D300 - Night photography (star-trails etc) is demanding on the camera batteries, even though I use a EL4a 2200mA/hr grip battery with the normal EN-EL3e 1500mA/hr in parallel, I only get about 3 or 4 hrs battery life, despite both being fully charged at the onset. I take about 60 pictures @ 1min expose and @10 sec intervals. The camera then goes into ‘standby’ mode for the remainder of the night. (I am in bed). In the morning both batteries are so flat that even the control panel is dead. First question is: is that normal or should I expect longer power supply? Second question is: I want to supply the D300 via a 12VDC-7.5VDC cable from a 12V battery but need a plug for the DC-IN socket. Does anybody know where to buy such a socket? Item 11 on page 4 of the user manual. I don’t want to use the 110/240V AC adapter EH-5a, as I do not have AC power available in the field. Any advice on these questions would be very much appreciated. Thank you
>I don’t want to use the 110/240V AC adapter EH-5a, as I do not >have AC power available in the field. > Any advice on these questions would be very much appreciated.
You might consider buying a DC to AC inverter (75 to 150 watt models are going for $19 to $29) so you can use your 12v battery in the field. If you use a laptop for tethered operation, you could then run your laptop on AC as well with a little bigger inverter .... along with a coffee pot, etc.
These units are pretty easy to find. In addition to online, auto parts stores, WalMart, kmart, etc., all carry them in various sizes.
The unit I have has a couple of cables that I can choose from to connect to my 12v source. I can use the cigarette lighter adapter cable or a cable with clamps. During a power failure last year that lasted several days I used it to charge my cell phone and laptop batteries. I'll never be without one again.
Certainly something to ponder about. Don’t have use for laptop in the field and really just wanted the plug or plug and cable to fit the socket in the camera. I could just buy the EH-5a and cut the cable off and use it to connect to a 12V battery and re-connect it to the EH-5a when I have AC available. But that is still an expensive way to go about it. But thanks for your suggestion.
I was also looking for the DC plug that goes in the camera (for my D700 ). It looks like the plug is proprietary. You can buy cheap aftermarket (non Nikon) AC Adapter for less than $30 including shipping from Cellular Factory http://www.cellularfactory.com/camera/NIKON/40/47756/653/ . Then you only need to make a battery or better DC adapter because the camera maybe does not like to have too much or too low voltage on the power connector.