You must Sign-in or Register to post messages in the Hobby Squawk community
Registration is FREE and only takes a few moments

Register now

Announcement

Collapse
No announcement yet.

MFC Unit Fried?

Collapse
X
Collapse
First Prev Next Last
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • MFC Unit Fried?

    So I got the red motors in from HL, and they were matched for the 6.0 (at least the way the connectors are)... so literally a plug and play. I get them in, but before I get them mounted back in the gear boxes, I wanted to test. So fire it up, starts... motors turn for about 5 secs and tank shuts off. Hit start button, and tank fires up again and motors move again. They are going fine for about 10-15 secs and same thing- tank quits. I check everything that there is to check... it's only four connections. and I have left motor to left connection etc.. Start tank again... going fine.. again for about 10+ seconds. Forwards/backwards etc. Then quits again. Now tank no longer starts. Headlight doesn't flash. There wasn't any pops, crackling... sizzles etc. No electrical burn smells... Changed batteries same thing... nothing. Is there any kind of reset on the MFC? Or is this puppy fried?

  • #2
    Originally posted by sfcfury View Post
    So I got the red motors in from HL, and they were matched for the 6.0 (at least the way the connectors are)... so literally a plug and play. I get them in, but before I get them mounted back in the gear boxes, I wanted to test. So fire it up, starts... motors turn for about 5 secs and tank shuts off. Hit start button, and tank fires up again and motors move again. They are going fine for about 10-15 secs and same thing- tank quits. I check everything that there is to check... it's only four connections. and I have left motor to left connection etc.. Start tank again... going fine.. again for about 10+ seconds. Forwards/backwards etc. Then quits again. Now tank no longer starts. Headlight doesn't flash. There wasn't any pops, crackling... sizzles etc. No electrical burn smells... Changed batteries same thing... nothing. Is there any kind of reset on the MFC? Or is this puppy fried?
    The RED 390 motor when used with the 6.0 and a few other systems need to be reversed wired black to red NOT black to black/red to red. This is usual found out without burning up the MFU.

    Not knowing what battery you used and you may not have done this, but I have seen 6.0 MFUs burn up if the voltage and amp draw is maxed out. The MFU is rated at 12 volts but can’t handle 12v plus the much higher amp draw of the red 390 motors. One reason I do not recommend 3 cell Lipos paired with 390 motors to be used with the base 6.0 system. (3 cell Lipos=12+ peak volts)

    There is no reset on the MFU. It will shut down a few times to try and save itself if there is an issues, but then tend to shut down and never turn back on. Try reversing the motor leads and use a NiMH 7.2 battery and see what happens.

    Comment


    • #3
      Wow.... Okay... Yea I disconnected the motors and tried to just turn on the tank without the motors connected at all last night and still nothing. I will try the reverse method later today.

      Comment


      • #4
        Originally posted by sfcfury View Post
        Wow.... Okay... Yea I disconnected the motors and tried to just turn on the tank without the motors connected at all last night and still nothing. I will try the reverse method later today.
        I learned the hard way experimenting and have three or four burned up 6.0 MFUs sitting in my trash bin. Good thing they are cheap....

        Comment


        • #5
          Originally posted by Rubicon99 View Post

          I learned the hard way experimenting and have three or four burned up 6.0 MFUs sitting in my trash bin. Good thing they are cheap....
          Well... i guess... but they are also out of stock!! lol...

          Comment


          • #6
            Originally posted by sfcfury View Post

            Well... i guess... but they are also out of stock!! lol...
            There should be a bunch on EBay. Just look for the ones that say “U.S stock” otherwise right now it could be 45-60 days from a China supplier.

            I am hoping Motion bring in a bunch along with the higher amp rates “6.1S” model. The 6.1S looks like it can easily handle brushless motors🤞.

            Comment


            • #7
              So the light came on... without the motors and cranked. So I attached the old motors... and it killed the tank again.... this time I think its dead dead.

              Comment


              • #8
                Rubicon: Did you come up with a formula for what works for you? I'm at the point of trying stuff with the new MFU's and really don't want to burn stuff down. All my new MFU's are 6.0's and I have with them ran 3S lipo's just because I'm an airplane dude and have a bunch, but things get hot and without low voltage sensors is not a good thing. I also wasn't running them hard and used tanks that didn't have metal parts but they still get hot. So I won't be doing that. I think I will just run the 7.2volt system. I have ordered red motors but they are on a slow boat but plan to put them in. I have the Walker that is medal and will make that a fast runner so would like to get it right out of the shoot.

                Comment


                • #9
                  Originally posted by Vaseline View Post
                  Rubicon: Did you come up with a formula for what works for you? I'm at the point of trying stuff with the new MFU's and really don't want to burn stuff down. All my new MFU's are 6.0's and I have with them ran 3S lipo's just because I'm an airplane dude and have a bunch, but things get hot and without low voltage sensors is not a good thing. I also wasn't running them hard and used tanks that didn't have metal parts but they still get hot. So I won't be doing that. I think I will just run the 7.2volt system. I have ordered red motors but they are on a slow boat but plan to put them in. I have the Walker that is medal and will make that a fast runner so would like to get it right out of the shoot.
                  Yes I have a formula that works for me. First I completely remove smoke system as it even when turned “off” (on the TX) still draws a lot of power to the heating element. Removing the smoke generator also frees up a good amount of internal volume which allows for more air movement. Removing it is no loss for me because I think it a waste with its toy like smoke effects. Second I no longer run the 6.0 MFU voltage any higher then 9.6. and do all the “after install” testing of mods at 7.2v.

                  With the smoke unit removed (or unplugged) you can run one small cooling fan off the smoke “pump” motor power port on the MFU or one off the heating element power port (or both). I use the “pump” motor power ports in my tanks for cooling fans as this can be turned on and off from the TX. The fans help with cooling the MFU dramatically if you choose to run it on 3 cell Lipos or higher then 8.4-9.6v. Not all the tanks can accommodate a cooling fan do to space limitations.

                  The MFU does have a low power cut off. It is right around 6v. At 6v the tank will start to shut down and need to be restarted. The lower the voltage the more this will happen until the tank will start but any attempt to move forward it will shut down. Lights and sound with still work. So you should be fine with low voltage limits with either 2 or 3 cell Lipos.

                  There are a few other little things that I do. These are based on whether or not one wants to keep the airsoft functions or is willing to relocate the MFU as far away from the motors as possible. Especially with 390s that get VERY HOT as voltage goes up much past 9 volts.

                  Here is a fun pictorial that may help some reading this.
                  Performance =🙂
                  Heat issues =🔥

                  7.2-8.4 volts🙂
                  8.4-9.6 volts 😀🔥
                  9.6-11.1 volts 😁🔥🔥
                  11.1-12.6 volts 😁😁🔥🔥🔥
                  12.6 - ? volts 😁😁😁😡😡😡🔥🔥🔥🔥$$$$$

                  Comment


                  • #10
                    Rubicon99 Do you ever burn up red motors? Is the heat issue mainly in regards the MFU or do other things start to melt? My thinking is maybe install a "firewall" with the MFU and a fan on one side and possibly another fan with the motors? This raises the question of how to ventilate both. Maybe some ducting to split the scale engine louvers/screen?

                    Comment


                    • #11
                      Interesting on the 3s lipo. What are you doing or suggest to use a 3s lipo? Where do you get the little fans that you use?

                      Comment


                      • #12
                        Originally posted by Beeg View Post
                        Rubicon99 Do you ever burn up red motors? Is the heat issue mainly in regards the MFU or do other things start to melt? My thinking is maybe install a "firewall" with the MFU and a fan on one side and possibly another fan with the motors? This raises the question of how to ventilate both. Maybe some ducting to split the scale engine louvers/screen?
                        Yes I have and do still burn up red motors. I run them really hard so I expect it will happen. They are cheap....usually and easy to replace.

                        Heat issues are mostly motor related. The red motors draw almost three times the amps of the stock 380 motors. They heat up fast at lower speeds in slow turns vs when running wide open at high speed cross country. Voltage has a lot to do with the heating. 9.6 volts is kind of the yellow arc where you get great motor performance and high yet manageable heat. At 8.4 volts everything is still in the green arc with good performance and moderate heating. My modern tanks like the Abrams, Challenger, Leopard and T72/90 all use 9.6 volt batteries and red 390 motors. The only ones that have issues with overheating are the T72 and T90. These even with the smoke systems removed have very little internal volume and the heat from the motors just build and builds. I have melted or warped a few parts on these tanks(mostly during the summer months when the outside temps are 100+).

                        Firewalls work and I do have them in a few tanks, but fans work much better. Venting is simple, I cut out and use the actual engine vents or vent through open turret hatches on tanks that have issues.

                        Don't over think heating just be aware of it and drive accordingly pausing every now and then to let temps drop a bit.

                        Below is a simple example of adding a heat exhaust vent. These are both T72s one with a vent one without.

                        Click image for larger version  Name:	B20E37FE-26C9-4498-B134-510E54374101.jpeg Views:	0 Size:	43.6 KB ID:	251388 No heat exhaust vent.

                        Click image for larger version  Name:	D74CF4B6-9CA4-4079-ACD7-BD23A314FE44.jpeg Views:	0 Size:	54.2 KB ID:	251387 With heat exhaust vent.

                        Click image for larger version

Name:	F84C7A54-6689-4016-A339-27C69EBB7FA7.jpeg
Views:	402
Size:	52.1 KB
ID:	251389 Vent louvre added to rear of T72 (red) to help hide the added exhaust port. Notice the far T72 does not have this added vent.
                        Attached Files

                        Comment


                        • #13
                          With red motors, If you were running a 2s NiMH (7.2v) or a 2s Li ion (7.4v), would this provide sufficient power for a modern tank with full metal upgrades or would you still be lacking scale speeds? Is heat even an issue at 7.2v-7.4v?

                          Comment


                          • #14
                            Originally posted by Beeg View Post
                            With red motors, If you were running a 2s NiMH (7.2v) or a 2s Li ion (7.4v), would this provide sufficient power for a modern tank with full metal upgrades or would you still be lacking scale speeds? Is heat even an issue at 7.2v-7.4v?
                            7.4 Lipos and Li-ion are putting out ~ 8.4v for the majority of their charge. One reason I recommend high 3000mAH+ is to be in the peak power range of these batteries as long as possible.

                            390 red motors with heavy metal or metal/rubber padded tracks at 8.4 volts is plenty to provide the power for turning in all types of terrain without much stalling yet also provide for a reasonable and noticeable increase in top end scale speed. For the modern tanks like the Abrams and Leopard 2 the 8.4 volt range will not be enough to reach top end scale speeds of 45mph. Instead you will see scale speeds in the mid 30s to 40mph range.

                            In general heat does not become an issues with the 6.0 system or motors until you get above 9 volts. I have WWII and early Cold War tanks that use 390 red motors and 8.4 volt batteries that can run and gun all day and only get warm at best.

                            Top performance has a price. In this case it is heating and reduced motor life. Both can be managed by using the max performance power only when it is needed and driving responsibly the rest of the time. With the new 6.0 systems ability to run in low power or high power mode this is easier to manage then in the past with the older 5.2/3 systems.

                            Comment


                            • #15
                              Wow Rubicon this is all good stuff thanks🤩

                              Comment


                              • #16
                                Originally posted by Rubicon99 View Post

                                The RED 390 motor when used with the 6.0 and a few other systems need to be reversed wired black to red NOT black to black/red to red. This is usual found out without burning up the MFU.
                                Is it still correct to reverse wire the red 390 motors black to red with the 6.0S MFU, and 7.2V battery?

                                Comment


                                • #17
                                  Originally posted by windmill View Post

                                  Is it still correct to reverse wire the red 390 motors black to red with the 6.0S MFU, and 7.2V battery?
                                  Yes.

                                  If for some reason it doesn’t work just swap it back to red red - black black. Either way it will not hurt anything. Just make sure you test it before you screw the upper hull back on top as this will save a lot of time having to unscrew everything another time.

                                  Comment


                                  • #18
                                    Originally posted by Rubicon99 View Post

                                    Yes.

                                    If for some reason it doesn’t work just swap it back to red red - black black. Either way it will not hurt anything. Just make sure you test it before you screw the upper hull back on top as this will save a lot of time having to unscrew everything another time.
                                    Good info. I've already opened the tank so often one of the screws stripped out, so I did the magnet modification. I was a little leery about the ability of 6 little magnets to keep it together, but it seems to be sufficiently secure when bouncing over obstacles.

                                    Comment


                                    • #19
                                      Originally posted by windmill View Post

                                      Good info. I've already opened the tank so often one of the screws stripped out, so I did the magnet modification. I was a little leery about the ability of 6 little magnets to keep it together, but it seems to be sufficiently secure when bouncing over obstacles.
                                      I've heard mix feelings on the magnet MOD; any new updates on your experience?

                                      Comment


                                      • #20
                                        Originally posted by Hellcat 7 View Post

                                        I've heard mix feelings on the magnet MOD; any new updates on your experience?
                                        Other than being mindful when picking it up, I haven't experienced any down side to it. I've hit objects with the main gun hard enough to rotate the turret against the slip clutch, bounce over 1X1 and 2x2, and tip it on It's side to access the battery without it coming off.
                                        I haven't done any flying jumps or anything extreme, so I can't say what would happen under such conditions, but I don't plan on abusing it in that manner.

                                        Comment

                                        Working...
                                        X