low voltage warning trouble

[hipollito]

Hello.
For a while nowI have been fighting to get this one fixed...I have a AW 260 35% with DA 100 Futaba 8ch rx 5200 lion fromeco batts and reg. and I can´t get rid of the low voltage warning the radio has.

I have changed the rx, batteries and I shortened the cables from the batt to the receiver, changed the voltage on the reg, etc...and nothing is working....Can someone tell me how to solve this?? or get rid of this low voltage warning....just to be sure...it is not the fail safe..I know you guys know what I am talking about...my dad is starting to have the same problem on his heli...

HELP!!!
thanks!!!!

[f5air]

i was having the same problem "hichicken", and was something internal on the rx, good look i did it cause later the problem went worse and i almost lost my airplane. Send the rx to hobbico. But try with another switch.
Mucha suerte

[3ddd]

did you try hooking the bats up direct with no switch?, also check that none of the connectors are corroded or loose,if not then i would send the radio in for a look. also i made a jumper to plug into my receiver and then hooked my battery tester up to that,wiggled all the sticks and watched the readout for low voltage

[hipollito]

I havent tried with different switch....will try that....now I am thinking I have two rx with some internal problem....that´s odd...anyway...will try the switch and see, any other suggestions??
I already checked all conections, even changed some extensions and cables so the batt is more direct to the rx....Won´t the rx be fried if I connect the batt directly?? (7.4 when worse, 8.3 usually)

thanks

[dullerud]

Hi

I had a 3W Yak 54 that crashed due to voltage drop. Probably reboot of servo's and/or Powerbox. I had a voltage/current logger on board. The batteries were 2 Fromeco 4800 packs.
It was the first run of the day with fresh batteries. The Fromeco Li-Ion batteries just can't keep up with the current-drain from many high performance servoes.

I've never used Li-Ion batteries after this.

The crash was pretty expensive.

I tried to get a comment from Fromeco. They never answered my mail.


Trond Dullerud
Norway

[yakpilot]

Dullerud, I'm very sorry about your loss! And welcome to Flying Giants. Could you please post a little more info on your specific set up? There are a lot of very knowledgleable people on here who could help you diagnose the cause of your crash. A lot of people have used those batteries with great success so I'm a lttle leary of placing the blame there. I'm not trying to say you don't know what are doing. Not at all. I just hope you'll keep an open mind and consider all possible causes. I only say all of this because I don't want this to happen to you again or maybe someone else who's reading this thread. I hope you figure it out.
Best regards,Rob

[ScottZ]

IMHO I always felt that I was living on the edge with LiIon batteries in my 40%ers. I did very simple tests on my bench 2 5600Mah TBM packs ,smartfly reg, all deans connectors and SmartFly PE with failsafe switches. TX on and RX on all surfaces taped and sticks in the corners for maybe a second or two. My H9 ammeter plugged into the AR 7000 rx was getting INITIAL readings of 4.2 volts and then rising up a bit till I let off the sticks. Now, when you have a full charge of 8.4 volts and you are regulated down to 6.5 volts and under a heavy load you go down over 4 volts I was a little nervous about this technology. This of course is a crude way of measuring but it seems possible that these figures jive with a second or third flight rx brownout that many people have experienced already. It is also probable that if your servos are being blown back in flight that you might have more amp draw than on the bench tests. A surface that is blown back is turning your servo motor backwards that is some serious amp draw. I got away without a single crash in all 5 of my large planes for 2 years and the batteries were getting low. However, and this is important I CHARGED AT THE FIELD AFTER EVERY FLIGHT, This is why I never had a problem, and the reason why I went with A123 batteries in all of my planes. Under the very same bench test I could not get them below 5.3 volts even when half the capacity was taken out of them.I have all HiTec 5955 servos and your results with the more powerful servos will be worse. Hope this helps. I wish I had this knowledge years ago!!!

[3ddd]

most receivers on the market today can handle up to 30 volts without damage,the servos are a little diff,you can hook your batterys up without the switch but still use your regulators,are you running two packs or just one?i use two packs ,into two regulators with two jr leads out,that gives me four connections plugged into my rec,remember each plug is only good for about 3 amps,easy to over power a 3 amp system

[hipollito]

I only have one batt pack of 5200...I used to have two of 2500 mah with two switches and the same was happening...one thing I have noticed is that my fromeco reg...is the one that you can change the regulated volts...I mean I have it set o at 6.1 that was the maximum that I could get form it...but in fromeos instrutions it says it can go up to 6.5 volts....well I only get to 6.1!!! so...I tested and when I move the servos voltage goes to 5.1 or 4.8...and thtas just wrong....I think that the reg should work in such way that it ALWAYS gives 6.5 volts to te rx...thats why it is called regulator..but anyway..this is the first time I use lion....I was against it...and know I don´t know if I should return to NImh batts... or maybe lipo???

Don´t know what to do....sometimes I am just flying straight and it happens....thank for posting your thoughts they got me thinking... and know I am just frustrated.. any more thoughts?
thanks

[flatspinjim]

Go to A123's. Constant 6.6 volts and no need for a regulator.