Lantern battery for DC input

cosmicap · 04-10-2010, 12:27 AM

Staff note: This post may contain affiliate links, which means Pentax Forums may earn a small commission if a visitor clicks through and makes a purchase. If you would like to support the forum directly, you may also make a donation here.

I used to take startrails with film. The old Spotmatic didn't bat an eye of course at 8 hour exposures.
Not to say that a star trail need be that long but 1 or 2 hours is a reasonable time.
Different matter with digital. My K200 has great battery capacity but I doubt that the Eneloops would last. I look for advice whether to make up a lead with a suitable plug to take power from a 6volt lantern battery such as Duracell and pop it straight into the Dc input. Assuming polarity is correct what could go wrong? Is it a dumb idea? Are there issues with the circuits being open for such a long time. Could I burn anything out?

GerryL · 04-10-2010, 05:08 PM

I don't think it is a dumb idea as long as you keep everything insulated and no exposed wires wherein a short can happen.
DC is DC and if the mah is enough or sufficient enough then why not?
Another way is to get the AC adapter intended for it.
You might find them now a bit affordable or a knock-off might already be available same as with the battery grips.

cosmicap · 04-10-2010, 06:06 PM

Originally posted by GerryL

I don't think it is a dumb idea as long as you keep everything insulated and no exposed wires wherein a short can happen.
DC is DC and if the mah is enough or sufficient enough then why not?
Another way is to get the AC adapter intended for it.
You might find them now a bit affordable or a knock-off might already be available same as with the battery grips.

Hi Gerry,
Hello again!
The idea of the battery is for being out in the field, away from Ac availability. Fits nicely in a pack. And cheap. These days I have a rechargable - its great. I guess as I am likely to be near my car I could take a small inverter to run the AC gizmo. Seems a long way round though and I would have to set up near the car. Leads trailing around in the dark etc.
One of my concerns remains: is there any risk to the camera's circuitry having the shutter open for hours on end?

**davidreilly3207** · 04-10-2010, 07:43 PM

Think you'd be better off with a legitimate power supply and one of these Black & Decker Portable Power Supply AC/USB Rechagable - eBay (item 390084698121 end time Apr-18-10 14:32:36 PDT)
Rechargeable to boot.

justDIY · 04-11-2010, 07:11 AM

Originally posted by cosmicap

I used to take startrails with film. The old Spotmatic didn't bat an eye of course at 8 hour exposures.
Not to say that a star trail need be that long but 1 or 2 hours is a reasonable time.
Different matter with digital. My K200 has great battery capacity but I doubt that the Eneloops would last. I look for advice whether to make up a lead with a suitable plug to take power from a 6volt lantern battery such as Duracell and pop it straight into the Dc input. Assuming polarity is correct what could go wrong? Is it a dumb idea? Are there issues with the circuits being open for such a long time. Could I burn anything out?

Keep the wires from the battery as short as possible. At the low low voltage of 6v, you'll experience significant voltage drop during high-amperage demand, like opening the shutter and flipping the mirror. If you can rig up some sort of caddy so the battery can hang on the tripod no more than a foot from the camera, it should work good.

You mention you have a rechargeable lantern battery? I'm willing to wager it's composed of rechargeable AA cells wrapped up in plastic and metal to look like a bigger battery. You could grab a 4 way D-cell holder and four NiCad or NiMH D-cells (8000-11000mAh) and have an external battery that will likely last for days of continuous usage.

As for damage to the camera from a long exposure, I don't know about the K200 specifically, but the newer K-x and K-7 have protection circuits, which monitor the temp of the sensor and shut it down if it over heats.

BillM · 04-11-2010, 08:58 AM

Howdy All,
hi Cos, exactly this has been used for 60 years by RC hobbiest, simply called
a field box. Follow guideline justDiy posted and youll be fine.
Hi just, you and I posted to thread a while back, in somewhat same regard,
cant remember if you or someone else gave me link to digi-key for required
connector. (swapped hard drives and that stuff inaccessible right now)
I shoot K20d and thermal shutdown of sensor is included with that body,
Way I understand it is if liveview is enabled for extended period of time
thermal shutdown occurs.might want to verify that for yourself though.

justDIY · 04-11-2010, 10:32 AM

Bill, I dug through my old posts, I think this is the one you're remembering:
https://www.pentaxforums.com/forums/camera-studio-accessories/88860-cold-cold...ache-help.html

Reply #13 from Russell:
Digi-Key - H10485-ND (Manufacturer - MQ172-3SA-CV(50))

cosmicap · 04-11-2010, 05:52 PM

Thank you guys for your help. Might be a little while B4 I get round to it but I feel much more confident now.
As for my battery its a Sealed Rechargeable Lead battery. It's quite heavy.
Rated at 6V 5AH/20HR
Other info on the label:
Costant voltage charge
Cycle use

cosmicap · 04-11-2010, 05:58 PM

Apparently the TAB key sends the message - live and learn!
To continue:
Cycle use.........7.2 - 7.5V
Standby use.....6.75 - 6.9V
Initial current...less than 1.5A
Max discharge current 1.5A

Should do the job? It's a little beauty. I've had it 5 years and charge it with my car battery charger that has a 6V option. Probably been taken off the market as it was too good!

justDIY · 04-11-2010, 06:15 PM

That sounds like a sealed lead acid / AGM type battery, rather than a 'dry cell'. Five years, if it was a high end battery, it's got another five left. If it was an average one, it's close to death.

I'm not sure that max discharge current of 1.5A would be compatible (or at least not recommended) for your camera, it is rather low. Something 2.0A-3.0A would be better suited.

04-11-2010, 08:58 AM	#6
BillM Veteran Member Join Date: Jan 2010 Location: Ferguson, Mo. Photos: Gallery Posts: 1,348	DC Field Box Howdy All, hi Cos, exactly this has been used for 60 years by RC hobbiest, simply called a field box. Follow guideline justDiy posted and youll be fine. Hi just, you and I posted to thread a while back, in somewhat same regard, cant remember if you or someone else gave me link to digi-key for required connector. (swapped hard drives and that stuff inaccessible right now) I shoot K20d and thermal shutdown of sensor is included with that body, Way I understand it is if liveview is enabled for extended period of time thermal shutdown occurs.might want to verify that for yourself though.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Lantern C&C	innershell	Photo Critique	5	09-14-2009 06:40 AM
By Lantern Light	Mike Cash	Post Your Photos!	4	10-30-2008 05:09 AM
Puzzling lantern?	vroom_skies	Post Your Photos!	4	08-27-2008 11:57 AM
Magic Lantern K200D	Elle	Photographic Technique	1	07-05-2008 06:39 PM
Paper Lantern	Mike Cash	Post Your Photos!	6	10-25-2007 07:38 AM

04-10-2010, 12:27 AM	#1
cosmicap Senior Member Join Date: Oct 2008 Location: Horsham, VIC, Australia Photos: Albums Posts: 108	Lantern battery for DC input Staff note: This post may contain affiliate links, which means Pentax Forums may earn a small commission if a visitor clicks through and makes a purchase. If you would like to support the forum directly, you may also make a donation here. I used to take startrails with film. The old Spotmatic didn't bat an eye of course at 8 hour exposures. Not to say that a star trail need be that long but 1 or 2 hours is a reasonable time. Different matter with digital. My K200 has great battery capacity but I doubt that the Eneloops would last. I look for advice whether to make up a lead with a suitable plug to take power from a 6volt lantern battery such as Duracell and pop it straight into the Dc input. Assuming polarity is correct what could go wrong? Is it a dumb idea? Are there issues with the circuits being open for such a long time. Could I burn anything out?

04-10-2010, 05:08 PM	#2
GerryL Veteran Member Join Date: Jan 2009 Location: CA Posts: 2,731	I don't think it is a dumb idea as long as you keep everything insulated and no exposed wires wherein a short can happen. DC is DC and if the mah is enough or sufficient enough then why not? Another way is to get the AC adapter intended for it. You might find them now a bit affordable or a knock-off might already be available same as with the battery grips.

04-10-2010, 06:06 PM	#3
cosmicap Senior Member Join Date: Oct 2008 Location: Horsham, VIC, Australia Photos: Albums Posts: 108 Original Poster	Originally posted by GerryL I don't think it is a dumb idea as long as you keep everything insulated and no exposed wires wherein a short can happen. DC is DC and if the mah is enough or sufficient enough then why not? Another way is to get the AC adapter intended for it. You might find them now a bit affordable or a knock-off might already be available same as with the battery grips. Hi Gerry, Hello again! The idea of the battery is for being out in the field, away from Ac availability. Fits nicely in a pack. And cheap. These days I have a rechargable - its great. I guess as I am likely to be near my car I could take a small inverter to run the AC gizmo. Seems a long way round though and I would have to set up near the car. Leads trailing around in the dark etc. One of my concerns remains: is there any risk to the camera's circuitry having the shutter open for hours on end?

04-10-2010, 07:43 PM	#4
davidreilly3207 Loyal Site Supporter Join Date: Sep 2009 Location: South Jersey Photos: Gallery \| Albums Posts: 720	Think you'd be better off with a legitimate power supply and one of these Black & Decker Portable Power Supply AC/USB Rechagable - eBay (item 390084698121 end time Apr-18-10 14:32:36 PDT) Rechargeable to boot.

04-11-2010, 07:11 AM	#5
justDIY Senior Member Join Date: Jan 2010 Location: Manistee, MI Posts: 295	Originally posted by cosmicap I used to take startrails with film. The old Spotmatic didn't bat an eye of course at 8 hour exposures. Not to say that a star trail need be that long but 1 or 2 hours is a reasonable time. Different matter with digital. My K200 has great battery capacity but I doubt that the Eneloops would last. I look for advice whether to make up a lead with a suitable plug to take power from a 6volt lantern battery such as Duracell and pop it straight into the Dc input. Assuming polarity is correct what could go wrong? Is it a dumb idea? Are there issues with the circuits being open for such a long time. Could I burn anything out? Keep the wires from the battery as short as possible. At the low low voltage of 6v, you'll experience significant voltage drop during high-amperage demand, like opening the shutter and flipping the mirror. If you can rig up some sort of caddy so the battery can hang on the tripod no more than a foot from the camera, it should work good. You mention you have a rechargeable lantern battery? I'm willing to wager it's composed of rechargeable AA cells wrapped up in plastic and metal to look like a bigger battery. You could grab a 4 way D-cell holder and four NiCad or NiMH D-cells (8000-11000mAh) and have an external battery that will likely last for days of continuous usage. As for damage to the camera from a long exposure, I don't know about the K200 specifically, but the newer K-x and K-7 have protection circuits, which monitor the temp of the sensor and shut it down if it over heats.

04-11-2010, 10:32 AM	#7
justDIY Senior Member Join Date: Jan 2010 Location: Manistee, MI Posts: 295	Bill, I dug through my old posts, I think this is the one you're remembering: https://www.pentaxforums.com/forums/camera-studio-accessories/88860-cold-cold...ache-help.html Reply #13 from Russell: Digi-Key - H10485-ND (Manufacturer - MQ172-3SA-CV(50))

04-11-2010, 05:52 PM	#8
cosmicap Senior Member Join Date: Oct 2008 Location: Horsham, VIC, Australia Photos: Albums Posts: 108 Original Poster	Thank you guys for your help. Might be a little while B4 I get round to it but I feel much more confident now. As for my battery its a Sealed Rechargeable Lead battery. It's quite heavy. Rated at 6V 5AH/20HR Other info on the label: Costant voltage charge Cycle use

04-11-2010, 05:58 PM	#9
cosmicap Senior Member Join Date: Oct 2008 Location: Horsham, VIC, Australia Photos: Albums Posts: 108 Original Poster	Apparently the TAB key sends the message - live and learn! To continue: Cycle use.........7.2 - 7.5V Standby use.....6.75 - 6.9V Initial current...less than 1.5A Max discharge current 1.5A Should do the job? It's a little beauty. I've had it 5 years and charge it with my car battery charger that has a 6V option. Probably been taken off the market as it was too good!

04-11-2010, 06:15 PM	#10
justDIY Senior Member Join Date: Jan 2010 Location: Manistee, MI Posts: 295	That sounds like a sealed lead acid / AGM type battery, rather than a 'dry cell'. Five years, if it was a high end battery, it's got another five left. If it was an average one, it's close to death. I'm not sure that max discharge current of 1.5A would be compatible (or at least not recommended) for your camera, it is rather low. Something 2.0A-3.0A would be better suited.