swathdiver

Those PZIIIs were dogs in real life, slower then the Tiger! I think they did 25mph flat out. When my tiger is done its gonna weigh a lot too. I forgot what my Pershing weighs and the Tiger will easily have a couple of pounds on it!

shenlonco

My Feedback: (2)

James if you are going to put the faster speed 400 motors in your bulldog why not upgrade the HL esc?

You know the black fets under the bent aluminum section I think 4 of them screwed to it...if you bring one to a electronic shop and let them see the # on them you can buy them and what you need to do is solder 4 more on the board in the same way doubleling up on the fets so there will be 8...... 2 on top of each other 2 each soldered in the same position X 4 on the board this will make the ESC be able to run hotter motors I do this with Kyosho mini Z boards it should work on the tanks also.

darkith

Just a note:
The motor h-bridge transistors on the TK-RX13 board are *not* FETs. One side of the bridge is comprised of a darlington pair, and I'm not sure of the other side (the transistors in the TO220 package) but doubt they are FETs. So, adding a second set of transistors might prevent them from properly saturating, which could damage the transistors or the board. It might work fine, but be cautious and check for overheating for the first few minutes.

Upgrading to the TK-RX14 board looks like it might be a good upgrade, since it does appear to use FETs. Wonder when Mato will have them available.

D.

shenlonco

My Feedback: (2)

Hi I don't think it matters if you put a extra one soldered in the same way for all of them that are screwed on the heat sink it will make you be able to run the hotter motors and they would run much cooler.......

HL should have used abetter part in this area...one that can handel more amprage.

darkith

Yeah, you can probably get away with it, but it's not as simple as paralleling FETs. FETs only need the appropriate voltage at very little current to be driven into saturation. Transistors need more current, so if you parallel more transistors, you can run into saturation issues if the base pins aren't driven with enough current. If transistor matching is poor, you can also run into output matching issues, so most people recommend a low resistance in series with the emitter. Finally, you can run into gate capacitance issues (though strictly speaking you can run into that with FETs as well), which can cause the transistors to be slow in turning on or off (which could lead to shoot-through and dead transistors).

Worth a try if you can identify what transistors are a decent match, just watch for heat! Heat sinking will only help if you're only marginally beyond limits. If they're exceeded completely, all bets are off.

I agree than Heng Long cut corners here. The darlington pairs are just dropping too much voltage and wasting too much power.

D.