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View Full Version : FMA Lipo Voltage Cutoff Review



mOOsE
01-13-2006, 08:16 PM
I recently received my new voltage cutoff device from FMA. It can be used on a standard esc or brushless esc that does not include a built in voltage cutoff. The device goes between the the ESC and the throttle input on the rx (so it will not work with the stock half8 ESC). It has a an Auto-Detect feature that will calculate which voltage to cutoff at depending on which battery you plug in. In my case, I used a 2cell LIPO so the auto-cutoff was set to ~5.3 volts. The device is simple to use, just plug your ESC wire into the unit and insert the wire from the device into the rx (throttle input). Because it does detec voltage from the battery, you must solder the red wire from the device onto the ESC's red wire. After that, setup is a breeze. The unit does include an option to set your own cutoff voltage (what I did) which is very handy. After installing, I gave it a test run with a slightly charged Nimh pack to see if it would cutoff at the right voltage....sure enough, the unit disabled the throttle when voltage reached my preset of 5.8 volts! woohoo! I can now safely run my lithium without worry of over-discharging and ruining the pack.

http://www.fmadirect.com/detail.htm?item=1897&section=2

pimpsmurf
01-13-2006, 09:45 PM
hot dog. I ordered mine through my LHS' website (www.edshobby.com which I think is horizon hobbies), and found out he had them in stock... grrr...

Can't wait to get that on my Mini LST Which I want to keep brushed for the next 6 months or so. Hopefully by then Losi and the aftermarket will have something done. I'm scared to spending $70 on a couple 16 turn trinity Cobalt 18s only to sell them off in 6 months...

-JNY

QuickEight
01-13-2006, 10:51 PM
On your mention of this the other day I ordered one and received it Wednesday in the mail and installed it yesterday and you are so correct in that it works just great.

Thanks for that tip Mr. mOOse. :)

pimpsmurf
01-26-2006, 10:18 PM
For us using it in high current applications:

If you are using the FMA sold seperately from the lithium polymer (scorpion?) cell sold for 1:10 electrics, then you have the code for airplanes. Using stock motors on my Mini LST, The voltage ripple is enough to make the voltage cutoff kick in when you change from reverse to forward, or when you punch it on asphault. This is corrected with the "car" code. All new FMA cutoffs will be shipped with the car code (in about 1-2 weeks.)

FMA tech support's number:
301-668-4280

Address:
5716A Industry ln.
frederick, MD 21704

Call and ask to speak to Nathan. He is the developer of the board. Ask him if you can send it in to have it programmed with the car code (it's just a short delay so torque doesn't kick in the overdischarge protection), and He will hook you up! :)

Of course, if you aren't having trouble, your cool, but my TP1900 2 cell lipo is rippling on the stock MLST motors. :rolleyes:

Hail to the King, baby...

-JNY

mOOsE
01-26-2006, 10:45 PM
thats strange....mine doesn't do that at all. I reset the voltage cutoff myself so maybe thats why. Cool to see they are backing their product though

pimpsmurf
01-27-2006, 03:24 AM
I set mine to 5.99v (close as I could get to 6), and it does it all the time on my MLST (mod motors w/ TP 1900.) I have just taken the lipo cutoff out of the loop until I can send it off and get it changed to the new code.

1 second or so of delay won't be a problem. You could always set your cutoff .1v higher. =)

BTW, I was having trouble with the losi ESC overheating with the stock gearing. I changed in the 60t DD slipper (only one available) to replace the 54 tooth slipper and all the trouble went away. Unfortunately, You have to mod the motor plate to install a 25 tooth pinion on a 60t slipper. =(

-JNY

mOOsE
01-27-2006, 10:33 PM
I think mine is at 5.7 or so. May still send it in after awhile.

Thomas P
02-20-2006, 03:58 PM
Thanx for this Info Mr:Moose, ive been w8ing for this kinda rewiew..this is it, il buying one :D