An ongoing blog about LiPos, as I feel my way around the topic.
The featured image, above, is taken from LiPo battery may have caused shop fire.
Resurrecting a dead LiPo. Note that this seems very dangerous and the LiPo could burst into flames…
Evidently a better way is to use a NiMh charger:
Yeah, I would probably go with at least a 3S battery. I actually haven’t heard of too many people flying a 2S battery on anything over a 330-sized frame; even a lot of the F330 guys fly 4S. 3S is good for all-around flying, 4S will turn your quad into a rocket. I think that if you went 3S 5000mAh, you would get about 12-15 minutes of flight time, maybe more depending on your frame and overall weight of your quad. There’s a max point when battery weight overtakes battery capacity in terms of flight time, but it gets a little complicated, so I won’t attempt to get into that. A battery’s C-rating also comes into play in flight time due to varying rates of discharge. In very basic terms, the mAhs are like the volume of a tank of water, and the C-rating is like the diameter of the hose attached to the tank. Higher mAh means you have more water to spray, and higher C-rating means you can spray a greater amount of water at any given time if you need to. The S part of a battery rating denotes the amount of cells it contains within the battery pack, and is analogous to the water pressure of the hose. I personally fly a couple of 3S 2200mAh with 20-30C because they were (and still are) pretty cheap, I don’t fly very aggressively nor do I fly ACRO (yet), and they offer a good balance of low weight and decent flight time. I get about about 8 mins of flight time per pack. Coupled with 1045 props (I flew 8045s for a few months and liked them a lot, but I strapped a heavy camera on my quad, so I need some more thrust), they offer plenty of grunt when I need it.
I would say it depends on what you want… honestly I think the best small filming platforms out there right now are quads with three axis gimbals on them. I would get you a zenmuse H3-3D on your 450… I get about 18 minutes of flight on mine with a 2D and still have juice to spare. I use 4S 4500 mah Turnigy nano-tech A Spec 65-85C batteries with the stock motors and 10 inch props.
In my personal opinion it doesn’t make sense to run a “small” (quotes because that’s a relative term) hex over a quad because of the flight times. If you are going to spend the money on a hex you should just go big or a 700-800 size quad with low KV motors. Those guys are reporting flight times of nearly an hour now!
The reason why I’m thinking a hex is exactly what Idahobell states about it being less risky about losing a motor or ESC, I’m worried about losing a good chunk of money because of 50 dollars worth of parts failing on me. Currently I have myself an F450 with stock DJI motors, 9×4.5 APC props with a Turnigy Nano tech 5000 mah 4s. Landing gear, tarot t2d as well as a mini 860mah 3s battery on there to run the gimbal and video tx. I’m getting aprox 12 minutes flight time now, with this combo. Originally I thought about just upgrading the motors and putting bigger props on but now I’m slightly worried about losing a motor or ESC. Which brings me to this point, but now you’re making me think twice about going to the hex. I do like the idea of possibly upgrading to a little larger gimbal and maybe a small DSLR which would be good for a hex.
From HMF S550
I have the e300 motors and props with simonk esc’s, and a walkera 3s 5200mAh (they are light) and it works great. Also have a zenmuse h3-3d. I get about 16 mins with this setup with my lipo alarm set to 3.4
I have flown two 5000mAh 4s in parallel onto the hmf s550 – now running on sunnysky x2212 980kv on 10×4.5 hq props (apc mr style).
I was doing a test to see if the hex can take a nex-sized gimbal. I loading up 2x 5000mAh battery in parallel, and at the same time strap an addition 500g of weight on top of the quad – bringing the auw of the quad to about 3.3kg. I also increased the gains setting of the naza lite I used.
End result? – It flew great! …I flew for about 6mins and landed with >50% battery left in the lipos. Motors were barely warm. There weren’t as “strained” as I thought they will be and I believe there is still capacity for some additional weight.
I’m flying at about 2500 AUW with a 4s lipo 5000 mAh. I get 10 minutes at that weight, put back roughly 3200 mAh and have battery voltage of 15.2.
For the NEX-5n (I had one on a little hexa) I’d get 8 mins flight time with it on board with 1 x 5000 mAh 3s. I was using 10×4.5 props, and small motors like on your list.
Most smaller rigs take 3 – 4S, most larger rigs take 6S.
motors are completely different as is ESC’s.
Never store your batteries at full charge. From Definitive Word on Lipo Storage Mode vs. Full Charge?
This is what Traxxas has to say on the matter, and since this subforum is only for Traxxas-branded batteries…
Originally Posted by Traxxas Battery Basics
1) I storage charge/discharge them to 3.85v/cell if they will not be used within 3 days.
2) If cell voltage is between 3.6-3.9v I will leave them if they will be used within 3 days.
The longer they are left at full voltage, the less cycles you will get out of them.
Undercharging to extend life
Making your LiPo’s last
I will just give an example of how much a small change in how a pack is taken care of can dramatically change how the pack behaves.
Two identical packs were both charged and discharged in the exact same matter…. except one pack was charged to 4.20v/cell and the other to 4.10v/cell. This was done in a very controlled environment… NOT in an RC.
After 500 cycles, the pack that was charged to 4.20v/cell had reached its life expectancy… it would not take more than 65% of its original capacity; meaning the LiPo was no longer able to be used safely.
The pack that was charged to 4.10v/cell was still at 70% capacity after 1,000 cycles… so the .10v/cell difference more than doubled the life expectancy.
Long term storage
So what happens if you store at 50% and don’t use for a year/ 6 months?? And when you get back to using they are below low voltage?? Wouldn’t you then be better to store at full charge so if storing for a long time they have longer to reach lowest voltage??
The self discharge rate of LiPo batteries is very low at about 1-2% per month so it’s highly unlikely that you’d fall below critical low cell voltage even at extended periods of storage starting at the 3.85V storage voltage. However it’s always wise to double check on your batteries every couple of month since the self discharge rate will vary with age of the battery, storage temperature and some other factors. Some manufacturers even recommend to cycle the battery every X weeks.
Storing at full charge increases the permanent loss of capacity over the storage period. Some tests showed an five fold increase of permanent loss at room temp storage over a years period of time when stored at full charge vs. 40% charge.
These tests where done on cobalt electrode based LiIo batteries and different LiIo chemistry/electrode make-ups will likely have variances on that loss but it will always be higher at full charge storage.
Posting LiPo batteries
It is not legal to post LiPo batteries in the UK, and it hasn’t been since 2013, see Posting lipo batteries is there any legal way. Note that this is a legal requirement and not a choice of Royal Mail, if they find them then they will destroy them, along with anything else that was in the parcel. There is a caveat though, which is that if the LiPo is included within another electronic device, then it is legal. There are some couriers that will handle them, but you can’t use the usual post.