schmism

Because i got confused trying to weed though all of that ill state what i know is a fact.

Battery packs come with 2 different important pieces of info. the Amp Hr rating (or milliamp hr rating as it were) and the voltage.

AHr rating is directly proportional to run time. the larger this number (1500 vs 3300) the LONGER the run time. Because NiCA and NIMH batteries discharge differently they may seem to perform differently for the same voltage. but fresh out of the box you shouldn't see a performance difference between the two different types for a given voltage.

so that brings us to Voltage. the more cells you have (depending on how they are wired) the larger the voltage. the larger the voltage the Faster and more Powerful the motors turn. but the total run time is unchanged. (again usually, depending on how they are wired)

SO in short, if you went with a 3300 4 cell pack you would have the *SAME* mAhr rating (run time) but a lower voltage, something like 4.8v which means the hopped up motors wont run as fast and as powerful.

IMO if your handy with a soldering iron, get you some unmatched single cells that you can solder up in to 2 four cell packs. it would be the cheapest, and easiest solution for ya.

crazzyforf1

just modify the throttle!!! put a plastic thingy next to the throttle and make it so i won't go so far in!

camra88

I have to say, putting a block behind the throttle on the remote is the best idea (and easiest). Prevents excessive acceleration, and dangerous top speeds. However, i know constant slow-driving heats up the ESC faster then you think. May actually cause it to over heat. ALso, the idea with plugging the motors in series. Genius. Half the power and speed, while the ESC shouldnt be harmed, nor the motors. Also, with changing the trim on the stock remote, if you set it back too much, the truck will start to go in reverse, or forward. This will not solve the problem. Also, a simple way to prevent the emaxx's gears to be shifted is to unplug the servo from the reciever, and set the servo in the correct position for what gear you want it to be in. Maybe use tape to make sure it stays in place? Also note, that constant excessive acceleration WILL be devestating on its drive train, especially since the emaxx weighs about 10 pounds with the batteries installed. So gearing it down has its consequences. It is not recommending to use a lower-count cell batterypack then 2-6 cells. I've read that it is not good for the speed control.

And about the mAh rating on a battery--- differences dont do anything for speed (as was pointed out, thankfully). Voltage is what makes the speed, amps make the power (grunts like Tim Allen). mAh means "milli amp hours", or how many milli-amps a battery can discharge constantly in an hour before being out of 'juice'. so a 2400 mAh battery is able to pump out 2.4 amps for an hour before having to be recharged. Also, different mAh batteries dont affect power

Boy im glad i got that outta my system

JP

schmism

not owing an Emax myself..

Does the left bat run the left motor, and the right bat run the right motor?

so if you only connect one bat you only power 1 motor?

camra88

Nope. Both batteries are connected in series, so the total voltage is 14.4 volts. The motors are then hooked up in parrelel to this, so each run on both batteries that are in a series. If people are confused, i can draw a diagram...

JP

spdfrek

My Feedback: (12)

seems odd you say mah dosent affect power or speed when you stated exactaly why it whill....the extra juice will give you more accel....there was a definit difference between my 1400mah and 1700mah batterys i had for my rs4 mt...the run time and speed/accel with the 1700 were much better....Basicly your saying that a big block motor will start fine with two 9 volt batterys wired for 18 volts.....cause all you really need is the volts.... drastic example,but still,if your motors are capable and you speedo is too,extra mah will always give you more torque.

camra88

The mAh rating on batteries tell you how many amps that can be drawn from them before they are out of power in one hour. This does not tell you how many amps it can pump out in a shorter amount of time (as you said). I think we can all agree that your electric RC car doesnt last an hour on one battery charge. If you've noticed, different batteries have differnt amperage outputs. Like some new emaxx batteries, i think they are rated 20 amps max they can pump out. Better quality batteries might be able to output 40 amps. This is that difference you saw between the 1400 and the 1700. Quality/brand/make was the contributing factor, not mAh. However, a battery with a higher mAh rating will be able to keep the amps coming for a longer duration then a similar battery with less mAh. Also remember that newer battery packs arent worn out, so they hold a higher voltage. Older battery packs have cells that start dieing little by little, and ultimatly affect performance.

Acceleration is determined by how much Voltage you have, and how much Amperage is available to the motor(s). If your batteries are 1400 mAh, rated max output of (oh lets say...) 20 amps, but the motor is capable is handling 40 amps (and the motor indeed is asking for that much amperage), then you will only get about half the acceleration. Now lets say you have a better 1400 mAh battery that is capable of outputting 40 amps. The motor would then have the punch it needs to really get up and go. Like i said before about amps givin it power... acceleration requires power because its starting from a dead stop (wheelies). Also, motors will be asking for more amps when they require more power (like driving up a grassy hill).

If you need more details, ask...

JP

clamdiglet

Easy way to slow down the E-maxx:

-Go to radio shack and buy 1 tamiya plug (the end that is connected to the battery not the ones on the EVX)
-Short the two ends of the recently bought Tamiya connecter wires by soldering or crimping them together. Use heat shrink to make sure there are no shorts. You can also shorten the wires to make it look pretty.
-Disconnect all the batteries and turn the on/off switch to "on" (if you have one)
-Take one battery and plug it into the "drivers side" of the EVX.
-The EVX should light up like it's on. If it doesn't, plug the battery into the other side and it should light up. Make sure the on/off switch is on as stated earlier.
-After you find out which connector on the EVX is the right one disconnect the batteries.
-Plug your shorted connector into the side that DOES NOT make the EVX light up.
-Turn off the on/off switch.
-Plug your battery into the remaining side.
-Turn on the transmitter
-Turn on the on/off switch in the Emaxx.
-Squeeze throttle
-Enjoy


If you really wanted to get serious you could open the EVX case and desolder the connector and solder in a jumper wire to eliminate the short plug and wires sticking out of the EVX case. I don't know why you would ever want to do this though because that means if you wanted to add the second battery (ie. son growing older) you would have to desolder the jumper and add that end of the connecter again so you run the risk of messing up your EVX.

clasher

i dont know anything about electric motors but cant you adjust a brushless motor?

clamdiglet

I think top speed stays the same though.
The adjustment only reduces rate of acceleration I believe.

mbx

why the hell would anyone want to go slow with rc, are you afraid to scratch your pansy ass body or something, not to be mean but you go slow you take the point outa having one you want a slow ass car go to wal-mart and buy a tyco or something don't disgace the E_MAXX[>:]you do that and i'll kick your ass leave it fast it more fun to race and crash and fix them

clamdiglet

If you read the VERY FIRST post you would know why he wants to go slow.

camra88

are you sure its safe the evx to plug one battery in, and short the other? I use to do this with my emaxx with the old VX-12, and when the new EVX came out, they said to stop doing that. Just wondering...

JP

clamdiglet

who said stop doing that? I've never heard that. I've been on the traxxas forums since day 1. No one listens to me when I tell them to do this. It's the BEST solution to getting 50% speed...period. No one does it because people say it'll ruin your EVX or associated electronics. THEY'LL BE FINE. You won't notice a difference in ANYTHING because you connected your battery to the side of the EVX with BEC. The 7.2V battery is supplying the BEC voltage AND the go power for the truck. All the short plug is doing is closing a circuit so that the juice can get past the BEC and to the motors to power the truck. Everything works with one battery connected except the throttle...guess what the shorting plug is for. try it for yourself if you don't believe me. Just hook up a battery to the "drivers side" of the EVX, no shorting plug.

camra88

I believe i heard it from Traxxas. Maybe on their website or maybe in a phone call... I know I heard it from someone though. I didn't know why it "wasnt safe", nor did i care, since i dont do that. But I'll remember what you said. But yeah, if that way is safe, is sure will work good at giving it half power as he wanted.

JP

gmouchawar

My Feedback: (17)

Disconnect /remove one of the motor and gear it down. That should keep the run time high, but slow.

entity

My Feedback: (14)

i know.. it's your son.. but i say... let him learn from what you bought..... you could simply put on some sort of brake on the throttle to stop him from going full speed... othewise.. like i tell my fiance who just got into r/c racing with a evader electric... to learn from what the kit comes in.. and once you master that.. then upgrade.... I feel that if you learn on the faster stuff... and get good at it.. then you'll be even that much better with modded cars.... that way he won't be "shy" of the faster cars in the future.

california_zephyr

The thing with moters is if u put less batteries in the truck. u are probably only going to burn through batteries very fast. to slow down the truck, u need to get batteries with less power.

schmism

<Sigh>
"batteries with less power"

follow along children as we have electronics 101...

"power" is measured in Watts (or horsepower which is nothing but 745.7 watt/hp) a Watt can be called a Volt-Amp. because W=V*A

the voltage is fixed as your not going to find anything other than 1.2-1.5 volt cells.

Any battery can put out the same amperage. The difference is how long they can sustain that current level output. thus the term Amp-Hr is used. (how many amps can you put out for one hr)

the "size" of a battery either physical or some number 1500,2000,3300 (which is in fact the amp-hr rating in milliAmps) will determine how much runtime you get out of the bat pack.

so if we use less (1.2v) cells in series (the method in which they are wired together) we will wind up with an overall lower voltage. BUT the SIZE of the batteries didn't change, so you still have the same Ahr rating.

so in short, "batteries with less power" can only mean one thing.... fewer cells. This will drop the voltage of the pack (we cant change the SIZE of the battery so the Amps stays the same) and the "power" of the battery pack will be less

pro5o

I used velcro tape 1/4 wide X 1/2 long. Glue softside to transmitter behind trigger and add stiff side LOOP to slow it down, take it out to go faster. used this to slow down an Evader for my 6 year old girl, take loop side out when I want to drive at local track. on our E-maxx i used smaller pinions and larger spur gear (will have to check sizes) and velcro, truck runs 20 minutes in ST. Augustine grass ( very thick )my 1500mah run about 9 mins. use to run 9 mins on 3000mah batts with stock gearing, also have trinity heat sinks on motors. still pops wheelies... and hurts when she hits me in the ankles