Using a dummy battery and backup battery.

[Marvin Jenkins]

Hi everyone. I have a Nikon D3100 and find the battery lasts about two hours shooting Astro. With darks bias etc I get about 1.5 hrs of actual subs, I want to extend this.

Now I know I could buy a second battery and swop during the session but sometimes I sleep when the rig is running. There is the option of grip and second battery but that is more expense and more weight on the focuser.

I have seen a video tutorial about using a phone backup battery pack with a voltage converter cable connected to a dummy battery in the DSLR. I have one of these 5 volt battery packs and thought great idea, not to mention the battery pack is taken away from the sensor and off the OTA if mounted on the tripod or mount.

My question is this. The Nikon battery is 7.4 volts, the camera allegedly has a max voltage of 8.4 volts. The only USB converter cables I can find are 5 volt to 9 volt. Is this critical as I have seen warnings about exceeding voltage which seems obvious to me.

If it is critical can anyone suggest where a USB 5 volt to 8 volt cable can be purchased that would connect to a dummy battery. Thanks in advance.

Marvin

 

[michael8554]

I'm not sure a USB converter will supply enough current - my mains powered dummy battery has a 2A supply, USB is usually 0.5 Amp max ?

Michael

[Alien 13]

Does the Nikon battery grip have the option of using AA batteries like the Canon one does, the reason I ask is because the Canon allows the use of 6 AA batteries which equates to around 9V or more. I have used a 5V power bank to 9V converter on my 80D but it does need dual 2.1A inputs to work.

Alan

[Robindonne]

Zwo had 12v dc in - 5v usb out converters.  And I think it has 2,5 a on the usb.  A good usb cable is important 

[david_taurus83]

I use one of these.

[Davehux]

I use one of these on my Nikon D5200. I cut the cable on the dummy battery, and soldered the voltage dropper onto the leads. 10 min job, and I can now run it off any 12v outlet (I use an ASIair, but any power outlet would do.)

Mine is simply velcro’d onto the bottom of the camera, for ease of removal if I want to use it as a normal DSLR

£4 for the dropper and £12 for the dummy battery, from eBay. Wait 3 weeks for them to arrive from China, and save a heap of money 🙂

 

 

[Messy Hair 101]

+1 for the dummy battery. You should just be able to buy them with a mains plug from Amazon. I got one for my Canon 6dmkii and it's  a life saver. No more messing with batteries

[Marvin Jenkins]

16 hours ago, KevS said:

Hi Marvin,

I used one of these for a while in its Canon guise and found I could get about 4 hours of useful power out of it. They are available cheaper if you shop around.

https://www.onbuy.com/gb/ex-pro-on-the-move-16000mah-battery-system-en-el14-ep-5a-for-nikon-d3100-d3200~c11440~p16632184/?exta=gshp&stat=eyJpcCI6IjYxLjk1IiwiZHAiOjAsImxpZCI6IjIyMDA5MTY4IiwicyI6IjEwMDAiLCJ0IjoxNTg4OTgwMjQzLCJibWMiOiIwLjAifQ==&lid=22009168&gclid=EAIaIQobChMIrOnvj8TC6QIVA-ztCh2q2w9nEAQYAiABEgIfBfD_BwE

However I have moved to a more semi-permanent set up and now utilise a power supply from a dew strip controller.

https://www.firstlightoptics.com/dew-prevention/lynx-astro-2-port-dew-controller-with-dslr-power-supply.html

Found the latter to be very useful.

 

Kev

 

Thank you Kev that looks perfect, just what I was looking for.
As for the Lynx Astro item that is a sore point. A while back before starting imaging I bought one of these great two port controllers but without the DSLR port.

If only I had future proofed that purchase by paying a bit more at the time, lesson learned I guess.

Cheers

Marv