LI-POLY POWER - I THINK I FIGURED IT OUT!!
 

This is my question – will this work????

Aircraft: TopFlite P40 Warhawk (10 – 11Lbs.)
Motor: AXi 4130-16 with Master Airscrew wooden elect prop 14x10. This should operate at @8000rpm pulling 49 amps working out to be 975 watts.
Jeti 77 opto controller NO BEC
Kokam Li-poly setup as follows:
(please click on link for diagram)
OK – is this correct or is this overkill? Is this a 8s2p set-up? Can you charge these all at once (Triton Charger); if so, what do you enter for number of cells when using Triton charger? OR . . . . is this completely wrong???? Any info would be greatly appreciated; I always try to read MANY threads before asking probably dumb questions.

RE: LI-POLY POWER - I THINK I FIGURED IT OUT!!
 

Dennis,

Yes, that looks right to me. Your 14x10 prop is much smaller than my 15x8 3-blade that has the effectiveness of a 16x8 2-blade prop. Since I used a 6s setup, your 8s setup looks correct.

I would use the new Astro Flight Lithium 109 charger to charge the entire pack at once with the current set to 4amps.

RE: LI-POLY POWER - I THINK I FIGURED IT OUT!!
 

THANK YOU GREG!! I'M GOING TO FINALLY ORDER ALL OF THE EQUIPMENT I LISTED (AND THE ASTRO CHARGER) AND GET IN THE AIR!!! AGAIN, THANK YOU FOR THE REPLY - WILL POST PIX OF MODIFICATION FOR THOSE WHO ARE INTERESTED.

RE: LI-POLY POWER - I THINK I FIGURED IT OUT!!
 

An 8S LiPoly will be a bit more than a 24-cell NiCd. In fact, it will be close to 27 NiCd cells. Each LiPoly cell is good to replace about 3.5 NiCd or NiMH cells. If it were me, I'd probably go with a 7S2P. It's the equivalent of 23 cells, and you're pretty much assured that you're not going to overstress the motor. I've heard rumors that you don't want to spin an AXi faster than it was designed to go, or draw more than the recommended amount of current. Besides, it'll save you about $42 and almost 4oz of weight.

RE: LI-POLY POWER - I THINK I FIGURED IT OUT!!
 

Ok - so then I should use the following set-up:

3-cell + 2-cell + 2-cell in series (all 2000mah @ 11.1V) PLUS another of the same set-up in parallel??

RE: LI-POLY POWER - I THINK I FIGURED IT OUT!!
 

You've got the cell count right, but you're a little off on the voltages:

3-cell = 11.1V
2-cell = 7.4V

Building from readily available packs, that's 3-cell + 2-cell + 2-cell, all connected in series. Do it twice, connect them both in parallel, and you're right on the money!

This sounds like one K - E - double-W - L kewl project! Of all the warbirds, the P-40 is probably my second favorite after the Corsair. My first successful flying experience was with a little Cox control line P-40. I'm still dizzy and puking from it almost 20 years later :)

RE: LI-POLY POWER - I THINK I FIGURED IT OUT!!
 

Wonderful!! Thank you for the additional info. I have always wanted to electrify the TF P-40; not only is it one of my favorites, but the cowl system is PERFECT for cooling all of the electronics ( even the top air scoop, which is going to funnel some air down to the batteries inside!!). :D

RE: LI-POLY POWER - I THINK I FIGURED IT OUT!!
 

Hi guys...

This is exactly the thread I was looking for since I was about to post a similar question.

I need to build an 8S4P LiPo pack and was going to use the new Kokam 2S 2000 mAh packs and theri series and parallel connection boards. I'm a little (OK, a LOT) confused about how to do this. Would someone kindly explain how to do this so that even *I* can understand?
:eek:

Thanks!

Curt

RE: LI-POLY POWER - I THINK I FIGURED IT OUT!!
 

This is amazing... using a piece of paper and a pencil I sketched out a solution (I think) to my own question!

1. It appears I need to buy 8 two cell Kokam packs, 5 series connectors and two parallel connectors.

2. I then assemble four packs of two (2S) packs using series connectors to give me 4 packs of 4S2p.

3. Next I connect two of these 4S2P packs using a parallel connector (and repeat for #2) to yield two 4S4P packs.

4. Finally I connect these two packs together in series to make 8S4P.

Is this correct? It sounds like a Rube Goldberg approach but it represents the limit of my thinking!

:D

The project will be a 1/5 scale Kangke Monocoupe (shipping very soon) and a MaxCim motor and controller. Tom Cimato suggested the 8S4P LiPo Kokam batteries and I'm just trying to figure out how to make this work!

Thanks again!
Curt