Light Weight Solution Battery

[Mendes Nabil]

Hello all, i'm planning to buy batteries and was thinking about a light weight solution: wire the battery to the camera and put it on a back-bag, and do the same with the hard disk, (looks like the belt solution, but cheaper).
Which cable do i have to buy to connect the battery (or v-mount plate ) to the camera (red one Mx)?

I've found this one:

http://www.aliexpress.com/store/pro...nton-Mount-Battery-Red/736284_1355946022.html

what do you guys think?

My friend which is an aeronautical engineer told me about a new generation of batteries, more powerful than V-mount batteries and much lighter and cheaper, he can make a direct connection between the battery and the camera (with a custom Lomo cable), so no more need of a v-mount plate, and the weight on the back-pack will be pretty light, why nobody has thought about such a solution? Am i missing something?

Thanks for all your replies guys

 

[Alex Kiritz]

As long as it supplies the proper voltage (11.5 to 17 volts) and can deliver the necessary power, any power source will work. What you're paying for with professional batteries is proven reliability and a rugged case.

The Red Brick's gravimetric energy density is around 140 watt-hours/kilogram. Considering how much of that weight isn't raw batteries, that's pretty good. Quite a few raw battery cells on the market aren't that energy dense.

Here's a lithium polymer battery pack that is pretty comparable to a Red Brick:



It's 200 grams lighter and has 8 more watt-hours of juice.

But, if you damage a lithium polymer battery, it will combust violently. Like this:

If it works for you, you can certainly get a lot more bang for your buck. If it's not your forte, you can end up in world of hurt. I think that's why most people tend to stay away.

 

[Mendes Nabil]

Thanks for your reply Alex, my friend told me about the risk with Lipos batteries (Lithium Polymer) and according to him, Li-ion are much reliable.. I' ve found this fire proofed one :

http://www.batteryspace.com/Li-ion-...x-Battery-14.8V-10.4Ah-154-wh-14.0A-rate.aspx

In term of capacity, it's better than the red brick, and much cheaper.

Now, i'll have to make a custom cable to connect it to the camera (with a lemo 2b 6pin?) , any advice will be much appreciated

 

[Alex Kiritz]

There is really nothing to it. Positive to positive, negative to negative.

If you want to make a custom cable yourself, your best bet would probably be getting the pack with a Tamiya connector on it and then crimping an opposite gender connector onto your Red One power cable.

I would also recommend getting a local battery pack supplier if you can find a good one.

 

[Mendes Nabil]

Thanks Alex, do you think that Tamiya connectors will do the job correctly? Are Deans (or ultra Deans) connectors not better for that?

For the cables, i was thinking about this one (attached to a Lemo 2b 6pin head) :

http://www.conrad.fr/ce/fr/product/...el-UNITRONIC-LiYD11Y-0033306/SHOP_AREA_90694?

Am i missing something? (Battery + Tamiya connector, attached to a cable made with 2b 6pin head and Tamiya gender)

 

[Tom Visser]

The Batterspace website linked to above is a great resource for DIY battery projects. The battery chemistry that you want to use is LiFePO4. This is the same chemistry used by the new Sony "Olivine" batteries for the F5/F55 system. LiFePO4 has slightly lesser energy density than traditional lithium chemistries, but it has several distinct advantages... it is possible (but not necessary) to build charging systems that charge the batteries much quicker. The number of charge / discharge cycles is much greater than traditional lithium, so they cost much more less over the full lifespan of the batteries. Most importantly, they do not suffer from the explosive characteristics of traditional lithium, something that is good for piece of mind, especially for a DIY project. (note that FAA policies are not yet in place to distinguish from traditional lithium and LiFePO4, so all the same travel restrictions are in place with LiFePO4 despite their actual safety)

The important thing to consider regarding lithium and charging / discharging is that you need to use specialized chargers that cut voltage to the cells at appropriate times, so have special sensors in them to monitor the current charge status. It is also best to utilize "PCM/PCB" boards that balance the charge capacity on a per cell basis, so that all cells are balanced. The PCM/PCB also performs an important function in that it prevents you from over-draining the battery pack. If any lithium cell is discharged below a certain threshold, they will become irreversibly drained and must be discarded.

The Batteryspace website provides all the raw cells, in addition to the PCM/PCB board to protect the cell, chargers, even fancier charge management boards that allow simultaneous charge / discharge, and of course fully built out packs. Each cell has a voltage of 3.2 voltage nominal, so packs can be built at 3.2, 6.4, 9.6, 12.8, 19.2V, etc... The voltage that you should be looking at is 12.8VDC.

 

[Mendes Nabil]

Really priceless informations here, thank you Tom!

So, my battey project doesn't look so bad according to your message..

About the charger, why should i look to a 12.8V while the battery i want to buy is a 14.8v?

So your choice would be to go for this one right ?

http://www.batteryspace.com/CMBfor12.8VLiFePO4BatteryPack-16Alimited.aspx


Isn't this CMB better for what i want to build?

http://www.batteryspace.com/CMBfor14.8VLi-IonBatteryPack16Alimited.aspx


Batteryspace is a really good website, the only problem is the shipping fees (almost 80$ to ship in France), do you know an european website or at least with cheaper shipping fees?


Edit: Sorry for my stupid question about the charger, i've found what i need But i'm still looking for a french store..

 

[Mendes Nabil]

Hello all! i have an emergency.. Batteryspace send me a message and told me that i can't receive this battery because of some new international restrictions, so they offer me to buy this one:

http://www.batteryspace.com/customiz...napproved.aspx

or this one:

http://www.batteryspace.com/Customiz...h-7A-rate.aspx

which one should i go with? (it is Polymer battery, i've heard about some dangerous stuff about these batterys, am i wrong?)

Or i can buy one in france, but it is a 12V battery (140Wh), 12v is too just no? As The Red one accepts Dc voltage between 11,5 and 17V, again, it is REALLY URGENT .... Thanks guys!