Problem with mgm 16018 under acceleration - RC-Monster Forums

munarin · **Problem with mgm 16018 under acceleration -** 01.26.2008, 07:23 AM

Hi,

Just wondering if anyone has a problem with their mgm esc under acceleration?

After reading much on this forum the finally setup I decided on was 2 venom 5000mah 2s lipos in series, so 4s into an mgm16018 speedy into an 8xl motor. The setup is perfect, no temps too hot but after I have run the thing for 10 mins with no problem, under acceleration (ie. fast squeezing of the throttle) the savage launches and as soon as it looks like it is about to really get going in dies. If I wait a sec, (trigger back to neutral) the motor is away again. I pulled the batteries and my voltmeter was indicating 7.234 volts per pack. My understanding from what I can read is that the mgm cuts power at 3.3 volts per cell so I am short of that as I have the setting on the controller to cut motor power once at the lowest voltage.

I have tried to find any other posts in the forum searches but have not turned up much that is helpful.

Any help would be great.

Thanks

Serum · 01.26.2008, 07:32 AM

Hi Munarin;

My best guess is the batteries;

Under load the voltage drops badly. that 7.234V you measured is in the most ideal situation (unloaded). I can imagine a 7.234V pack would drop way bellow 3.3V per cell under load. A fully charged lipo pack measures 8.4V on 2S. I would say the 7.234V is a rather empty pack.

so either the packs are not up the task, or the cells are not fully charged.

01.26.2008, 07:49 AM

Change the setting to "reduce rpm" and get some better batteries. I had the same problem with Maxamps cells. Some packs just don't hold the voltage under load as well as their advertising claims. I really wish there was an independent cell tester for RC!

munarin · 01.26.2008, 08:44 AM

Thanks for the quick reply. I will be off to get some new batteries come monday. Hopefully they may last a little longer. Does anyone have any recommendations based on their own experiences?

bdebde · 01.26.2008, 12:33 PM

I too have found than some 20c batteries don't do well (tried 2 brands) with the way the MGM low voltage cut off works. I switched to the Neu Energy 25c batts and all is well!

01.26.2008, 01:21 PM

+1 on the Neu's. Two other brands that are good are Flightpower and TrueRC.

jhautz · 01:41 PM

I had the same experience with the MGM 16018. It needs top notch batts in order for it to work well. Anouther option is for you to change the acceleration time setting to a longer spool up time. It slows down the aceleration a little bit, but it also draws a little less amps and allows you to get away with batteries that may not be totaly up to the task.

EDIT: I'd pass on the 10c TrueRC batts for this application. Id be looking more for the 25-30c packs.

BTW: To me this stupid LVC on the MGMs is the only real weak point of the controller.

munarin · 01.26.2008, 05:25 PM

Gday,

I just changed the acceleration back to .69 which has helped a bit but I have now ordered some neu batteries. Thanks again for the quick replies. All very useful.

bdebde · 01.26.2008, 08:15 PM

Quote:

Originally Posted by jhautz

BTW: To me this stupid LVC on the MGMs is the only real weak point of the controller.

Well it is a pain in the a55, in fact I thought something was wrong with mine after trying with 2 different 20c batts. But, it will probably make our lipos live longer!

jhautz · 01.26.2008, 08:17 PM

Quote:

Originally Posted by bdebde

Well it is a pain in the a55, in fact I thought something was wrong with mine after trying with 2 different 20c batts. But, it will probably make our lipos live longer!

agreed on all points