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IrusTheVirus's Avatar
"Experienced user"
IrusTheVirus - 1.11.09, 9:22 am Post #1: | Reply With Quote
Hey im trying to get into Lipo, and Brushless. So i have a few questions.

Q about Lipo.
1. Why are the batteries 11.1v ??
2. What is the difference between 2s, 3s, 4s, 5s, 6s Lipo's
3. The max discharge is say 30c, what is that, like how long the battery will last, or ???
4. What is hypertencion taps ?? Is it the white plug that is used to balance the battery.
5. Do most battery chargers come with a balincer or will i have to buy on, if i have to buy do i just plug it in the white plug, and before or after i charge ??
6. Do i have to do anything special when discharging or charging, or can i buy a charger to where i set it and all i have to do is plug it in.

Brushless
1. What is the turn on brushless, like if i bought a mamba max esc could i hook up any motor ??
2. I want one with a programmable low cut off right ??
3. Is Deans the best plugs to use ??

Radio
Say i want to get a spectrum radio, then i get a RX from spectrum, will they automatically detect the RX, and then what about the little surface thing in the back of radio's, will i need one of those too.

http://www.atomicmods.com/Products/S...ec__13859.aspx

http://www.atomicmods.com/Products/S...ed__14540.aspx
Lets say i get this radio, and the little thing about, that is suppose to plug in the back, kinda like a crystal ?? And what about the thing that says Fut/Hitec, what does that mean ?? And if i get that radio, it already comes with a RX.

Thanx for all the help.
IrusTheVirus's Avatar
"Experienced user"
IrusTheVirus - 1.11.09, 9:23 am Post #2: | Reply With Quote
Oh and on mamba and sidewinder it has KV after a number, is the higher KV better like a 5400 better that a 4200, or is it just it supports a higher S lipo battery ??
speed_bandit85's Avatar
"Army Signal Soldier"
speed_bandit85 - 1.11.09, 10:29 am Post #3: | Reply With Quote
the higher the KV the better per cell (explained more deailed below in terms of limitations). the (X) in Xs is the number of cells with an optimal voltage of 3.7V/cell. That being said:
1S 3.7
2S 7.4
3S 11.1
4S 14.8
5S 18.5
6S 22.2
... and so on
and then there's the monster
12S 44.4

Now in terms of discharge rate (30C) that is the rated constant discharge rate in Amps. you take the mAh and convert it to Ah. 4000 mAh is 4 Ah as mA is 4000/1000 of an Amp. That being said the capacity of the battery is 4A, to get the dicharge rate you mutiply the capacity times the discharge rating (30C) so the constant dicharge in Amps is 120A.

Charging Lipos
your max charge rate of LiPo batteries is 1C so using the 4000mAh battery, the max charge rate will be 4.0A and also invest in a good charger. i use a TP610C which is 12V DC only so i had to get a votage converter for it to go to 110AC but it comes with a blancer already. I would strongly suggest not skimping on a charger as my first charger wasn't to kind to my batteries, bloated them and I started one on fire... not a pleasant experience. On a final note with chargers. When you charge it all you have to do is tell the charger how many cells you're charging unless it's auto-detecting of that.

That being said get a Lipo Sack. It's made out of Neoprene and will contain any fires that might happen. If you take care of your batteries you should have an issue though. for batteries look at SPC, TP, -[b][DISALLOWED LANGUAGE re-read the forum rules][/b]--[b][DISALLOWED LANGUAGE re-read the forum rules][/b]--[b][DISALLOWED LANGUAGE re-read the forum rules][/b]--[b][DISALLOWED LANGUAGE re-read the forum rules][/b]--[b][DISALLOWED LANGUAGE re-read the forum rules][/b]--[b][DISALLOWED LANGUAGE re-read the forum rules][/b]--[b][DISALLOWED LANGUAGE re-read the forum rules][/b]-. I suggest staying with household names for lipo batteries. Don't go cheap on those either. It might hurt the pocket in the begining but you'll get more bang for your buck in the end, and they'll last longer.

Onto the number of cells for a motor.
Most motors have a max RPM of 50,000. KV=RPM/V. Castle motors however can go up to 60,000 RPM. It's a fairly simple equation to work out so not much more is needed to be said on that. Except for the fact that:
7700 will be faster than a 5700 on 2s each. the same with 5700 faster than a 4600 on 2s each.
a 5700 on 3S will be faster than a 7700 on 2s
the 5700 and 4600 both have a 3s max. However if you go outside of Castle motors and get an even lower kV motor. Say a 3300 for example would be capable of 4s which would be faster than the 5700 and 4600 (both on 3s). With the Mamba though you will need a BEC. Castle makes one you can use to handle the 14.8 volts of 4s

Onto the Mamba/Sidewinder
If you are willing I would suggest the Mamba. It's more flexible, can handle more power and it has the USB programming port on the side. Untimately the best option. Also the Mamba can handle any brushless motor out there as of current. Castle even makes a 9900 kV, which is rediculous amounts of power out of the box, and the Mamba can handle that with no issues. Also be aware of the difference between sensorless and sensored systems. For raw power go sensorless, if you're looking for drift spec you'll want to go with something like a Novak. The difference is that the sensored systems send feedback to tell the ESC exactly what the rotor position is. The result is more precise power application, especially in low throttle moments. If you're looking for WOT fun then go with the Mamba. You'll also want a IR thermometer to keep and eye on temps. Even though the MM has a thermal cutoff it's good to know what temps you are running at as high heat is a result of wasted power. X amount of watts are given to the motor, any Watts that aren't used are converted to heat. a good operating temp without much waste is around 145, 150. Lastly on the MM, it has built-in LVC (low-voltage cut-off). However it works up to 3s only, when you apply 4s it becomes glitchy. As soon as it senses low voltage it will cut power to the motor and allow you to steer it to a stop. Seconds later, it will reapply power to let you bring it back to you... this works to a point. If the car if to far away you might have to go through this process 2, possibly 3 times to get it all the way back.

Connectors.
Plain and simple DEANS. I use the TRX high current connectors but there are to many factors to go wrong as in clip in contacts. If you put to much solder on them they don't clip in and slide out. deans connectors are by far the best design I've found and I am slowly converting to them as we speak. Save yourself the trouble and GO DEANS.

in terms of turns.
when you look at brushless motors to purchase it will tell you usually what the approx turn comparison is.
Turns is construction of a brushed motor
kV is RPM/Volt without a load on it.
There is really no way to make a comparison of the two.
I'm not really to familiar with a detailed comparison of brushed to brushless as I only ran brushed for about a week of 2 and ended up diving into the brushless scene. I can say that my 12 turn speed gem motor is slightly comparable to to my 5700 C4 Big Stick with the 5700 being faster slightly. So I would say a 5700 would be around a 10T if i had to give you an answer.

To conclude this post let's talk Radios
I use a Spektrum DX2.0 and I like it with the simplicity of no crystal operation. However if you just want to bash and don't have a need to change crystals I wouldn't worry about changing. You sacrifice range for the benefits of 2.4GHz operation and no crystals. If you're going to be racing, I would suggest it in a heartbeat. There's nothing more beneficial than not having to swap crystals or someone having the same crystal and causing interferance plowing you into a wall. In terms of binding. You will have to do this when you get the TX/RX. it is in the instructions. All you do is hold down the button on the Rx apply power to it by turning on the ESC(green light flashes on Rx. you then hold down the button on the back of the Tx and apply power to it by turning it on(greenlight flashes on Tx). when both go solid green they are bound and you're good to go.
The plug in the back is to charge the embedded Lipo back-up battery. You shouldn't need to charge it for any reason in the near future. The sole purpose of the internal battery is to store the binding information for your system(s) in the event of the batteries being removed/ going dead.

I apologize for the long-winded post but this is pretty much verbal vomit of all the info i could think of being relevant. I hope this helps you out. Best of luck.
(Last edited by speed_bandit85 : 1.11.09 at 10:35 am)
Distributor of International Communications... K?
R/Cs:
4.6 Monster GT, SLASH, Brushed Tamiya M04-M, Brushless TC3 (top-speed runner), Mini RS4 miata, Air Hogs 2 Ch heli, Air Hogs 4 Ch Havoc Heli, 3 Ch Micro heli
IrusTheVirus's Avatar
"Experienced user"
IrusTheVirus - 1.11.09, 2:18 pm Post #4: | Reply With Quote
wow, yes that helps the best. Time to go brushless n lipo. Yay
speed_bandit85's Avatar
"Army Signal Soldier"
speed_bandit85 - 1.11.09, 2:38 pm Post #5: | Reply With Quote
Like I said sorry for the long post. I apparently made an error in the motor section, but to i think it has to do with what's faster... but the 5700 on 3s is faster than the 7700... this i know. I have someone that's busy at the moment but said something was wrong but has to go over it. I'll post with the changed information. Have fun with your brushless. The difference is night and day. if you're putting it in a pede or something similar you COULD go with the monster mamba... Otherwise the regular mamba will have all your needs in any 1/10 vehicle. it is even more than suitable in a monster truck. it's just that the monster has the combo with 2XXX motors and 6s capability. Won't even break a sweat in a 1/10 app. just be aware of the 5mm motor shaft.
Distributor of International Communications... K?
R/Cs:
4.6 Monster GT, SLASH, Brushed Tamiya M04-M, Brushless TC3 (top-speed runner), Mini RS4 miata, Air Hogs 2 Ch heli, Air Hogs 4 Ch Havoc Heli, 3 Ch Micro heli
IrusTheVirus's Avatar
"Experienced user"
IrusTheVirus - 1.11.09, 2:44 pm Post #6: | Reply With Quote
Well the first brushless i am getting is for a mini t.
speed_bandit85's Avatar
"Army Signal Soldier"
speed_bandit85 - 9.20.10, 4:29 pm Post #7: | Reply With Quote
so a look back at this thread and i cant believe that i have all this knowledge tucked in my brain. i been awa from rc for so long i might actually be able to learn from myself... LMBO
Distributor of International Communications... K?
R/Cs:
4.6 Monster GT, SLASH, Brushed Tamiya M04-M, Brushless TC3 (top-speed runner), Mini RS4 miata, Air Hogs 2 Ch heli, Air Hogs 4 Ch Havoc Heli, 3 Ch Micro heli
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