yea jets are expensive. It is a blast to watch 2 planes flying 40-50MPH collide head on. it makes a nice popping noise then you hear both pilots go full throttle and try to get up some airspeed before they hit the ground. You score 1 point if you hit a plane and he crashes into the earth while you manage to fly away.

The most commonly broken items are control rods (6 for $2.00 and 5 minutes of labor) and Props. 2.50 a peice and 3 minutes of labor. I would guess that I crash about 10 times typically before I need a repair. I even have a guest plane ijn case a freind visits :)


highflier

NP on the cells. MGMs rate their controllers based on the highest charge voltage, tho BK is so screwy I don't know if I'd push it either.

Anyway, I ran 5S2P w/ my 8xl/mm combo and it was great. The 9Xl should be too.

Where in philly are you? Do you ever race the truck? Where do you fly the planes?

>I'm now running a 10S A123 pack w/ a 1100 kv motor and everything runs dead stone cold. :) Once you go HV you don't go back

@Finnster
Great to hear that your plan worked out. I really would be interested to see a new thread of your setup (with pics). btw welcome to to the 10s efficiency club:lol:

Truck is to stock to race right now. IMHO it is barely bashable. However I hope to be bashable plus a little once I get the Chassis, UE steering, 5s2p pack, new tires and rims. I am planing on proline mulchers 40 series unless sombody talks me out of it. I want some sort of beadless rims.. Advice???

I fly the planes at local schools, I am actually north of Philly by 20 miles. But I did not expect anybody to know where Holland PA, was.

I'll be getting most of the stuff ordered in the next 2 days. I can not make up my mind on the chassis... that is my biggest issue right now :(

I'll post a link soon that showes a little e-combat.

highflier

Yes, I agree, 5s2p would be the indeal way to go with A123 batts. A 6s1p will only get you 1080 watts roughly, you need more than that to give you the 'brushless grin'. :diablo:

I run a 1512/3D on 7s1p A123 pack and I get up to 1500 watts from it, I get roughly 15 mins runtime, and I can charge it back up again in 25 mins. It's great. I also have a 7s2p pack I use mostly though. I am thinking about trying out some FlightPower 6s packs sometime.

Just for reference, each M1 cell can deliver a 'solid' 180 watts. When I say 'solid', I mean 'useful' power that can be drawn by an R/C power system.

Hey, you are just ~5mi from me. I'm just S of Doylestown. I know Doylestown has a big RC airfield @ Turk park, but anywhere would do.

IDK about chassis, left the maxx along time ago. My fav tires are mashers for a good go-everywhere tire, but I hear badlands are also good for that. Mulchers are great for very loose dirt, but too hard of a surface and they will wear quickly.

@ Otello:
So far I am loving it, but amp draw is quite a bit less than I expected, I've only been able to pull 45A out of it. It does ~40mph w/ really strong TQ. The ET data shows quite a bit less power than the 8XL combo (upto 120A), but you don't see it. I chalk that up to the good motor and eff. If anything I cert could have gone with the 1515/3D (1360 kv,) altho the power is great and I can add some cells if I want to go nuts. I'm planning a post when I get everything sorted out.

@Finnster
When first using a 1100kv (Fun 600/11) motor with 10s A123 i also didn't see spikes above 40-45A. With HV and the right motor the power is lesser wasted in heat. I also saw 100-200 Watt less on my eagletree with the same feeled amount of power in comparision to my 4s setup. At 1200-1400 Watt with 4s you will need 80-100A. At those Amp levels motor efficiency might be at 80% (at most with a Feigao). This translastes to 240-380watt in wasted heat and 960-1120Watt of usefull power. To reach 960-1120 Watt with 10s A123 you would only need 1050-1250 Watt because your motor still is in the 90% efficiency range (35-45A). So get yourself used that you will see lesser Amp and Watt spikes with the same feeled amount of power than your LV system due to higher overall efficiency ... which also translates to a slightly longer runtime.

Looking forward to your thread.

Sorry for offtopic (thread highjacking).

Well I am starting to lean back to 6s2p for my setup. I just made a charger that will charge a 3s pack in 10-12 min. The charger cost me less then $10.00 and worked like a charm. Put 2300 MAH in the pack in no time at all. For bashing do you think the extra weight will really mater?

Highflier

What kind of charger did you make? A simple CC charge with a cutoff?

I can not take credit for the idea. It is being called a zip charger.

I used 20' of 18 guage speaker wire. Put a deans on one side and alligator clips on the other side. plug the battery in and connect the alligator clips to a deep cycle battery. You just watch the voltage (I used watt meter) until it hits about 11.5 volts and your done. This setup gave me a 6 amp charge rate. I think I will cut about 5' of the wire off so that I can get closer to 8 amp charge.

Just a warning wire length and guage are critical to the charge rate. Don't mess with it unless you have knowledge or comments from others. Oh this will only work with 3s packs. But that is fine for me.

Do you think 12 of these cells in the e-maxx will be to heavy?

Highflier

12 M1 cells is about the same weight as 14 NiMH cells, but has 36% more energy under it's belt, and much higher discharge capability. It would have about 2200 watts of usable power, but, you would never use that much in an R/C, even a MT.

I like to use my 7s pack for times when I want the Revo to have great agility, and it performs at roughly 5s lipo equivalent. I also have a 7s2p pack, and I get a pretty decent boost in punch, and it has marathon runtime it seems with the 1512 motor. The 7s2p pack doesn't feel that heavy, believe me.

A 6s2p pack should be perfectly fine, if you are not a 'every last ounce' racer.

I think that is the route that I will go then 6s2p. At least until I decide to get a new ESC that could handle higher voltage.

I tried my Zip line charger last night.
I discharged 2000MAH from a 3s pack
Then put it on the charger. 15 min later it was fully charged and had taken 2300 MAH. I am going to make another one of these chargers so that I can charge packs as fast as the e-maxx will use them :)

Highflier

Oh, so it sounds like this zip charger is relying on the resistance from a long and smaller gauge wire to limit the current.

A better way would be to build a simple constant-current source using a high current transistor like a 2N3055 or similar. You'd still have to monitor the voltage (or add other circuits to do the cutoff), but this setup can be made to have an adjustable and constant current.

You could also use a regular NiMH charger since those are CC chargers. Still have to monitor the voltage.

When charging A123's, does the voltage dip at all at the end of the charge? If so, you could set the delta peak value of a NiMH charger to a really small value...

Highflier, that really does make me nervous when I hear you using the 12v battery 'mod' as a charger, I have seen it be done, but I prefer some decent electronics.

Brian, the A123's don't dip at all, but instead anything over 3.8v/cell, the voltage takes off like a sky rocket. At that point will most likely be very damaged if allowed to go over 4.0v/cell. But I hear 4.0v/cell is actually doable with these things.

If you want to use JUST CC, then you could use 3.8v/cell and use roughly 10 amps or more per 1p configuration, and then terminate charge once voltage is reached... I believe this will get you 96% SOC.

That method is called the "nuclear charge" as I've seen it. Yeah, basically the wire is to provide some small amt of resistance so its not quite a dead short. Like a CV charge w/ barely limited current. I saw a wattmeter graph of it, and some of the initial charging was like 40-50A+ :eyes: but obviously tapered off towards completetion. The idea is you try to match the # of cells to the lead batt, ie for 10S you would hook up to a 3S lead batt, then cutoff before it overvolts. Some people were charging M1s in like 5min depending on current limiting.