Did I just kill my MMM v1???
 

Hello,

Another new thread today.

I finished soldering 6mm plugs on my new Zippy 5S battery and on my v1 MMM. I got a decent spark when I plugged the battery in, and now the MMM won't start.

The lipo still reads around 21v (it's freshly charged), but my v1 MMM just won't make a sound...

As I don't have another battery around, how can I verify if my MMM is effectively dead?

Thanks

Loa

Hopfully you soldered your positive to positive and negative to negative bullets on correctly.You may also have a bad or cold solder joint.:angel:

I doubt it, but it could be. The battery-side bullets must ok because I can check for voltage with a voltmeter, and the battery charged perfectly fine.

How can I test the MMM-side bullets?

Loa

If the polarity was accidently swapped the ESC would have had a FULL MELTDOWN rather than no worky.

Castle will (should) replace your ESC no questions asked since it's a V1 model. I know your out of country but it shouldn't matter, just a longer shipping time.

BTW- this post should be in Castles thread, then they would be more inclined to comment and give you some details. Ask a mod to move it ?

Thanks bondonutz. I'll check for a replacement, but the shipping charges alone will probably make that a less interesting option for me.

And indeed, if a mod can move this thread to the Castle section, that would be great. (Thanks for the move!)

Thanks

Loa

If you still have the switch on the ESC, remove it, strip some of the silicone off the switch wires, and twist them together. Then try plugging in a battery. Bad switch is only other thing to check for. After that it would have to come in to us unfortunately.

Well, what do you know: it *was* a bad switch!

Thanks Joe! My MMM v1 still lives!!!

Now, is there a way to prevent that spark? It did it again (after I shorted the switch wires) when I plugged the battery in.

Thanks again,

Loa

The spark is caused do to the capacitors charging, you cannot avoid this.

EDIT for wrong information.

Not with a MMM! castle explicitly say No to this...

Which is why there is a note on that page...

Whoops... Sorry guys. Maybe I should go back to 1st grade reading class.

In that case, embrace the spark! It makes people jump!

I didn't see the post before you edited it out, so no worries.

The set-up works just fine right now, and if the spark isn't dangerous for the MMM or the battery, I'll learn to live with it.

The one thing worrying me now is my 9XL motor: it gets very hot very fast with my 5S, 5000, 40C lipo (on a converted 3.3 Revo)!

Thanks for the info guys

Nisaea

How hot is hot? And how are you geared?

Hot is too hot to leave my finger on it for 1 second after 10 min general bashing, and I'm geared 20/38. And I already have a RC-Monster heatsink on it.

Loa

You're geared for about 50mph, which for that motor is a bit much for general bashing. I'd try 16/40 or 18/40

Yeah that motor could destroy itself pretty easy on 4s geared for 40 (broke 3) - 5s and 50mph is asking for trouble...

Best to look around for a CC 2200 in due course...

Thanks for the suggestion. As I'm still afraid to go full throttle with the new 5S battery (even on flat roads!), I'll go low: 16/40 or 16/38.

Since it's been 2 years since I last bought spurs/pinions for this truck, I want to get this right. I remember buying the 5mm mod1 pinion gear and I'm still using the original 38T spur from the 3.3 Revo.

So to get the 16/40, I need these:

http://www.rc-monster.com/proddetail...=5mmmod1pinion
http://www.rc-monster.com/proddetail.php?prod=TRX3955

Is that correct?

Loa

I am, just waiting for my budget to settle a bit. :-)

If I do get that CC 2200kv, will my gearing change significantly? Not sure about the 9XL's kv.

Thanks

Loa

A 9XL kv is around 1853. If you use a CC2200 motor, you will have to gear down a bit to retain the same speed.

Thx BrianG. I found your calculations page. Thx for these!!!

Loa

http://scriptasylum.com/rc_speed/_top_speed.html

Use this page.

total_motor_rpm = motor_kv * battery_voltage
Speed (in miles per hour) = ((total_motor_rpm / total_reduction_ratio) * tire_circumference)/1056

Or, just use this instead. :smile:

Hello,

Using the formulas on the scriptorium, going from 20/38 to 16/40 means a 25% decrease in top speed, which will be fine by me. This will be easier on the motor, but will it also be easier on the battery?

Also, I remember from back when I was shopping for my Revo conversion motor that a lower kv motor was better for monster trucks. Going from the 1850 9XL to the 2200 CC-Neu seems like a big jump upwards.

Loa

The cc2200 is a much better motor and will be fine on 4/5s - It actually runs ok on 6s for bashing and I've run ok on 2s for training my son...

Thanks.

Before I place the order on Mike's store: do I need the mod1 pinions? And if so, will those pinions work on the CC Neu 2200?


Loa

Er, is there a pact of silence on the mod1 pinion gears? Every time I ask a question I get great, instant answers here.

But I asked the pinion question twice and got no answer! :-D

I just don't know the difference between a regular 5mm and a mod1 5mm pinion.

Thanks

If your running a converted Revo with the stock spur gear then yes a Mod1 pinion is what you'll need.

MOD1 is the pitch of a gear 5MM is the motor shaft diameter.

Thx for the confirmation. Pinion and spur ordered!

Loa

I've ran 3 9XLs on 5s lipo, geared for 40mph; didnt last more than a few runs each time in my 13lb GorillaMaxx, they just arent that great really ( regardless of specific brand ). Keep an eye out for bargains though as used Neus and CastleNeus pop-up all the time, along with new brands or revived brands like Medusa ( for sale on the Neu website ).