A123 Power Setup
 

Hey All,

I was thinking of putting an A123 setup in a 50cc plane. Do i need to separate the power to the servos so it bypasses the rx or can i run such a setup through the rx?

The servos in question are Hitec 7955's with a 617rx. I was going to run a Y lead for the power inputs as all the channels are full but wasn't sure if that would be ok? (Dual outputs from the switch)

RE: A123 Power Setup
 

I run 2-cell A123's into a power regulator that puts out 6v continuous. Try Smart-Fly.com. They sell the one I have. It's really easy to program, under $25 and will make sure that you never push too much power through the Rx. Also, you may want to think about 2x 2-cell packs. For redundency, it's a way of guaranteeing that you've always got power running.

Smart-Fly also sells the BatShare. It only sends power from the one battery that has the most juice at any one time. It will switch back and forth seamlessly. And no, I don't work for 'em. ha ha

RE: A123 Power Setup
 

A 50cc plane can easily get by with one battery (2400ma). You aren't putting enough load on the servos to worry. I have run two A123s right thru the rx with no problem. If you just want to spend money, get some of the fancy electronics. I ran one plane with a single battery. After two normal(IMAC type) flights it only took about 200 ma to recharge. A123s are easily charged after every flight if you want. A 50cc plane is just an overgrown glow plane (I have three 50s and three 33%ers). Only uses 5 servos. The Z connectors are rated for 3A, and the wires (22AWG) are rated for about 7-8A. That is FLA not dynamic load. The rx can handle more than that on the power bus on the pcb. If you are worried about using a Y harness, use two to spread out the load. I once ran one on the batt input and one on the throttle servo with a Y harness.

RE: A123 Power Setup
 

I run 2 A123 directly into the receiver on my 35% Extra using 2 8611a's per aileron and one each 8711 on the rudder and elevators. I also use a single 2300 A123 into the ignition on the DA100. I've had this setup for close to 2.5 years now, no regulators or anything else. I charge the whole setup using a Fromeco Cube with the A123 cards. I could use a faster charger but I charge every 5 flights and use around 1400MaH between both batteries (about 700MaH each give or take a few MaH)

They top off at 7.2 volts but immediately drop to 6.6 as soon as I turn the plane on.

Since you cannot really load test them, for the first several flights, charge after every flight to get an idea of how much MaH you use per flight and increase the flights between charges as you see fit and are comfortable with. Even with the Cube at max 2.9 Amps I can still charge both receiver batteries in about 1/2 hour. With a faster charge I could probably be done in 15 minutes but for me, the 1/2 hour break is nice. I charge the ignition battery every 12 flights and only use 1500 or so MaH on that battery

My flight are all IMAC style flying and the 8711's draw more power than most other servos, especially my rudder servo since I'm consistently in the rudder for wind correction

RE: A123 Power Setup
 

Can you use a standard servo for throttle and choke with this setup or is a regulator needed? Henry

RE: A123 Power Setup
 

Hey Bubba, what switches are you using in your setup?

RE: A123 Power Setup
 

ricomari ..to answer your question if it is in re guards to the a123 batts system no regs are necessary in any part of the system at all

I use a standard futaba 3004 servo on my throttle and a manual choke with a ignition kill switch [link=http://www.troybuiltmodels.com/items/WRCIBEF.html]from TBM wike r/c [/link]

and for my switches i use [link=http://www.troybuiltmodels.com/items/MPI3470.html]MPI HD switches [/link] one for rx the other for my ignition . running a single battery for both ! A123 2300 mah

i have flown this system now for to seasons,i just added the kill switch this year

RE: A123 Power Setup
 

I run every airplane I have with dual unregulated 2300, or 4600 Mah A123 packs. Im totally happy with those batteries and the cell pro 10's charger

RE: A123 Power Setup
 

I have been using the Turnigy charger balancer. It will charge up to 5A and balance all types that need balancing(and it comes with a selection of adapters with Deans-type plugs attached). $34.95 from Hobby King. They also sell a 5A power supply for $9.95 or so to enable 115vac power usage. I have two of them to be able to charge at least two items at once. Xmtr, ign, and both batts. Quick that way. No need for regulators and Li-fes have more charge cycles.

RE: A123 Power Setup
 

Through RX is fine.

You can Y the switch outputs with the servos no problem. Use two Y's, one on each of two servo channels, take your pick.

RE: A123 Power Setup
 

Fromeco older failsafe switches, can't remember the exact name deans on batt side, 2 outputs on the receiver side

I just replaced a couple planes out to the JR1222 receiver so I am now using deans onbatt side and EC3 on receiver side