Are Zippy Lipos safe with a Castle MMM Speedy?

Originally Posted by Unsullied_Spy

It held up fine under the Zippies but when I dropped down to a smaller pinion and switched to my Maxamps packs it smoked like a chimney, hmmmm.

Dayum!

[Unsullied_Spy]

Originally Posted by Freezebyte

Dayum!

When I found out how over-geared I was I was amazed I didn't cook anything. I figured that by gearing down and dropping the voltage I'd be going to a safer setup. I was surprised, to say the least, when I flipped the switch and the MMM started puffing smoke...

[georgec]

I ran the whole last season on 4s 5000 mAh 30c Turnigy batteries in a converted D8 with the CC 2200kv combo. geared 15/48 and won most races in my class. Even in the hottest days of August the motor never got above 160F after a 15 min. main! I don't need $200.00 battery packs to win races thank you very much

[emaxxnitro]

i ran a 4s 5000 20c turnigy last season in my mbx5, it was a great battery but its time came. it puffed. but i was great battery while it lasted. strong lil pack

[georgec]

Originally Posted by emaxxnitro

i ran a 4s 5000 20c turnigy last season in my mbx5, it was a great battery but its time came. it puffed. but i was great battery while it lasted. strong lil pack

Try the Turnigy 25c packs they don't cost that much more and the higher C packs seem to last longer IMHO

[shaunjohnson]

are zippy lipo's safe to use with MMM?
http://www.rc-monster.com/forum/showthread.php?t=24618
set-ups used in the mud are zippies, everyone at club runs zippies (oh...but i run zippy and turnigy).
answer...
YES!!!

Cool, i'll be purchasing some Zippy or Turnigys next spring then, i'm done with SMC

So what was the final resolution on this? Do cheap lipos cause ESC failures or not? If so could somebody please explain the technical reason for this. I'm just a Mechanical Engineer Dummy, so 'splain it slowly. All I saw in these posts was something about voltage ripple, didn't make sense to me. I don't understand how a DC power source would "amplify" a voltage ripple, cheap or otherwise.

Thanks

[georgec]

Originally Posted by GordonFreeman

So what was the final resolution on this? Do cheap lipos cause ESC failures or not? If so could somebody please explain the technical reason for this. I'm just a Mechanical Engineer Dummy, so 'splain it slowly. All I saw in these posts was something about voltage ripple, didn't make sense to me. I don't understand how a DC power source would "amplify" a voltage ripple, cheap or otherwise.

Thanks

It's not really the motor or ESC, it's the batteries that get hit hardest. If they can't keep up with the wild voltage spikes, they end up not being able to control the voltage being sent back through the ESC. This causes it to switch parts that shouldn't be on on, resulting in a situation where the ESC is switching on and off thousands of times a second. This is called RIPPLE EFFECT. This will boil the liquid in the caps which then leaves the ESC fets open to the voltage spikes, and they will blow almost immediately, hence the fires seen recently in Flux ESCs.

The problem is the MMM esc has such a low internal resistance, it is more vulnerable to any changes in amperage and voltage outside of it's normal operating range. This is why Castle say you MUST use high quality cells that can control and absorb the voltage created during regenerative braking. Rather than lumping it back through the ESC.
Hope this helps

[scarletboa]

the conclusion:

hobbycity lipos are fine for the MMM as long as you get one with enough of an amp rating for your rig. if you are running a buggy, a 100a constant rating or higher is recommended. if running a truggy or not so heavy MT, 125a or higher is recommended. if running IE, an extended savage flux with 7" tires that weighs 15lbs, 150a or higher is recommended.

all these ratings are for rigs geared for less than 50mph. for over 50mph, but less than 65mph, add 25-50a. for over 65mph, unless you are just doing a few speed runs, all i have to say is good luck

maxamps packs are more likely to cause problems than the zippy and turnigy packs. so, as long as you get a high enough rated battery, you should be fine.

edit: some people may be able to get away with smaller or lower rated packs. it all depends on their driving style. if you are just going to bash, you might not need huge c ratings, but if you are going to drive in tall grass, sand, gravel hills, or race it, you will need better packs.

update-My Flux and the original ESC are still working just fine exclusively on Zippy packs. I have since moved to Hobby City's Flightmax series of packs as the Zippy H packs I was using have been phased out. Either way, I still run the old packs and have had no problems to note other than a wire coming off of one of the Deans on the ESC side.

The basis of this argument of whether or not Zippy packs and ESC failure go hand in hand holds no water per se as there's a whole lot of guys/gals running Zippy or Hobby City lipos in their MMM powered rides and they are not having issues. Consider this the RC version of Myth Busters. Busted. lol

[Chadworkz]

Yea, I have a ton of hours on my BL Revo 3.3, which has a CC MMM³ ESC, CC/Neu 2200kV Motor, and Zippy Flightmaxx LiPos (2x 30C 4S 2650mAh in Parallel [30C 14.8v 5300mAh 159A])...I have never had a single problem

Sooooo, now it gets even more interesting. We've got HPI with updated documentation stating that 100amps of continual current pull will suffice for Lipo's on the MMM. I coulda swore Castle Creations stated that nothing below 125amps would be sufficient to be reliable and safely run the MMM, especially on 3S power to prevent all the ESC meltdowns we had following the Flux's launch last year.

So, once again, what say you Castle?

http://www.hpieurope.com/manuals/upd...ate_060309.pdf

[scarletboa]

Originally Posted by Freezebyte

Sooooo, now it gets even more interesting. We've got HPI with updated documentation stating that 100amps of continual current pull will suffice for Lipo's on the MMM. I coulda swore Castle Creations stated that nothing below 125amps would be sufficient to be reliable and safely run the MMM, especially on 3S power to prevent all the ESC meltdowns we had following the Flux's launch last year.

So, once again, what say you Castle?

http://www.hpieurope.com/manuals/upd...ate_060309.pdf

look at my post higher up on this page........

it pretty much explains everything you need to know. your savage with stock gearing should be run with 150a+ batteries to be safe. 125a batteries can suffice with a stock savage, but your savage has been upgraded to XL size and you can now put more power to the ground, requiring better batteries.

edit: didn't realize this was a new page starter.....look on the last page (pg.19) for my post.

[BrianG]

Min battery is completely dependent on usage. I can run my 8th scale XT8 truggy with a battery capable of only 30A all day with no problems.... IF I gear low and apply gradual throttle input (no, that isn't fun, but I could do it). Then again, I could gear a truggy to the moon and hammer the throttle and could blow a 150A battery.

My advice: err on the side of caution and go with the 125A figure. The only thing that will cost you is a few extra dollars for a better battery. Heck, to be really safe, go with a 200A capable battery.

Or, use what you have and run the setup with a logger. Look at the graphs after running the way you plan to run all the time. If voltage is dropping too far under acceleration, you lose a lot of usable capacity before LVC, get false LVC trips, and/or battery temps are too high, then use a better battery.