Bombers_410

I think he means that the havoc doesn't come as a kit designed for electric use. You had to customize that truck it didnt come that way.

RURC

Well I will make the kit. That is one of the things I do. I still have the CNC files.

RURC

Going to try photos again
Still wont load


Oh well here is a link to them. The first one is a detail of the insides of the Havoc. Note the old tires. I really like the new ones.


[link]http://pg.photos.yahoo.com/ph/michaelmeisman/album?.dir=/9f28re2&.src=ph&.tok=ph9fGpFBh8HKKehg[/link]

$

yeah I know that it is electric. Now I am thinking about buying a nitro monster truck kit and converting it to electric. How hard would that be?

$

they should make this kit in electric;
http://www2.towerhobbies.com/cgi-bin...?&I=LXJKT0&P=0

RURC

Many of the manufacturers are having a hard time working brushless electric into their scene. I am working hand in hand with some of them to develope cars. But I have a real bias against RTR cars that can reach speeds of 80 to 90 mph. There are some things that the general population should not be able to readily get. I want them to sell them in kit form. This limits their liability. That part they like. They make more money on RTR's then kits. The shops like them because they get to sell repair time for the cars. I relate this to my kite flying. I know you are saying 'kite flying, what a wuss'. I have kites that require that I wear a bridle and either I ski down the beach or I have to anchor myself down, they pull that hard. 2 and 4 string stunt kites. Great fun. Anyhow I wanted to get kevlar string. Pure kevlar not dacron coated or anything, just kevlar. Well there is one manufacturer of this string and they are very careful what they do because of liability. I had to goto a kite show in Palm Beach (about 150 miles from my home) and fly one of my kites to demonstrate to them that I was qualified and not some moron to get allowed to buy the string. The problem with the string (they call it a problem I call it aerodynamic advantage) when it gets pulled very tight it becomes like a razor blade. Imagine a 3 mm elopse of kevlar with razor edges front and rear with 100 to 500 pounds of tension on it flying through the air. Not the safest thing in the world. Can you picture going across the horizon then someone you did not see gets their head lopped off. Although that is a bit extreeme there are too many unintelligent people out there. Someone will get hurt and then sue the manufacturer.

$

wow never knew kite flying could be that dangerous[sm=eek.gif]
yeah that would be great if someone would come out with a electric stadium truck kit. I am shure a lot of people would buy it and switch over to electric

Bombers_410

Hey manblue, if you want the hpi rsf mt2 in an electric, then just search for a roller, without an engine on ebay or somewhere, and buy it. That way you will save $ because you dont have to buy the engine. Or you could just buy the kit that you said off of towerhobbies, convert it to brushless, and sell the engine somewhere. That would be fairly efficient money-wise

RURC

That is what I do. I just find a roller. Right now I am looking for a HPI BAJA 5B with damage or broken. I want to make an electric one of those. I buy rollers all the time.

Krakit

ummm...7 cells. you sure? I've talked to my Novak rep and he says to use only 6 cell batts. Mamba allows you to use more that 6...cool if absolutely true!

RURC

You can positively run way more than 6 cells. The Novak is so out classed by the Mamba that it is just gross. The Mamba Max will, again I say will run 5 cell lipo or 16 cell nimh or nicd. That is over 18 volts. How do I know this? I do it. Please understanf that the Novak and LRP are in no comparison when you look at almost every other brushless system on the market. They are a sad statement to what brushless was about 6 years ago.

-Inverted-

Thats great, but I would rather get something built to work with that voltage as money doesn't come easy for me so if something happens I would rather get it replaced then be screwed, but Im just a poor peasent boy so thats my opinion.

MacDuff

My Feedback: (2)

Yeah I wanna do that too, but the only thing holding me back is the making a custom motor mount..

RURC

Vert I know you are a smart guy. Look I run this thing hard with 4 cell constantally. I will have videos soon. I also have ran it with 5 cells with no real problem. Now I personally know many at CC this next statement has NOT been told to me by them but I think that the only reason they gave the limitations they did is bceause of warranty issues. Again this is my personal thoughts not CC's. Vert I think you know me well enough to know I will not suggest something that is a real problem. I have a reputation on this forum as being rather knowledgeable on brushless sysems. I will never intentially steer someone wrong. I generally only make suggestions based on the fact that I have done it. I have the luxary of being able to burn these things up and they just keep sending them to me. The one thing I will tell the readers is when you go to high voltage, 4 cells or more I personally use a seperate BEC not the one on the esc. Also On larger cars and trucks I will use a servo controled brake not the esc for brakeing.

-Inverted-

I know, im just saying, in my opinion, I feel safer running an ESC that is guarenteed to have no problems running it, because if something happens to me I dont wanna be screwed. Are you using Castle motors, I thought they had a rotor problem at that rpm.

RURC

No I generally dont use CC motors for anything other than standard 1/10 units. I mostly use Neu Motors then Hacker and Kronk. I ha

Access

RURC when you do 4-cell or 5-cell do you have to use some kind of additional cooling like a fan or exposing it to the outside air? To stop thermal shutdown? I believe in their own tests CC said that 4x LiPo with a 4600 would thermal the controller (even if it was within the motor spec).

RURC

As you increase voltage you actually lower your current draw. This in turn lowers the the temperature. It is the current flow that creates the teperture not the voltage. Have you ever replaced a ballost in a fluorescent lamp? If you have you will notice that the wires are like 18 gauge. These things see voltages in the thousands of volts but almost no current (amps). If you go from 2 cell lipo, 7.4 volts to 4 cell lipo 14.8 volts, you will effectively cut the current draw in half. Now this is not 100% true because of the way VFD's work, but it is close enough for any talking about here. Unless you want to go into electron flow and the skin effect then look into the general nature of VFD's. BTW a VFD is the ESC. It is because of the advancement of VFD's (variable frequency drive) that you have such nice ESC's that work on 3 phase motors (brushless). Look at it like this, with twice the voltage it requires half the current to do the same amount of work.

To answer your question on the fan's. sometimes I do and sometimes I dont. It is dependent on the usage and environment. To me it is important to build a whole system not just a stick a fast motor and esc in a car. I start with what speed I am looking for and reverse build from that. I stuck a Mamba Max in the Havoc and it thermaled right away. But I think that is mostly on the motor side of things. I have not had time to do more research on that because of my over hectic life, but I will. I have also run the Mamba Max on 1/8 on road racers with no problems. It dose not even get warm. Now on road cars are generally harder on motors and esc's because of the severe increase in traction. But here this is not the case. Again I think it is generally the Hacker motor and the monster spurr gear on the Havoc. The on road car I run it in just plain hauls butt no matter what.

Access

I guess it depends on the KV of motor you are using. If you are over-rating the number of cells -- you are using a 5700 with 4 or 5 cells or a 4400 with 5 cells and just don't let the motor over-RPM by how you drive it, that will draw less current (than the former with 3 or the latter with 4), and may be a little more efficient also. But if you run a 3000KV motor off 6 cells you'll draw as much current or more and get monster power (than running a 6000KV motor off 3 cells). Too bad Castle hasn't built RPM-limiting into the controller yet.

Those hacker motors are expensive, I know from my aircraft where I always end up going with E-flite b'cos they're still good motors and cost less. Maybe it's just the markup some places charge but hacker always seems twice the cost or more.

RURC

If I am understanding you correctly in the first statement, no. What ESC's (VFD's) do is chop the power output. They basically, very basically, give full power all the time but they chop it on and off up to thousands of times per second. Work is a product of voltage + current (amps). If you increase the voltage the current can be less for the same work produced. The ESC is like a electrical limiting fan. It litterally cuts the power on and off like the fan chops tha air. The greater time it leaves on the flow the more power you receive. The finer it chops it up the less peak potential you get. Motors in this case are a red hearring. The motor kv is just that, at no chop it will turn X rpm's at 1.0 volts RMS with no load. A motor efficiency will remain the same provideing that is stays in a given temperture. As temps increase so dose resistance thus lowering a motors efficiency.It has nothing to do with rpm. I dont know if rpm will be that soon because the circuitry dose not look for that. Now there are RPM sensors that use the flyback pulse to give you a rpm value. I have some coming from Eagle Tree that should be here very soon and I will know from the motor what the rpm is not off some gear down line.

On the Hacker side, please dont read into the next statement. Look at it for just what it says. Hacker is a very well built and designed motor, if you get the German ones. Not all Hackers are made in Germany. To the best of my knowledge only the "C" series are fully made in Germany. The rest seem to be made in China or Korea. This said the Hackers are by no means the best match for the Mamba Max. In the vast majority of uses the user may never see a problem. But when you are pushing all sides to their limits that is where you will find the limitations. Please buy and use Hackers but if you feel that you are pushing the edge of the performance line start doing some real studying. Also the Hackers are very good but they are hardly the best. The Neu Motors and the Plettenberg's really out perform them for not much more money. If you have a use for a Hacker look into a compairable Neu or Plett the difference could be staggering.

Bombers_410

Dang RURC. You sure do know a lot about electric motors and speed controllers.