Lithium Ion ( A123 ) Batteries.

[G Doggett]

What is the verdict on Lithium Ion batteries for F E use ?
They appear to be much safer, more user friendly, and having a hard body less likely to get damaged.
Most of us are still trying to get our heads around lipos but this new technology appears to have many advantages over lipos for the type of abuse we give our batteries.
They are a weird voltage at 3.3 volts per cell though.
Are any of you guys using them or planning to ?
Graham.

[ED66677]

I did read a thread on these cell on a french forum, some guys have been testing 3 or 4 cell on a H&M DrifterS, it seems to be a rocket, 4 cells is even too powerfull for the total weigth, 3 cells seems reasonable... I only readed it quickely!
Search for A123 here in this forum there are several post

[LJH]

I just got a 4S pack that I am using in a couple of my planes. I have only had two flights with the pack but I have to say I am impressed. I was running a 3S 2100mah Thunder power pack and I replaced it with a 4S A123 pack. With the Lipo I was pulling 37A and putting out just under 400 watts, with the A123 pack I am pulling 40A and putting out 440 watts. The pack was cool after use and I was able to recharge it in under 15 minutes with my Hyperion 1210I charger. I personally think for boats this is the chemistry to use because they are so durable and the quick recharge times. After christmas I plan on getting 10 cells and making up a 5S2P A123 pack for my OM29/11XL set up.


Cheers,
Jim

[Darin Jordan]

It is my understanding that the A123 cells don't hold up under high-amp setups... they drop voltage quickly over 60A or so...

If you search the "red board" for A123 or something similiar, you'll see all kinds of info on this, some from the self-proclaimed god of FE himself (all the way from Germany...) talking about what I mentioned above... He gave some good information on this...

Basically, A123s are very good sport cells, but don't stand up to Lipos for high-end race use...

[LJH]

Daren,
You are totally correct,there is a lot of talk on the E flight board I am on and it seems that 60A constant is the limit with bursts to 120A. Depending on your set up this may or may not work. My personal set up is a OM29 with a 11XL spinning a M645 and my average draw is just under 40A so I will be fine using even 1P but just to get the run time I am looking for I will go 2P not to mention I need the weight to keep the boat on the water.....I have tried running the boat on a 4S4000mah 1P but I have a hard time keeping her on the water so I have gone 4S2P and she runs great and I get 10 mins of run time at right around 40MPH. Another possibility is using a HV set up and keep the amps down but then you start running into a weight issue, not as bad as NiMH but not nearly as light as Lipo's.......Did I mention I love the short charging time .


Cheers,
Jim

[SJFE]

So to be clear the c-rating to mah formula can equate to a +60 amp capability...But that don't matter?? The cells will lay down if pushed over 60 constant for more than a burst?? I would like to hear Mr Hills opinion on that data.

[LJH]

Tom,
The cells are concidered to be 30C cells and the most common A123's are from the Dewalt 36V battery packs and have 2300mah rating so that would mean 66A with a burst rating to 60C (132A). I have done a fair amount of research on this chemistry because I am very frugal (german heritage coming out there LOL) and except for the weight they have a lot of good things going for them. A lot of the information I have gathered is from here http://www.rcgroups.com/batteries-and-chargers-129/ . There are a lot of guys on that board who seem to have a huge amount of Knowledge and time to test (not that Steve does not) on batteries of all chemistries. In my albeit limited use of these cells I would say that they produce great power at 20C and from what I have read they do hold decent voltage to 30C. Last night I was messing around with my old F5B plane that has a Aveox F12LMR in it and found that I can get it to ballance with teh 4S A123's in it....the better half was already in bed so it would not have been the best move to fire up the 1KW motor so I will check that out tonight. I am not holding my breath but the hey maybe in bursts they might be OK. I will let you guys know what I find.


Cheers,
Jim

[SJFE]

Thanks for the info and link Jim. I am considering them for 2 boats at the moment. The M1s is the one I worrie about. 3s-2p on a 7xl maybe pushing it amp wise proped up.

[Darin Jordan]

Thanks for the info and link Jim. I am considering them for 2 boats at the moment. The M1s is the one I worrie about. 3s-2p on a 7xl maybe pushing it amp wise proped up.

Like I said... I think they are probably excellent, perhaps superior, for sport type running on sport type setups... but info from those who have tried them for all-out racing show them to be inferior in voltage under load...

I'm not saying they are bad... just that they have their place and are better for some applications than others...

For sport boats, I'd love to have some myself.... In fact... I'm considering converting my Traxxas Stampede to be able to use them... I think they'd hold up better to the dirt and grime and beating they'd take in a Monster Truck better than the soft-sided lipo packs...

[SJFE]

Well since I am Mr SportBoat I guess they are right up my alley then hu

[LJH]

Tom and Darin,
I hear ya....Since I have never seen another FE boat run in person I think I am the true sport runner LOL. I find the A123's really attractive for the durability aspect and the fast charging and the price. You can run the cells down to 2V per cell and not cause any issues and the same goes for over charging them, the aluminum case should make them pretty impervious to the occasional salt water bath (Lipo's do not tend to like that) and I can charge them at 10A on my Hyperion 1210I in less them 15 minutes. I guess coming from the E-flight side of things I always try to make my watts by going up in volts rather then amps. To me anything much over 50A, except for my LMR type planes, is getting up there in terms of amperage. When I bought my B125 I was like "jeez....who would ever use 2000+ watts in a boat but I guess to go really fast requires a bucket load of watts. I guess running in open water and seldom able to use all 550W's in my OM29 is a blessing of sorts .

Cheers,
Jim

[G Doggett]

There appears to be a lot of R & D going on with these new batteries , even GM is in on the act.
Maybe higher mah cells will be available soon, such as 4500 or 5000, which would make them ideal for high performance FE.
My impression is that they will quickly overtake lipos mainly because of the user friendly and safety advantages.
A lot of people, myself included , are very nervous about lipos in the hands of non-expert users.
I think industry will adopt these very quickly and we can take advantage of the spin off.
Graham.

[SJFE]

After a bit of thought the 15 minute charge factor would cut down on the amout of packs I like to have on hand. I wouldent need 2 or 3 sets per boat. I can leave the batteries in boat A and charge in almost the time it takes to prep and run boat B. Very atractive indeed :). Puts a new spin on things. I need to do some research and possibly amend next months shopping list.

[Flying Scotsman]

great thread. As Darrin and LJH have pointed out great sport batteries, but at this stage of lithium development, poly has the power advantage. That is not to say that lion can not be copmpetive, only a few years ago li-po chemistry was only capapable of 10 to 15C

Douggie

[sjslhill]

Darin is correct......A123 non parallel is not for really high amps.

However, I don't ever plan on racing like Darin. Don't take this wrong though, it's his choice. 10,000mah LiPoly and 4 hp motors are not for me.