lipo question
 

I am buying lipos for my brushless Jammin CRT with lehner 2240
I will be using 8s lipo
I will either buy 3700mah 20c packs 74A constant 111A burst
or 4800mah 20c packs 96A constant 144A burst
I want to know if I will see any performance difference besides runtime by going with the 4800s

i dont really think so except for longer runtimes.

What cells are the 4800's?

New kokams via FMA Direct they will be avalable the 20th of March

then 4800's it shall be! just look at their size, they might be too big for your conversion, i don't know..

They will fit, but will the extra amps give me more speed, punch, or anything other than runtime?

Well if they fit and the money is very little I would go with the 4800.

$250 vs $170 each, I am not skimping on this truck but if runtime is the only difference would rather buy the 3700s and buy more packs to switch between, but if my system wants to pull a lot of amps I want lipos that can deliver, problem is I have no idea how many amps the 2240 will pull. If it is greater than 74A I will get the 4800s if my setup will never pull that many amps then I will get the 3700s (or if there is some other benefit besides runtime that I dont know about). I am mainly considering the amp delivering ability but I dont know if I will see a benefit on my setup.

that is quite a price difference.

Promod uses the 3200's on his 2240, it can take SERIOUS power from the batteries, but that are small peaks.

The 3700's will serve you right and be lighter as well.

Benefit of the 3700 lighter truck heavier wallet!

I wonder which truck would win in a drag race to 60mph everything else equal except lipos?

Lol, Yeah..

Well, the 4800's can put more current out on paper. But at what voltage is that? you need to know more about the cells then.. Hard to tell.

The flightpowers are very good, from what i've seen in Viruss his eagletree recordings. their voltage stays rather high.

One other thing NL, you don't need to reply the entire quote if you reply in the thread, okay?

I think that the 4800's are 2S 2400's bytheway (they do the same with the peak performance cells, those are 2S2P too)

That is a bigger jump than expected. I would go 3700 at that price.

I think you'd be hard pressed to notice any performance benefit apart from runtime considering how much power we're talking about already.The extra 200 grams (ish) may settle the truck down a little,help control perhaps.At this level of power,the limiting factor to acceleration is largely traction.It's like trying to notice the difference between crazy uncontrollable power and slightly more crazy uncontrollable power,lol.Should be fun!

I'd just go with what size/weight and how much runtime you want,it'll be mad fast with either.

I'd go with the 4800s. They would provide better punch, since they can handle higher amp spikes. Also, since they wouldn't be stressed as much as the 3700s, they should provide more cycles.

4800
http://static.rcgroups.com/forums/at...742324.attach?


info on the 3700, cant find a graph anywhere:032:
http://aircraft-world.com/prod_datas...vx-lithium.htm

Look at this page of a graph of the Polyquest XP cells (these are the same as the Hyperion Litestorm cells):
http://www.elektromodellflug.de/akku-test/polyquest.htm
You'll have to scroll down a little bit to get to the 3700mah.

Yay graphs for comparison

Attachment 930

Attachment 931

Now can we decide which will win the drag race
3700 save 184 grams or .41 pounds
4800 may deliver more volts at given amp draw (I think)

I'm confused,the table says the 4800 are 14C continuous.

Where?

In the table on page 1 of this thread,says 67A continuous.

Different specs shown here:http://www.kokam.com/product/product...0mAh_Grade.pdf
says 96A continuous,192 amp peak! eh?

Oh, I see. That pic didn't load until I opened it up in a separate browser.

I think I've read that the Orion and Peak Lipo packs are 2p, and not single 4800mah cells. Unfortunately, I don't recall the source of this information.

In an rc car action add, it says it's 2s2p and 72 amps max continous.

Thwe Orion packs are indeed Kokam cells, configured in 2s2p. I plan on using the Orion cells this year myself. The packaging/size etc. is perfect IMO, and the extra runtime form 4800mah is a nice bonus. Also, the Orion 4800 packs are around $150 each.