Need Tekin FXR advice

[MikeSSS]

I use 6 cell NiMh batteries in my present crawler.

Soon I'm buying a used crawler that has a Tekin FXR and uses a 3S, 1300 mah LiPo on the front axle.

Can the FXR use both 3S LiPo's and 6 cell NiMh batteries without changing settings on the FXR? Will it recognize the type of battery plugged into it? If settings have to change, is it easy and fool proof to do out on the rocks?

Reason for this question is the crawler will use up the coming months toy money and my present Hobbico charger will charge LiPo's but not balance them. Money for a better charger isn't available for a while.

Thanks

[JohnRobHolmes]

Nope, you will need to either use no cutoff, or swap back and forth between profiles. It is a pain.

[MikeSSS]

John,

can battery types be swiched back and forth easily on the Torquemaster HH ESC?

Thanks,

Mike S

[EvilTwin v2]

Originally Posted by MikeSSS

John,

can battery types be swiched back and forth easily on the Torquemaster HH ESC?

Thanks,

Mike S

You're going to need to change the settings when you change battery type, regardless of the ESC that is used.

[JohnRobHolmes]

relatively easy on the torquemaster, yes. It is the first option. The sequence is plug in holding full reverse, hold full throttle for no cuttoff, then unplug. For cuttoff it is plug in holding reverse, reverse again, then full throttle.

On the Tekin it is still pretty quick, just a lot of button pressing. Hold mode while turning on, then hit mode 5 times, then hit INCR button until the first LED is on for no cutuff, or the third LED is on for 3 cell lipo.

[MikeSSS]

I'll never get those settings correct out on the rocks, got to stick to one type of battery I guess and it looks like LiPo since they mount easily on the front axle.

Thanks

[JohnRobHolmes]

Yessir, just stick to lipo. You won't regret it!

[chevellian]

Here is a cheap charger that will get you by till funds are available for a better one.

Turnigy-3S

[Shadow Fox]

LiPo is the way..that 1300Mah Lipo will give you a good 30 or so min runtime...with no loss of power!

[mxracer33x]

I make changes on the FXR in my daughters rig all the time. She runs both 2s and 3s lipos, so I changethe cutoff when I change the cell count.

FXR:

Push mode 5 times I believe. (VC option)
Use INCR button to select:
one light is no cutoff
2 lights is 2S
3 lights is 3S
4 lights is custom (set via tekin hotwire programmer)

[Maxx_Savage]

Although it may seem complicated at first, it's really easy to change between the 2 VC settings. The other programmable functions are quite useful as well and it will be to your own advantage to learn what they do and how to programme the ESC.

After a running with a certain setup for a while, you get to know how long a certain pack lasts. I will happily run 30min on a fully charged 1300mah 3s without setting the VC. You also don't need to balance charge every time, and if you slow charge, you could safely do 10 or so cycles in between balancing.

[MikeSSS]

After reading the replies a few times it all makes a lot more sense, even I can do this if need be.

I drove this crawler the other day with a 3S 1300 and the battery lasted probably 45 minutes, that's pretty amazing for such a small, light battery. Two of these batteries would last about an hour and thirty minutes, about the same as one sub-C 6 cell NiMh pack. The AX-10 I'm getting looks like it doesn't have room for the NiMh 3300s on the front links but the 3300 LiPos fit just fine on the front axle. Carrying three or four spare LiPos is the way to go, besides they are a lot easier to change on the front axle than changing the NiMhs on the front links of my present WK based crawler.

I haven't flown NiCd or NiMh for six or seven years, the LiPos just fly better, so why use NiMh for cars? LiPos are just better and using only them avoids the switching back and forth problem.

Thanks guys for pointing me in the right direction, this is a great site with excellent members and ours is a very fine hobby.

These ARE the good old days.

[MikeSSS]

Got the AX-10 and a couple E-Flite 1250 3S batteries. Last night I checked the FXR, it is set for 3S cutoff. Today I ran the AX on trails, crawling a creek bed and on steep hillside trails, it ran 1 hr 19 minutes before I got back to the car. It never did slow down or hit the low voltage cutoff. Balance charging at 1.1 amp took 66 min 57 sec, the charger indicated about 1150 mah put into the battery. So, 1250's should be good for 45 min to an hour, they are light and easy to carry and easy to switch out on this AX since they sit on the front axle. Problem solved, just take two extra 3S batteries and a 2.5 hour walk n crawl is covered.

This AX-10 has a higher center and lower CG than the Wheely King based crawler I've been using, it can do some pretty amazing things. The one change I'll make on it is to replace the FXR with a HH Torquemaster and see if that quiets the AX down a bit. The FXR can go into the WK that badly needs braking on descent.

Life is good.

PS, thanks for the help guys!

[EvilTwin v2]

You'll find that the FXR is far more effecient than the Castle made ESC's. I'm not saying that the Holmes isn't a great ESC. It is, and I run a pair of them on my Super! However, your findings as to how long you can run on a battery will differ greatly between the Holmes and the FXR.

[Leprasol]

I do not want to make new thread, so i ask here. I have read somewhere, that when using FX-R with 3S, you have to use external BEC for servo. I just want to ask, if it is possible to run without it (i plan to use it in my scaler with 35T motor and 3S Lipol), or it will cause some problems. I have read a lot about BEC and I know it is basicaly a thing to have when you crawl in competitions, but I am just not sure about this case. Thanks a lot for any info.

[EvilTwin v2]

Originally Posted by Leprasol

I do not want to make new thread, so i ask here. I have read somewhere, that when using FX-R with 3S, you have to use external BEC for servo. I just want to ask, if it is possible to run without it (i plan to use it in my scaler with 35T motor and 3S Lipol), or it will cause some problems. I have read a lot about BEC and I know it is basicaly a thing to have when you crawl in competitions, but I am just not sure about this case. Thanks a lot for any info.

The FXR has a built in BEC (or battery eliminator circuitry). Basically, a BEC takes the voltage from the battery and converts it to a lower voltage that the electronics can use. The built in BEC in the FXR is pretty weak. You might be able to run the receiver and a low torque servo (hitec 645 or smaller), but it's not strong enough to power the high torque servo that we use on today's crawlers. You will either not supply enough power to the servo or most likely burn up the speed controller by trying to overpower it's internal BEC. By adding an external BEC, you can now take the stress off of the speed control, but also you can set the specific output voltage that you need for your servo.

I highly suggest that anybody running a crawler use an external BEC. $20-$25 for a Castle Creations BEC is cheap insurance to protect your $85 + Speed control.

[fastfred28]

I have tried to run the FXR with no external BEC using 3S lipos .The ESC got hot and went into thermal shutdown(it started glitching, then shut off. after letting it cool down it worked again for a minute, then the same thing.) it will not work without the external BEC if your running a 3S lipo.If you plan to do this break down and spend the $25 to get a Castle Creations BEC.

[Shadow Fox]

good to know...I run 3s LiPo on my FXR....I just ordered a CC BEC on eBay $19 shipped.

I'll also be running a winch soon...and I've got LEDS on it..and a 2075 Traxxas servo...need to upgrade that Lol

[Leprasol]

thanks a lot for this info, i am going to buy CC BEC...

[EvilTwin v2]

You might want to also pick up a Castle programmer (unless you know somebody with one) so that you can set the correct voltage. Out of the box, they're set pretty low.