BarracudaHockey

My Feedback: (11)

http://www.readyheli.com/HTC-X4-Hite...x_p_38017.html

Or if you want to deal with HK the Turnigy version has been showing up a lot now at our field and the guys really like it.
http://www.hobbyking.com/hobbyking/s...dproduct=11170

BuschBarber

My Feedback: (2)

The FMA Fuel Guage may not be Accurate, but it is very Repeatable. I have been using my FMA 10S chargers for several years, charging batteries for several Electric Aircraft. After a couple of test flights, on a new aircraft, I know how many minutes I can stay in the air and when I land, I always find that the Fuel Guage reports the same percentages. I try to stay above 15%. I can always look at the Individual Cell Voltages, as well, but the Fuel Guage has given me a Reliable, Quick look.

rmh

I also use the FMA10 exclusively but never checked the repeatability of the guage

Jezmo

I don't want to comment on the Eneloop cells as it would just start a big dustup, however I DO want to say that my CBAIII from West Mountain Radio pretty much mirrors your chart on the LiFe batteries. At higher discharge rates the line begins to slant more instead of being flat but at that low discharge rate it is not apparent to me. Not sure what Tim is talking about but from my point of view (Or maybe my CBAIII's) the Hyperion is showing you the real goods.

Also, for those interested the FMA Cellpro chargers can have the fuel gauge adjusted to more closely match you particular cells if you have the USB Interface and PC software.

rmh

Discharge rates are one of the prime causes of "my radio quit".
Without some type of watt measuring device, the drain on flight batteries is just a WAG.
I just ran some tests on a small electric motor I aquired - -not what I really wanted (a 1400kv Turnigy) but I thot I would see how it performed .
Compared to a 1100 kv - -same motor - BIG difference
Point being - one motor would not really depress battery very much on a 11x6 prop - the other would peg the amps over motor rating. The power pack also took a nose dive as the motor tried for all it could get.
At our altitude - I can use a 10x6 on this motor ( we are at 4350 ft elevation) but at sea level it would likely smoke it.
The LIFE type battery (not a genuine A123 )typically won't stand really high discharges
Also LiPos - unless they are larger , 30-40 c will also drop like a rock on these high power consumption motors -OR high consumption servos .
The ENELOOP were never intended to be used in apps where consumption is over a couple hundred MA and this means -as a rx pack - don't do it. I use em all over the house and in my tx's.

TimT2000

My Feedback: (1)

Perfect ! Thank You
Tim

Jezmo

I'm only using genuine A123's here Dick. As far as the "my radio quit" issue, I agree with you 100% sir. I also agree the Eneloops were never intended to be used in high current draw applications, however it can be done. I ran the 50cc Extra 260 in my avatar for over 3 years with 2 parallel 5 cell Eneloop packs. It has 5 Hitec HS-5985MG servos and 1 HS-5955TG on the rudder. That was with the Spektrum AR7000 that had the slow reboot or "Brownout" issue. Never had a single hiccup. According to my CBAIII the "Genuine Sanyo" Eneloops can pull over 8 amps without the cell voltage going below 1 volt per cell. (I'm not talking about cells that are significantly discharged) I haven't found another AA NiMH cell that can do that but the Sanyo A size NiMH cells come close. The Extra now runs on dual A123's and has been Huckin' for almost 5 years.

Also, just for note, there are MANY MANY MANY fake knockoff Eneloops out there. They are junk and are quite difficult to tell apart from the real deal. Package and all looks authentic. You've gotta look really close at the actual construction of the cells to spot em. There are numerous flashlight/battery forums out there where this issue is discussed.

Yeh Baby keep her low....

rmh

wow 8 amps -on how many cells?
I bought all my ENELOOPS at Costco -on their 12 cells n a charger for 29 buck deals
I use em in my DX8 tx's and every AA and AAA application in the house.
I still use 2300 A123 for flight packs and as the power pack on a 32 Eflite 3D setup (5 cells in series )- all up 3.75 lbs on an ERATIX it is a rocket
Ilike it better than LipO- instant recharge at the field 15-20 minutes cycles at 4 amps input.

MetallicaJunkie

so am i hurting my Li Ions not letting them get below 7.5?.... fresh off my 42% Products charger i get about 8.4 volts... Lion and Life have similar characteristics in that they hold their charge unlike nimh and nicads, based on what ive read i own no Life packs yetallthough a123 is what i will go for

a1pcfixer

My Feedback: (7)

I've been flying with Li-Ion's for years, and often fly the packs down to 7.2 v.
At around abouts 7.0 v., they're nearly empty.

Li-ion's are nearly as good for maintaining a steady line voltage as LiFe/A123's.....almost.
Either are better than NiCD/NiMh's.

TimBle

Ifully agree, the Hyperion EOS is indeed doing what required of it.
My coment was based on a situation where the graph would be used to illustrate how difficult ti is to measure used capacity of a LiFePO4 battery and packs. In reality the line is never perfectly flat, there is always a slope which makes the capacity discharge measurable.

Ionly noticed later that the graph was taken under a constant load. In this sitaution yes the discharge curve could very well be absolutely flat for around 75% of max capacity but the Hyperion EOSdoes not measure the remaining capacity under load AFAIK. It merely read the voltage to 0.001 V and interpolates. the fact that is conservative is already an inbuilt safety margin. It is basically saying that when you hit 0% capacity that its time to recharge and this is typically around 6.2V for a 2cell pack. It's telling you to recharge before you hit the drop off point of the curve.

Silent-AV8R

I have not seen the spec that the Hyperion meter reads voltage to 0.001 volts. It only displays to 0.01 volts. BTW - it is not the meter I used for my discharge curves.

rmh

LiIons work well except under heavy loads they are not as good
The problems I have seen is where a linear reg and LiIon is used - then really power hungry servos are added
The regs heatup and the system then delivers very low output till it cools .
I detest regs -won't use em unless forced to at gun point.
The new Switching types are far better but still just one more failure point
using A123 directly into rx is -(my opinion) as good as it gets - till something better comes along
(Dilithium crystals?)
beam me up!

BuschBarber

My Feedback: (2)

If you have servos that are not 6v compatible, you have to use a reg. My JR 791 Retract servos need 5v and there are no other comparable Retract servos.

I have been using LiPo Rx packs, for years, with Regs. Never an issue.

Pilot232

My Feedback: (3)

Look at the Spektrum A7000. Comparable to the JR791 and adjustable end points and speed.

Warm Regards,

Travis

TimBle

the Hyperion measures to 0.001V.Connect the battery and click on "cell". It will display individual cell voltage to 0.001V.

Jezmo

The last ones I bought I paid 14 bucks for 4 cells in a blister pack. I have some low self discharge NiMH cells from another manufacturer and they are great in that respect but they won't hold up under the higher discharge rates. The pack tested at 8 amps was 5 cells hand built using short heavy leads for the test so very little current was lost. Eneloops are in my DX8 as well and the battery cover has been modified with an Ernst charge receptacle so I can charge with my good charger instead of the internal. I'm sorry Spektrum, the internal charger is junk for charging NiMH batteries. A123 flight packs until something better is invented, no regs for me either.

Sorry the pics a little blurred but the Ernst Receptacle can be seen.

rmh

slick - I just charge for a few hours -and make sure to not leave em on overnite.

BuschBarber

My Feedback: (2)

Thanks! I will check it out. How can End Points be set for Retract servos? They are not Proportional.

Silent-AV8R

Got it. I was speaking to the total pack voltage displayed when you connect it. Regardless, it still indicates a much lower remaining capacity than I replace when charging. Usually by about 15% or more. It will indicate that I used 70% of the pack and when I recharge I find I only "replaced" 55% or 60%. That is for both LiFePO4 packs and Lipo.

TimBle

Thats correct. ACcording to the distributor theres a built in error to account for the drop off end of the curve. It only measures the capacity before drop off.
Also its conservative in your favour. Thats a good thing

Also when you connect a fully charged Lithium battery it never shows 99% capacity like with a Nickel battery. Again I've been told the Lithium batteries need to be loaded to show fully capacity. Not sure how much truth there is in that but it does indicate that the checker is loading the lithium battery pack.

pilotpete2

This new Spektrum retract servo is proportional, and has gobs of torque, probably due to a higher than normal gear ratio.
Very interesting[8D]
Pete

rmh

The new porportional retract servo is really slick-especially using the DX8 speed adjust
As a caution- many retracts rely on the speed of the gear leg (an inertial thing) to make it from point A to B and lock properly
so i possible - adjust any helper springs to make for a low energy from lock to lock.

Years back-we rolled to inverted on take off , to allow the crummy Goldberg gear to easily lock these could be fussy in getting UP lock..
that was 35 years ago - later designs with rolling blocks are better but some are still balanced poorly.
Especially on scale stuf with heavy legs n tires n doors etc..

jak_kkaall

Refering to an 2S 6,6v LiFe 2100mA accu. Selected LiFe balance for 2S and 1A current but the charger didn't raise it above 03A and it took about 4 hrs to put 1200mA in it until I got bored and turned it off. Tried to select again, this time 2A, same thing...charging current won't raise above 03A. And from start to finish the pack voltage staid at 7,2v on the chg display and the cells went from 3,33 to 3,38v/cell. Same with the other pack. Why ? Before charging I start tuning the 50cc engine on the ground, and burned about one tank. During this running on the ground it took 1200+mA from the pack?! Thank you.

hookedonrc

I have been reading this thread with a lot of interest because I am going to convert to A123's on all my planes moving forward. I keep hearing the charge time at about 15 minutes and to me there is a simple solution. Maybe not the best, but workable. Usually I don't fly within 15 minutes after I land anyway. I like to watch others fly and to BS with the other pilots. So, although somewhat of a pain, recharging after 1 or 2 flights seems very doable. If the graph is accurate, you have almost 3 hours of flight time on the Hyperion's before you gotta do something. If I am flying gassers, that is more time than I usually spend in the air when flying all day.

Of course, electrics are a completely different story. But I recharge them every time anyway....it's just the flight time I would need to watch.