RC-Monster Forums - Li-Ion Power Tool cells work great for RC!

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- - Li-Ion Power Tool cells work great for RC! (https://www.rc-monster.com/forum/showthread.php?t=2748)

yeah 110A bursts are okay for the 9920.

I only found the evo 20 packs. didn't see no 50c packs.

Serum said they are called the "New Formulation" or something. ;)

These new lipos look great, I wish I could trade mine in for these

just look a bit closer country.. They are there for sure.

Did anyone happen to notice the temperature graph of the cells? 75 deg. C is a lot! (160 deg. F) Lipos usually shouldn't go over 140 deg. F or 60 deg. C.

In case anyone didn't notice, they posted the same graphs for the regular 20C packs as the "New Formulation" 20C-50C packs. So how do we know that the cells are any different?

Quote:

Originally Posted by Nick

I love the charge rates with these packs too! Tested at 2.5c.

While it certainly is conveniant, it also decreases the number of cycles that a pack will hold up for. Most Lipos these days are capable of 2C charges, as long as there is a balancer (the differences in the cells' internal resistances is amplified two times with a 2C charge).

Quote:

Originally Posted by BrianG

I'm all up in the air about this stuff.

One minute I want to wait for the A123Systems M1 cells from the DeWalt 36v line, but then I find they are only 2.2Ah, are kinda big (26mmD x 65mmL @ 70g), and aren't exactly like typical Li cells; they only charge to 3.6v (not 4.2v like others), which will make charging a little challenging. By the time I set up a 4s2p or 5s2p pack, I'll be at the same weight and size as equivalent NiMHs (or close to it).

Next, I think I'll try those Emoli cells from the v28 packs, but then I don't want to go with a 2p arrangement for weight and space (each cell is 26.5mmD x 70mmL @ 99g) since they don't have the burst capability.

That leaves LiMn, NiMH, or Lipos. LiMn are a bit pricey for what I need, but seem like the best choice so far despite some peoples mixed feelings. NiMH are just too heavy and bulky for what I want to use. Lipos, well, I won't go into that again.

:032: :032:

If you are that concerned about weight, then round Lithium-based cells are not for you. They weigh more than prismatic cells mainly because of the (usually) steel casing. You just can't get much lighter weight than a plastic pouch!
If you go Emoli and use 1p, you're going to need a high voltage for the pack to hold up well.

Lipos last alot longer than Nimhs though right? If used correctly.

Do lipos "fade out" like some nimhs, for example towards the end of a run there is less power?

From my experence nick. The packs run about the same from beginning to end. I don't see much difference if any. If it was not for a lvc i can see where you would mess up some cells.

On the Flightpower Lipos, what is the little connector (looks like a reciever plug) for?

^ is correct. At the end of a charge (or from about 3.8v and up) it keeps the individual cells at the same voltage.

I finally found someone with an extra cell that they sold me. It'll ship tomorrow. Soon I'll be able to try out a 4S2P emoli configuration.

I tried out the 4S1P in my MT2 this morning, and it did better than I anticipated, considering the potential amp draw of the 9L. I did several speed runs up and down the street and recorded a max gps-verified speed of 48 mph. This is just barely less than the 50 mph I achieved with 12 IB3800's. I only ran the emolis for about 5 minutes, but the cells didn't heat up at all. When I get that extra cell, I'll be able to see how 4S2P performs.

Let us know how they work out. Do you expect abovethe 50 mph with the 4s 2p?

I am sure you will get above the 50mph with two of them P