Hi folks I'm running a M5 and going crazy with all batteries. - the M5 lipo 4S - a switronix pro X (v mount) for a black magic - a USB battery for paralinx transmitter - a Sony NP or canon for my monitor view Please, I'm looking for tips so I could make my system lighter and easier to assemble. 1. as I'm new to it, how should I calculate (maths )voltage/amp in order to find which battery could power all itens, or maybe camera/monitor and paralinx? I get lost with all different voltage/amps and I don't want to burn anything. 2. a Lipo could charge at least my my BMCC, paralinx and monitor? which one? Can't find any clue! 3. Can I get a generic Lipo to charge my M5 or it must be only the one sold by Freefly? I'm looking foward for an answer Regards paulo gambale.

You're asking valid questions, Paulo. The general strategy is to make a list of all the devices and the voltage they need and the amount of current they draw. e.g. Black Magic: Volts = x, Milliamps = y Paralinx Transmitter: Volts = p, Milliamps = q and so on. If you can create such a list either I or someone else can walk you through the calculations. The 4S battery will delivery from 16.8 volts (fully charged) down to about 14.4 volts. It can supply a *lot* of current, but the more current it supplies, the shorter the time it will last. Can you post the table with the information filled in, please? Andy

Thanks for answering Andy. Specifications I found at the AC power of each equipment: Marshall monitor VLCD-50: 5V, 2amp Paralinx crossbow (HDMI/SDI): 5V, 2amp Paralinx transmitter arrow+: 5V, 2amp Blackmagic prod cam4K: 12V, 2,5amp Right now I have a big Switronic battery (77 Wh, 5.3 Ah, 14,8V) to power the blackmagic. also a USB 2amp battery to power the paralinx a canon DSLR battery LP6 to power the marshall monitor and the M5 Lipo 4S battery (1,3ah,14,8V), which powers only the M5 I just want to learn the maths so I could choose the right voltage for most of it, and also amps in order to have a better and lighter performance. regards paulo.

The maths involved is based on Ohm's law: Voltage = Amps x Resistance. And the additional math that Watts = Volts x Amps. However, the first step is to understand the pattern of requirements. You have a battery that that operations from 16.8 to 14.4 volts (depending on its state of charge). Given the devices you list, they divide into one that needs 12 volts, and three need 5 volts. So that tells me that you need two different DC to DC converters. One at 12 volts and 2,5 amps. And one at 5 volts at 6 amps. In both cases you want to add some spare capacity, so I would tend to go for: a. One DC/DC converter that produces 12 volts at 4 amps. b. One DC/DC converter operating at, say, 5 volts at 8 or 10 amps. Bearing in mind that the numbers for the amps you show are probably maxima rather than the actual steady state, you can afford to choose DC/DC converter that are a little bit closer to the rated amps you show above. Now you know that, you can start to search for DC/DC converters, however, you'll quickly discover that many DC/DC converters are sold based on the maximum output Wattage they can provide. So now you look at your Watts = Volts x Amps formula. We know the voltage -- it's either 5v or 12v. So for the three 5v devices, you need 6 Amps. So 5 x 6 is 30 Watts. For the 12 volt device you need 2.5 Amps. So 12 x 2.5 is also 30 Watts. (Just a coincidence...don't attach any significance to it). So then you do a Google search for: DC/DC converter 5v output 50 watts -- and that's where you'll need to find local suppliers. Note the 50 watts -- that's just to give some spare capacity. Then do the same kind of search but for 12v output 50 watts. Hope that helps Andy.

----- Andy, thank you very much for your explanation. Finally I got it...ohm's law...understood! Just to make sure, As I'm trying to lightweight my rig (M5), as you said I'll need: - 5v, 50W (monitor, paralinx, crossbow) - 12v 50W (for blackmagic 4k cam or even the pocket) - M5 Lipo 4S battery (1,3ah,14,8V) The M5 battery I'll keep the one sold with the rig, solved. I'll need two more, with different voltage...(so I could replace all others, even the switronix which is heavier than the camera!) Could I use Lipo batteries? are they the best option (performance and weight)? What would you suggest? Regards! paulo gambale. BR|SP

Paulo: You say "I'll need two more with different voltage..." but I'm not quite sure why you say that. The M5 Lipo voltage produces from 16.8 v to 14.4v (that's the typical useful range). If you use two DC to DC converters, you can take that output voltage and produce 5v with one converter, and produce 12v with a second converter -- both converters receiving the output from the M5 LiPo. The converters will be different models, of course as one has to drop the voltage to 5v and the other to 12v. So you do not need two more batteries -- although the additional load will shorten the discharge time for the M5 battery and therefore you might choose to use a higher capacity M5 battery. How much larger capacity -- that's purely a function of how often you want to change the battery. If you double the capacity of the battery, you will (as an approximation) only need to change it half as often. Andy.

If you're handy with a soldering iron, something like this could work. It's a small power distribution board that will take any voltage in, and distribute it, but also has a 12V DC tap and one adjustable tap that you can set for 5V DC. I've been using one of these for quite some time in my big quad (running 6S) and it works great. But there are definitely other ways to do this. EDIT: HobbyKing now sells these: http://www.hobbyking.com/hobbyking/..._Distribution_Board_and_Dual_UBEC_In_One.html

----- Got it Andy. I think I'll keep the M5 battery for itself and add another 4S or 3S Lipo for all other stuff (monitor, paralinx, camera...) actually I'll have to test and try some options. Find small DC converters, right conectors for all devices, best place to fix it on my rig. I didn't realize, but it takes time to set ip up with 100% functionallity... Let me check what I can find over here and will get back to you. thks again! paulo.