Eagletree with A123 Butt saver setup!!!!!!

[sprice50]

Awesome thread

[crazyjoe]

If i get six 15 minute flights i consider that a great day
If i plan on flying more I hit them with the charger while i grab a bite to eat
just like to keep them fresh to avoid a reboot problem ( 2 - 2800 tbm lions )
I'm building another 35% now and have 2 2300 a123s going in it
nice to know i can fly 3 hours without fear of a reboot and also the ability to quick charge safely
If you don't like batteries that are safer, stronger, last longer, charge quicker, don't need regulators, and if your willing to build them yourself are cheaper.
Then these are not for you.

[Kiwi]

Guys,

The 10 minutes for 200 MaH was a real surprise for me as I wrung the ring out of that plane. For me to do more than five or six flights a day would be a record. To know I have something like 300 minutes up my sleeve says I dont ever need to charge during the day but as Dick states, you can go grab a coke and take a P and your fully charged anyway if you like to run on the top end of the curve.

I'm totally sold on these A123 cells. There's no way I'm ever going to suffer from low voltage or low current no matter what I do. This is like having a darned car battery in your plane.

I have a box of 3000 MaH cells due in the next 10 days or so. These are being sourced from China and they have been slow to get them out the door but I see them as being my salvation for the new 3M Yak.

We are also using the A123 (M1) technology for remote controlled mining equipment. We radio control 100 ton bulldozers and stuff. Pretty similar technology to be honest to our planes but just a whole lot more fail safes and stuff in the box. Plus bulldozers dont fly so when they quit you don't go and pick up the pieces. Funny thing is the charger for the commercial packs is only a $15 unit. Funny what happens to prices when you get away from the glitzy hobbies and stuff.

Once I have these in hand I will let you know how they go. They are rated at 40C but I take spec that with a grain of salt and even if they are only 50% of that rating they are still very powerful. At 40C we should have some 240 amps available on a burst. Now thats going to smoke up some servos and stuff if you get it wrong.

Andy the Data logger device is $70 and the panel close to $40 from memory. You really dont need it but it was the easiest way for me to really get the facts and not another opinion. As every setup is different I would do say four ten minute flights and then re charge. See what you put back back in the pack and from there on its just a matter of counting the flights.

But if your a gadget freak the EagleTree system is really worth the investment and you can use it on anything you like later on. One of the things I like about inline systems is doing setups and ganging servos etc. I have three pairs of ganged servos on this 260 and idle current is 200 MaH. Just by touching the elevator or aileron I can double that so it really helps me see all the way through the control surface movement if I have any binding.

Thanks for the comments guys and again. Save those old 4.8 volt packs for setting up. It will save you some serious dollars.

[Panzlflyer]

I had a linkage hang up while ganging 2 5955s on a A123 setup, fortunately it buckled the ply! Sure glad Hitecs reduce the load when they get hot.
good point about the 4.8 tho

[rbarnett]

[quote=Kiwi;347183]
I have a box of 3000 MaH cells due in the next 10 days or so. These are being sourced from China and they have been slow to get them out the door but I see them as being my salvation for the new 3M Yak.

Hey KIWI,
What is the source, and the price for those 300MaH cell? Are they supposedly the same technology as the A123 cells?
Thanks,
B.B.

[Kiwi]

Yes they are supposedly the same technology. The photos I have show they are not exactly the same as the A123 cell as in the way the center post is shaped but apart from that they look the same animal.

Once I get these I will post on here how they go and if they are indeed any good so I wont go posting where to go find them until I see if they are really what they are supposed to be, but I promise I will share with you once I get my hands on them.

[BTerry]

I am also interested to hear how they work. Other people have tried some of the LiFePO4 cells without much luck.

Apparently the Nanophosphate structure is the secret to the technology, and that portion is proprietary to A123 Systems.

[dick hanson]

Is anyone willing to steal some of the new cells destined for the Chev Volt?

Is anyone willing to steal from any other sources -these cells ?
I don't know where to go to get a B&E job done -so I am just asking--

[Sin City Jets]

The Chinese LiFePO4 cells are considerable different than the A123 cells. The discharge rate capability is more in line with Li-ion. I do not know about the life cycle and fast charging capability. Batteryspace.com has been selling those cells for a while and they are definately NOT the same.

[BTerry]

A123 batteries are manufactured in China, but...

A123 Systems grew from a project at MIT to a company with 500 employees in less than 7 years. I have to think they would VOCIFEROUSLY protect their product, since they know its potential.

[gareth.ky]

Good report Kiwi!

I would say that if your problem can be solved by getting more data then you don't have a problem, you have a lack of information.

I would love to see a device that can do what the Eagle Tree does for 2 packs, plus detect shorts and individual battery failures. Add a fail safe switch and a really really loud buzzer so that if the thing fails in the air you can hear it. I think any battery setup would benefit from that.

[Kiwi]

Gareth,

I know a few guys who can make something like that. Let me pass on what you have in mind.

This is the spec from the supplier I have and this is for the 2300 MaH cell. I have seen the discharge curves and they certainly look to have what it takes for RC use. Your correct in the statement that the nano technology is what makes the A123 what it is. However if I can get a 3000 MaH cell that is 20C, that I can still charge in 20 minutes and it's light and means I dont need regulators and extra stuff then it will certainly do me for what I want.

Its sort of like not really needing a Porsche Cayenne to take the kids to school. Its nice for sure but a Nissant does the same job for a tenth of the price.

Guys these new packs might be junk, thats my mistake if its so, but if they are up to snuff then thats my win. The old saying, nothing ventured, nothing gained.


Description: Name: ABF LiFePO4 battery 26650(3.2V/2300mAh)
Nominal voltage: 3.2V
Nominal capacity: 2300mAh.
Highest charged voltage: 4.0V-4.2V.
Lowest discharged voltage: 2V
Max. continuous discharging current: 50A
Max. pulse discharging current(5 second): 75A
Diameter/Height: 26mm/65mm
Weight: 78g

[Show871]

So in a nutshell you are saying just use 4.8v when using a programer and setting up servos???I just ordered 123's and am setting up my new YAK. Thanks871

[Kiwi]

Well the programmer has its own 4.8 volt battery anyway.

The problem comes if you bugger up something in that programming. With me the reset function failed for some reason on one servo. I done my setup using the 14 channel Rx and the radio. Well in a setup like that if you have one servo way off center or perhaps with an end point seriously out of whack (my case) when you plug in those A123 packs its like connecting them to a welder. They show no love for a bad connection or a bad adjustment. They just smoke what ever is causing the problem.

If you done that with a 4.8 volt Rx pack the servo would stall but likely not melt. Thats the reason I say do all your setups and adjustments with a small Rx pack. Once you have it right then go for broke. Hook up those A123's and fly it like you stole it.

[Show871]

Thanks for the heads up Kiwi man871