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Old 06-30-2006, 03:49 PM   #1
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Default Tekin needs a battery cap for mod motors.

UPDATED INFORMATION "The recent increase in power available with today’s batteries and motors is incredible. When using a modified brushed motor with the Tekin speed controllers you need to use a large capacitor across the battery voltage. Something like a 16v to 25v, 1000uf to 3300uf caps will work well. The cap should be mounted between the +bat and –bat post on the speedo with as short of leads as possible for maximum effect. DO NOT USE larger than 3300uf.

The cap we will be offering is a 16v, 1000uf selected specifically for our system. Off the shelf "average quality" caps need to be larger to be effective but will work.

We do not think the addition of a motor diode is necessary at this point. Our flyback circuit is so much more efficient that adding a motor diode really does little since the power will still take the path of least resistance… But it does not hurt to have. Use at least a 36amp diode module or parallel at least 4 of the typical 8amp axial lead diodes that have been around for many years. Again we will be offering a good motor diode solution from Tekin soon.

The next few years will be crazy as we make use of all this new power. Should be a lot of fun. Stick with us and we will give you what you need to handle it and still have that Tekin smooth feel.

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Old 06-30-2006, 04:42 PM   #2
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A couple of questions...

What is the result of NOT using a cap across the + and - and running a hot mod motor?

If you currently use Tekin and are running modified motors, is there any harm to not using a cap if you currently don't experience any issues?

In your testing, what issues have popped up, and under what conditions, that would cause you to make this announcement long after so many contemporary Tekin ESCs have been sold and promoted "without any external add-ons."



I use Tekin ESCs in all of my cars (and have for many years), but honestly, the size of the ESCs is an issue to me. Without any other add-ons, the size and footprint is relatively similar to other speedos, but now having to use the same caps and diodes as your competitors will make it that much more difficult to fit a Tekin ESC in the cramped quarters of some touring cars and 12th scale cars with low profile bodies and narrow chassis. Without a smaller solution from Tekin, I may be forced to look elsewhere for ESC solutions for my layouts that are short on space, and I'm not real happy about that.



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Old 06-30-2006, 07:51 PM   #3
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Could this be why my brakes no longer work in my tekin g12cIII?
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Old 07-01-2006, 03:57 AM   #4
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From my understanding, the voltage being produced by the current cells in use, has reached a point which is now getting the FETS hot and when they get hot, they are inneficient in their opening and shutting, which will make them hotter. The Capacitor helps the fet gates open and shut better under the high voltage high load conditions.

Hope that clears it up a little.

They are not recomended the power cap for stock and 19t though.
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Old 07-01-2006, 04:48 AM   #5
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why isnt the proper cap being sold with the speed control??
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Old 07-01-2006, 05:10 AM   #6
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So the Tekin Speedies are basically rated 19t and above?
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Old 07-01-2006, 05:33 AM   #7
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no, the Tekin isn't been rated 19t and above.

I regularly use mine with a 12 and 10x2 and have no issue's but thats in off-road. If you have high ambient temps plus running a hot modified, Tekin are now recomending the use of a power cap.

The reason that they haven't been supplied with a power cap is that they have only been fully confident that this there is a problem with the current cells and hot mods. So they are now recomending the use of a cap.
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Old 07-03-2006, 12:34 PM   #8
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Increase in current.. period

Our G11 is actually rated to 10 cells so the extra voltage is not an issue, but these batteries hold a much higher voltage under load… meaning they deliver a lot more current. The fact that we have to start and stop that huge current thousands of times per second is the issue. It’s like starting and stopping a freight train.

Mod Touring cars are pushing a 45amp average discharge and considering we really never draw the ave, we draw much lower currents and much higher currents, imagine what the high currents look like…. Pros are melting the wires off the motors they are pushing them so hard!!!

Good 6cell 3300 assembled packs use to hold 6.7v to 6.9v at 30 amps with 1.18 to 1.20 cells
New 3800’s are holding 7.0 to 7.2 at 30 amps with 1.21 to 1.23 cells.. some at 35amp
I am told the new 4200’s will hold 7.3v to 7.4 at 35amps WOW!

Even with all this increase in capacity we still dump them in 6 minutes…. Tells you a lot.

Even 19t motors are pulling a lot more watts. Imagine what the 7 and 8 turn motors are pulling….. 10turn was the lowest motor allowed in a ROAR race not long ago…. And now a 14t pulls what a 10t did and a 19t is maybe a 14t.

It was never that Tekin did not need a battery cap, we just chose to put a very expensive high quality cap inside. The Tekin philosophy of passing all the power combined with the increase in power available…… and the internal cap is not always enough. If cap technology gets better then it will get smaller and go back inside.... or you want to use wimpier batteries...

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Old 07-03-2006, 12:54 PM   #9
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Quote:
Originally Posted by JoelV
Could this be why my brakes no longer work in my tekin g12cIII?
This could be flyback current.. also a symptom of high drive currents. The motor diodes both internal and on the motors are way under rated for todays currents. A standard motor diode is about 9amps and you need about 4 at least for todays mod motors. Lots of older speedos will likely have brake fets issues with todays batteries and motors…

Could also just be failed brake fets.. which does happen and we can fix it for you.

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Old 07-03-2006, 12:59 PM   #10
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Quote:
Originally Posted by burbs
why isnt the proper cap being sold with the speed control??
We just determined it was needed.... with the latest round of incredible batteries It will be included with the units in the near future and offered as an accessory item.

A high quality motor diode will also be available...even though we do not need one.

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Old 07-03-2006, 01:05 PM   #11
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Quote:
Originally Posted by PerformanceRC
So the Tekin Speedies are basically rated 19t and above?
This weekend one of the best mod drivers in the country ran 7x1 motors in the CA heat on smokin hot pavement with screamin batteries and had no issues other than melting the motor wires off... showing how much power we really pass and that the weak link may be moving to solder joints and motor generated heat at these power levels.

Ya I am pretty sure we can handle more than a 19turn motor.... smarty pants

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Old 07-03-2006, 02:48 PM   #12
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Quote:
Originally Posted by TeamTekin
This weekend one of the best mod drivers in the country ran 7x1 motors in the CA heat on smokin hot pavement with screamin batteries and had no issues other than melting the motor wires off... showing how much power we really pass and that the weak link may be moving to solder joints and motor generated heat at these power levels.

Ya I am pretty sure we can handle more than a 19turn motor.... smarty pants

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That driver was using my motor.....I didn't know the motor wire came off.... He better not return it slow
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Old 07-06-2006, 11:25 AM   #13
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HMP (high melting point) may become the standard... but that just means something else will likely give somewhere because if we are melting standard solder ( @360F) we are pretty hot for all the materials to handle during normal operation.

FYI all of our solder post have HMP solder so they do not melt when you attach the wires. You still still be on and off quick with the solder iron.... 1 2 done... or you need to clean your tip, pre- tin the post and wire or learn how to solder. Cloudy, cauliflower solder joints have more resistance than the whole speedo... and make nice little heater elements when passing 100 amps thru them.

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Old 07-10-2006, 05:30 PM   #14
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I ran my G-11 pro with an external capicator on the battery this weekend and it worked flawlessly with a 7x1 in a sedan.
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Old 07-10-2006, 05:39 PM   #15
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Quote:
Originally Posted by mo
I ran my G-11 pro with an external capicator on the battery this weekend and it worked flawlessly with a 7x1 in a sedan.
Uh ...yea I would say so ..can you say MOTOR ANYONE THAT GOT IN YOUR WAY!!!!
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