juanes1969

HI guys, I´m building a TOC1 YAK, 30% and this is the first time I´m using digital servos. The servos I have are the Futabas 9153, 167 on/in of torque at 4.8 volts. I´m using 5 of these servos on all surfaces and one standard servo for throttle. Right now, I cannot buy Li-Ion with regulators, so what i have are two NiMh (hidrimax) rated at 2000mAh. WILL THOSE BATTERIES BE ENOUGH FOR THE DEMAND OF MY SERVOS?
I have one of those Jomar battery backers that I can use with two more batteries (futaba 4.8V at 1500 mAh each) but i don´t want to put too much weight on the plane.
So, my quetion is, can i fly it with only the two NiMh 2000 mAh batteries?
Thanks
Steven

JNorton

My Feedback: (2)

Here is a rational response to what you are asking. http://www.hangtimes.com/weightcompare.html

John

JNorton

My Feedback: (2)

The Jomar battery backers activate the backup battery if the voltage on the first falls below a set point.

I'd rather have both batteries in parallel using two sets of switches and switch harnesses. Don't use a "Y" to plug both batteries into the receiver as this creates a single point failure. Use a separate Y" plugged into the receiver with one end going to a servo and the other to the battery harness. Using parallel batteries gains you capacity as you now have 4000 mAh instead of 2000 mAh that you'd have using the Jomar switch. More important it also lowers the internal resistance of the battery pack allowing higher surge currents to be supplied. Digital servos create these surge currents

Just my two cents,
John

juanes1969

Thanks John!!! well, according to the article, I will not have a problem and with your advice with the "Y" harnesses it will be safer...
I really appreciate your help.
Best regards
Steven

Josey Wales

My Feedback: (61)

What he said!

juanes1969

So, to connect the two batteries that way I have to connect the Y harness to one servo and the other end to the battery (say the elevator servos) and then to channel 2 in the receiver. Then, i can connect the other Y harness (say to the aileron servos) and the other end to the battery and the whole thing to the channel 1 in the receiver. (of course having the switch between the battery and the Y harness) Mi question here is, Do I still have to connect the receiver battery? or will those other two batteries connected this way, provide the power for the other servos and receiver? I´m just a little confused about this, have never done it before.
Thanks
Steven

pettit

My Feedback: (23)

From the top:

2 batteries into 2 separate switches.

Plug one switch output into the receiver battery socket on the receiver.

Plug the other switch output into either an unused receiver channel or into one leg of a Y connector that comes from any channel and also goes to the servo on that channel

I use throttle channel if necessary.

For example: Unplug throttle, plug in Y cord (the shorter the better) Plug throttle servo into one leg and second switch output into the other leg.

Nogyro

My Feedback: (10)

This tells you everything and even has a picture.

http://www.rcbatteryclinic.com/ Once on the home page, scroll down and read. "Parallel Operation = Reliability and Flight Time"

Geistware

My Feedback: (16)

Steven,
This is what I do but I run two servos on the rudder and since it is a long run with high demand, I run each switch to a "Y" then the receiver while the other end goes to the rudder. I usually run my rudder on 4-6 or 4-7. (Futaba)