ltc

My Feedback: (3)

I need to buy more 5s batteries so I started trying to figure out "which one is best"
I realize it's impossible since it's somewhat subjective, but being OCD with numbers, I decided to at least try

So I went on the web and looked up some of the popular (most often seen and discussed) 5s LiPo batteries for F3A. I only looked for 'standard 4.2V" LiPo batteries, since i'm not quite sold on 4.35V 'high voltage LiPo batteries' quite yet

I took for granted the specifications provided by the manufacturers (specifically weight) since sometimes its unclear or difficult to compare a battery without leads to one with leads since you don't know exactly what type of connectors each person uses and how much a few grams may effect the results.

I also did not take in to account personal preferences on C rating, since its well accepted that a higher C rating means more weight given the same capacity (yes lower IR is nice, but if you aren't abusing your packs in flight, the extra weight for lower IR doesn't do much good except perhaps extend longevity slightly .... but if you only charge to 4.1V and stop at a reasonable voltage, and store the properly between flights, you will get longer life anyways)
I created a simple spreadsheet for the data (manufacturer, capacity, discharge rate, dimensions, weight, price) then calculated "2 figures of merit" to try and describe how someone might select a battery

1. Capacity per Dollar. How many mAH you are getting for each dollar spent
2. Capacity per gram. How efficient is your battery for a 5kg F3A plane

A few comments:
The TopFuel Hacker F3A batteries have no price, since Ive been completely unsuccessful in trying to find someone who will sell and ship them to the USA
The ThunderPowerRC battery was the only 10s, since they sell it as a 10s (split cell interconnect for shipping) and as a standard 5s. It turns out buying a 10s instead of 2 5s actually might make sense

The results are in the attached 3 spreadsheet snapshots.
The first spreadsheet is just the raw data
The second one is sorted by Capacity Per Dollar
The third one is sorted by Capacity Per Gram

Not surprisingly, if you just want to get the 'best bang for your buck', it's hard to beat HobbyKing batteries
But, if you want the most efficient battery (capacity per gram), then ThunderPowerRC seems to be the battery to buy here in the USA. the 10s is slightly better than 2 5s, simply to due better packaging

In the end, I still don't know which battery to buy (unless I get lucky and ThunderPowerRC has another 40-50% off sale...not sure if they still do those or not), but at least doing this killed a few hours today!

barnowljenx

Thanks for that analysis. I agree with you that the HK supplied packs are difficult to beat. Even if they don't last as long as some of the more expensive packs they still represent excellent value. Also, I've never found them wanting except when you get a pack going sick on you - but that happens with expensive packs as well. I shall keep looking for alternatives to the Zippy but I suspect it will be hard to beat.

flywilly

My Feedback: (121)

Thanks for the charts.
How about comparisons of ESCs and motors? I am a diehard glow guy (more than 50 years), but want to give e-power a try. I have purchased a Flight Hobby Neo Stage kit (the 2m version) and now need to acquire all the e-power stuff (I have nothing); so a motor, ESC, batteries, charger, ESL meter and anything else I'm unaware of. Any suggestions, comments, recommendations are appreciated!
-Will

ltc

My Feedback: (3)

I would highly recommend using eCalc
It gives very good results for electric planes. Let's you play "what if" with props, batterids, motors
Very inexpensive to buy online.

If you are going to use a Hacker motor, there is a free version just for hacker motors as well.

If you have further questions PM me anytime and I'd be happy to try and help

Bubblehead575

Great information. Thanks.

However there is a Major consideration that is hard to measure without the help of others (or a lot of money and time), and that is Quality (or Longevity). I have flown many of these at one time or other. I used to fly HK Zippy Compacts for the afore mentioned value. But something changed in the chemistry or QC, because when I replaced my packs after getting over 150 cycles per pack, without any failures, my next set of 6 packs,(12 5S packs) all failed between 30 and 55 cycles. None of the 5S packs even lasted 70 cycles.

I know you are not likely to find a battery brand that will not have failures (cell not balancing, high resistance cell, etc), But something has changed in the production of many of these batteries over the last 5+ years, as we are not getting the cycles we used to. I know when I get to the field and talk with other pattern flyers and the discussion turns to batteries, it is more about the number of cycles we are getting then anything else, Next comes weight, then price.

Without taking into consideration how many cycles you can get out of a brand you are only looking at the price to buy, and not value

Regards

flywilly

My Feedback: (121)

Thanks for pointing me to eCalc, it sounds very useful.

Thanks Bill, for your comments. I was going to suggest a table of cost per cycle, but that would require the accumulation of a LOT of data, as you pointed out. I have been following the evolution of e-power in pattern since Dave Von Linsowe back in the late '90s. It seems that the number of cycles went up from the early days until a peak and then decline. I had expected that battery performance would only continue to improve with time. Cost has decreased somewhat, maybe a lot on a purchase price basis, but on a per cycle basis maybe not so much. Just based on your observations, the battery lifespan has decreased by more than 50%. I know that pattern flying is a pretty harsh environment for these batteries, but how long do they last in the myriad of battery powered hand tools that are available? Still, if you compare the per flight costs of glow versus electric it is about $2.50 - $4.00 per flight for glow (just fuel, no maintenance) versus $1.00 - $1.50 per flight for e-power and that does not take into consideration the increased longevity of e-powered airframes and equipment compared to their glow powered brethren.

I will always fly glow powered airplanes, but e-power has some pretty attractive advantages.
-Will

ltc

My Feedback: (3)

flywilly

My Feedback: (121)

I agree completely.
The batteries we are using were not specifically created for our use and the environments we use them in.
I believe a better approach is to determine what we can reasonably do to meet the manufacturer's optimum conditions for battery use to maximize the battery lifespan. Probably easier said than done. It does seem that the number of serious battery failures (fires) is been significantly reduced, but I do not know if that is due to a reduction in reporting or actual incidences.
-Will

ron_van_sommeren

Marketing 'optimism', nonsense and outright C-rating lies, with uniform tests. Active thread:
Battery Load Test Comparisons - RCG

Prettig weekend Ron
• Without a watt-meter you are in the dark, until something starts to glow •
• e-flight calculators • watt-meters • diy motor tips&tricks • Cumulus MFC •

barnowljenx

Flywilly - it took me around 4 years to really learn how to use the throttle when flying F3A. In the process, I burned out quite a few packs. I should also say that having started on a monoplane (EF Vanquish - great machine to start with) I then moved to a biplane, Oxai Amethyst, where the drag was considerably higher but you also needed to fly the aircraft more slowly as it was a biplane. Sounds obvious, but it takes time to learn all this stuff along with everything else that is going on in your brain.

I've just given away 2 flight packs (one a Zippy Compact with 96 cycles and one a Turnigy with 90 cycles) where voltage balance was good and IR still in the high teens. I would never have imagined that when I started F3A. The other point is that buying expensive packs may mean they last longer (though there is no guarantee of that) but they may not last as long as the percentage increase in price. I use either 20C or 25C packs but you could use higher C packs but they come with a weight penalty. Everything in aerospace is a compromise.

As for recommendations on what to buy, best to try some of the folk like F3A Unlimited and others of their ilk for a good combination of price and performance trade off. I've seen some folks using Hobby King motors and ESCs in a 2 mtr quite successfully. We are all guilty of wanting the best kit but rarely does our flying live up to the quality of the kit! So, take a good look at your flying ability and do yourself a favour by not splurging on the best to begin with. Better still, consider buying a second hand bird that has been tried and tested. F3A airframes hold their looks and value much more than run of the mill airplanes. I think I've only bought new on one occasion and have never regretted the choice.

ltc

My Feedback: (3)

SAB

ITC,

Those conditions are just not practical for 2M pattern - I know of no one that doesn't charge to 4.2V/cell and the rule of thumb is no less than 20%
Getting through a schedule whilst meeting the weight requirements are the reasons for this.

Also, post earlier says something has changed with Zippy compacts - I agree, I have packs from 2016 with 100 cycles & still going strong but all my packs from 2018 have 50-60 cycles at best. Zippy Rhino's were a similar story when I first used them in 2008/9 they were great but later ones from 2010/11 were considerably worse.. seems as they get more popular the quality goes down.

Steve

ron_van_sommeren

And
LiPoRatings.com - Everything about LiPo Batteries.

Prettig weekend Attachment 2264967 Ron
• Without a watt-meter you are in the dark, until something starts to glow •
• e-flight calculators • watt-meters • diy motor tips&tricks • Cumulus MFC •

neil4066

Nobody else has yet replied to your questions, so let me say what I think.
MOTOR
Play it safe and buy the best Plettenburg or Hacker. Do not get a geared motor, as you do not need maintenance. A lesser known brand such as Scorpion or Axi might be a lot cheaper and still good. F3AUnlimited also do an even cheaper motor that might be good.
ESC
I would say pay a bit extra and get a Jeti 99. This has all the fancy brake options, and will last virtually for ever.
BATTERIES
Get at least 6 sets of 10s. The cheaper Zippy or Turnigy brands work very well, unless saving every gram is important.
CHARGER
I strongly urge you to get an iCharger 3010b for $190. These are compact, run cold, and give you lots of fancy stuff like measuring batteries IR. This runs at a huge 1000 watts, so it needs a 1000W power supply for it, like a Meanwell. Then get from Progressive RC the matching parallel charger board to charge lots of batteries together, which is very quick and safe. The only decision is whether to us the yellow XT plugs or the 4mm shrouded banana type, which come standard on Zippy or Turnigy batteries.

Use a standard prop recommended for the motor, like 21 X 14. Then you never need to check amps etc or use any fancy calc program. Just go out and fly a few thousand flights with no worries!
Neil

ron_van_sommeren

...a lot of the time, C stands for crap ...
Have you ever wondered how a 100C battery gets away with an XT60 connector that is only rated for 60A? If you use lipo batteries in your RC planes, helis or drones then you need to watch this video and learn why the C rating of your batteries might not be what you think it is. There's also some other lipo info in this video that hopefully everyone will find interesting and of some value.


Vriendelijke groeten Ron
• Without a watt-meter you are in the dark, until something starts to glow •
• e-flight calculators • watt-meters • diy motor tips&tricks • Cumulus MFC •

flywilly

My Feedback: (121)

Thanks, guys!
There was a very informative article in a recent K-Factor about the 'mythical' C-ratings. I am slowly getting educated...

bem

My Feedback: (1)

Hi,
For what it is worth:
Post #199 -> about Hacker TopFuel Eco-X 4600 mAh F3A Edition. I'm not the only one that had trouble with these I'm afraid.
http://www.rcuniverse.com/forum/elec...en-etc-10.html
/Bo

ltc

My Feedback: (3)

Apart from having no power, have you measured or tracked the IR?
I'm curious what the numbers are ...

UKMouldy

I can't agree with the comment that F3a is a harsh environment for batteries. 3D heli's and general EDF, now that's harsh!

I'm using Optipower batteries, 5S 5000 in series and to date have logged over fifty flights on three pairs. The IR in these cells is starting to increase and at present are showing an average of about 2.6 milliohms across all six batteries while being charged on a PL6

Peak power during the last flight was 71A, this was hit once, mostly power peaked at around 68A. Batteries are rated at 25C so they are hardly in a harsh environment! And yes, I do understand that C ratings are not that accurate although I believe Optipower to be one of the more honest distributors.

However I will caveat the above by saying that if it's windy then I am landing with around 19% left which I know is not ideal. This is partly due to the draggy aeroplane I have and can also be attributed to my lack of good throttle management when it does get windy. On clam days I can land with 48% left after a P-19.