MGM Low Voltage Cut Off - Owners READ

Yup, on cut-off mode. Didnt try the Reduce RPM mode yet, will try it tomorrow.

I dunt know if MGM will actually do something about it, but wats the workaround to this issue? An external LVC and set the MGM to race-mode?

[bdebde]

Originally Posted by fkadir

Yup, on cut-off mode. Didnt try the Reduce RPM mode yet, will try it tomorrow.

I dunt know if MGM will actually do something about it, but wats the workaround to this issue? An external LVC and set the MGM to race-mode?

An external LVC and set the MGM to NiMh-mode, then you still have the over current protection

Found a nice LVC : http://www.dimensionengineering.com/CellShield.htm

Whatch out, your LVC don't work for car use:

CellShield is intended for aircraft with 0-100% style one direction only throttle. A future product will be aimed at cars.

Good catch. I guess Mike's Li-Saver is the best for our use. :)

I'll save myself some typing and just paste the email I received tonight.

Dear Mr. Barret,

we tested this motor/controller/battery combination and we find this problem.
When avarage current (no peak current) go over the 105% of nominal current (current fuse start activate), can caused this mistake and controller save absurd value (and can cut off motor also).
Please, send controller back to us, we update new SW version (from Feb. 13) to controller, without this problem. This new version has one advatage also - SW is possible update via www, your PC and USBCOM+ module, no necessary send to factory for next newest version.

Best regards,
Grisa Dvorsky
----- Original Message -----
From: Shon
To: mgm@mgm-compro.cz
Sent: Tuesday, February 12, 2008 5:11 AM
Subject: 22418 LVC

Greetings,

I am having trouble with my new MGM 22418 – 3. It seems that there are many others who are experiencing this similar issue.

My setup:

22418
Neu 1521/1Y
Flightpower EVO25 6S 5000mah 25c
HPI Savage

When I have the controller set to race mode everything works well. I don’t want to use this mode due to the loss of protection to both my Lipo and the overload protection. When I use reduce RPM mode the performance is poor, and I am pretty sure that the controller is reducing RPM even when the battery is full. When I use cut off mode the cut off is initiated anytime I go past roughly half throttle. My Lipo is a very high quality lipo with 125 amp continuous, 175 amp climb outs, 250 amp max burst capability.

I have attached a word document with screen shots from each of these settings. They were taken with the lipo fully charged and the truck being held off the ground. I also set the acceleration to 2.99, the slowest setting. Even when the truck is held off of the ground these symptoms persist.

Please notice the MAX PEAK CURRENT [A] reading for the 3 settings:

Race Mode – 260.55 [A]
Cut Off – 1679.1 [A]
Reduce RPM – 1515.05 [A]

It seems like there is something wrong with the calibration. In Race Mode the max peak current seems reasonable at 260.55 amps. In the other 2 modes the reading is over 1515 amps, which seems unrealistic.

Please let me know what I can do to remedy the situation. I have run auto tune several times and tested all of my connections. Let me know if you need any other information.

Thank you,

Shon Barrett


So there it is. The new software fixes the cut off problem I have been having, probably everyone else's as well. Also after you get the update you will be able to update the software from your own computer. Its like they read this thread and raced to get this solved (I know its a fluke but still....).

Mine is on its way there.

I replied and let her know about my controller frying the other night. Hopefully they will take care of it.

Seriously I feel like celebrating!

w00t! Sent them an email to see how I can return it to base for the software upgrade.

Typically, How long will the downtime be?

Thanks Shon!

Originally Posted by fkadir

w00t! Sent them an email to see how I can return it to base for the software upgrade.

Typically, How long will the downtime be?

Thanks Shon!

I have no idea how long it will take, but they told me to declare a value of $15 or less on the customs form to expedite getting it through customs.

Just got a reply from them about the upgrading of my controller. Apparently once they receive the controller, it will only take a day or two to turnaround.

[jhautz]

Nice Job BashOn.

So it turns out it wasnt the LVC, it was the overcurrent protection kicking in.

That new feature that allows software update via USB is nice also.

Sounds like they are getting on the ball.

BTW: What software version was yours?

Someone post the shipping address for MGM when you get it. I have one I need to have sent in to be fixed.

[othello]

Glad for you guys that you have found a solution for your problem. A friend of mine uses a MGM 16018 (race mode as he uses A123 cells) and he experiences troubles with freewheeling. No matter if he switches it to on or off when he releases the trigger from fullspeed to neutral the car seems to brake for a split second. I also red some of you guys are experiencing a similar phenomenon. I'm wondering if this could be related to this current fuse. Otherwise he does not have any problems with power delivery. Anyone having a solution for this problem. I will try to auto tune his ESC and have a look if this could solve this last issue.

>When avarage current (no peak current) go over the 105% of nominal current (current fuse start activate)

Am i the only one wondering about this phrase. A MGM 22418 has a nominal current ability of 224A. What kind of setup is required to maintain 105% of 224A over a certain (undefined) period? Could it rather be it activates well below its nominal current ability. Just a thought. What matters in the end is that the problem got fixed. Guess they will see a lot of ESC coming back home to base in the next few days and weeks. ;-)

Othello, I think the problem was caused by the incorrect calculations of the current and thus the over-current jumping in to protect the ESC.

(When avarage current (no peak current) go over the 105% of nominal current (current fuse start activate), can caused this mistake and controller save absurd value (and can cut off motor also).

Race Mode – 260.55 [A]
Cut Off – 1679.1 [A]
Reduce RPM – 1515.05 [A]

Originally Posted by 83gt

Someone post the shipping address for MGM when you get it. I have one I need to have sent in to be fixed.

MGM Compro
Ing. G. Dvorsky
Sv. Cecha 593
76001 Zlin
Czech Republic