Funtana Conversion Battery Question
 

I have a Funtana 40 converted to electric using the following setup:

Axi 4130/16
Jeti Advance 77-3P
ThunderPower 6s2p (made up of 4 3s TP 11.1v 2100 mah packs)
APC 16x10e
AUW 6lb 14oz

Not flying in a 3d manner, but rather in a typical aerobatic manner w/ most flight around 1/2 throttle.

Plane flys great, but am getting only around 9min flight time from the pack. Is this what I should expect or should I be looking for an issue?

Thanks,
Bob

RE: Funtana Conversion Battery Question
 

Thats great!!!! Thats a lot! With only 2100, i would expect around 5 minutes. You're proboaly pulling arouund 45 -50 amps though. But since you said you're flying around 1/2 throttle, it sounds good.

TTYL,
Andrew T.

RE: Funtana Conversion Battery Question
 

Andrew,

I should have been more clear. I am running 4 TP 2100mah packs wired up in a 6s2p configuration. If I am not mistaken, that brings my pack to 22.2v and 4200mah. Since this is my first electric, I am still learning the terminology.


Thanks,
Bob

RE: Funtana Conversion Battery Question
 

Bob,

I think Andy understood you ok. Your setup and duration seems fine.

What we get into here is a debate on how Manufacturers rate their Lithium cells differently. Without going into detail or pointing fingers, your setup results look fine.

Depending upon when you purchased your packs, you may have newer or older TP2100 cells. The older cells were rated at 7C continuous and 10C burst. The newer cells are slightly larger and heavier but are now rated at 10C continuous and 12C burst.

Good luck with your Funtana!

RE: Funtana Conversion Battery Question
 

Greg/Andrew,

Thanks for the info. Looks like I should adjust my expectations to a solid 8min flight with my setup. BTW, I have the newer TP packs.

I provided the additional information as I thought that he was viewing the battery system as a 2100mah overall, however, I must have been mistaken.

Again, I am new at the electric thing, so I am happy for all of the information provided both from Andrew and Greg.

The reason this question first came up was that I was seeing 8-9 min and when I purchased this setup my hobby shop was telling me that I should be able to get 2 8min flights comfortably. However, I think that they miscalculated the cell count as a 6s4p instead of a 6s2p. Not a big deal, just need to adapt and learn. Note: I am not at all unhappy with the hobby shop(just the opposite) , they have helped me a great deal with this conversion and many other things.

Am I correct in my thinking that the higher the mah rating, the longer a pack will last? Also, is this a good configuration for this application (AXI 4130/16 and 6s2p lipo)?

Another question, I am using a Astroflight 109 charger. I currently charge each of the 4 3s packs individually taking approx 4hrs total. Is there a more efficient way to do this charging (maybe charging them as 2 6s packs)?

Thanks again,
Bob

RE: Funtana Conversion Battery Question
 

I would strongly look into the 6s2p pack made with 2480 Apogee cells Bob. You would have about a 4 oz gain max and at 10.5 c THESE SUCKERS ROCK!!! I flew a 10c 4200 TP in my Jitterbug and I sware the think cant touch the 2480 3 cell pack. I know 4 oz can make a difference but the TP wouldnt turn a 13x6.5 prop at 6000 rpm. Thanks, Terry.

RE: Funtana Conversion Battery Question
 

Bob

I too am getting ready to covert a Funtana 40. Can you post some photos?

Also I use Kokam 2100 Mah 20C batteries in a 4S1P in my EMagic and get 7 minutes. My son probably thought you were talking about something like that. A 6S1P setup is what they used in the FLYRC magizine Funtana conversion. I will try a 5S1P in my conversion.

Again Post some photos!!

RE: Funtana Conversion Battery Question
 

Stephen,

I will take some pictures later this week and post them. Is there anything in particular that you would like to see?

Bob

RE: Funtana Conversion Battery Question
 

Bob,
I'm buliding a electric Funtana 40 also. I'm glad I found this post, as I'm trying to figure out which AXI motor and battery combination to use. What kind of performance do you get with this set-up? Do you have unlimited vertical? Do you think it would hover the plane? With the 16" prop did you have to use a taller landing gear? Also APC makes a 15x8 electric prop that might give you a little long run time. I would like to see pictures of the way you mounted the motor.

Thanks,
Chris:D

RE: Funtana Conversion Battery Question
 

Bob

how will you mount that motor? I mounted my MEC system earlier today. With the offset gearbox, it took forever to line it up.

RE: Funtana Conversion Battery Question
 

What issue of FLYRC mag was the Funtana conversion in? I would like to read it if still possible....;)

RE: Funtana Conversion Battery Question
 

There's been a number of Funtana 40 conversions over the last few years. When using the 8000 mAh Thunder Power packs, duration was typically 20+ minutes per charge. With 6000 mAh packs, duration is closer to 13-18 minutes, so around 9-12 minutes with the 4200 mAh pack is just about right.

For the best overall balance of power, duration and weight, the 6000 mAh packs seem to be first choice. Typically, most use the TP 5S3P packs, or 6S3P (2 TP3S3P packs in series) for even more power. The most popular power system is the Hacker C50-10L, geared 6.7:1 on 5S3P with an 18x8 or 18x10 prop (requires taller carbon gear to clear this prop) or the same motor/gearbox with a 16x8 prop and 6S3P (can use the stock gear and has more power but more weight than the 5S3P set up).

You can see one detailed conversion here:

http://www.rcuniverse.com/forum/Hang...1258419/tm.htm

RE: Funtana Conversion Battery Question
 

JB

Sept or Oct, the one with the Corsair on it. I'm slacking at work and can't check right now.

RE: Funtana Conversion Battery Question
 

It is in the October issue

RE: Funtana Conversion Battery Question
 

Chris,

I am using an Axi 4130/16 coupled to a Jeti 77 opto speed control. Using 4 Thunder Power 2100 10C 3S packs wired in a 6S2P configuration. I am using a taller carbon fiber landing gear from fibertech (if I remember correctly). I have flown using a 16x10e and a 14x10e prop. The 16x10e I like much better. It gave me very solid vertial and great pull. The 14 flew it ok, but the vertical performance wasn't there. My plane is 6lbs 14oz. I am using hitec 5745 digital servos (had them on hand) and an onboard 4cell battery for the radio. I mounted the lipos in the area right behind the firewall. Then just positioned the receiver and battery for balance. Didn't have to add any additional weight to the plane to balance.

I am estimating run time to be around 10 minutes of aerobatic flight (no 3d, I don't have the skills for that yet). However, I am still working out the run time.

On the 14x10e prop, static numbers prior to first flight on pack for the day (packs have 4 cycles in them):
RPM: 7050
AMPS: 30.7
Starting Volts: 12.4 per 3S pack

RE: Funtana Conversion Battery Question
 

bhouin; Thanks, Ill try to find a back issue............

RE: Funtana Conversion Battery Question
 

John,

If you can't find it, let me know and I can scan the article and email it to you.

RE: Funtana Conversion Battery Question
 

be very careful running those packs in only a 2p configuration (tp 2100's). you are well over their rating with a 16x10 prop. make it a 3p set and you will be much safer(and have a little more power).

RE: Funtana Conversion Battery Question
 

Kevin,

Can you expand on your comment a little bit? As I noted before, I am still learning this various aspects of electric setups and would like a little more information on your comment. I am assuming that you are referring to amp draw, but not sure. If I remember correctly, my amp draw on a 16x10e was around 43.

RE: Funtana Conversion Battery Question
 

i didnt realize you were only at 43 amps with a 16x10, which makes my wonder (check it again and let us know). a friend of mine ran this setup with a 15x10 prop and got 43 amps. he used 6s3p packs (63 amp capable). i would imagine you should be over 43 amps with a 16x10 (with batteries that can take the load better(more in parallel ). your voltage under load is dropping more thus producing less power. the 2100 cells are rated at 10 c (42 amps total for your pack) but i myself have come to the realization that 10c might be a little high since i have had problems running a 3s1p pack at 20amps. overall. if you use the throttle liberally you shouldnt have a problem, just make sure to give full throttle a break once in a while.

RE: Funtana Conversion Battery Question
 

Hi bhouin; That issue has been returned by my LHS. If you have the time, I would greatly appreciate it if you would scan & e-mail that article to me. I e-mailed Thunder Power with my set up and the answer from some guy named Chris was "to call Horizon" or "there might be some info in the instruction manual." The manual said "4 parallel 5 cell 8000mah cells" That seems mighty excesive AND expensive...You have my e-mail.......Thanks in advance [8D]

RE: Funtana Conversion Battery Question
 

Bhouin

Did you need to put in any scoops to keep the batteries cool? There seems to be a lot of flow around the motor area, but not in the battery area.

My Funtana with a MEC 36-50-2950 geard 4.67:1 w/a 15x8 prop is ready to test fly when I get the weather I need. I'll post pictures when I get home tomarrow. Your plane looks so nice.

RE: Funtana Conversion Battery Question
 

It's called "voltage depression." All cells suffer from it under load. The higher the load you place on the cells, the more pronounced the voltage depression. LiPolys are far more sensitive to voltage depression, which is why they come with very strict "C" ratings. You need a rough idea of how many Amps your setup is going to draw, then you need to parallel enough LiPoly packs to handle the load.

According to the AXi website, a 4130/16 with 16x10 prop on 20 cells (same as 6S LiPoly) should draw 43.7 Amps. From your measurements, you seem to be right on.

Okay, we know the motor is going to draw about 44 Amps, and you're going to use current-generation TP2100 cells. These are 10C cells. 10C times 2100mAh equals 21000mA, or 21 Amps. Each "P"ack of TP2100 cells will handle 21 Amps. Simple math shows that two in parallel will give you 42 Amps of total continuous current draw capacity.

Your motor wants to draw 43.7 Amps, and you've got 42 Amps of capacity. Not quite enough. You've got two choices:
1. Add another pack in parallel.
2. Use full throttle only in short bursts.

If you plan on running the plane at full throttle the whole time, you'd better get another pack. If you plan on using only enough throttle to get the job done, what you have should be sufficient for a decent flight.

It may seem excessive, but when you run the numbers, it ain't.

RE: Funtana Conversion Battery Question
 

Matt,

Thanks for that explanation. That makes alot more sense to me now. I think based on your comments that I will be ok. I am not flying this in a 3D mode. I am actually doing more conventional sequence type aerobatics. I am only full on the throttle in certain circumstances and not for very long. Most of my flying is around 1/3-2/3 throttle. But I will definately keep it in mind if I change my intent for this plane.

On another note, I would think that this motor would not be the best for a Funtana40 that you were wanting to 3D. In order to get the power to the motor properly, you would require too many cells thus creating a weight problem.

RE: Funtana Conversion Battery Question
 

Bhouin

I was able to mount my MEC system using a GP 40-60 adjustable glow mount from my EMagic. Also how do you keep your batteries cool?