Hello RC Universe,
I picked up the DHK Wolf BL:
http://www.rcuniverse.com/magazine/a...rticle_id=1498
Specification of power system:
Brushless 3650 3970 KV motor (power 21 volt / empty load current 2 amp 10 awg cables)
Toro brushless sensor-less 35 amp ESC (10 awg cables)
7.4 v 2S 2300mah 20c lipo battery (10 awg cables)
There's a lot of conflicting information on the web and You Tube videos. These are the current assumptions I'm under:
1) Having a higher C rated battery is better?
- I'm working on the thought that MAH is the size of the "fuel tank" and the C is the "size of the pipe to allow the fuel out". The Motor will only pull what is required up to it's maximum amperage rating. I don't know what the Wolf BL motor wattage is. It's not in the instructions, so I can't work out it's amperage. In the manual there's nothing either, just the above 21 volts.
The wolf came with a basic 7.4 v 2S 2300 mah 20C lipo. I understand you do 7.4v X 2.3a = 46 amps continuous amperage. Possibly a burst of 40 c is 92 amps. Again, C could be a randomly assign "best guess" by the manufacture.
I put in a friends Reedy Wolf Pack 7.4 v 2S 6500 mah 25c lipo and ran the car hard for about 10 to 15 mins. Went on clay and gravel onto tarmac and jumped ramped kerb a few times. There was no "magic white smoke" and the engine didn't feel as hot to touch. I'm going to invest in a IR thermometer to take some readings.
The battery had already run my friends RC for good while before putting into mine. The 6500 mah definitely makes a differences compared to my 2300 mah.
The wolf power system uses 10 awg cables. I noticed the Reedy Wolf Pack has 14 awg cables. Should I be worried about that? The bigger cables meaning they're better suited to the power flow?
2) ESC amperage doesn't worry about C rating?
- The ESC and Motor amperage is the important rating. I've read and watched that you'd want a ESC with about 10 to 20% more amperage than your motors maximum. So a 50 amp motor, you'd match a 55 amp ESC or a 60 ESC. I've read that putting a 80 amp ESC on a 50 amp motor would and could cook and kill a motor?
The Wolf BL has a 35 amp ESC. Using what I've read and watched, it could mean my motor might be 30 amps? (21v X 30a = 630 watts motor? It's a 3970 KV which is 29378 rpm motor (or there abouts))
I'm waiting on an email from DHK. So far they have answered all my emails. My most recent about engine wattage is un-answered. Probably due to Christmas and New Year holidays
But, I got aother conflicting piece of information in another video on You Tube. A guy had a battery which put out 33 amps continuously and was using a 25 amp ESC. He said it's a no no and swapped in a 45 amp ESC and said that's better!? That confuses me...I have a 35 amp ESC with the out of the box 46 amp continuous amp lipo...
3) The RTR power system could be close to it's max already?
- All in all being a ESC at 35 amps with a 20C lipo and a motor I can't figure wattage / amperage of. The set up could be at it's edge already and putting more C through it could push it beyond and cook it?
In the manual the ESC specs has a motor rating column with 35C and 35A side by side. That leads me to believe I could use up to 35C discharge batteries? The next rows have 45C / 45A and 60C / 60A and finally 120C / 120A ESC specifications with batteries and turn ratings.
Having a higher C apparently keeps the power system cooler as well and gives a longer battery life?
Again, conflicting information tells me that a higher C could also damage or cook components. But it's the motor pulling the amps, not the battery pushing. So this confused me as well.
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Ultimately what I'm after is a bit more "fun". I'd like my car to last longer when just playing on the tarmac and gravel carparks. I don't want to burn out or cook it. I'm not afraid to try things though and do more reading and learning. I'm actually finding this part of the hobby as fun as the racing. I work in a technical job, so numbers and reading / learning are interesting to me.
If you got this far thanks, I appreciate you spending your time reading this and hopefully you can clear some things up for me.
Happy New Year