Who using A123 batteries?

[hubb]

from this past weekends contest - 3 contestest rounds on Satruday (Unlimited) 10-12 minute flights. I put back (roughly) 750mah into each pack. that would mean I use roughly 500mah (250x2) for each flight? so theroetically I could fly an entire contest weekend without charging assuming typical 5 rounds; 3 knowns on Sat and Unknowns and Knowns on Sunday. the only limiting factor for me right now would be the Iginition Nimh. I only feel safe flying 3-4 flights on it.....sound about right? what size pack would you run on the Ignition? (DA 150)

[WrongWayRC]

I use an A123 1100 on my DA-150 igniton and recently ran it dry at the Joe Nall..... was having too much fun and twice forgot to re-charge it. (a successful dead stick though) I almost made it to[Edit: the end of the] the 6th flight with the flights being 10 minutes long. I put about 1050 back in it.
Considering that, you might look at the A123-2300. For W&B considerations and convenience I will switch mine to a 2300 when I get the chance.

Richard

[Zeeb]

I run 1100's on single cylinder engines and 2300's on twin cylinder engines.

Lots of opinions, but for me the extra 3 oz. on a 2300 just isn't an issue on models big enough to be running twin cylinder engines and those ignitions do pull more power from the batteries.

JMHO, YMMV....

[MODE 1]

Me

[STLAV8R]

	Quote: Originally Posted by WrongWayRC
	I use an A123 1100 on my DA-150 igniton and recently ran it dry at the Joe Nall..... was having too much fun and twice forgot to re-charge it. (a successful dead stick though) I almost made it to[Edit: the end of the] the 6th flight with the flights being 10 minutes long. I put about 1050 back in it. Considering that, you might look at the A123-2300. For W&B considerations and convenience I will switch mine to a 2300 when I get the chance. Richard

So if you over doubled the capacity of the pack, then you could get almost 20 (10) minutes flights on the ignition?

[KrisW]

	Quote: Originally Posted by wildhare
	Partially true, connectors are the bigger problem. But, I did a test recently, I had a 24 inch extension which I made from 20 ga. silicon insulated wires (good ones) with Deans plugs on each end. I ran my usual A123 load test where I see how much current I can pull from a pack without going below 5 volts. Usually this will give me 20 amps, +/- a fraction depending on the state of the pack. With the 24 inch extension in the circuit voltage was way down. My recollection is that I was able to get only about 4.4-4.5 volts when pulling my normal 20 amps. I removed the extension and the results came back to where I expected them to be. So I shortened the extension to 6 inches and performance came back up but not to where it was without the extension. Clearly smaller wires and especially long runs of small wires will affect performance. The voltage difference is enough to have an effect on servo performance in a hard snap on some planes where servo torque is marginal to begin with. TF

A look at the chart on this page: http://www.eskimo.com/~billb/tesla/wire1.txt will give you an idea of what is SAFE. .what is marginal, and what is unsafe, when wiring up a plane for high current draw applications, such as using A123 cells and high-torque Digital servos.

Figure your high end Digital 5955, 7955, 8711, etc etc etc. . .will pull a maximum of 3 amps of current . .PER SERVO. The leads for these high-draw servos should be 18 gauge to be on the engineering "safe side" for never having a voltage drop and unlimited flying with no degradation of the servos' performance due to current limitations of the wiring itself. But, we are limited to about 20 gauge maximum wire diameter for our leads, simply because of the size of the servo plug pins, which are only good to about 2.5 amps maximum anyway. I've modified plugs and pins and soldered 18 gauge to the + and - pins, using standard 24 gauge wire crimped to the pin for the signal wire, but this is really time consuming and tedious work, and for the most part unnecessary, since we seldom intentionally hold our servos at stall, and the flight load dynamics rarely put the servos into a full-stall situation. So, for servo leads, 20 gauge is plenty adequate 99% of the time, but 24 gauge should be totally avoided on the best high-end systems using the heaviest draw servos available.

Usually the most powerful servos are pulling less than 2 amps, making the HD 20 gauge pre-made wiring more than adequate for anything we can think up in the way of loads and flying applications, It is better to be overkill on the wiring, though, so keep that in mind during setup and build of the plane. And any servo less than that will do just fine on 22 gauge, or 24 gauge for analog high-torque servos.

When it comes to the main power cables, though, 12-13 gauge is what you want for the A123 cells, according to the chart, since that wire diameter can handle 10-12 amps continuous flow, all day long, and you will not get voltage drop restrictions along it's length no matter how hard you push the servoes. Figure a maximum of 5-7 HD Digitals per 2300 ma A123 pack (equipped with 12-13 gauge leads to the switch and power expander), to be on the safe side . .which parallels the popular setups for most 40-43% planes. . 3 per wing, 3-4 on rudder, and 2 per stab (13-14 total). Again, remember, the servo connectors are going to be the current limiting factor most of the time with a setup like this, keeping the system from ever pulling more than 35 amps TOTAL from 14 servos, and that only if ALL the servos were in full-stall mode at the exact same time, which never occurs.

I use the "spaghetti wire" for RC Trucks that is 12 gauge, and the Zero Loss or Deans connectors, since both are rated at 20+ amps, and 12 AWG comparability. The difference in weight between 12 and 16-18 gauge power wires should never be an issue for larger planes. A couple of ounces is nothing when you have 2600-2800 inches of wing loading and a 40 lbs plane. Likewise, the difference between a 24 gauge wiring setup, and 20 gauge, throughout the entire plane, will be less than 4 ounces, so why bother going with the cheap stuff??

On a side note .. .there is some El Cheapo (like $2/lead) servo wire out there, that is 22 gauge but made of ALUMINUM. . .Stay away from this stuff. . . it's current capacity is about half of comparable copper leads, because Aluminum is not as good a conductor. They were selling these leads at Joe Nall last year, and I bought a bunch, thinking they would be a great bargain (because I thought they were copper, not aluminum. . . ). . turns out that the "bargain" turned into something I would not consider for any servo stronger than an 8411 or 5945 hiTec. Over 1.5 amps of current, and it's likely you will start running into voltage drop issues, especially on longer leads. It's probably okay for the "average" RC plane, but I'd never consider it for a 35-40% plane, where I wanted to get all the performance possible from every component.

[wildhare]

Kris and all:

After re-reading my own post it's clear that I wasn't clear.

I was talking about extensions of the power supply wires coming off the battery supplying power TO the receiver. I was not referring to extensions FROM the receiver to the servos.

These are also important, but the supply TO the receiver must carry power for all the servos, rather than just for one.

Sorry for any confusion.

TF

[Hammbone]

I'm really glad to see that you guys (you know who you are) have finally realized the need for better connectors and wiring, and are no longer telling people that standard connectors/ wiring are fine to use.

Jim

[4stroke]

for great info on using A123's go to hangtime hobbies and/or battery university I am using 123's on 40% cub...and if you set the system up as Steve (hangtime) recommends ..it is a great system. (can't use on ignition w/o regulator however) he explains quite well how to monitor flight times ,etc......btw...battery university gives great info on all battery systems (nimh,lithium ion,etc)...check it out

[KrisW]

	Quote: Originally Posted by Hammbone
	I'm really glad to see that you guys (you know who you are) have finally realized the need for better connectors and wiring, and are no longer telling people that standard connectors/ wiring are fine to use. Jim

And then there are the cases of extreme overkill to the Nth degree, rather than properly engineered and designed systems that are both inexpensive and bullet proof. . versus eye candy and bling bling setups that are designed to handle 50% planes and are installed on 35% Birds.

There are simple, effective, and cost effective ways of supplying power to receivers and servos. . .most of the double/quadruple switch setups. . mucho $$$ powerboxes. . and power distributors with gah gah regulation and isolation are entirely unnecessary, especially in light of the A123 cells that do not need ANY of those components, and the inexpensive but extremely robust switches available in a variety of configurations to fit most any application.


Radio Shack has a DPDT switch capable of handling 20 amps continuous. . they cost $3 each, and 2 are more than enough for any 40%plane out there . .12 AWG in and out, split to 4 leads to receivers and servos direct, no regulation needed. . and for $30 yoiu have a complete "power setup" without all the bling bling and name recognition that people love to flaunt and show off with. Of course if you WANT bling bling. . . be my guest. . nothing like bragging about how much you spent and how cool it looks with all the little diodes and knick knacks and gee gaws inside. . Personaly I'd rather spend my money on things I need.

[cjcyclesrc]

	Quote: Originally Posted by KrisW
	And then there are the cases of extreme overkill to the Nth degree, rather than properly engineered and designed systems that are both inexpensive and bullet proof. . versus eye candy and bling bling setups that are designed to handle 50% planes and are installed on 35% Birds. There are simple, effective, and cost effective ways of supplying power to receivers and servos. . .most of the double/quadruple switch setups. . mucho $$$ powerboxes. . and power distributors with gah gah regulation and isolation are entirely unnecessary, especially in light of the A123 cells that do not need ANY of those components, and the inexpensive but extremely robust switches available in a variety of configurations to fit most any application. Radio Shack has a DPDT switch capable of handling 20 amps continuous. . they cost $3 each, and 2 are more than enough for any 40%plane out there . .12 AWG in and out, split to 4 leads to receivers and servos direct, no regulation needed. . and for $30 yoiu have a complete "power setup" without all the bling bling and name recognition that people love to flaunt and show off with. Of course if you WANT bling bling. . . be my guest. . nothing like bragging about how much you spent and how cool it looks with all the little diodes and knick knacks and gee gaws inside. . Personaly I'd rather spend my money on things I need.

Better yet. Run your 16ga wires straight from your batteries to your AR9100/R922. No inline switches to fail and plenty of current capacity to the RX.

[KrisW]

	Quote: Originally Posted by cjcyclesrc
	Better yet. Run your 16ga wires straight from your batteries to your AR9100/R922. No inline switches to fail and plenty of current capacity to the RX.

the simpler, the better. . . .

The AR9100 setup is about the best I've seen on the market

[Hammbone]

	Quote: Originally Posted by cjcyclesrc
	Better yet. Run your 16ga wires straight from your batteries to your AR9100/R922. No inline switches to fail and plenty of current capacity to the RX.

Best set up there is. I use 13ga wires and the 1222 rx though.
This is the simplest, cheapest, and best set up around.

Jim

[cjcyclesrc]

I've been very pleased with the AR9100's. I wouldn't even think of setting up a plane any other way. I don't like the little switch that comes with them so I just make up my own little pin flag and it works great.

[KrisW]

	Quote: Originally Posted by cjcyclesrc
	I've been very pleased with the AR9100's. I wouldn't even think of setting up a plane any other way. I don't like the little switch that comes with them so I just make up my own little pin flag and it works great.

There is still the problem with routing major current to multiple servo/control surfaces, though. 3 7955's on an Aileron, or 3-4 on rudder, should still have their own voltage supply from a discrete switch, simply because of the limited number of pins on an AR9100 receiver. If you have 3 servos per channel, you will quickly overload the connectors into the AR9100, so external power, from a switch, is still kind of necessary to keep the servos fed and happy. Dual AR9100's might solve the problem, but then you are shelling out $200+ just so you can have another power buss and receiver in the plane, instead of just adding a switch and some wires to provide direct power while tapping into the signal coming off the receiver. If you are using external switches to add additional servo power feeds, it kind of makes the AR9100 setup unnecessary, and you can use almost any receiver you want since you have the power draw isolated from the receiver power buss anyway.

It still requires additional feeds on the bigger planes . . . but on 35% birds the AR9100 is a great option.