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Thunder Power RC . Real Raptors . Mikado Modellhubschrauber

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e-Electric Batteries & Chargers > What is currently the best brand/model LiPo battery
 
 
rexxigpilot
Senior Heliman
Location: florida

I would appreciate opinions on what you think is the best brand and model of liPo battery available now. Looking for the most robust packs out there.

I fly approximately 2 hours average each week and go through LiPo batteries like water. I presently use mostly Flight Power EVO20/25's and Thunder Power eXtremeV1/V2's. Almost all flights are 80% capacity or less (never exceed 90%. Packs are balance charged with high quality chargers. Never push close to rated continous amps. However, too many packs of any brand I've used crap out due to internal failure causing high internal resistance (after 10-40% capacity, pack output voltage drops sufficiently to activate ESC/regulator cut-off circuit). This most often occurs in less than 25 flights.

I'm about ready to go back to nitro and gas only. The cost of large (5,000 mAH) LiPo packs is not acceptable considering the poor quality the manufacturers ar producing, IMHO.

Has anyone found a brand that is more reliable?
05-06-2008 03:21 AM
 
 
nappyroots2182
Key Veteran
Location: Moline, il

i dont know why your going through so many packs. maybe your batteries cant handle your motor? what is your whole setup. you sound like your doing things right but we need more detail please

DX7, Trex 600N, YS50, JR770 gyro, trex 500
05-06-2008 03:29 AM
 
 
rexxigpilot
Senior Heliman
Location: florida

My electric helis are all T-trexes - 600 and (2) 450's. Motors are stock Align, ESC's are Align and Castle, Deans Ultra connectors. Flying style is moderate 3D and hard sport.

I have checked the amps with meter and don't come close to maxing out their capacity on the 450's. The batteries in the 600 are pushed harder (±12° on collective). But I don't hold full collective long as I switch up manuevers often, so I only briefly get into the burst rating of the batteries. Does that help?
05-06-2008 03:48 AM
 
 
nappyroots2182
Key Veteran
Location: Moline, il

well now i might be stumped. this should not be happening. is there something with your charger or balancer that could be hurting these packs as you say it on both of your different size helis. ive got lipos that are years old and hundreds of flights on them even without balancing.

DX7, Trex 600N, YS50, JR770 gyro, trex 500
05-06-2008 03:54 AM
 
 
coptercptn
Senior Heliman
Location: Beach Park, IL. USA

I may be a bit biased here but I have the Trex 600's and 450's The only packs I use are the Air THunder packs. I fly at least 10 hrs a week and have yet to loose a pack...I'm using the brick style ^s 5000 for my 600's and the 3S 2200 for the 450's. I also have an E620 Raptor running 2 5S 8000 in series. I have used up 4900Mils on the 5000 packs without any damage to them. Still going stong at 128cycles!!

Trex450(x3), Trex Huey,MD500/Trex600 ,E620 Raptor.."Air Thunder Dealer"
05-06-2008 04:26 AM
 
 
rexxigpilot
Senior Heliman
Location: florida

I charge the big packs with the TME Extrema and the small packs with either the Extrema, Triton or a CommonSense charger. The inline balancer is a V-balancer from FP. All appear to work fine.

I have 20 packs currently - that work that is. This is typically how many I keep around. The packs that simply wear-out slower lose capacity and are ultimately retired at about 75-80 percent of original capacity.

This is something different. I've had 2 large packs and 5 small packs go bad in the manner describe in original post. This has occured over about a 2 years span.

I take it you don't think it is a brand/model problem. Is there something better than what I am using? I don't see how it could be the charger. The only charger that has charged them all is the Extrema, but wouldn't a charger problem affect all my batteries?
05-06-2008 04:40 AM
 
 
rexxigpilot
Senior Heliman
Location: florida

coptercptn,

How hard do you fly and what % of the battery capacity do you normally use each flight? Have you tried FP or TP batteries in your setup for comparison against the Air Thunders?
05-06-2008 04:46 AM
 
 
coptercptn
Senior Heliman
Location: Beach Park, IL. USA

I had TP and they puffed on me..I have scale fuses on most but I do like to extend flight times in them...and loading with a large scale fuse can really work the batteries. My 450's I do fly a bit harder and there is the problem with the TP packs..Haven't had that happen with the AT packs..

Trex450(x3), Trex Huey,MD500/Trex600 ,E620 Raptor.."Air Thunder Dealer"
05-06-2008 04:56 AM
 
 
helicraze
Veteran
Location: Victoria - Australia

25 flights is too low. There must be something wrong. Do you store them in a discharge state? If i know i've discharged too much i will charge them back up a bit before putting them away.
05-06-2008 06:06 AM
 
 
pcliftonjr
Key Veteran
Location: Phoenix, AZ

Onboard monitor...

Do you have an Eagletree? Unless you're running one or something like it you really can't know how much the system it being loaded.

Paul
05-06-2008 06:18 AM
HOMEPAGE  
 
 
Wyn
Senior Heliman
Location: Oregon, USA

Overcharged? How about checking the cell voltages at/near the end of charging with an accurate digital volt meter. An old trick for measuring voltage in a wire without an accessable testpoint is to poke a small straight-pin or needle from the sewing kit through the wire insuluation (on the balance connecter extension).

Wyn
VoltMagic
05-06-2008 08:18 PM
 
 
rexxigpilot
Senior Heliman
Location: florida

Quote 
Do you store them in a discharge state?

I keep them charged at all times between flights. But they never sit fully charged for more than a week or two as I fly often.

Quote 
Do you have an Eagletree? Unless you're running one or something like it you really can't know how much the system it being loaded.

I may have to get a flight data recorder. But, I'm not running a setup others at my club don't also use.

Quote 
Overcharged? How about checking the cell voltages at/near the end of charging with an accurate digital volt meter.

My chargers have very accurate voltage meters. I also checked with a electronics grade meter. Not overcharged. I even check cell to cell voltage to make sure there is no cell imbalance and resulting overcharged of any single cell.
05-07-2008 12:11 AM
 
 
pgoelz
Senior Heliman
Location: Rochester MI

FWIW, you are not the only one. I too have contemplated going back to nitro only due to similar pack failures. I fly electric planes and helis and none of the packs I fly can be taken anywhere near the rating of the packs in the air. For example, I fly 3S 2100/2200 packs in both my Trex and my Mini Funtana. Both craft pull about 29A WOT static. The packs are rated for a lot more than that, even if I flew WOT 100%. My average flight is about 8 minutes with maybe 20% remaining, so I am using about 13A average. I always check remaining capacity upon recharge and it is never less than 20% remaining... usually more. I recharge at 1C or less with a Cellpro and before that, with a regular LiPo charger and a Blinky at 1C. Neither has ever reported that my packs were seriously out of balance.

I have had a PolyRC pack and a TP pack fail at less than six months old with abnormal internal resistance, and I have had two TP1320 packs from a smaller plane fail the same way, although they were older. All TP packs were replaced N/C but they failed to answer my question re: why did they fail. The PolyRC pack was replaced at a 50% discount and Pat has tried to convince me the problem is that I store my packs fully charged.

I do store my packs fully charged but from what I have read I refuse to believe that full charge storage can be blamed for a high internal resistance failure in less than a year or two. As a compromise I am now storing my packs in a small refrigerator in the basement (usually fully charged). Storing them partially charged is not logistically realistic so the fridge was the best solution I could come up with.

So you are NOT the only one. From what I can gather from reading and talking to a couple manufacturers, LiPoly cells are inherently life limited to maybe three years. You can make that worse but you can't make it much better. My two cents is that there is a HUGE amount of price pressure in the hobby market and manufacturers and vendors are playing games with cell ratings. The result is that we are very likely abusing them without knowing it because the published rating is not realistic or compatible with long life.

Paul

Paul Goelz
Rochester MI USA
http://www.pgoelz.com
05-07-2008 08:04 PM
HOMEPAGE  
 
 
helimatt
Key Veteran
Location: Lafayette, IN

I'm having similar experiences particularly on the Trex 600 first with stock motors, then with a Z30A motor. The batteries work great at first, but it seems one or maybe two times discharging them beyond 80%, and they die.

I have two FlightPower EVO's (one Evo20 and one Evo25), both will fly at reduced power, but clearly one cell has issues in each of these by the way they are so out of balance at recharging. Just recently my TP extreme V1 pack has gone bad and will only give me half the flight endurance before severely dropping output voltage (per flight characteristics and the ESC cutoff kicking in). I have a PolyQuest Enerland 20C pack which was good for around 30 cycles then pooped.

I have a TP V2 only about 15 or fewer cycles its pretty good, but just started coming down quite hot at the end of the flight. I need to cut back the flight time, but still taking less than 80% capacity.

Right now only my Airthunder keeps on delivering. A little less power at the start of the flight comprared to the TP V2. I am looking to get more of the Airthunders, even though they are heavier. I notice the weight in the way it flies, but not a show-stopper.

I am flying timed 5-minute flights. I think the 6S setup rips the guts out of the lipos, even though we are not even close to the rated continuous and burst ratings.

I think FP and TP will give warranty or serious discount if you return the bad packs to them with an explanation. I'm going to do that myself.

Never, ever, ever, ever give up.
05-08-2008 04:18 PM
 
 
helimatt
Key Veteran
Location: Lafayette, IN

BTW, for the 450 using a 3S setup, the TP extremes I got about a year ago did not last (dropped power pretty fast). I think that was a common issue. I got some 25C packs from Hong Kong on Ebay, they are doing great, lots of power (can't remember what they are called off hand). Hyperions are pretty good too, and I have one new-ish FlighTPower EVO25 which kicks butt. But my favorite bargain, and most powerful pack I have now is a Hextronic V2 from HobbyCity, $36 shipped, and its going strong, but only about 50 cycles on it thus far, but it hasn't lost a thing.

See this thread-
http://runryder.net/helicopter/t417201p1/

That is the best battery I have run aside from the old Kokam 15C 2000mAh packs. I haven't tried Kokam (CellPro) lately, but they had been best of the best.


My setup: Medusa 28-23-2400, 13T pinion, Ace/ThunderPower 40A ESC, 5.5minute timed flights of 3D. Consistenly putting back 1650-1700mAh at recharge. I store my packs charged, but the are flown a lot too.

Just sharing my experience there. As they say, your mileage may vary.

Never, ever, ever, ever give up.
05-08-2008 04:38 PM
 
 
rexxigpilot
Senior Heliman
Location: florida

I appreciate everyone's input. I'm glad to know I'm not the only one having this issue.

Is anyone out there havng problems with AirThunder or Hextronic? Also, does anyone actually store their batteries at half charge? If so, what is your experience with battery failure?

Paul, how long have you been doing the fridge thing and do you see any improvement in pack life?
05-08-2008 11:48 PM
 
 
pgoelz
Senior Heliman
Location: Rochester MI

Unfortunately, I have only had the fridge for about a month so no results yet. I do have a couple small packs that used to fly in some very small planes that have been in cold storage for about two years (I kinda forgot about them). I'll have to check them out to see how they did. I think they may have been Kokam cells.

Paul

Paul Goelz
Rochester MI USA
http://www.pgoelz.com
05-09-2008 12:36 AM
HOMEPAGE  
 
 
beeflyer2
Veteran
Location: Woodstock, GA

Quote 
I would appreciate opinions on what you think is the best brand and model of liPo battery available now.

FMA Revolution are the best I've tried. I'm used to packs getting weak around the 75 cycle mark, but these are still going strong well over 100 cycles.
05-09-2008 01:11 PM
 
 
pgoelz
Senior Heliman
Location: Rochester MI

Think about that statement..... packs getting weak at the 75 cycle mark. Assuming $70 per pack for 3S 2100mAH packs, that is a buck a flight..... if they make it that long. Is that really acceptable?

I think my summer project will be to get a couple A123 packs and try them. I love what LiPoly cells can do but I am tired of the hassle and expense of having to replace them prematurely. If the fridge doesn't stop the failures, I am probably back on my original track of getting out of LiPo electric at least temporarily.

Paul

Paul Goelz
Rochester MI USA
http://www.pgoelz.com
05-09-2008 02:54 PM
HOMEPAGE  
 
 
rexxigpilot
Senior Heliman
Location: florida

I think I may take the same path as pgoelz. Anything less than 200 cycles (typical manufacturer's claim) for a LiPo is unacceptable to me. The A123's are heavy and, therefore, don't have the power to weight of a LiPoly. But if it lasts much longer than LiPo as the manufacturer claims (1,000 cycles), has less chance of fire/explosion and has a faster recharge rate, it may be the best bet.

Does anyone have long term experience with the A123 cells they can share? I guess we can no longer trust manufacturer claims. Could we ever?
05-09-2008 05:21 PM
 
 
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e-Electric Batteries & Chargers > What is currently the best brand/model LiPo battery
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