View Full Version : lipo and brush motors, will it work.
fatnasty 01-18-2009, 08:13 PM I'm new to the rc world. I got my 5 year old son a HPI T10 FIRESTORM for chrismas, it has a 15t brushed motor in it. I also purchased a 6500mah lipo MAX AMP. At first it ran like a rapped ape, but seems to be slowing down. I have a Hyperion charger and it balances the batteries so i don't think it is the pack. I also have the low volt warning so not running the packs down. I think i'm over heating the motor, pack runs the truck for about 40 minutes. Any information or input would be very welcomed, tnk you.
RCRacer45s 01-18-2009, 08:53 PM Voltage is voltage, you can use a LiPo battery on a brushed motor. Make sure you are not overheating your motor. With more voltage you will build up more heat in the motor. I wouldn't suggest running the truck for 40mins straight if that is what you meant. Run the truck until the motor gets warm, around 120-130 degrees.Normally around 5-10 mins depending on how you are using the truck. Also keep an eye on your speed control. You can risk overheating that as well. The slowing down is most likely due to the motor heating up, or the motor may be wearing out and in need of a rebuild.
hankster 01-18-2009, 08:54 PM Most likely by this time the motor needs rebuilding or could even be shot and needing replacement.
fatnasty 01-18-2009, 11:47 PM Tnks for the information. I'm guessing the motor is worthless now since it has slowed alot. What would you guys recommend for a good and affordable brushless motor. It's for a 5yr old so doesn't need to do 70mphs, 69 would be fine lol, tnks again
hankster 01-19-2009, 12:29 AM The Novak Havoc systems go for about $150 and includes the ESC and motor.
TillRodsFly 01-19-2009, 03:45 AM The Novak Havoc systems go for about $150 and includes the ESC and motor.
+1 Hank. From what I have "read", (I am a 1/4 scale guy) this seems like a nice, reliable setup. In fact, due to me only being able to run 3-5 1/4 scale races a year (NCS Series), I am serously considering building a vintage Trans Am car with this same setup since my local track supports it. (need to race more than once every other month)
jgullo53 01-19-2009, 04:34 PM (need to race more than once every other month)
yeah, that would b really boring to get out that little!!!
fatnasty 01-19-2009, 06:31 PM Tnks guys, Ok i have more questions how come some of the brushless motors seem to have two diffrent turns like the 17.5 or the 8.5, i would guess there both fast, how come such a spread. I need info lol tnks
kevinm 01-19-2009, 08:06 PM The 17.5 brushless motors have performance roughly equal to a 27-turn stock brushed motor (but require major changes in gearing). From the pictures of the Firestorm I found, I'd guess that the 15-turn brushed motor it came with is actually a fairly mild modified motor, since it doen't have adjustable timing or replaceable brushes. It has slowed down because, well, that's just what brushed motors do without frequent maintenance. :rolleyes:
Anyway, brushless motors come in several different winds (the "Havoc" ESC just isn't bundled with all of them). I suspect that a 13.5 or maybe 10.5 brushless would probably perform like your 15-turn when it was new. The 8.5 would make you think the original motor was a wimp. With a 5 year old driver, you should probably stick to the "mellow" end of the spectrum and go with a 17.5 or 13.5. Either way, you'll probably want to change gear ratios, since these motors have tons of torque but don't turn alot of RPMs.
theres alot more turns then that. 10.5 13.5 and more .17.5 is like stock or 21.5 also.
fatnasty 01-19-2009, 09:08 PM Tnk you, As far as gears go what should i look for. Do i just need to change the pinion gear ? or do i have to change the spur gear also ? I have a old rc10 i was think of dropping a motor in since i baught two max amp 6500 lipo packs. I got a little money into it now hehe. So with the turns does the lower the trun the faster the motor. Can you plz explain how this goes. Because from the treads i was reading alot of ppl had the 17.5 and i thaught the 4.5 was the faster of the motors. Just tell me everything a moron needs to know lol. tnks again
hankster 01-19-2009, 10:24 PM Generally the lower number of turns the faster the motor is. In most cases you would just need to change the pinion gear. Making a wild guess, if you went with a 13.5 brushless motor you could most likely use the same gearing you are now using. You want to change your gearing by motor temperature. For long life you would want to keep the motor under 150 deg. The Novak does have an overtemp. sensor so if the motor or speed control gets too hot, it shuts down to prevent damage. So if it shuts down because of overtemp. you can always gear down a bit.
fatnasty 01-19-2009, 10:46 PM If i get the Novar/ Hovak system, what else do i need to get a pinion gear set. Does it come with the wire for the esc and the motor leads ? Sorry i know nothing about this stuff didn't see it in the picture. Make a shopping list for me lol. If i get the 4.5 pro motor what speed would rc10 car get to compared to the 8.5, both using a lipo 6500mah tnks again. What are the pros and cons of the faster motors, tnks again guys.
hankster 01-19-2009, 11:11 PM The 4.5 would be faster but I have no idea on the actual MPH. When racing we really don't worry about the top end speed so much as lowest lap times. This means car setup, tires and driving are ultimately more important then blinding speed.
Wiring is included with the Havoc system.
kevinm 01-20-2009, 06:56 PM A 4.5 would officially be designated as "stupid fast". 50+ MPH would be easy to achieve if geared right (assuming you're just "bashing" in the street), but you'd probably melt your diff. And if anything gets in the way.... better stock up on suspension parts. Also, the battery won't last nearly as long with lower turn motors, and the Havoc is limited to 8.5 or more turns. Using one with a 4.5 would let the magic smoke out.
fatnasty 01-20-2009, 11:27 PM Tnks, The only problem i see is the esc, they cost more then the motors and lock you into a motor, i was looking at the novak 3.5r with a gtb esc. That esc does most motors. And the cost is only 100 dollars more and i'm done i beleive If this is totally stupid let me know, do i need a metal spur gear lol. tnks again. Just scared to get a motor and esc and then want to go faster and be out the money. So figured get the biggest motor and be done.
swtour 01-21-2009, 02:16 AM The motors can be bought separately as well. So if you buy the HAVOC system with (we'll say) a 13.5 motor, and you want to have a faster motor to play with on occasion, you can buy a 8.5 motor and pick up some speed. (You just have to be able to cleanly re-solder the wires to the motor.
If motor swaps are something you wind up liking to do more frequently, you can solder short wires with connectors to each motor, and to the end of the wires from the ESC, then when swapping, you can just plug in and un plug...
fatnasty 01-21-2009, 07:06 AM I was gonna go with the 8.5 for sure, but if i want to upgrade i can't so...I was looking at the novar 3.5r with the gtb esc. I'm scared to get the novar hovac system and be locked into the 8.5 motor. For 100 dollars more i can get the gtb and run alot more motors. But i'm new and this could be a stupid move, let me know what you guys think, tnks again. If i get the 3.5r what other parts should i get beside pion gears.
420 Tech R/C 01-21-2009, 01:09 PM I was gonna go with the 8.5 for sure, but if i want to upgrade i can't so...I was looking at the novar 3.5r with the gtb esc. I'm scared to get the novar hovac system and be locked into the 8.5 motor. For 100 dollars more i can get the gtb and run alot more motors. But i'm new and this could be a stupid move, let me know what you guys think, tnks again. If i get the 3.5r what other parts should i get beside pion gears.
WoW a 3.5??Really? For your 5 year old I would seriously recomend either the havok/17.5 or 21.5 system.Keep in mind that the 17.5 is the approved BL stock motor,BUT since the 15T that came in the truck was a sealed can throw away motor that the 17.5 geared right could reach about the same top end speeds, just with a little less oomph.The 3.5 on the other hand is just stupid fast, and is more for on road cars.The most motor I keep in my box is an 8.5. I run them in mod truck and my 4wd car, and I am NEVER lacking in the motor dept. If you want to go for the 3.5 be prepared to have quite a hefty bill for diff and tranny parts because a 3.5 will SHRED the drivetrain of an off roader.Look at it this way , a 17.5 turns 16,280rpm @7.4v,while a 8.5 turns 42,920 rpm @ 7.4v. A 3.5 turns in the ballpark of 74,000 rpm @ 7.4v plus the lower winds(3.4,4.5,5.5,6.5) are more temperamental about gearing.If you want to toast a gtb, just over gear a 3.5 and try running that for more than 5 min. and poof, instant waste of a 250.00 BL system. Keep in mind that the 15t motor that came stock in your son's firestorm was turning in the range of 25-30,000 rpm when it was new if you got a good one.PLUS brushless motors have a MUCH broader torque band than brushed motors so I know you can gear a 17.5 to be in the same top end range as a sealed can 15t motor.
hankster 01-21-2009, 01:25 PM Just to compare, the Traxxas Rusler with the Velineon Brushless setup is rated at 70mph by them. The Velineon motor is a 10.5 turn motor but to get that kind of speed uses a 3 cell LiPo motor.
The Velineon motor is rated at 3500rpm per volt so with 11.1 volt battery that is 38850 max RPM
The Novak 3.5 motor is rated at 10500rpm per volt so with a 7.4 volt battery that is 77700 max RPM.
So you would not only be getting a motor that is very sensitive to proper gearing, use, maintenance, etc. but also getting to speeds that can seriously hurt or even kill someone.
fatnasty 01-21-2009, 08:42 PM Tnks very much guys, i would of gotten that 3.5. I will go with the other set up. tnks again.
jgullo53 01-28-2009, 10:34 PM 3.5 and ud b movin well...
Mike D. 03-19-2009, 10:11 PM i have the 4.5 novak system in my emaxx, and cant control it at all, thing is crazy crazy fast, really no fun when you cant control it, i would stick with the 8.5 or higher, ive been racing for a few years and this 4.5 novak system is so fast it almost funny, people laugh when they see it just go NUTS. THATS MY OPINON, good luck!!
CClay1282 03-23-2009, 02:21 PM I would go with a 7.5, or 7.5 light for the stadium truck. A 4.5 would be as quoted "stupid fast"! LOL.
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