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        Question Using 3 cell lipo to run RX directly (Nitro plane)

#1 maverick64 Mar 12, 2012 11:24 AM

Using 3 cell lipo to run RX directly (Nitro plane)
 
Hi,

After speaking to a friend at my MC he told me that it was possible to use lipo to run the receiver. He advised a small 3 cell 800maH. Having realised that a lipo is generally much better all-round i started to read up on RCG's and found that people had regulated batteries.

My question- What is meant by regulating a lipo and how do you go about doing so?

P.s. Excuse my lack of knowledge


Regards
TOM

#2 Toysrme Mar 12, 2012 11:38 AM

a voltage regulator regulates the voltage it output.

R/C radio equipment is almost universally made to work with 4s nickle (3.2-5.8v) or 5s nickle (4-7.25v) supply voltages. (with some more expensive "high voltage" equipment out now for premium price)
a 2s lipo fully charged is 8.4v
a 3s lipo fully charged is 12.6v

if you didn't use a voltage regulator, you are highly likely to fry every servo as soon as a load is placed on it and possibly fry the receiver (receivers have always been some what more tolerant of over voltage)

#3 jetmech05 Mar 12, 2012 12:03 PM

A 3 cell is too much voltage....you'll let the magic smoke out if you don't run a voltage regulator ..whats the magic smoke? It's what makes everything work...if you see the magic smoke well whatever it came from no longer works

#4 coriolan Mar 12, 2012 01:17 PM

Quote:

Originally Posted by maverick64 (Post 21011769)
Hi,

After speaking to a friend at my MC he told me that it was possible to use lipo to run the receiver. He advised a small 3 cell 800maH. Having realised that a lipo is generally much better all-round i started to read up on RCG's and found that people had regulated batteries.

My question- What is meant by regulating a lipo and how do you go about doing so?

P.s. Excuse my lack of knowledge


Regards
TOM

Your friend should try it on its own receiver and learn something:popcorn:

#5 600Bob Mar 12, 2012 02:06 PM

Use a 2s LiFe unregulated for any servos rated for 6v.

http://www.hobbico.com/radioaccys/hcam6415.html

#6 mazjag Mar 12, 2012 05:42 PM

I was going to go the Li-po way on one of my planes that was a little too heavy..I use a 5cell 2500 Ni-MH..After I weighed the Li-po and the regulator I was going to save about 25 grams..I stayed with the Ni-mh as I don`t have to worry about the regulator going out..

#7 1320fastback Mar 12, 2012 06:41 PM

Yes this regulator reduces the voltage to something the servos and receiver can survive.

I use lipos and Castle BEC's on most of my fuel planes.

A simple 4 ch. trainer can use a 2S 750Mah Lipo. This will be enough battery for several flights (5 or so)

#8 mazjag Mar 12, 2012 07:03 PM

This is were I disagree with some..I don`t want to charge my rx battery..no matter how fast the re-charge is..I want to fly all day and not worry about it or go up with a dead one.everyone has different deal..J

#9 1320fastback Mar 12, 2012 08:40 PM

It's just a different way of doing it. Mah is all that matters and is adjusted acording to servo draw and servo quantity.

Like before I use a very small 2S and small regulator in my Strega Mustang. This plane weight matters as weight is lost speed. Flying it at most you are using the ailerons and rudder at once so it is probably drawing less than 1 Amp on a regulator rated for 10A.

My Avistar and Bobcat both have 8 servos so I use a 3S 2200 in them. Both can fly ALL day without a recharge.

The other good thing about Lipos is they retain their voltage better than a Nixx battery. Even though they do get lower it is not as drastic especially at such low levels of discharge.

I got into this hobby when Lipos and brushless was common place.
I don't even know how to charge a Nixx?????

I do NOT use cheap Hk electronics though.... Have yet to have 1 issue with any of them.

Use what your comfortable with.

#10 Evan03 Mar 12, 2012 09:56 PM

ive got castle cc bec pro 20amp i use sometimes this will regulate to what ever voltage you want.

battery pictured is 4cell lipo voltage regulator is set at 6 volts
http://i661.photobucket.com/albums/u...o/IMG_3819.jpg

i ran the 4cell because its what i had on hand, im curious why you run the 3cell isnt that just uneeded weight. a 2 cell 2200 is tiny compared to 4cell.

heres my 2cell 2200
http://i661.photobucket.com/albums/u...o/IMG_3991.jpg

sorry im heli guy butting in, i now fly the 600 with 7100r reciever that is voltage reglator insetself so i have the 2 cell lipo plugged directly into it.

i was planning to run a similar sized 2 cell lipo on plane build with my cc bec pro. i also have 3 cell 2200 batteries, just curious why 3 cell is better

#11 1320fastback Mar 12, 2012 10:10 PM

I was using it for CG purposes, it was shoved up into the nose to help offset the .75 hanging off the back.

A 1/2x5" carriage bolt took care of the rest :D

#12 Thermalin Mar 14, 2012 09:24 PM

I use 3 cell l1000 mah ipos with a regulator instead of 2 cell b/c if a cell goes out during flight your still ok. With a 2 cell lipo, if you lose one, the voltage will be to low for the receiver and you just re-kitted your plane.

#13 ChillPhatCat Mar 14, 2012 11:10 PM

Quote:

Originally Posted by Thermalin (Post 21037159)
I use 3 cell l1000 mah ipos with a regulator instead of 2 cell b/c if a cell goes out during flight your still ok. With a 2 cell lipo, if you lose one, the voltage will be to low for the receiver and you just re-kitted your plane.

The same goes for any battery. Why risk it with only 3 cells? What if two go out? :eek:

Have you ever had a cell die on you mid flight? :popcorn:

#14 ACKopter Mar 15, 2012 07:40 AM

Quote:

Originally Posted by 600Bob (Post 21013106)
Use a 2s LiFe unregulated for any servos rated for 6v.

http://www.hobbico.com/radioaccys/hcam6415.html



This is the route I took. Unregulated straight to the Rx, simple, light weight and effective. 1300 mah on my 40 size glow plane and I can fly at least 6-8 times with no worries. I cant remember ever having to charge back more than 50% of the batteries capacity.

#15 earlwb Mar 15, 2012 08:07 AM

You really need to look up the specifications for your brand and model of receiver. There are some receivers now out on the market that can handle higher input voltages. But this is mostly for two Lipo cells in series. I haven't looked to see if anyone makes a high voltage receiver that can run off of a three cell Lipo pack yet, but there may be some.

The next problem is your servos and anything else you have plugged in, as to whether it can handle the higher voltage or not. The high voltage rated servos are quite expensive so far.

You can use a voltage regulator unit to lower the Lipo battery pack voltage down to a safe level for your receiver and servos. Plus for other things like sensors, gyros, etc too.

As mentioned many folks opt for the LiFe two cell packs as it is easier to find receivers and servos rated to handle the voltage for a LiFe pack.


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