Traxxas XL-1 ESC and Electrical Upgrade - Project Stampede Exclusive
So you are at that point where you want to replace that stock motor but don't want to buy a new ESC on top of buying a new motor. This is a very low cost upgrade that will not only bump up the performance and power delivery of a stock Traxxas XL-1 ESC, but will greatly reduce the heat the ESC generates. This upgrade is also good insurance to take out if you just want to run a 16T or 17T modified motor on the stock Taxxas XL-1 ESC, and don't want to have to buy a new ESC. How much will it improve performance? If you upgrade the entire electrical path starting
One thing I noticed right away was that the XL-1 really heats up even with the stock motor and normal driving and really had to be watched with the 17T Trinity Pro Amber modified motor. But all this can be fixed easily and cheaply.
A little electrical resistance 101 lesson - Mechanical friction = stress on motor = resistance = motor load = heat = more resistance load = more currant draw = more resistance= more motor load = more heat...etc. Kind a perpetual circle. The same goes true for the ESC, the more current that the ESC has to manage the hotter its going to get. The idea is to remove or reduce as many of the components creating resistance on the electronics. Would you rather push a car an a perfectly flat road or up an off road trail with lots of big boulders to push the car over. Looking at this logically, aside from the RPM 5x11 wheel bearing upgrade, and making sure the motor is lubed, the gears are not binding and properly lubed, the mechanical friction elimination part is pretty much taken care of. For the electrical part, upgrading to a motor like one of the Trinity Speed Gems with bearings instead of bushings will reduce resistance at the motor. A good upgrade at this point is to move completely to Deans connectors (about $3 per connection point.) The ultra low resistance Deans connectors will be one of the best overall electrical upgrades you can make to a stock Stampede and will make a very noticeable difference in power delivery. Also sooner or later you will melt the Tamiya plugs anyway (by the way batteries don't like to be shorted). A 12 gauge wire has about 1/3 the resistance of the stock 14 gauge wires so upgrading to 12 gauge power wires from the motor with gold or soldered connectors will decrease the resistance significantly (i.e. heat
So what about this XL-1 Electrical upgrade part? I also noticed that the wire on the ESC were getting warm after a good hard run even after all the above upgrades (a good indication the wire gauge is to small for the current draw), so I decided that I should also upgrade the incoming and outgoing power wires on the XL-1 ESC to 12 gauge. It may seem like overkill, but the 12 gauge wire transmits those "get going quick" current spikes to your motor a lot better. If you are doing the upgrade and are using 10 gauge wire to your motor, you might as well do it right and use 12 gauge on the ESC.
The thermodynamics game: set up some boundaries around a "system" that separate "system" from its surroundings, with the following definitions
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isolated system = no exchange of matter or energy with surroundings
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closed system = no exchange of matter but some exchange of energy
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open system = exchange of matter and energy with surroundings
Thermodynamics - Another part of the upgrade was laying down the ESC in a more traditional style on a RPM ESC mount. This accomplished a couple of things - it shortened the wire runs to the battery and motor, cleaned up those levitating power switch and receiver power wires, and most importantly greatly improved air circulation around the ESC. Heat rises, so by laying down the ESC the heat sinks naturally allow air to flow through them and up. The stock orientation creates a heat wall with heat sink fins that run horizontally and 90 degrees from optimum. I'm sure design limitations and cost prohibited the heat sinks from pointing the correct direction, but the stock horizontal heat sink orientation does not allow for natural airflow and thereby creates a "thermodynamic closed system". The new orientation changes the ESC to a open system, allows for both forced air cooling (while the truck is moving) and natural air circulation (i.e. cool air in and hot air out the top of the fins.)
Final performance - I noticed a huge decrease in heat generation on the ESC and coincidently a cooler running motor (I guess the motor wasn't getting all the juice is needed either.) Even at it's worst with 15/87 gearing and a Trinity 17T Pro Amber motor, the ESC was at worst warm. Although I didn't do any lab testing, the old "eyeball Dyno" looked like about a 15%-20% increase in get up and go on from the ESC after the upgrade. The difference was really noticeable after about 5 minutes or at the point the stock ESC and motor would be really hot (remember the hotter the electronics, the more resistance and less efficient everything is.) In the end, I think I spent $10.00 on 1 ft. each black and red 10 gauge power wire and some extra Deans connectors. Although it doesn't convert the XL-1 into a Novac Super Rooster, the conversion does add a lot of durability and make the stock ESC a much better performer.
The How To - Traxxas XL-1 ESC Electrical Upgrade
Its pretty simple just go slow. Note that you do need to have some soldering experience. It should go without saying, but make sure you let everything cool down in between soldering steps and care should be taken not to overheat and de-solder the other components on the ESC circuit board.
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First disconnect everything from the ESC and remove it from the truck.
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Unscrew the two screws holding on the heat sinks and remove the heat sinks. Unscrew the four screws on the back of the ESC and remove the cover.
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CAREFULLY remove the ESC guts from the shell.
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De-solder and remove both the positive/red power wires.
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Re-gauge the ESC end of the 10 gauge leads to 14 gauge as shown and then tin the wires. If you tin the wire end properly and seat the "stepped" lead fully into the ESC board as shown, this will be a very strong low-resistance connection.
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Prepare and tin your +/- power leads and terminate with Deans plugs. (it can be tough to solder the plugs after you have soldered everything up to the ESC, so it good to get the Deans plugs installed first.) Slide on the shrink warp and shrink to cover the exposed wire and plug pin.
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Carefully heat the inner power hole on the board with the tip of the soldering iron and slide in and seat the appropriate power wire. Once the wire is seated, heat the tip of the wire sticking through the other side of the ESC circuit board to solder the wire in place. You should have enough residual solder from tinning the wire end and the solder left on the board that do additional solder should be needed.
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Repeat with the other power wire.
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Now remove the negative/black power wires and run through the above steps and get them soldered in place.
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Re-route the thinner BEC and power switch wires in between the positive. These should be at the bottom of the "wire pile" closest to the circuit board.
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Trim about 2mm off the crescent shaped wire holder off the back cover.
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Extend the top cover wire inset by about 1/8" or as needed, just to the point that all the wires are snuggly held in place.
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Trim off the ESC side mounting tabs.
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Re-assemble.
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Cover the setting/tuning holes with black electrical tape to seal out dust and moisture.
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Mount with double stick tape or Velcro. I use the "heavy duty Velcro", it has no positive and negative stripes. This Velcro is made of all hard plastic interlocking balls and is much cleaner and tougher.
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Done - You now have a cooler running ESC with a lot less resistance and about a 15%-20% performance increase.
Testing Criteria and Warnings for the Upgraded XL-1
I have spent the better part of a month moving from a very conservative 13/87 gearing to and 18/87 gearing again using the Amber 17T motor. The 18/87 gearing using a 17T motor is about the limit for my testing for this phase, it runs about as hot as is did in completely stock ESC/motor configuration during my testing. That said, I think the ESC has demonstrated the ability to handle enough stress for me to test a 15T, 16T, or maybe a P94 16T. My hope is that I will be able to dependably and cool-ly run a 15T motor – we’ll see.
Warning – Don’t just pop a 17T with 18/87 gearing in your car, I'm not going to listen to you bitch after you blow your ESC. I am using a very methodical controlled testing process and have very slowly moved up to that gearing over a period of a month or so. If you run the car slow or use it to rock climb at that gearing, you will probably blow the ESC.
Max recommended gearing - You should have no overheating problems (after the XL-1 upgrade) when geared from 13/87 –16/87 with the Trinity 17T pro Amber.
Goals - My goals in this experiment were to primarily define the stress limit of the XL-1 after going through the electrical and orientation/cooling upgrade on the ESC. Secondly, develop a low cost/no cost method for everyone out there stuck with XL-1's to safely run hotter motors such as the Trinity 17T Pro Amber.
Testing criteria:
Gearing: From 13/87 – 18/87 (6.69 – 4.83)
Body: Attached – stock position.
Ambient Temp: 30-50 Degrees F
Runs/Time: 2 at about 10-15 Min. each
Batteries: 6-Cell 3000Mh
Track: Urban - 50% Road – 30% Lawn – 20% Rock (landscaping)
Throttle Control: Top 50% of throttle range
Braking: Hard and controlled braking.
ESC: XL-1 Modified See Above
Other: All power wires upgrade to 12 gauge wire
RPM Bearing carrier and bearing upgrade
All power connectors upgraded to Deans Plugs
The final review and post for the Project Stampede upgraded XL-1 ESC
Sadly, the upgraded XL-1 time’s came after I got a little cocky and did not properly winterize my upgraded Project Stampede XL-1 ESC before going out in some really wet slushy snow in Omaha’s one again –off again weather patterns. Yep, you bet I fried that sucker like a well-done piece of bacon, but I was able to complete my testing before it’s untimely demise.
As you will see in the above posts, I did some upgrades to the stock Traxxas XL-1 ESC to see if it could safely handle the more extreme modified motors without melting down.
It can and it will do it very well. First let me lay down this warning – “Although I was able to run the Xl-1 with a both a 17T Trinity Pro Amber and a 15T Trinity Titanite motor without blowing anything up. I only recommend going with the 17T Pro Amber and only if the upgrade is completed” The reason is that when running the 15T motor the upgraded Project Stampede ESC runs at about it’s stock hot temperature and I really think this is too hot to expect any really long-term durability. Using the 15T is definitely not something you want to do a lot of very slow maneuvering with as the ESC is very close to it’s limit with a 15T motor.
The 15T motor was geared up to 13/87 with no adverse effects during higher speed maneuvering (no rock crawling). However, I very carefully worked up to this gearing starting at 12/90 with initial testing only on the road at full throttle (the easiest on the ESC).
So there you have it, I have sacrificed my XL-1 for the sake of experimentation and for the enjoyment and education of all.
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