a123s or lipo? again....
 

hey guys iam at the point to where i can buy my batteries and i want to make sure im making the right decision.

one of the other members said there was a deal at amazon for 105 per 36v battery with free shipping. so that means i can buy 3 of the batteries for the same price i would be spending on the evo 30s i was planning on buying.

there is a thread on rcgroups on how to build the pack without buying any other peices.

so it would be 315 flat for 5 6s packs.

with the lipos it would be 300 for one 5s 5ah pack.

which means if i got the lipos the i would have one battery that lasts for about 30 minutes ORRRRRRR each a123 pack would last for about 5-10 minutes... dont really know exactly.

so the least amount of runtime out of all the a123 packs would be 25 minutes... but it could go for as long as 50 minutes.

with the a123s i could charge them extrememly fast too im sure. im guessing around 20-30 minutes per pack?

if i built a 6s configuration it would weigh aproxx 1lb. im sure thats about the same as the 5s lipo right?

only real downside i can think of with the a123s is that i personally have to build the packs. which is good and bad at the same time. i liek soldering stuff and building my own stuff, but i dont want to mess anything up.

a plus with the a123s is that they will put out more power than the lipos... they will be pushin 30c's at 19.8V correct?

wheras the lipo will be 30c at 18.5v i beleive.

only thing i think i might have to worry about is the A123s heating up.. idk if they will... idk anything about them really.

can anyone enlighten me about this?

ive asked questions before and had this exact same thread a while ago but now i am actually going to buy them.

also i have a truck ready for them.

thanks alot!

A123s can be charged and discharged faster than Lipo with fewer problems, because they are more resilient to overcharge/overdischarge.
A123s can do many more cycles than Lipo packs, and over time instead of losing both capacity and power output, they only lose capacity.
As you noticed, A123s are super cheap.
A123s are far more durable.
A123s are a bit heavier.
At 30C, an A123 cell will be at about 2.1-2.2v (6s1p A123 @ 30C will drop down to about 13.2v, I'd go with 2p).
I like to think that each A123 cell is good for about 200watts in peaks.
A123s don't have much of an issue with heat (none of mine have).
I just bought my fourth Dewalt 36v pack through Amazon ($105 shipped is a steal!).

maybe someoen can come in here that really likes lipos and do a rebuttle

where is aqwut at? lol

Lipo's are lighter
Lipo's have more voltage
Lipo's have much more current capability (there are Lipo's which can do 30C and hold ~3.3v per cell). Thats a .4v drop off nominal, while a A123 drops ~1.4v off nominal.


I personally like Lipo. Sure it takes a bit more attention since they aren't as "solid" as an A123 pack in terms of safety, but really its as simple as following a few simple guidelines. You can actually get a NiMH cell to explode with a "BOOM" to it if you overcharge it...I've experienced it twice (was at the track when someone made the mistake).

well i just like the fact that i can get 5 packs for the price of 1 lipo...

it will be fun building them too. the way i see it is im getting either 2 6s2p packs and 1 6s1p or 5 6s packs.

plus if i do a 6s2p configuration it will balance the truck out a bit more im sure.

idk.

I just bought a dewalt pack myself. I've already got three 2s2p packs. I'm planning to make the new pack 5s2p. For me, it's all about the safety. I'm not real careful with my batteries, so I like knowing that I can leave them in my hot car in the summer without worry, and that I can charge them and not stand over them the whole time.

i'm a fan of lipo because of their size and weight to power ratio, but since i've jumped on the a123 bandwagon, i'm hooked. before you would really have to budget a project to afford the batteries, but not really with the a123's. another benefit that i really like is that even though you take up more room per power with the a123's than lipo, you still get more mounting options for these custom builds because of the individual cells. i have some very different looking 6cell packs i'm making for my flm emaxx. and i also used a pair (shot gun) of 4s1p's on my ls10 project.

Hello all,
I am in the process of building a brushless CEN Matrix TR so I bought 2 dewalt 36v packs. I called A123 yesterday and talked to Brian and he said that he is getting 21min out of a 6S1P battery in an 8ight with a
Neu 1515-1Y and a MM combo on the track that tops out at 45mph. The amp draw peak was 40A in the 21min on the track. So I can't decide weather to try a 5S1P or a 5S2P in the truggy I figure that 30mph is fast enough for the track.

ya 30mph on a track is a reasonable speed.

you might want more if its a big wide open track but even then.

if you cant control it at 30 then why would you want anymorE!?!?

id go with the trueRC lipo packs or the hextronic lipo packs. cheap, durable, and i personally love the blue wrap on the hextronics!

Hey..! rebuttle not needed... I like them both...
What I like about Lipos..
more capacity, good discharge(25-30C), good charge rate(2C), good price (for me anyways)..
What I don't like..
Too sensitive to physical damage..

What I like about A123
Awesome charge rate (3-4C)/discharge rate (30C), good price($90 of ebay), able to take a physical beating.

What I don't like about A123
low capacity, and awkward shape.

The weights of bother me too much..

Those are my thoughts.. but I love them both.. I have a hard time choosing, so I just buy both... but my decision leans towards lipos..
If you decide to get lipos... P.M. me.. I can get you a good price...

i do have a true-rc pack right now and all i would have to buy is a 2s pack... but the only thing is that if i decide to get a123s how am i going to mount them? they are completely diff than the lipos... idk as usual.

pmed you aqwut!

i have a123s now, and it's fine for bashing in both my stealth and the upcoming eXT8. but once i start getting into racing, i'll pick up lipos... much less weight. the a123's are awesome for all the reasons already listed, though. SUPER fast charging and stupid-safe, which i need.

ya if i get a123s i will use them primarily for times when im going to be stupid with my truck.

i might pick up 1 of these things and make 2 5s packs and call it good.

when i want to drive it dumb and mess around ill bust these out!!

thanks alot for your input.

A123s seems to be your cheapest route... $90 for a "VERY" good 5S2P pack...

Yeah, 6s1p SHOULD allow the same power output as a 5s2p in a given vehicle, and a given motor choice... because the 6s1p will have higher voltage drop.

Right now, I am running a 7s1p pack in my Revo on Neu 1512, and I love it, it's light, it's powerful (~equivalent to 5.5s flightpower lipo), it has 15 min runtime, and i can charge the pack up in another 15 mins, it's great.

Tmaxxracer32... just go with A123's man and be done with it, enough of this.

Aqwut, personally, I think the TrueRC packs are his best bet. He can get a VERY good 4S2P 8000mah pack for $140 as apposed to $90 for a 5S2P 4600mah (I think?) A123 pack thats ALOT bigger and heavier.

5s2p A123 will be quite a bit larger than a True RC 4s2p 8000mah pack, but the weight difference will be about 70g, depending on how the 5s2p A123 pack is constructed.

What DOD (depth of discharge) do people here discharge their lipo's to? % wise.

If you want maxx play time and it's not hard core competition the A123's are the way to go.

Make it a 6s2p pack... (12 cells)
For the 3 packs you listed that means you will have 6 cells left....
If you do your setup right you can charge the 6s2p pack in under 10-15 min. and the charging system is super cheap!!! Therefore you could run the remaining cells 6s1p. while the others charge. You will be a little heavier.. but with 6s2p there will be tons of power availible.

Now if you are going to the track to race, You'll want to shed the weight, and your run time requirements will be lower, So lipo's would be your best bet. You can pick up some charge between races and should have no issues with several races with a single pack.

I personally went the A123 route... but If I start going to the track I will get a set of lipo's to race with.

In Conclusion. Buy which ever matches your use plan.

Highflier

probably the best description for me....

you hit the spot with eevrything you said.

i am going to be racing this truck so it looks like lipos it is.

i may buy 2 dewalt packs just to have for when i go bashing.

thanks guys

Very true dude, but gotta love the power output.... the 5S2p would pump close to 2300 Watts where as the 4S2P TrueRC would only pump about 1200 watts.... and you could charge the A123s 3-4 times faster with the appropriate charger... but the TrueRC pack would last longer for sure...

what would you say the lifespan of the a123 cells are?

and can you charge them at like 4c or something?

I think it's about 2000 cycles... and upto 4C charging... you really can't go wrong with either lipo or a123 M1.. batteries are beautiful...:lol:

I'am very interest to make a 6s2p A123 for my 1/8 buggy for bashing session (because for racinc i've already a Flightpower 5000, 4s).

OK explain me three thing please.
First: wich charger can charge A123 cells? because i've a ICE charger and not sure if i can charge this A123.

Second: Must i balance A123 pack when charging? If yes, how could i make a plug to balance it?

Third: where can i buy it?

Thank you

Which aspect of 'lasting longer' are you talking about? Life time, or runtime?

As for cycle life, no one knows yet... that's how awesome they are, I am getting close to 300 cycles now and have only lost 75mah in a 1p configuration. Impressive.

Here's a link which shows you how to make your own balance plug for your A123 packs but I read somewhere these don't have to be balance. Can't find the site that had that write up.

http://www.rcgroups.com/forums/showthread.php?t=599316

Here is the real thread on how to charge the A123 cells fast
http://www.rcgroups.com/forums/showt...=8#post8593235

I charge them at 10+ amps. I start at 15+ and it tappers off as it goes.

You must use 3s or 6s packs though.

I balance them before and after the first few charges.. Then they are pretty good check them every now and them and you should be jsut fine. They take a good lickin and keep ticking.

Highflier

that thread seems hard to follow highfligher

i got bored after just skimming through the first couple posts.

I would go with lipos Evo 30s are a great choice.

if i have the money then that is what i am going with.

Here is the short summary,
Take 15' of 18 guage wire. Connect to a car/deep cycle batter and connect the other side to a 3s A123 pack. wait 15 min disconnect and you have a charged pack.

Can not get cheaper and simpler then that.

Highflier

PS. By alterering the length of the wire you can get charge times down to 5-10 minutes

i dont think i would be able to trust that...

I wouldn't trust that... unless you had a power analyzer on it...

ya idk what that is but if i had something measuring mah and volts i would trust it... but idk.

I have done it with a Astro Watt meter. I started with 20' and have shortened it to 15' which gave me the results I wanted. View the thread I posted if you want to learn more. I works just fine and there are many that will tell you that. Just the same, If you don't feel compfortable with it then don't do it. I just wanted all to know. I enjoy charging virtually as fast as I discharge. in my planes.. I charge faster then aI discharge.. :: All I need is 2 batteries and I can fly all day long :)

Highflier

that is true i wouldnt mind a never ending runtime (have multiple batteries... charging then running charging then running.)

yeah, ur absolutely right.. but that wouldn't work for guys that run higher voltage.. unless you had more car batteries... :lol:

Ahh....., you can set packs up a 3s pack and use a harness to serial them for higher voltage.
I use 2 3s packs for 6s, But you could go to 9s or 12s also.

Highflier
PS. Yes you can drain a car battery pretty quick if you are going through the watts.

props high flier, I believe the saying goes...

I have done so much, for so long, with so little. Now I can do almost anything, with absolutly nothing :)