Rustler VXL on A123 cells?

[tc3_racer_001]

how can you tell? thanks...

[tino_ale]

Originally Posted by tc3_racer_001

how can you tell? thanks...

It's just that the seller opened the pack to check the cells...
Annoying that not all Dewalt packs have A123 cells in them. What cell type have they replaced them with?

[tino_ale]

Ok I got my rustler running

I really have to say that I'm extremely impressed by this rustler VXL. I mean for the price you get a RTR model that includes everything, to hear it run is as easy as i can get, yet what you get is a BEAST of acceleration and top speed. It's almost criminal to sell that kind of stuff to anyone who has $270 in hands without a background check

I bought the FLM extended chassis along with it. Mounted everything was extremely easy. As I am more used to 4x4, this model just looks so simple and straight forward that my other models actually look very cluttered and messy now.

I initially planned to used two 3S A123 packs in parallel but I have tried to use them one at a time and they work extremely well. Runtime is very useable too, since the car is so lightweight. Unless you are really making speed run repeateadly it's easy to get 20 min of bashing around on a single charge.

Here are a couple of pics of my rustler. All stock except the FLM extended chassis :







My only complains are :
- all the scews run directly into plastic parts, no metal inserts, so you need to be carefull not to strip the threads
- the little protection behind the motor broke quite easily I ordered two spares but might also consider a more robust skid plate or something

Bottom line is I would totally recomment A123 for the rustler VXL. Only the FLM chassis is really needed to make this work, since a 3S pack would not fit in the stock chassis. You get some serious power for a very limited budget, and so far it work fine for me. It was very easy to make the packs from a Dewalt 36V since I kept the stock tabs. The rustler seems to have strong enough parts to take the power without breaking instantly.

Besides, charging in 15 min is just too good to be true, yet it is true. OK maybe 17 min is the pack is flat empty.

Thanks again for your input and cheers!!
Hey do you guys think I am abusing my A123 pack by using them one at a time? Should I stick to two packs in parallel (eventhough the car gets heavier) ?

[tino_ale]

a few action shots

[tino_ale]

Originally Posted by tino_ale

Hey do you guys think I am abusing my A123 pack by using them one at a time? Should I stick to two packs in parallel (eventhough the car gets heavier) ?

Ooops, looks like I have many questions in addition to this one... Let's summerize my ??? and make it simple for someone to reply :

- is it ok to run a 3S1P A123 pack with the stock ESC and motor?
- is it ok to run a 4S1P A123 pack with the stock ESC and motor?

- is it ok to run a 3S1P A123 pack with a mamba max ESC and 7700kv motor?
- is it ok to run a 4S1P A123 pack with a mamba max ESC and 7700kv motor?
- is it ok to run a 2S2P A123 pack with a mamba max ESC and 7700kv motor?

In each setup I'm worried of abusing either the cells or the ESC+motor, or both. Please tell me what I should not do before I fry everything

if anyone has answers to these questions I'd greatly appreciate the info
Thanks!!

[Sammus]

I run 4s A123 with a unmodified sidewinder and a 2700kv motor. It's fairly insane. temps are no problems, I have two packs and can go straight from pack to pack and run for as long as I want, one on charge, one in the car. Nothing gets too hot or anything, and that was running out in the sand dunes with paddles (ie a lot of load!). Gearing is 30/86.

I also have the extended FLM chassis, I recently installed the FLM gearbox but havent run it yet. I wasn't too impressed with it to be honest, the gear mesh was a lot better in the standard plastic gearbox. I guess I'll see how it goes though. Also, for some reason the shock tower screws you have to use nuts on the other end, the tranny isnt threaded there. I much prefer to use loctite than locknuts. Oh well, its still pretty good. As with all FLM parts I used I had about a million screws and nuts and left over that didnt seem to have a place anywhere on any of the parts I have. Oh well...in the misc screws box they go :)

And for your questions, I havent run those particular combos before, but I wouldnt run anything over 2s (maybe 3s if you want to push it) with the 7700kv motor - or else youll get some serious heat issues. 2s2p is fine, just higher capacity. 3s A123 is less than 3s lipo, which apparently the stock esc/motor is OK with, so 3s A123 would be too. I'd assume 4s would be OK as it is in the castle speed controllers, but couldn't be sure having never used the traxxas one.


Another thing, I noticed you have your batteries very far forwards. This is opposide to me, I put them as far back as I possibly could, and I still have trouble holding traction anywhere but on asphalt. More weight over the rear I say! Wheelies only become a problem when you have traction.

Nice photos btw :)

edit: I forgot to say I've only ever ran 1p, I was running 3s for quite a while, and I agree with you 100%. I think a lot of people on here just want to do ridiculous speeds on ashphalt back and forth with extremely tall gearing - noone seems to think 1p is enough. I even run 7s1p in my revo and it is more than enough power on tap. I don't care how much more power I would get with enerland Lipo cells, I've got more than enough already :P

[tino_ale]

Thanks for your reply;

you're right, I have some room between my pack and receiver, I will try to push the batteries backward. I have maybe almost an inch of room to adjust. I would like to keep current ESC and receiver arrangement since I find it looks very neat as it is.

Now about the 1P vs. 2P battery configuration, as you said the 3S1P is already a GREAT setup with the stock ESC and motor. Honestly I don't need or want more.

My only concern with 3S1P would be to pull too much current from the cells, which voltage would repeatedly sag under 2V (when under heavy load or accelerations on concrete)... I don't want to abuse them, I know they are robust but I just don't want a reduced lifespan

So : is the stock Rustler too hard on a 3S1P A123 pack sums up my thoughts

thanks for all the other answers. I don't think I'll try the 4S.

[snellemin]

3s A123 with the VXL motor is just fine. You will not pull that many Amps out of them with that motor. The peak is only at startup and once your truck starts rolling ampdraw goes down.

[tino_ale]

Then I'll stick running with a single 3S1P pack, the other one charging. When the first pack is empty, the second is ready and so on... then the fun never ends

I have a Mamba Max ESC laying around, would it be a plus to mount it instead of the stock ESC? Not sure if it's better, the stock seems to push it pretty hard already.

Hum... I might still swap for the MM since the later has more braking options. But I'll keep the stock motor, I only have a 7700 motor otherwise.

Thanks!!

[snellemin]

The MM esc will give you more power options to play with. You would be able to tone down the power some more, thus increasing run time a bit or visaversa.

[tino_ale]

In case anyone is interested, I have made this speed measurement on flat concrete.

My rustler is totally stock except the FLM extended chassis.

It was powered by two 3S1P A123 packs in parallel.

Result was : 48mph (77km/h), using a bushnell radar gun.
Measurements were very consistent run after run!

I have not made any measurement with a single A123 3S1P pack, but I suspect it can go a little faster (more lightweight) maybe 50mph