Suggestions for K3 III Battery Charger

Spock · 05-24-2022, 10:48 PM

Originally posted by cdw2000

I am an electrical engineer. The third terminal is marked "T" for temperature. The batteries contain an embedded temperature sensor. For rapid charging, the charger uses the temperature data (along with the charging current) to help determine when the battery has reached full charge and to ensure it doesn't overheat during the charge cycle.

What is the 4th pin for as used in some newer batteries and the Pentax K-BC90H charger?

**StigVidar** · 05-25-2022, 01:48 AM

Originally posted by Spock

What is the 4th pin for as used in some newer batteries and the Pentax K-BC90H charger?

+
-
T: A resistor, 10kohm, probably temperature dependant between T and -

the fourth terminal could be the middle connection between the two cells in the battery. But I am only guessing here...... The battery have some internal electronics to make sure the cells are balanced. But they can only handle currents up to a certain level. If you want to quick charge batteries, the charger itself could make sure the cells are balanced and my guess is that the 4th connection is for this purpose.

angerdan · 05-29-2022, 02:12 PM

Originally posted by SpotmaticGuy

Hi, I just took delivery of my K3 III and my first new Pentax in about a decade. I'd like to get an auxiliary battery charger, one that plugs into a wall socket and that can charge a standard battery for the K3. Any suggestions? Thanks!

I like to recommend this charging times comparision table:
New Ricoh Charger - Page 3 - PentaxForums.com

Originally posted by angerdan

Charger	Time	Watt	Current	Voltage	source1
K-BC90	5.3 h	3.4 W	400 mA	8.4 V	ricoh-imaging.co.jp/english/support/man-pdf/k-01.pdf#page=42
AC-U1/2	4.5 h	5.0 W	1000 mA	5 V	ricoh-imaging.co.jp/english/support/man-pdf/k-3-3.pdf#page=42
D-BC177	4.4 h	6.7W	800 mA	8.4 V	ricoh-imaging.eu/eu_en/blog/pentax/high-speed-charger-for-pentax-standard-rechargeable-battery-d-li90/
K-BC177	2.5 h	12.6 W	1500 mA	8.4 V	ricoh-imaging.eu/de_de/battery-charger-d-bc177-1#product-specifications

gatorguy · 05-29-2022, 02:28 PM

Originally posted by angerdan

I like to recommend this charging times comparision table:
New Ricoh Charger - Page 3 - PentaxForums.com

FYI,
Your last link isn't good, going to a German site.

angerdan · 05-29-2022, 02:50 PM

Originally posted by gatorguy

FYI,
Your last link isn't good, going to a German site.

Thx, i replaced it with the backside image of the charger.

Zafar Iqbal · 05-29-2022, 09:29 PM

I've had 6 of these for some years and been happy with them: https://pts-trading.de/en/patona-synchron-usb-charger-f.-pentax-d-li90-d-li90-with-lcd-3187

Biggest downside is the battery plate, which over time can get deformed due to heat. They can be temporarily fixed by unscrewing bottom plate and straightening it - and in worst case, replace them entirely. I've so far straightened some recently, but not replaced any yet.

**madison_wi_gal** · 05-30-2022, 07:18 AM

I got this, works fine for K-3 III (and K-01) batteries

https://www.bhphotovideo.com/c/product/640555-REG/Pentax_39835_K_BC90_Batter...981&

angerdan · 05-30-2022, 10:26 AM

The new USB powered BC77 charger is 4 times faster than the old BC90.

**Just1MoreDave** · 06-02-2022, 03:35 PM

I just got the D-BC177 Travel Charger. I have a couple of the old BC90s so I'm good for plug-in charging and I don't need speed. I have a cheap DLi90 charger with a micro USB cord, Kastar brand, but it only works now if you wiggle the cord just right. Inevitably I'll get it working and it stops when I look away, not good for charging. The D-BC177 Travel Charger has USB-C so it's the wave of the future. What was not clear to me was the required voltage input. It looks like it will still charge connected to a 5V 2A source. I'm sure this is a slow charge, but when actually traveling, I'm likely to plug into an unspecified USB port on a hotel lamp or airport chair or a rental car. I don't want to worry about the twenty different USB connectors and permutations. It seems like the D-BC177 Travel Charger will cover my needs.

SpotmaticGuy · 06-10-2022, 09:28 AM

Originally posted by kkoether

The new D-BC177 can use the usb cable and plug that comes with the K-3 III.

That's useful information. I'll be leaving for a few days on a little photo expedition, and that should give me a better idea of what I'll need. I'm inclined to go with the D-BC177, but I'm unsure about a more powerful battery. The Pentax battery is 1800 mah (doing that from memory) and I've seen some batteries rated at 2300. Might there be a problem with higher-rated batteries? Thanks!

**UncleVanya** · 06-10-2022, 12:19 PM - **1 Like**

Originally posted by SpotmaticGuy

That's useful information. I'll be leaving for a few days on a little photo expedition, and that should give me a better idea of what I'll need. I'm inclined to go with the D-BC177, but I'm unsure about a more powerful battery. The Pentax battery is 1800 mah (doing that from memory) and I've seen some batteries rated at 2300. Might there be a problem with higher-rated batteries? Thanks!

Most third party batteries have inflated mah figures. I’ve never found any that outlast the original. Some are close to equal, none are better.

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05-24-2022, 10:48 PM	#16
Spock Pentaxian Join Date: Aug 2009 Location: Perth, Western Australia Photos: Albums Posts: 674	Originally posted by cdw2000 I am an electrical engineer. The third terminal is marked "T" for temperature. The batteries contain an embedded temperature sensor. For rapid charging, the charger uses the temperature data (along with the charging current) to help determine when the battery has reached full charge and to ensure it doesn't overheat during the charge cycle. What is the 4th pin for as used in some newer batteries and the Pentax K-BC90H charger?

05-25-2022, 01:48 AM	#17
StigVidar Site Supporter Join Date: Nov 2006 Location: Norway Photos: Gallery \| Albums Posts: 705	Originally posted by Spock What is the 4th pin for as used in some newer batteries and the Pentax K-BC90H charger? + - T: A resistor, 10kohm, probably temperature dependant between T and - the fourth terminal could be the middle connection between the two cells in the battery. But I am only guessing here...... The battery have some internal electronics to make sure the cells are balanced. But they can only handle currents up to a certain level. If you want to quick charge batteries, the charger itself could make sure the cells are balanced and my guess is that the 4th connection is for this purpose.

05-29-2022, 02:28 PM	#19
gatorguy Moderator Join Date: Feb 2015 Location: Central Florida Photos: Gallery Posts: 6,094	Originally posted by angerdan I like to recommend this charging times comparision table: New Ricoh Charger - Page 3 - PentaxForums.com FYI, Your last link isn't good, going to a German site.

05-29-2022, 02:50 PM	#20
angerdan Pentaxian Join Date: Feb 2015 Photos: Gallery \| Albums Posts: 2,643	Originally posted by gatorguy FYI, Your last link isn't good, going to a German site. Thx, i replaced it with the backside image of the charger.

05-29-2022, 09:29 PM	#21
Zafar Iqbal Veteran Member Join Date: Oct 2010 Photos: Gallery Posts: 1,229	I've had 6 of these for some years and been happy with them: https://pts-trading.de/en/patona-synchron-usb-charger-f.-pentax-d-li90-d-li90-with-lcd-3187 Biggest downside is the battery plate, which over time can get deformed due to heat. They can be temporarily fixed by unscrewing bottom plate and straightening it - and in worst case, replace them entirely. I've so far straightened some recently, but not replaced any yet.

05-30-2022, 07:18 AM	#22
madison_wi_gal Loyal Site Supporter Join Date: Sep 2016 Location: Madison WI Photos: Gallery \| Albums Posts: 926	I got this, works fine for K-3 III (and K-01) batteries https://www.bhphotovideo.com/c/product/640555-REG/Pentax_39835_K_BC90_Batter...981&

05-30-2022, 10:26 AM	#23
angerdan Pentaxian Join Date: Feb 2015 Photos: Gallery \| Albums Posts: 2,643	The new USB powered BC77 charger is 4 times faster than the old BC90.

06-02-2022, 03:35 PM	#24
Just1MoreDave Site Supporter Join Date: Feb 2007 Location: Aurora, CO Photos: Gallery \| Albums Posts: 6,340	I just got the D-BC177 Travel Charger. I have a couple of the old BC90s so I'm good for plug-in charging and I don't need speed. I have a cheap DLi90 charger with a micro USB cord, Kastar brand, but it only works now if you wiggle the cord just right. Inevitably I'll get it working and it stops when I look away, not good for charging. The D-BC177 Travel Charger has USB-C so it's the wave of the future. What was not clear to me was the required voltage input. It looks like it will still charge connected to a 5V 2A source. I'm sure this is a slow charge, but when actually traveling, I'm likely to plug into an unspecified USB port on a hotel lamp or airport chair or a rental car. I don't want to worry about the twenty different USB connectors and permutations. It seems like the D-BC177 Travel Charger will cover my needs.

06-10-2022, 09:28 AM	#25
SpotmaticGuy New Member Join Date: Nov 2019 Posts: 23 Original Poster	Originally posted by kkoether The new D-BC177 can use the usb cable and plug that comes with the K-3 III. That's useful information. I'll be leaving for a few days on a little photo expedition, and that should give me a better idea of what I'll need. I'm inclined to go with the D-BC177, but I'm unsure about a more powerful battery. The Pentax battery is 1800 mah (doing that from memory) and I've seen some batteries rated at 2300. Might there be a problem with higher-rated batteries? Thanks!

06-10-2022, 12:19 PM - 1 Like	#26
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,454	Originally posted by SpotmaticGuy That's useful information. I'll be leaving for a few days on a little photo expedition, and that should give me a better idea of what I'll need. I'm inclined to go with the D-BC177, but I'm unsure about a more powerful battery. The Pentax battery is 1800 mah (doing that from memory) and I've seen some batteries rated at 2300. Might there be a problem with higher-rated batteries? Thanks! Most third party batteries have inflated mah figures. I’ve never found any that outlast the original. Some are close to equal, none are better.