Move to Brushless
 

Hi Guys,
I've just got back into RC Cars, I used to race 1/10 touring about 15 years ago.

I've bought myself a second hand Ansmann Madrat 2WD 1/10 buggy.
I'm using my old electrics at the moment (except for new nimh batteries)

I'm using a 12-4 motor as all the others I have are 27T stock and a bit tired.

I'm looking to get into racing at my local club but I also want to be able to have fun in the back garden with it.

At the moment it doesn't have much guts at all on the grass and on the loose stuff it's not got a whole lot of punch, I'd like some more speed too.

I'm looking at going to a brushless motor/ speedo combo and I've been looking at the 9T SKYRC. Does any body have any advice/ better suggestions for what I'm after?

I guess I need a mix of torque and speed.

brushless in madrat
 

Iv'e had a similar system(ezrun 6000kv)in my rat,i would upgrade the idler gear to the hpi firestorm truck item(steel)for racing as i destroyed a few.It will be sensorless so gear it lower (19-20),apart from that no probs,jon

Thanks for the advice, I'd of stripped it!
I've only had the car a day and wanted to get it running quickly (like a kid at christmas) not been in the gearbox yet to to inspect, just fitted a motor/ pinion. Is the idler gear inside the gearbox, is there anything else which needs uprating whilst in there?

I'll order the part regardless as it can only be a good thing.

idler first, shocks next if they are the stock ones , a little weight at the front around servo works well..

I've upgraded the shocks to metal ones, just ordered the idler.

After researching some bits the other day, people where saying not to go lower than 9T in a 2WD buggy, are they just weak people :)? And higher Turn = more torque/ find a balance?

To me lower turn, more RPM sounds GOOD :D

Obviously 6000kv is considerably higher RPM than say a 4000kv, what's the torque difference like, e.g. launch? If it's going to get going in grass on it's own will the lower turn motor have as much torque?

You'll have to forgive me, I'm new to this newfangled brushless technology - I need to get pulled out of the 90s.

Also I should add I'm still on 6-cell NIMH, running 5000mah. Not jumping to Lipo for a while, that'll be something for later in the year (baby steps)

You'll have to be very gentle on the throttle with low turn motors in 2wd. I run a 6.5t in a mid/front motored 2wd (so very well balanced) and mashing the throttle will get the front wheels airborne (or the back wheels spinning madly) at almost any speed.

I'm only using it as is the only spare motor I had.
I'd prefer to use an 8.5t. Which is what I run in my 4wd, but I've not got round to buying one yet.

If the esc has features such as boost, turbo, timing and so on. You'll be able to get a significant turn of speed from it, even with the 9t.

Maybe less so with a nimh, I'd go lipo asap.

Are we talking same voltage lipo as 6 cell NiMH or higher voltage?

Ability to pull wheelies sound good but maybe not spinning up tyres when already at speed.

If I get something that's programmable can you usually limit the power? Thinking so I can learn the car, do some racing and then open it up later. Rather than upgrading motor.

Also what kind of life can you expect from a brushless motor?
I'm used to changing brushes every race meet on olden days

You can limit the power using the transmitter and then increase it as you get more confident.

LIPOs are 7.4v rather than the 7.2v of Nimhs, plus theynare lighter and have lessof a voltage drop as they are discharged.

Brushless motors last much longer as they don't require maintenance - a friend of mine has a Novak 10.5t with approc 120 hrs on it and still going strong!

I ran my firestorm on a 4700kv 4 pole motor and I didn't have any problems with my gears.

If I trim down the throttle on my transmitter will it not auto brake when I come of throttle or is that aspect adjustable on the speedo?

Also my NiMH batteries register as around 8.2v on Schumacher cd2000 charger (throwing more vintage names out there) - do lipo get this extra voltage or is it more that NiMH provably drops to below 7v after a min of run time where as lipo does not?

Apologies for my spelling... Damn autocorrect on phone (or poor typing)

LiPo are 8.4v fully charged, more importantly, they barely dip at all under load. A nimh may dip a couple of volts under load.
The discharge curve is also very flat. You'll get 10+ minutes from a Lipo with almost no loss in performance, more in a light 2wd.
Auto brake will be unaffected by turning the end points down.
A brushless motor will last almost indefinitely compared to a brushed motor. And requires virtually no servicing, just a blast with compressed air if it gets dirty and a drop if oil on the bearings once in a blue moon

I didn't know anything about LiPo batteries when I got back into the hobby in 2011 but this article told me everything I needed to know:

http://www.rchelicopterfun.com/rc-lipo-batteries.html

It's a long read but well worth it, hope this helps:thumbsup::thumbsup:

Ok, sounds good. So it sounds like I should probably buy something a bit more future proof, reduce my end points, not jam the throttle and then give myself more rpm as I get more confident/ competitive.

I've looked at the LiPo stuff, I understand more now and can see why everyone I speak to is trying to convert me. I was thinking the only benefit was extra run time - But the stuff about voltage drop under load, etc makes sense so I can see why they'd make a difference to performance.

I'll look into upgrading to LiPo as soon as possible.

You won't look back when you do - they also last much longer than NiMhs (I've got a set that I've used for 4 years and they are still going strong!). Lots to choose from but Gens Ace and Turnigy are probably best value. Just make sure that you buy hard-cased ones and have a LIPO charger too. I use this one and can't fault it:

http://www.hobbyking.co.uk/hobbyking...dProduct=25406

Oh, didn't realise it was so cheap to move over.
That charger is brilliant value and I've looked at the turnigy batteries on ebay, they are reasonable for a 5000mah hardcased one. Do you need anything else other than a battery pack and a charger?

charger
 

The Accucel charger is perfectly fine. . . If you get a good one ! Charging LiPo batterys carefully, especially ones that need balance charging to get the best from is very important. Spend a little more on your charger and have no worries. I bought one and chucked it in the bin after I found it was overcharging my cells - voltage too high !

So based one the more speed thing and limiting it to start with.
Is this a good combo? (Hobbyking 6100kv / 100a esc) http://www.hobbyking.co.uk/hobbyking...00KV_100A.html

With you being able to limit the throttle, acceleration, etc with the programming card.

Looks like its lipo only though or would it work with NiMH for a month while I save for a lipo & charger.

Good combo but something like this is better:

http://www.hobbyking.co.uk/hobbyking...arehouse_.html

http://www.hobbyking.co.uk/hobbyking...arehouse_.html

For use with NiMhs you just need to turn off the voltage protection. With 2-cell lipos you must not discharge below 6v and this feature automatically shuts off the esc if the voltage drops below 6v, turn it off and it will run until the cells are flat.

Motor seems a lot lower spec on paper, is it just a better quality motor? Guess I could upgrade the motor at a later date if I get such a beefy ESC.