dlaque

Whats the best Rx pack to get, i have a R60 with regular servos and a dig. on the tail (GY 401 combo).
Right now im running a Hobbico NIMH 2000mah and it doesnt seem to last long (2 flights)
on a R700 JR reciever, XP8103 TX.

Is going lithium the answer with a voltagr regulator????

Happy flyin'

David

rander1

wow... how old is the pack??

I have a 2500 on my R50 3151's and a 9253/401 and my battery lasts FOREVER!! seriously like more than 7 flights....I think

-Rob

dlaque

My pack is new!!! Maybe its just a bum pack according to the voltwatch its not usable after 1 flight!!!
Any ideas ?????????

Thanks for the info.

David

rander1

Umm a little bit of fuel and a lighter comes to mind....

I dunno, did you charge it overnight? You definitely dont need a lithium pack though, I would return it if possible or warranty from the manufaturer? did you test the voltage on it?

-Rob

RotorNut

Since it's a new battery try cycling it a few times. Like rander1 implies you should get more flight time. I get about 4 or 5 flights on a 2500mah with all digital servos 3 high torque on the swash a governor and gyro. When you say regular servos what kinda servo's you talking about? The reason I ask is if the torque is under rated for the application it can cause a high load on the battery. Also what kinda charger are you using? And make sure you don't have any binding on any of the servos.

rusirius

Ummm let me take a guess here.... You have a 2000mAh NiMH pack and your using the standard charger that came with your radio to charge it???? Not gonna happen... Well, depending on the pack, it MAY, but your talking something like a 32 hour charge time... You really need a good charger for a pack like that... A superbrain, hobbico, triton, etc...

Other thing, like rotornut said, NiMH packs need to be "formation charged" when new... They need to be charged at around 10%C (in your case, 200mA) untill full.... Then discharged at around 10-20%C to around 1.1v per cell... Then charged back again at 10%C.... etc.... 3 times.... That "forms" the cells to get them to function properly... Otherwise they just won't ever get the "charge" that they should.... One of my raptors has 4 9001 servos, a gy401, a 9253 digital on the tail, a PCM receiver, a GV-1 governor, AND a micro wireless video cam... I only have a 1000mAh pack on it and usually get 3 to 4 good flights (12+ minutes) out of it with everything up and running...

dlaque

OK, i have a Hobbico quick field charger, when i got the pack i charged it at 2 amps (2000mah) correct??????

I didnt think you had to cycle NIMH packs!!! How could i do that with my charger or do i need something like a battery bug??

My servos are hitech hs645bb's and the new digital one that comes with the Futaba GY401.

Thanks again.

David

RotorNut

The charge rate depends on the size of the cell AA,AAA,C and so forth. The max recommended charge rates are as follows.

A - 2 amps
AA - 1 amp
AAA - 600 mA
N - 300 mA

Anything bigger than A size is fine to charge at 2 amps

In case you didn't already know when you charge a battery with that charger you have to let it trickle charge to get a full charge.

dlaque

Thanks Rotornut, i will try to charge the pack at 1 amp and let it trickle charge from there.
I was charging it at 2 amps, they are AA size cells so i guess it was peaking too soon.


David

cgroves

My VoltWatch tends to be very conservative. You need to verify this by running some tests with an accurate voltmeter but with my 3000mAh pack the VoltWatch is solidly in the yellow/red while moving the cyclic and I still have 2 flights left before I am at risk. My personal min standard is make sure that at the *end* of the last flight before charging that I am 250mAh above the point at which I read 4v WITH the 2 highest torque servos jammed and all servos moving rapidly YMMV. On my R30 I run a GV-1, 502, 148DP, 9254, 3x9252 and they all list 3.8V as the min operation voltage.

I did a test and found that this is what my VoltWatch displays:

5.4V Max
5V
4.95V
4.8V
4.75V
4.6V Red

Again, you need to test your own unit but it may be too conservative.

rusirius

2amps is definately pushing it for AA cells... As Rotornut said, 1 amp would be a much better QUICK CHARGE RATE... But remember, that is a quick charge... Not a standard slow charge...

Also, NiMH packs SHOULD be formation charged (charged and cycled) at no MORE than 10%C...

Your right that you don't have to "cycle" NiMH packs... They don't form memory like NiCds do, but, you DO need to formation charge them when they are new... Here's some reading you can do on formation charging....

Here's a FAQ that talks about formation charging...
http://www.hangtimes.com/rcbattery_faq.html

Here's another link dealing with batteries...
http://www.rcbatteryclinic.com/

dlaque

I did not slowcharge the pack, the only charger i have is the Hobbico quick charger!!!

Do you think the pack is still good??

One more question, can i slow chage with the hobbico field charger?

Thanks again.

Daivd

RotorNut

Sorry for the slow response, I did some checking on your battery and it is shipped form charged. So what you need to try is charge the battery at the lowest setting which is 200 mA let it charge till the charger says its done. At the 200 ma setting it won't go into a trickle charge, So after it's done set it to anywhere between 500mA and 1A and start it again. It will try to do another peak charge but should quickly go into trickle charge mode let it charge for a few hours to top off the charge. You should get better flight times out of it after that. After the initial charge you can charge at 1 amp and then let it trickle charge for a while I usually let it trickle for about 45 minutes when I'm not in a hurry to fly. If you do just a peak charge you'll only get 1 or 2 flights out of it. Hope this helps.

dlaque

Thanks Rotornut, today will be 65 here and ill have a chance to try it

David

rusirius

Ohh crap... I missed where he said it was a hobbico... Sorry about that! Yeah, do as rotornut suggested and give it a nice slow charge for a change... Should be just fine! If you do what he suggested, and still don't get hardly any time out of it, it's possible it has a bad cell or something, though, usually NiMH's fail open, and the pack would be completely dead... May just be a bum pack... But hopefully you'll be good to go!!!

enrico74

My Feedback: (6)

Hi All, I also have a hobbico charger and I build my own battery packs. (Usually a battery pack brought from the US to Ecuador costs 50% more than in the US!![X(] ) So i build my own. Currently I have 3 battery packs built from energizer cells. 2 of them are 2300 mah and 1 is 2500 mah. First time I charged them with 50mah for 24 hours, then connect them to my heli and let my 1 yearl old son move the radio sticks for about 1 hr (he really likes doing that, of course everything in hte safety of home with the engine off). 3 times I have done that with each cell. Now in flight I get 7 flights with the 2300 mah batteries using Hitec HS655BB (3) 1 Jr 810 tail servo, JR450 gyro, and a HS325 in the throttle. It`s pretty basic but I get 80 oz torque in the cyclic and pitch. With the 2500 mah batt I get 8 flights. My flight pattern goes from hovering to FFF with some stall turns, 1 or 2 loops and rolls and some low surface tactical flying. After those 7 & 8 flights the packs drop to 4.8 to 4.7 Vlts and I go back and slow charge them with 50mah again for the next day having a complete charge to do other 7 and 8 flights as above. Of course having 3 packs I have never had the chance to run out of receiver batteries, just the tx battery that I don`t have a spare one, so that calls it for the day. Just my 2cnts. Happy flying, Enrico

misileman

My Feedback: (8)

Cycle the pack a few times and it will increase the energy capacity. NiMH are that way, I call it memory. The biggest thing you need to keep in mind is not to overheat the cells.

I use 3300mah matched 4 cells used for 1/12 scale car racing that are designed for 20 amp high discharge rates. The first time out they were dead after only 2 tanks of fuel. Now I run out of fuel before the RX battery gives up on me and I mean run out of fuel that I take to field with me. And I use all 9252's even on throttle and a GY401 with 9254 on a Rappy 60. The battery will come around but be consistant with whatever cycling technique that you use, the battery will last considerably longer.

Talk to the electric car racing guys, they live by battery conditioning and what's current. That's where I learned. Just keep in mind that car racing is about big power "now" and we want lasting power. But I had problems with the digitals needing lots of power and the NiCd would not keep up with the draw and it was a 3000mah. After seeing what they were demanding from the battery, I went from there.

Good Luck

dlaque

Thanks everybody!!

I hope to get a chance to fly this week

David