 4.8/6V is the same whether it's a 4xAA, 4xC, 4xD or anything else, including a 6V HD, as long as it can delivery the sufficient current. Unfortunately, anything rechargeable Li-Ion/Li-Poly (not non-rechargeable Lithium) ain't an option, because of the inherent electrical potential (voltage) properties of those materials, for a system designed for 4.8/6V.</p>

[thebs]

<p>Has anyone found an actual, technical reference to how much current (amps) the Pentax K100D pulls? Or at least the total power in Watts or Volt-Amps? I haven't.</p>

<p>The reason why I ask is that I just ran across <a href="http://www.powerstream.com/AA-tests.htm">this page on how many current-hours (amp-hours, Ah) you'll get out of different batteries, based on current (amps, A)</a>. I'm sure there are many others out there as well.</p>

<p>As you can see, the number of amps (A) <b>drastically decreases the usefulness of Alkaline</b> once you start pulling more than 0.5A. Alkalines should be capable of 2Ah if you're only pulling 0.1A, and this chart shows that. But once you pull 0.5A, it drops far closer to 1Ah, and is less than 1Ah for 1-2A in most cases. I.e., you're getting less than half, possibly only one-third, the total charge out of Alkaline batteries when pulling 0.5-2A -- versus 0.1A nominal out of most Alkaline usage.</p>

<p>That's not merely that the battery drains 2, 2.5 or 3x faster. It's actually 2, 2.5 or 3 multiplied by the increase in current. So just increasing the current 5x (0.5A) results in the batteries losing half (1/2) the current-time, so drained in 10x the time. For 10x (1.0A), 40% (1/2.5) of the current-time, so in 25x the time. And for 20x (2.0A), third (1/3) the current-time so drained in 60x the time. For pulling 5A, Alkaline is utterly useless, as to be expected. That's why you can often pull out "dead" Alkaline (or NiMH) batteries from a K100D and get hours upon upons of use from them in other, much lower current devices.</p>

<p>Also of note, he also compared Energizer Lithium to PowerStream NiMH 2000mAH (2Ah) rechargeables. The former gave a solid 2.8Ah (4x most Alkalines, 3x Energizer Titanium Alkaline), whereas the latter was around 2Ah -- although it still was able to deliver 2Ah at 5A as well.</p>

<p>As such, again, I'm curious if the Pentax K100D is pulling well beyond 2A -- and it probably is. It might be even 3 or 4A, bringing the power consumption up to 18-24VA (roughly 18-24W, long story, it's not exactly that). That would really explain why most NiMH batteries are unable to cope, and quality is a huge factor. It also explains why Lithium is solid.</p>

[thebs]

<p>Okay, I don't know what to tell people.</p>

<p>I just fired off <b>over 500 shots</b> -- not including countless auto-focus, re-focus, metering, etc... -- today before replacing one pack. And then a <b>second set</b> was solid <b>for the other 500 shots</b>. In both cases, the battery <b>never read less that totally full</b>, and it gets even better.</p>

<p>When I discharged the first set when I got back, it discharged 1.7Ah. <b>The set had 1.7Ah remaining!</b> that means it used <b>under 1Ah</b> during my firing off 500 shots. No flash, I know, but 500 shots?!?!?! Wow!</p>

<p>Both were Energizer NiMH 2500. But where completely discharged at 250-350mAh and recharged at 500-750mAh in my aforementioned LaCross 900 series. It's not a perfect recharger, but virtually any issues I've ever heard about the unit have been all at 100/200 discharge/recharge. I run well above that to avoid the alleged "DeltaV" changes (or lack thereof).</p>

<p>I never had to dig into my Lithium backup, which seems to be a continuing reality of using the K100D with solid, proven, trusted -- as well as appropriately cycled (full discharge, discharge/recharge every few weeks), etc...</p>

<p>And I said, I don't know what to tell people other than what I already have.</p>

[azemerov]

About energy consumption.

 

I used external Heavy Duty 6 volt lantern battery and digital multimetr. The results are

 

Power Off 4 mA

 

Power On 110-93 mA

 

Power On + Flash 150 down to 93 mA

 

Unfortunately, the last result can be questionable - it looks like my battery is not fresh enough and during flash charging it's voltage goes down from 6.03 V to 5.3 V which affects current. But anyway, current consumption is much lower than 1 A.

 

What is strange for me - camera still consumes 4 mA when it is off - not too much, but anyway I would expect zero mA. May be something is wrong with my camera. I noticed after I install fresh pack of Energizer 2700 NiMH I get half voltage indicator in 2-3 days even if make only 20 pictures (and I don't use flash!).

 

Alexander Zemerov

[thebs]

<p>First off, your voltage drop is due to insufficient current, not the other way around. Remember the old joke, "it's not the volts (electric potential) that you need to worry about, it's the amps (electric current)." You can touch a 10,000V line and not feel much at all, if it's delivering less than 1mA. I stupidly put my hands on a live, high gain filter circuit of only 15V in college, which was delivering over 30A -- doh! 6V ain't 6V if the device is trying to pull more current than it can supply at 6V -- hence why it voltage drops.</p>

<p>Secondly, the microelectronics consume an extremely small amount of electricity when the unit is off. This is for various things, including the RTC (real time clock). 6V*4mA=24mVA~24mW is not unexpected.</p>

<p>Third, as I've said many times on this board, respect NiMH for the PITA it is, if you use it. That means you have to do full discharge and recharge cycles. Doing less will result in partial, incomplete charges. It only takes 1 battery delivering insufficient current in a series circuit to cause a voltage drop across all. If you don't like dealing with NiMH, just use non-rechargeable Lithiums. If you don't like dealing with those, then get a more expensive camera with more expensive regulator logic that supports Li-Ion (or even newer, more stable Li-Poly).</p>

<p>Lastly, there are great number of NiMH AA models out there that supply an insufficient amount of current for the K100D, even when fully charged. E.g., I found the All-Battery Tenergy NiMH 2600mAh AA batteries only reach 2100mAh at a full cycle, and still show half battery in the K100D. That means even when fully charged, those Tenergy AAs don't provide enough current. On the other hand, as I stated above, even when my Energizer NiMH 2500mAh units have only 1700mAh of charge left, they are showing a full battery on the K100D. I find that when my Energizers start getting close to 1000mAh charge left, that's when their ability to provide adequate current for the K100D drops below their usable threshold.</p>

<p>Never seen the Energizer NiMH 2700mAh models. Are they new? Or old? Or budget? US? Non-US? Etc...? Here in the US, I've only seen the 2500mAh for the past couple years. I've only had my K100D for a few months, but they've been solid. I'm desperately trying to find some solid, electrical specifications on the K100D's actual current draw. From that, I should be able to compare it to the engineering specifications from various battery vendors, and notice where they come up short in actual ability to deliver current.</p>

[azemerov]

First of all - I recall my previouse results - my battery was realy incapable to keep current. I will try later with more reliable sorce of power.

 

to Bryan Smith, - "First off, your voltage drop is due to insufficient current, not the other way around."

I don't agree - correct expression would be "voltage drop is due to high current battery can not cupply without lost in voltage".

 

"I stupidly put my hands on a live, high gain filter circuit of only 15V in college, which was delivering over 30A -- doh!" - was 30A actual current value in cicruit or it was value this line was capable to hold? In any case 15v could not hurt you too much, even if line delivered 1000A. Human body has impedance > 1000 ohm (depends on many factors - moister, amount of alcohol in blood and some others) so in any case you could get no more than 15/1000 = 15mA which can be sensitive, but not much. May be in your case you connected line and ground and voltage between line and ground was more than 15V.

[renatoa]

Even more correct is: voltage drop is due to higher internal source resistance.

 

> to Bryan Smith, - "First off, your voltage drop is due to insufficient current,

> not the other way around."

 

> I don't agree - correct expression would be "voltage drop is due to high

> current battery can not cupply without lost in voltage".

 

I agree with the below.

Else, if true that means you can be hurt by any battery car, having 14.4V and able to deliver 250A for short period?

 

> "I stupidly put my hands on a live, high gain filter circuit of only 15V in

> college, which was delivering over 30A -- doh!" - was 30A actual current value

> in cicruit or it was value this line was capable to hold? In any case 15v

> could not hurt you too much, even if line delivered 1000A. Human body has

> impedance > 1000 ohm (depends on many factors - moister, amount of alcohol in

> blood and some others) so in any case you could get no more than 15/1000 = 15mA

> which can be sensitive, but not much. May be in your case you connected line

> and ground and voltage between line and ground was more than 15V.

[thebs]

<p>First off, I was <b>not trying to be precise to an EE-level</b> on current. The original poster stated, <i>"it's voltage goes down from 6.03 V to 5.3 V which affects current."</i> I was merely commenting that it's the current draw that causes the voltage to drop. But yes, that increased current draw is due to the higher, internal source resistance.</p>

<p>BTW, a car battery is capable of stopping your heart! If you bridge it with a conductor, like a wrench, you can also get enough of an arc to burn flesh.</p>

[azemerov]

It is very unlikely your heart can be hurt by car battery - may be it is possible if skin on your body is damaged and wet or you apply voltage dirtectly on open chest :) Rezistance of flesh inside of human body is less then 1 Kohm, but skin saves us - the dry one has very high rezistance, usually more then 10 Kohm. And about arc on shortened battery - it is irrelevant example - burn will be caused by the current running through arc, not the current running through your body.

 

Oops - offtopic...

[azemerov]

First of all I want to apologize to Bryan Smith if my posts were somehow offensive - I didn't mean.<p><p>

Second, I want to share updated results of power consumption test. This time I used fresh charged lead-acid battery. Even with highest current I didn't notice significant voltage drop. Results are -<br>

Power Off - 4 mA<br>

PowerOn, idle - 90mA<br>

PowerOn, focusing, metering <= 200 mA<br>

PowerOn, focusing, metering, flash charging <= 1.8 A.<p>

 

I used mutlimeter with noticeable delay (about 1/4 second) so obviously it couldn't show very short time peaks. But anyway, it looks like K100D maximum consumption is about 2A.

[jaycai]

Interesting usage numbers. Questions I have:

 

1. what is the "delta V" phenomenon?

2. How much power does reviewing pictures on the LCD use? Such as in playback mode.

3. What are separate current draw numbers for focusing versus metering. These are interesting so I can have an idea of how much extra power is used when using AF.C versus AF.S, and changing the metering time from 3,10,30 secs.