Real world results with A123 pack.

[Stu_D]

	Quote: Originally Posted by JimC-MD
	Not a 9100 but a 9000 and an EQ10. 8 x 8711 plus one digi throttle servo. 2 x 2300 for RX through Kodiaks (so I have a visual) and one 2300 on the ignition. Six flights of 8-10 minutes with IMAC and some moderate 3D and work on snaps. Oh, throw in some rudder power tests too The Kodiaks showed .9 per side and the packs took 940/1000 mah to charge. They were topped off in about 15 minutes. .

Almost the same set up in my plane AR900 on the Power Expander (not EQ) .
There are 9 off 5955 plus a std digi on the throttle and the usage is between
150 and 200 for each 10 min flight of IMAC with a bit of stuffing around .

Batts are 2300 x 2 Boomarc and the plane is a 3.0 comp arf with a 170 up front .

The ign is the 1100mha Boomarc .

Stu

[rdb127]

On power usage here is a little test I did this morning.

I have three home made 2S1P A123 2300's on deans connectors in my electric goodie bag. I also dug out a power-expander and the Smart fly super switch so I could run the servos off of the A123. Servos are 3x925 2x645 and one HS 81 mini. Receiver is Futaba R319. I set the servo test mode in my Futaba 9Cap so that it would continuously cycle all servos.

The three batteries (1,2,&3) were sitting in the bag and had not been charged for about two months so I topped them off with the TP-1010C at 1.0 amp A123 charge. They took (in the same order) 59, 22 & 24 mah to fill up. When the charger shuts off they are all very close to 7.26v coming down to (all) 7.22 after about 5 minutes. From there I started the test. Again all reading are in order battery #1 then 2 then 3.

Cycle time 10 minutes

voltage/mah to top off.

6.70/88... 6.70/83... 6.70/84

Cycle time 20 minutes continous.

6.66/174... 6.66/167... 6.66/165

I seem to recall about 110-120 mah usage for 10 minutes some time ago in my EF-88 with all digital servos so one might take an educated guess that flight loads add to the power draw. (not to mention different servo's)

Also the analog servo's were noticably cooler to the touch than the coreless servos I shot them for temp at at about two hours into the experiment and the air temp in the shade of the trailer is 91... the 645's 96 and the 925's 102 degrees. The module on the 9c at 119 degrees.

Next I will run the same test, twenty minutes at a time on one battery and record the voltage on the way down and at some point where I am nearing the bottom of that well, I will recharge to see what I have drawn out for a total.

[macanaw]

	Quote: Originally Posted by dick hanson
	Makes one wonder why anyone would bother with other systems doesn't it. I have done tests and soldering setups and charging and discharging setups with A123 that would simply kill any other battery - all with no problem to the cells - The only problem I have had and seen others do - is trying to "top Off" the A123 cells and getting em out of balalance in the process - however - discharging em and recharging em fixes this - You can make the FMA charger confused by doing the unbalance but again discharging and recharging seems to fix em. I have done the discharge/recharge with a plain old Nicad charger -and simply checked the cells with a cheap Volt meter as I went . I won't use anything but the A123 .

I fought with Dick left and right on this, but have now seen the light. I have (2) 40% planes and (1) 30% plane all running on a123's for about 6 months now. My consumption is 250mha per flight with the plane that has 8611a's and about 450mha per flight on the edge that has (11) 8711's. I charge my packs at 10+ amps and don't worry about cold weather killing them like the last set of li-po's I had.

David

[rdb127]

Today's test part 2.

My idea was to try to share some common ground (running the same load with Futaba servo mode cycling the servos as before) and see if there was/is a pattern in voltage and mAh used. This test is for educational purposes, please don't take my word for it, explore for yourselves.

I cycled on the same setup as I used in post 158 running twenty minutes at a clip and then checking the voltage at the end I recharged with interesting results. In all but one voltage reading the volts hot off the 20 minute cycle would come up .02 if you let the battery sit for about one minute. I am posting the raised voltage as that is what one might likely see after returning the plane to the barn and going for a recharge. Once or twice I waited 5 minutes before the next cycle but the voltage did not change by letting the battery rest any more.

I used battery #1 from the above test which was at 7.22 volts starting fresh off of the TP-1010C at 1 amp.

cycle time in minutes/voltage after 1 minute

20/ 6.66
40/ 6.66
60/ 6.64
80/ 6.62
100/ 6.60
120/ 6.60
140/ 6.58
160/ 6.56
180/ 6.54
200/ 6.50
220/ 6.46
240/ 6.40
260/ 6.22

I then recharged the battery at 1 amp and put back in 2150 mAh of juice.

There were 13 of the 20 minute cycles. When you divide the total 2150 mAh by those 13 cycles you get 165.39 mAh per 20 minute cycle and that is just about what I got in my shorter tests earlier today. (might be some consistency there)

It is interesting that the charger would not come on past a trickle until it got up to 6.4 volts. The A123 people must know something there because when it got below 6.4 the voltage change was faster in a given time period.

This battery has about 10 or so cycles on it since I put it together 6 months ago so it is fairly new.

So if any of you guys are going to charge your battery and want to post the starting voltage and mAh returned it would be interesting to see if the pattern holds.

Way cool that this 6 servo setup went for 260 minutes (over 4 hours on the cycler) and although not representative of any airplane it can be used to compare with your results.

There is always a right way/

and a

WrongWay

[Zeeb]

	Quote: Originally Posted by macanaw
	I fought with Dick left and right on this, but have now seen the light. I have (2) 40% planes and (1) 30% plane all running on a123's for about 6 months now. My consumption is 250mha per flight with the plane that has 8611a's and about 450mha per flight on the edge that has (11) 8711's. I charge my packs at 10+ amps and don't worry about cold weather killing them like the last set of li-po's I had. David

Well not to add fuel to the fire as he is mostly correct and I had the same discussions with him....

But if you have the CellPro 4S chargers that came out initially with the A123 programming, there was a slight hiccup with that firmware. Now I never really noticed an issue with the 2300 size cells, but it was quite apparent with the 1100 size VPX cells that I've gone to in my glow models and want to use for ignition, at least on my 50cc size bird.

I talked with an engineer at FMA on several occasions about the problem and FMA came out with a firmware update for the A123 charge routine. Now if you never try to top off a pack for whatever reason, you probably wouldn't notice the difficulty I saw. But with the update that problem goes away and I'm not sure if anything else was changed.

The update is free if you send your 4S chargers back to FMA and they paid the return shipping on mine as well, both of them....

[GooseF22]

I ran my 8S 2300 setup this weekend for my little nitro cat. Its turning a new medusa 1600 kv motor. Static load testing results in 73 amps at 18 volts and stabilizes at about 65 amps after 10 seconds. then go to idle. it repeats the cycle, 73 initial then down to 65 or so. that repeats until about 1400 mah is gone, then it begins to drop off.

At 1800 mah expended, I could still get 63 amps burst with 55 loaded.

With lipos, I could get a little better voltage stability, but it would take at least a 4000 mah 25 c battery to give me this capability.

Also, I am still using 12 volt cutoff because it want it to cut under load. the batteries recover and when I landed it was back over 20 volts even after the cut.

Im using a ubec to power the servos. they are all small ones. 5 mins of pure fun.