View Full Version : HELP! HLD4 Grip vs single BLM1

13th March 2010, 05:32 PM
I guess this might be an idiot question and the answer is really down to trying it out, however I will ask the question anyways - Does anyone know if using the HLD4 Grip with the 2 BLM1 batteries in will last as long or longer than using 2 single BLM1s in the E30 body, or will the singles give longer usage, based, for sake of argument on normal everyday use?

13th March 2010, 05:41 PM
I think 2 BLMs will last exactly the same amount of time weather used as single units or as a pair in the HLD4 :)

13th March 2010, 08:33 PM
It varies depending on what setup you are using. Live View, long exposures, etc., etc...

The biggest difference I have found is temperature dependent. I tend to use the grip in the studio and have just one battery in it. Outside I just have the batter in the camera. I've always known that battery performance is reduced in the cold (bit like me :o) but I find I need 2 sometimes 3 batteries to get through a day outside, when only 1 will do in doors.

On the basis that it's supposed to be better to fully discharge a battery before charging it, I tend to only use one at a time.


13th March 2010, 10:48 PM
There is also the issue of current drain and voltage drop. Two batteries in parallel can give more current without dropping the output voltage too much (google "internal resistance" to see what I am talking about). There is some anecdotal evidence that the bigger lenses and the SWD lenses focus quicker and more reliably with two batteries in the HLD-4 because of those lenses higher current requirement.


13th March 2010, 11:54 PM
There's no such thing as an idiot question, only idiot answers and no-one's given one yet:)
All the previous replies are essentially correct. The key factor is "all other things being equal". ie two identical batteries of equal capacity will deliver twice the energy of one. However as others have noted the number of shots/time a battery or batteries last between charges depends on many other factors such as temperature,use of liveview,type of lens(size of focus motor) and recording format ( jpg. raw. jpg+raw ) and even the amount of detail in each shot. So using a pair of batteries in a grip will give approximately twice the time/number of shots between the need to change/recharge but the exact time/number will vary depending on the above factors.
The Li-Ion batteries used in our Oly cameras should not need to be fully discharged before rechargeing as they don't suffer from the "memory effect" which was a characteristic of the old NiCad rechargeable batteries.
Trust me I used to be an electronics engineer.:eek:

14th March 2010, 04:41 PM
Thanks to all of you for responding, very interesting. The proof will be in the pudding?