gliderguy100

Hey guys. Looking for some guidance on a flight pack battery selection. I've been flying various models from basic gliders to standard 40 to 60 size power planes for 30 years. Everything I've flown has always used just a basic 4 cell NiCAD or NiMH flight pack. I recently acquired an older, larger-sized plane and wondering if the flight pack battery should be something bigger? It's an Edge 540 with 57 inch wing span, a 120 four stoke power plant, dual aileron servos, dual flap servos, and dual elevator servos. Is a standard 4-cell NiMH adequate of do I need something bigger?

oliveDrab

So it's got:
- one servo for the left aileron
- one servo for the right aileron
- one servo for the left flap
- one servo for the right flap
- two servo's for the elevator
- and I assume one servo for the rudder and one servo for the throttle?
.....8 servo's. My gut instinct tells me that's a lot of servo's for a 4-cell NimH. Maybe use 6.6 volt dual LiFe's. The LiFe's don't self discharge like the NimH's do.

I did use a 5-cell 6.0 volt NimH with 8 servo's but I could never get the flaps to work right ... so I feel uneasy recommending that.

krokodyl

Wouldn't recommend using a nixx battery for that many servos especially if they are high torque servos.

I agree with oliveDrab, that a life would be the best option. Even better, a A123 pack, but they are hard to come across. Radicalrc sell them pre made.

Hubert

jwrich

My Feedback: (17)

I agree with the others, LiFe or A123 batteries are the best way to go with larger models. I have changed out all my receiver batteries to the LiFe/A123 batteries. This is how I have them set up, 2 LiFe/A123 batteries, 2 switches plugged into 2 ports on the receiver. You can use a y extent from a servo if needed. I charge each battery separately thru the balance port. Charging is quick. I buy my LiFe/A123 batteries from Value Hobby.com. Their prices are very reasonable and I have had no problem with them.

Fair Winds & Happy Flyin'
Rich

gliderguy100

Thank you for the input. Olive Drab - yes, you are correct on the servo count of 8. But now I gotta ask, what is an A123 battery? Not familiar with that and finding it difficult to get an understanding from a google search. Are these like c size batteries or what?

mogman

A123 or more commonly used LIFE batteries are very popular these days. They basically do not self discharge like a nicad or nimh. They can be charged in the plane, unlike LIPO's which are recommended to be removed for charging.

A123 or LIFE are 3.3v per cell and are usually packaged as a 2 cell pack 6.6v. You will need a charger that is lipo/life capable (lots available and not too expensive.) You will need to make sure the servos you have will accept the higher voltage or you might have to use a voltage regulator.

You don't mention what radio you have, but if you have a Spektrum you would be well advised not to use a low capacity 4 cell nicad or nimh due to possible high servo current draw leading a voltage drop which leads to a "brown out" (ie loss of control). Google this for all sorts of info. Nothing wrong with Spektrum, just use an adequate battery.

I'm sure others will chime in here with advice.

Good luck.

jwrich

My Feedback: (17)

LiFe (lithium iron phosphate) is a lithium-based battery technology that is more stable and safer than LiPO. A123 batteries are based on LiFe technology. LiFe packs can be charged very rapidly and be discharged all the way without damage. Their lower voltage make them suitable for receivers that use 6V receiver batteries. On the downside, LiFe packs have lower voltage and smaller capacity than LiPOs of the same weight. They safe to use with your receivers in your airplane.
Check out this site, http://www.hangtimes.com/ has an answer to all your questions about batteries. Read these A123 Batteries FAQ and A123 Setup Guide. on their site. They do sell batteries, chargers, switches, etc. More important, you can educate yourself on the different battery system available.

I fly 1/4 scale WW I aircraft, I travel to events around the country, some lasting 3 days or more. I always worried about charging the batteries in my planes. The NiCAD/NiMH require a longer charge time or a quick charge at the field. Over time quick charge is not good for these batteries. In many cases we would our planes stored overnight at the field with no charging set up.
The A123 battery does not loose charge when not in use and they charges quicker with a field charger. They are some much better and I feel more comfortable flying them. I have change all my planes to these A123 batteries.

Check out these site http://www.hangtimes.com/ and Value Hobby.com/.
Hope this helps you

Rich

Xpress

I have to ask, which Edge 540 is this? Because I am not aware of any Edge 540 in existence with flaps, they all generally have full span ailerons.

When you get up to these larger models, models using an engine bigger than about a .40-.60 glow engine, you really need to look away from nickel cell packs and look into using lithium based batteries. Me personally I would equip the airplane with all HV capable servos and run 2S LiPo direct, but you can get away with LiFe or LiIon very easily depending on how you want to fly the airplane.

A123 used to be a brand of LiFe battery but to my knowledge they went under and no more 'true A123' cells are being made anymore.

gliderguy100

O.K. So this is my bad. This plane does NOT have flaps. I was just temporarily confused (again). Problem is the same time I picked up this plane I also acquired a collection of pieces and parts of several different planes and I was just looking at the wrong wing when I posted my question. This other wing is similar in size, shape, and color but it doesn't fit the Edge. There is no fuselage in this collection that it does fit and it has bee broken and patched up . It's probably going to end up migrating to the junk pile. So anyway, this Edge is not 8 servos, it's only 6. But my initial battery question is still valid. I appreciate your recommendations and will do some shopping for LiFe batteries. Oh... And I am intending to run this on a Spektrum radio. Thank you all.