I agree; this is why you need to measure the actual IR to determine the true C discharge rating, or that lower-C-rated but higher capacity pack may still overheat and puff. Some chargers will do this; I like the Giles IR meter, because it not only measures IR, but uses a verified program to estimate true C rating. Unfortunately, Wayne just announced he is making his last batch.
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Admiral Batteries vs. Turnigy
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Sorry if this has been addressed before. I'm in a bit of a hurry and have a question about charging my lipo's. My charger wants inputs for both charge rate and discharge rate. If I'm only charging the pack, do I just ignore the discharge rate setting?Bob Duncan
The only real helicopter is the CH-47 Chinook. The rest are just sling loads!
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Originally posted by BadBob View PostSorry if this has been addressed before. I'm in a bit of a hurry and have a question about charging my lipo's. My charger wants inputs for both charge rate and discharge rate. If I'm only charging the pack, do I just ignore the discharge rate setting?
Also, you can "charge" without plugging in the balance plug. However, if you "balance charge", then the balance port needs to be connected.
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Originally posted by BadBob View PostSorry if this has been addressed before. I'm in a bit of a hurry and have a question about charging my lipo's. My charger wants inputs for both charge rate and discharge rate. If I'm only charging the pack, do I just ignore the discharge rate setting?Lon
EFlite F-16 80mm, EFite DRACO, EFlite Night Radian, E-Flite P51 1.5m
Freewing A-10 80mm, F-86 80mm, F-15 90mm, Avanti. FMS DHC-2 Beaver, Fliteline P-38L ,HSD HME-262, HSD F86.
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Originally posted by xviper2 View Post(My 2 cents, probably not worth even that much.)
I have many Admirmals, both the regular ones and the Pros. Same goes for Turnigy, of all "C" ratings. I've started to use the HobbyKing Graphines lately as my flying buddies say they are spectacular. My first purchase of the Graphine resulted in 2 dead cells on arrival (6 cells total) but HK replaced it immediately free of charge. The replacement was fine.
As WintrSol just posted about the "real" C-rating, I try to buy the highest C rated battery of any brand now. I've always had the feeling that there was something fishy about the stated rating. I'll buy the Admiral Pro whenever they are available and when the price is good. I will only buy Turnigy Heavy Duty whenever I can. The other Turnigies just don't cut it. The HD have worked very well for me so far, even though the QC on them is a bit random (some cells don't charge up evenly). The prices for the Admirals and the Turnigy HD are similar, with the HD coming in a bit cheaper. The jury's still out on the Graphine. The price on those are much higher.Bob Duncan
The only real helicopter is the CH-47 Chinook. The rest are just sling loads!
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Originally posted by BadBob View Post
Coincidence would have it, a friend of mine is deploying and won't be flying for a while. He just gave me 2 brand new Turnigy "heavy duty" 3300 60-120c packs. Being a C rating of these as 60-120C, do you think they will be good for the P-38, stock motors? They fit right in. Might have to do a re-balance tho.
Yes, those will work just fine my the P-38 so long as they haven't been damaged by severe discharging (ie, brought down to below 3.0v per cell). I believe, given related test data, that these will give an honest 25 to 30C, with a boost rating over 30C for several seconds. Most planes will fly quite well on an actual 30C rating. In fact, my alternate set of batteries for the P-38 are 3000mah, 20 - 30C "regular" Turnigy and they perform adequately in the plane. My usual Admiral Pros, 3600mah, has a bit more "grunt" and flight time, but the lower C (probably closer to 10 - 15C actual) seem to work OK, so your 60 - 120C should perform similar to the Pros at a rated 50C.
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Originally posted by xviper2 View PostI have been a fan of the Turnigy Heavy Duty for some time. My first choice is currently the Graphenes, then comes the Admirals and then come the "Heavy Duty", but they are all "up there". (Since that last quoted post of mine, Graphene quality control has been much better and nobody I fly with who has bought any lately, has seen any with dead cells.)
Yes, those will work just fine my the P-38 so long as they haven't been damaged by severe discharging (ie, brought down to below 3.0v per cell). I believe, given related test data, that these will give an honest 25 to 30C, with a boost rating over 30C for several seconds. Most planes will fly quite well on an actual 30C rating. In fact, my alternate set of batteries for the P-38 are 3000mah, 20 - 30C "regular" Turnigy and they perform adequately in the plane. My usual Admiral Pros, 3600mah, has a bit more "grunt" and flight time, but the lower C (probably closer to 10 - 15C actual) seem to work OK, so your 60 - 120C should perform similar to the Pros at a rated 50C.Bob Duncan
The only real helicopter is the CH-47 Chinook. The rest are just sling loads!
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Originally posted by BadBob View Post
Put in my Turnigy Heavy Duty packs and man, I just can't can't find that sweet spot for balancing now. Now matter were I move the packs to, I get either too much nose down or too much tail heavy. Frustrating!!!! They both weigh in at just around 1.5oz ea. (3oz) more than the regular Turnigy 3.3's I balanced with. Is this much extra weight a concern?
Besides, that CG in the manual is only a recommendation anyway and is used as a reference point. Don't forget the few degrees of UP elevator as stated in the book for neutral trim or you'll think the plane is too nose heavy when it flies.
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Looking at the photos, it appears the batteries sit above and below the chord line of the wing, so whether you try to balance right-side up or upside down, the CG of the battery will be above the wing surface. In this case, I find the only way to get a stable balance point measurement is with the Vanessa machine.
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Originally posted by xviper2 View PostI think what you're experiencing is the "teeter totter" effect. Some planes just seem to be hard to balance even if it's dead on. Are you doing it upside down, right side up? You move the plane just a bit too far from center and it goes over and it's the same in the other direction. Know that this plane is NOT that sensitive to CG placement. I fly Turnigy 3000mah (not even heavy duty) on one flight and then throw in Admiral Pro 3600mah the next. The pros go all the way back and the Turnigy NOT all the way back. I don't even try to get them in the same spot every time. The plane flies just fine. You might need a few clicks of elevator trim either way, but that's not a big deal. I feel some folks just stress themselves out way too much about balancing a plane. They swear that their planes fly differently if the balance is off by 2mm. Of the 50 planes I've flown, not a single one cared if the CG was off by 5mm, sometimes even 10mm didn't matter. Light planes seem to be more affected. This is not a light plane. I have a HobbyKing Hawk (yeah, it's a bird plane and a light one at that) and I've flown it with the battery varied by as much as 2 INCHES. A little elevator trim and it flew the same.
Besides, that CG in the manual is only a recommendation anyway and is used as a reference point. Don't forget the few degrees of UP elevator as stated in the book for neutral trim or you'll think the plane is too nose heavy when it flies.Bob Duncan
The only real helicopter is the CH-47 Chinook. The rest are just sling loads!
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Originally posted by BadBob View Post
I guess if you're using the heavy duty packs then the extra 3oz. is OK. Does it handle any different than with the lighter packs?
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I have several Admiral batteries that I've cycled hundreds of times that are still good with low IR, I also have purchased several of the economy batteries such as Floureon and Zippy which haven't performed anywhere near as good as the Admirals so the old adage "You get what you pay for" is very true.
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Originally posted by BadBob View PostI just checked my 2 turnigy, 4s 3300 heavy duty packs and I get an IR of 9, 6, 6,and 8 on one and 9, 11, 9 and 10 on the other pack. Doesn't look good to me. Shouldn't they be lower and closer together?
My Turnigy 4S 4000 'High Discharge' 30-40C packs measure 3.4, 3.8, 3.64, 3.68 and 4.12, 3.44, 3.48. 3.88; both had been resting at 78F for over an hour before measurement. Under those conditions, I would expect about 20% higher readings for yours, but IR changes very quickly with temperature, so you can only compare when the temperature is stable at a common value.
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Originally posted by WintrSol View PostWhat conditions were they kept in for the hour before measuring? What was the temperature? For example, if the first had been charging, or discharged, not long before the measurements were taken, the middle cells would be warmer, and measure lower IR. Also, if the temperature was less than 77F (25C), the numbers may be higher than expected.
My Turnigy 4S 4000 'High Discharge' 30-40C packs measure 3.4, 3.8, 3.64, 3.68 and 4.12, 3.44, 3.48. 3.88; both had been resting at 78F for over an hour before measurement. Under those conditions, I would expect about 20% higher readings for yours, but IR changes very quickly with temperature, so you can only compare when the temperature is stable at a common value.Bob Duncan
The only real helicopter is the CH-47 Chinook. The rest are just sling loads!
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Originally posted by BadBob View Post
They both have been sitting out on my bench inside the house overnight and read this: 1st pack: 11, 9, 7 and 9, 3.82/.83v per cell. 2nd pack: 11, 13, 10 and 11 and 3.83/.84 per cell. These readings are from my Hitec X2 A/C charger in the "Batt. Resistance" mode.
I found this comment on a thread on this charger at rcgroups:"... the internal resistance meter feature built into the charger was very inconsistent. The resistance values would fluctuate inconsistently by up to ~10 milliohms when using the same battery within seconds of hitting the button", which was followed by another user that said he got readings consistently in a +/-1 mOhm range. Maybe there is a variation between chargers?
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For the curious, I just received a new Graphene 4S 4Ah '65C' battery, and even though the temperature is lower than I'd like (69F), I tested the IR. The results are as expected: 1.88, 1.92, 1.88, and 1.88 milliOhms, for a safe continuous current draw of 116A - a true 29C. I expect that at my normal test temperatures, the numbers will improve to yield 30C or higher continuous current. Of course, the Graphene weighs 3.5 ounces more than the Admiral or Turnigy batteries, at 17.9 ounces, and is a bit larger in all dimensions. It won't fit in my FMS P-51, but does in my 3D SaberX, but I'll have to recheck balance.
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Originally posted by WintrSol View Post
Any idea what the temperature was? In any case, the packs seem to have a fair amount of variation, but I don't know how that charger measures IR, or how repeatable it is. I use a meter designed by Wayne Giles, which is available at ProgressiveRC. With it, you move the cell probe from one to the next on the balance connector, so the same circuit measures each, and it is very repeatable; also, the probe only measures the Voltage drop of the chosen cell when a current pulse is applied to the main power connector. I wonder if a bit of DeoxIt on the connectors will change the readings you are getting; it doesn't take much contact resistance, if the measurement pulse is applied to the balance cable.
I found this comment on a thread on this charger at rcgroups:"... the internal resistance meter feature built into the charger was very inconsistent. The resistance values would fluctuate inconsistently by up to ~10 milliohms when using the same battery within seconds of hitting the button", which was followed by another user that said he got readings consistently in a +/-1 mOhm range. Maybe there is a variation between chargers?Bob Duncan
The only real helicopter is the CH-47 Chinook. The rest are just sling loads!
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Originally posted by BadBob View Post
Temps are at a constant throughout the house, which at the time is 72°. I just rechecked the 3300, 4s and now get a reading of 12, 10, 8 and11, a difference of +1 ohm as I understand it. I just ordered the Wayne Giles meter. Is Deoxit the same as an electric contact cleaner?
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