Battery weight versus performance

[Scott Drysdale]

Two colleagues raved about the superiority of their Thunderpower batteries as compared to my Turnigy Nanotech batteries so I thought I should investigate further.

The common specs for both batteries are: 6S 25C 5000 maH

The Thunderpower battery weighs 695 grams.
The Nanotech battery weighs 769 grams.

This weight difference seems to extend across both product lines although it is difficult to assess when one makes a 6600 mah battery whereas the other makes only a 6000 maH of the same C rating.

On the assumption that the specs are accurate for both, it is clear that the Thunderpower batteries will enable noticeable longer flight time due to the reduced MR - AUW.

Also it appears that the Thunderpower batteries are more expensive....

Since weight is such a critical factor for MR airtime.... it seems appropriate that a comparison be performed between a wider range of battery manufacturers.
http://www.rctoys.com/rc-toys-and-p...S-THUNDER-POWER-6-CELL-LITHIUM-BATTERIES.html
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=11937

 

[Fat Corgi]

Reducing the C-rating of the lipo's you use (whilst maintain a safe current-draw buffer) is another way to reduce the weight of the batteries you fly with.

 

[Motopreserve]

Reducing the C-rating of the lipo's you use (whilst maintain a safe current-draw buffer) is another way to reduce the weight of the batteries you fly with.

I'm curious about this as well. I've read several things online (always a crap shoot) about trying to get the C rating lower, within reason, to save on weight. That the multirotors typically don't need massive C rating. Is this what you guys believe as well?

ive been running RMRC orange batteries for a while and they seem decent. Definitely lighter than many I've seen.

 

[Fat Corgi]

It's not that hard to calculate the total max current your rig will pull, or you can use an elogger to get a good idea. The maximum C-rating on a lot of lipo's would have to be taken with a grain of salt, but if you added roughly 20-25% to your maximum draw then you'd be able to figure out the minimum C-rating your lipo required.

Scott, I would assume you're correct with regards to reducing weight. Any weight savings are going to be beneficial to your flight times. I've got a bunch of the Nano tech 35C packs that I use on a TRex 700 AP ship, and their average weight is 780g with plugs.

 

[econfly]

C ratings tend to be inflated in the first place, so it's a bit of a guessing game.

For example, I have a hex that pulls about 70 amps in hover and I power it with a pair of 6s 25C 6000 mAh nano-techs. So I only need 70 / (2 * 6) = 5.8C to hover. Maybe 10C (120 amps) at most for takeover, etc., and that's an overstatement. These 25C batteries are therefore way more than I need if the C rating is correct. But it probably isn't. I would, however, be happy to try a lighter battery at, say, 15C, if I could find such a thing at a reasonable price. And that brings me to the ultimate point: I have had good luck with these nano-techs in the past year, and just about every decent alternative seems to cost twice as much.

Like a lot of the RC world this is a gray area with lousy specs, confusion, scammers trying to re-label something and sell it for more, etc.

I have a nice 1200W electronic load for the test bench inbound and when it gets here I'm going to start doing some careful battery testing. With a 1200W load I will be able to drain a 6s 8000 mAh battery in about 8 minutes. So I should be able to get some very practical and relevant results -- hopefully.

 

[Motopreserve]

C ratings tend to be inflated in the first place, so it's a bit of a guessing game.

I have a nice 1200W electronic load for the test bench inbound and when it gets here I'm going to start doing some careful battery testing. With a 1200W load I will be able to drain a 6s 8000 mAh battery in about 8 minutes. So I should be able to get some very practical and relevant results -- hopefully.

im looking forward to your testing.

 

[222GR]

I had a couple 25C 5000mAh Thunderpowers and a pair of equivalent nanotechs. The fact that they are lighter seems great but I found my flight time difference to be negligible between the 2. Honestly I wouldn't spend the money again.