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-   -   mamba max on emaxx with 2 6s lipo packs (( HELP)) (https://www.rc-monster.com/forum/showthread.php?t=27882)

mwe-maxxowner 08.22.2010 12:16 AM

mamba max on emaxx with 2 6s lipo packs (( HELP))
 
I have an emaxx with the stock batteries powering the Mamba Monster. I just ordered from hobbyking.com two 6s 5000mah lipo packs. I am nervous about runningt the packs. I do not want to overheat anything or creat too many voltage spikes and ruin the motor. I know that if i run the packs in parallel I will double the voltage which could creat that voltage spike. Should I sun them in series or parallel.Or sould I just run one pack at a time. I do want it to be stupid fast but so fast I will over heat anything. Again i have already ordered the 6s 5000mah packs. What shoud I do????? Sould I be Worried????? Also Just like everyone else who upgraded from brushed to brushless I also recieved a significant improvement in power and run time, and I am sure I will see another increase when i go to lipos. BUT I DO NOT WANT TO RUIN MY MOTOR OR LIPO'S. Should i gear down A little to reduce heat or what????????? ((( HELP ME OUT)))

scarletboa 08.22.2010 03:59 AM

if you can get the packs to fit in your truck, run them both in parallel. it will double your run-time and REDUCE voltage spikes. the voltage will be the same unloaded and a little higher loaded due to less stress on the packs.

mwe-maxxowner 08.22.2010 11:25 AM

what is the difference in performance between series and parallel? Wont running two 6s packs in parallel double my voltage. Are my packs too strong?

redshift 08.22.2010 11:41 AM

Calm down man! lol

Parallel is your only choice with 6S packs.

Series wiring doubles voltage, and the MMM is rated for 6S, NOT 12S lol. There is no such thing as 'too strong of a pack' as long as you are within the rated voltage. A single 5000 is ok to run but will make your truck heavy on one side, not really a big deal. Running both will double your runtime. Up to you. But you MUST only run parallel adapter.

Run it 2 or 3 minutes and check your temps, another 2 mins, check again. If things are hot then check back in and let us know what is getting hot, motor or MMM.

Also we need to know what you have for a motor?

mwe-maxxowner 08.22.2010 11:47 AM

2200kv


What about gearing?

mistercrash 08.22.2010 11:49 AM

You cannot run your 6S lipos in series with the MMM. It is rated for 6S max so you will have to plug them in parallel if you run both of them at the same time. Plugging in parallel increases the total milliamps, not the voltage. Your two 6S 5000 mah lipos plugged in parallel will stay 6S (22.2 volts) but will double the mah to 10 000 which will give looooong run time. If you plug them in series, the opposite will happen as the mah will stay at 5000 and the voltage will double to 12S (44.4 volts) frying your MMM.

For gearing, you can use BrianG's website to calculate your top speed. I know you want your truck to be crazy fast but most people gear to go around 40 mph to keep the temps down. Brian works hard to keep this useful website up to date so feel free to donate something to show your appreciation. Here's BrianG's RC calculation website.

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

redshift 08.22.2010 11:51 AM

2200 x 25V(6S fully charged) = 55,000 rpm, you will want to gear on the low side with that kind of motor speed. As for exact ratio, we don't know if you have an old or new Maxx, but use the smallest pinion with the largest spur you have, that's the best starting point I can give you.

mistercrash 08.22.2010 11:51 AM

I took too long to write my post, I repeated most of what redshift said :lol:

redshift 08.22.2010 11:54 AM

Quote:

Originally Posted by mistercrash (Post 377677)
I took too long to write my post, I repeated most of what redshift said :lol:

A little backup isn't a bad thing :smile:

mwe-maxxowner 08.22.2010 11:59 AM

16.8 v emaxx long chassis. It wasent brushless when i purchased it. I put the mmm on it. The mmm came with an 18tooth pinion gear and i thing the emaxx came with a 62 tooth spur gear.

redshift 08.22.2010 12:05 PM

Quote:

Originally Posted by mwe-maxxowner (Post 377680)
16.8 v emaxx long chassis. It wasent brushless when i purchased it. I put the mmm on it. The mmm came with an 18tooth pinion gear and i thing the emaxx came with a 62 tooth spur gear.

That's the same as stock gearing with the Titans IIRC, that's gonna be way high. Probably something like 14/66 or 14/68 will be much closer. But then again if you're looking to do 65+mph then make sure you do short runs, like under a minute and keep a very close eye on temps. But do check BrianG's calc for precise speed first.

mwe-maxxowner 08.22.2010 12:06 PM

Lol, guys this thread is from a friend of mine, who has the e-maxx. He has the most recent edition of the e-maxx, when they started coming out with the BL e-maxx straight from the box. I tried talking him into buying the BL to start with, but he went brushed, then bought the motor within a week :D.

Right now the truck has stock brushed gearing, so we need to look at brian G's website to find the recommended gearing for the motor and esc? It has the very same motor and esc as if it had been bought the BL edition. The truck will mostly be used for bashing, really no competitive racing, so keep that in mind when recommending gearing. The main thing is trying to keep temps in check. Where would you guys recommend purchasing a good budget-friendly temp gun?

Also, it is okay to charge the 6s 5000 packs at 5 amps for a one hour charge time, no?

redshift 08.22.2010 12:07 PM

Quote:

Originally Posted by mwe-maxxowner (Post 377680)
16.8 v emaxx long chassis. It wasent brushless when i purchased it. I put the mmm on it. The mmm came with an 18tooth pinion gear and i thing the emaxx came with a 62 tooth spur gear.

That's the same as stock gearing with the Titans IIRC, that's gonna be way high. Probably something like 14/66 or 14/68 will be much closer. But then again if you're looking to do 65+mph then make sure you do short runs, like under a minute and keep a very close eye on temps. But do check BrianG's calc for precise speed first. It is stickied at the top of the Brushless forum, click back once and you're there...

redshift 08.22.2010 12:11 PM

Login timed out on me grrrr... sorry for the double post :whistle:

mwe-maxxowner 08.22.2010 12:18 PM

wouldnt by putting a bigger spur gear and pinion gear give me more top end speed and less low end torque.


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