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Mammoth ST Electric Conversion questions??

8K views 21 replies 5 participants last post by  RatsacK 
#1 ·
Hi All,

I'm hoping to get a heap of advice on converting my XTM Mammoth ST to electric and look if you dont want to read my whole post fair enough, its a bit of an essay, but in summary I'm after a shopping list within a sensible non-racer/hobbyist budget. I've seen a few conversion kits but am hoping to fabricate motor mounts and mod batt mounts myself where possible so its the main parts like motor, batt and power controller selection advice I'm after. Any pics of completed conversions would be great too.
I've had this truck for about 3 years now and it just doesnt get the play time I'd like due to the prep and commitment of a nitro car. Yep I'm lazy and would rather just charge a few batts overnight and have a good a ole fashion bucket of fun without all the extra bits and pieces. The build will be purely for havin a RC car for all fun, no racing but I hope to get on the local truggy sized track at times. Maybe some rookie racing would happen one day. Much easier to take camping for new terrain and just generally whippin it out for some good gravel drift and BMX track action.
If anyone can answer any of my questions then I would much appreciate it.. I'm really after a general shopping list as I dont know stuff all about RC (pure user) and even less about RC electric. I am prettu handy around the work bench. I have done a few suspension mods and changed 2 speed for a centre diff... fiddled with both diff and shock fluids, and am pretty handy with a soldering iron...

So... the questions..... and suggestions...
The motor- I'd say I'll be the sorta driver that will have 3 or 4 batts and look to head out for an hour so an djust brun all batts so I guess the motor and heat disapation has to come in to the plan.
Value for money? vs Grunt? vs Reliability?
Motor mounting options?
Batts - as per the motor speal... I'll be looking for a hour or so of fun so minimum batts for max fun. Prob not a lot of long full throttle runs.
Size? vs Weight? vs
Mounting options?
Gearing? Ratios?
I'm looking to keep the centre diff and not go back to the 2speed.

If possible, how do I use my exsiting control gear, Spektrum DS3 controller & Spektrum SR3000 receiver?

A lot of questions there and I appreciate those that didnt finish reading my post... Those that did and can help out... much appreciated
 
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#2 ·
First up welcome to the forum.
I'm not familiar with this car, but I can shed some light.
The best way to convert 1/8's is to use big brushless systems, such as castle creations mamba monster, tekin Rx8 and xerun 150a is also good.
These systems aren't cheap but you will get great power out of them. All of them are able to run on up to 6s lipo, (read up on lipo use) but you will probably run or 4 or 5s generally.
Batteries get from hobbyking, best value
Centre diff is good, theres no need for a 2 speed with brushless.
Motor mounting-not sure as I don't know the car, but theres plenty of motor mounts around to choose from surely one should work. If not its custom made.
Your radio gear will be fine. Your steering servo will stay the same and the esc (electronic speed control) will plug into the throttle channel.

Great first post you had a lot of detail which is good.

Hope this helps a bit:thumb:
 
#3 ·
First up welcome to the forum.
I'm not familiar with this car, but I can shed some light....

Hope this helps a bit:thumb:
Awesome...... thx for the response. I'm glad I can keep the radio gear.

I've seen a few conv's done in the US and self fab is a option for motor mounts.
The Castle kit seems to come up alot....
Would it be worth looking for second hand gear at all? Theres a lot of 'garage sale' style posts among forums. I really just wanna get this car running and see about solid kit when the $$$ allow...

I'm thinking I'll dump the mech brakes. Save weight and gain reverse...

Whats the deal with water proofing some of this gear? Do-able? Not that I am a mud slinger but just curious if its worth doing during the build....
 
#4 ·
yeah castle is good.
2nd hand is fine, just make sure you know what your buying and the condition of it.
Get rid of mech brakes reverse is a good thing.
Waterproofing, can be done, but will exclude you from warranty.
Although some escs now come water resistant/splash proof.
 
#5 · (Edited)
#12 ·
So charger and batt advice?

I'm looking at either of these... mostly due to price. Both look pretty nifty allowing diff batt types, cells and also storage mode...

The first is a 8 cell charger max... does this mean with a splitter loom I could charge 2 x 4S?
http://www.hobbyking.com/hobbyking/store/__5606__Genuine_IMAX_B8_Charger_Discharger_1_8_Cells.html


The second one will run on 240v aswell as a 10-18v power supply. Saves an extr abit of kit but I guess I can only charge 1 x 4S at a time right?
http://www.hobbyking.com/hobbyking/...AC_Charger_Discharger_1_6_Cells_GENUINE_.html
 
#13 ·
i had a imax b6 charger, was fine charging batteries on 2s, then i got some 4s batts, and the charger could only charge 1 at a 3.3amps, so i got a icharger and a power supply, do that from the start and u wont regret it
 
#15 ·
Could I run my charger off my SLA deep cycle battery which sits in the shed most time as its purely for camping and running the bush fridge? I have one in a plastic box for camping and a decent charger for that. The batt gives out 11 or so volts.... Seems feesible to me.
 
#17 ·
You don't need a separate power supply or switch for the receiver. The receiver is powered by the XeRUN ESC, which has an inbuilt 5.75V BEC (battery eliminator circuit - which is designed to convert whatever battery voltage is connected - 2s to 6s - to 5.75volts)

...a bit wordy...

So plug in your ESC to the receiver, and when you switch on the ESC, the receiver should power up too.
 
#18 ·
OK cheers. Not too wordy at all mate. I appreciate the detail and time. I just wasnt sure as there is only one signal path from the ESC to the Rx and that goes to the Throttle port on the Rx. I am hoping the Rx knows what to do after that.
 
#21 ·
A little update.... Conversion done. This thing hammers. Lovin electric. I'll post up some pics and maybe a vid or two when I can get a photog and some open space.

Thx heap sfor all your help. Def sent me in the right direction for all my questions.

Cheers guys.
 
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