lipo plan!
 

hey guys,

my original plan was to go back to 12 cells with an 8L to keep weight down, but i think i found a better and lighter solution and still run my 10L. the kokam packs that mike runs are a very good deal now that i did the math. i will be buying a 3s and a 2s 3200mah 20C packs from tower.

http://www2.towerhobbies.com/cgi-bin...&I=LXJSJ1&P=ML

http://www2.towerhobbies.com/cgi-bin...&I=LXJSJ2&P=ML
then i get another $25 off, so that is about $175 for the batts

problem is my triton can only charge 4 lipo cells at a time and only at 2.5 amps. that would mean over 2 hours of charging. that just wont work. so then i found this charger

http://www2.towerhobbies.com/cgi-bin...?&I=LXKSY1&P=7

it can charge all my nimh batts for the qualifers and then can charge 5 lipo cells (what i will be running) at 3.2 amps, so that means recharge of only 1 hour. the charger is also a killer deal at $82 bucks. looks like im going lipo! just gotta save a little more and wait till the charger comes out. but after thinking about the price and WEIGHT of 3300s, the lipo seems like a way better way to go. also, in all i will save about 1 1/2 lbs in batts compared to my 3300s! they will also fit perfect into a g-maxx chassis. i have heard that if these cells get hit, they will explode. do i need to make some kind of gaurd? thanks guys.

supermaxx your inspiring me. Keep it up.


When your finished figuring out your battery and charger situation on the lipos please LMK how much its cost

If the money isn't to outrageous and the run time can last a 15min main I'm so going brushless on the revo.

Revo conversione wherever you look. That's great guys!

I'll keep an eye on the Lipo thing, but might get me a batch of GP3700 first.

That charger your talking about is great! it is very, very small and very powerfull.

Those Kokams are the real thing.

cheapbatterypacks and maxamps sell 20C lipoly's too (whitelable and polyquests) but i personally take those kokams over those. If you have got the ability to weld on a few taps, you might consider using a charge balancer as well. (i use them for my 3S mini-t packs too) I thought Mike uses his Kokams without balancer.

rc bro- the runtime will be about the same as gp 3300s, but less than half the weight.

serum- do you mean solder on the taps? or weld? BTW. the packs are not in parellel, so will i still need to use a balencer?

ill wait to see what mike has to say before i buy them.

yeah that charger is nice I knew that you would like it. I remembered it from rcx 05 and searched on tower. Pretty mint that something that small can do 5 lipo cells. What amps does it charge at though??

That charger sonds like a good deal, but the astroflight charger is only around $20-$25 more. The astroflight can charge up to 9 cell Lipo packs at a higher charge rate as well, so you wouldn't have to wait longer to charge a larger capacity pack(which will likely be available soon!). I don't balance my Lipos, either.

yes, but the astro flight cant charge nimh packs.

Might even be able to alittle more run time now that there is less weight which mean less stress which means less amps being drawn. Probably won't be a very noticable difference in run time though. I can't wait.

i cant wait either. i may order them later today and use the triton until the new charger comes out.

You already have a triton, so you don't need another charger to charge nimh, do you?

ill sell the triton and buy the multiplex...then i will have an all in 1 charger at a cheap price.

I will still stick with my initial comments. In a short while, I am positive there will be much higher capacity Lipos, and a charger with an ability to charge more Lipos at a higher rate would likely be a better purchase plan. Unless, of course, you could just sell the charger and upgrade at the appropriate time.

I thought lipo also gets longer runtimes?

arg! lol

Lipo CAN get longer runtimes if you have higher capacity. Just because it is Lipo though, doesn't automatically mean it will run longer (kind of like "nimh gets longer runtime than nicads" A 1000mah nimh won't run nearly as long as a 2400mah nicad).

mike- the multiplex can charge 5 cells (most i will run) and up to 5 amps for lipo. thats not bad at all for the price. the astroflight can charge 9 amps, but thats not a ton more. i can get by with the multi plex even if i buy new packs.

Man I so wish I could compete with the Nitro MT's with my electric truck but lasting those long mains 15-30 mins isn't going to happen. A battery change would eat up some time.

5 cells at 5 amps isn't bad at all! So, this could charge a 5ooomah , 5s pack in about an hour. Not too shabby. The Astro could charge a 8000mah 5s pack AND a 8000 mah 4s pack in the same time, though!

yeah thats what i was thinking. i just cant afford to have 2 chargers, so the multiplex looks perfect to me. all in 1.

Can't beat it for the price.

Oh, it can be done. 15 minutes would be pretty easy, actually. In racing, you could always sacrafice some top speed in exchange for runtime as well. Speed doesn't win races-it is usually the driver that wins. There is a user on this board that gets about 15 minutes of run time in an electric revo with gp2200 cells! Also, one pit stop in a 30 minute main would still allow you to be competitive.

I 2nd that!!! Just took out my maxx with 2000XL/18cells. Temps here are around 33*C today. I ran my truck for about 20-25minutes of speed runs and some pootling around in 1st, and the batts still had PLENTY left. Batts were cold, 7020 was barely warm, and the 2000XL was quite toasty. My batts are 3300's, but took 3575mah when charging.

A 15minute main should be no problem with 3300, and with a decent set of lipos (4000mah+) and a high turn motor (1600XL/1200XL), a 30minute main should be no problem.

Whats the average time to exchange batteries.

In the larger west coast races they normally have two seperate classes. Electric and nitro correct? Maybe I only need to last 15 mins.


So I'm looking at like $400 for lipos and charger? So many decisions! Thats why I love this hobby lol

-Thanks guys!


** Edit **

Well Mike maybe my esc or motor was toast because my run times were horrible. When I get it back I'll re-test my runs times.

I'm drastically thinking about going electric revo. Maybe keep e-maxx stuff that I need for T-maxx then sell the rest and buy another revo? Hmm.... lol

It's not the cheapest setup, as a matter of fact it may be the most expensive for the numbers, but I'll be running FMA/Kokam's new BalancePro packs in a few weeks (when they're actually out).
I'll be running two of the 2s2p packs in series. It will work out to 14.8v and 6400 mAh. I'll also be getting the specialized charger for the BalancePro. This should mean I'll get both batteries charged to 90% in about an hour. The charger goes up to 10 amps and the batteries can be charged up to 3C with the specific charger.
This is the setup I'll be using to get my 1/8th buggy through a 15 or 30 minute main. I'll probably be better off going from the 8L ot the 9L for this (Mike?).

I also have 2 of the 3s 3200 Kokam packs (20C) that I'll run in parallel for the same purpose. These are charged with my ICE charger at 1C each, which takes about twice as long.

For 14.8 volts on a 1/8 buggy, you should probably go to the 10L motor.

You'll see the order for one in about 3 weeks :)

Just make sure that the buggy hasn't got a metal spur.. (it has got an untaimable hunger for pinions... ;) )

Are Lipos safe, I really want to try them but get really put off with all these warnings that they are very unstaible? What is it that makes them unstable?

That is a loaded question(are they safe). A primary reason they are more dangerous than their nimh or Nicad counterparts is the fact that they contain more energy. They also don't have a hard case like the nimh, so they are more prone to damage this way. If they are cared for properly, they are pretty safe. I haven't had any disasters and I run them all the time.

How do I know how many Lipos my charger can do? It says upto 5 at 8000mAh. Is this good? Are Lipos just 1 cell? Is that all you need?

Hmm. Think I will stick with my NIMHs.

No lipos cells are 3.7 volts, (nicd and nimh is 1.2 per cel) so you need as much that takes to reach the demanded voltage and put these in serie.