Mamba Max on a MR-4TC

[FninjaP90]

I just got a great deal on a MR-4TC SSG chassis, and would like to add a brushless system to it. I have my sights set on the Mamba Max system. I have some questions:

1. Can the MM safely handle a 14.8V 3100mah (http://cheapbatterypacks.com/main.asp?sid=608156&pgid=tp&sort=PQ#prodtop) PQ4S-3100N pack?? Some sites that carry the MM say 2-3 Lipo cells, yet the datasheet allows the MM to be set to a 12V cutoff for a 14.8V pack.

2. If it can handle 14.8V, the most logical motor to buy is the 4600 right? I'd think the 84000rpm is a bit too fast for the 5700 if it were given 14.8V.

[glassdoctor]

It can do 4s but you have to run a separate bec or rx pack.

Definitely the 4600 is the best choice if you want to do 4s.

[FninjaP90]

Alright, how do I wire a 2S 800mah receiver pack to that setup? How do I allow 7.4V to the receiver and controller while letting 14.8V go to the motor? Is there a diagram that'll show me?

[TheSteve]

Those cells won't handle the load very well. If you want to use them try a 2S/2P setup instead - 7.4v @ 6200ma, then they will run the 4600 or 5700kv motors nicely, they still won't do the 7700. I am speaking from first hand experience, I have some of those cells.

[tcolesen]

You don't need to use a separate Lipo battery as a receiver pack. You can use a UBEC like this:
http://www.xushobby.com/servlet/Detail?no=38
It just needs to attach to the output wires of the batteries (all 14.8v) and then it plugs into the receiver in an empty slot. This is the same UBEC that I and others are using, and it is small and works very well.

[FninjaP90]

Why won't those cells handle the load very well? I'm guessing 12C continuous 16C burst isn't good enough? I'd like to get these cells since they're on sale. Any other brands' cells with the same rating is like $140 each. Why are you using 7.4V to run the 4600 and 5700 motors? Isn't that way too far below the motors' RPM limits?

As far as I know, a seperate UBEC won't be as efficient as a seperate receiver pack. A seperate receiver pack will allow the main pack to have a bit more runtime. Adding up the individual weights, putting the receiver on the main pack's side of the chassis also offers me better weight distribution with the weights of the Mamba max, receiver, and servo on the other side.

[starluckrc]

You don't have to run anywhere near the rpm limits to go fast. Generally around 35-40,000 rpms will keep things efficient and from getting too hot and still be fast. While average discharge will be fine for those packs, the surges when accelerating are going to take there toll which is why most now run 20C cont. discharge packs at lower capacities and jump up to 6000mah or more when running 12C discharge packs. Battery drain from a voltage regulator is minimal to the pack overall and is offset by the weight savings.

[FninjaP90]

Alright, so if I get a PX3S-3300 (http://cheapbatterypacks.com/main.asp?sid=608346&pgid=tp&sort=P20#prodtop) 20C pack, it will work perfectly with the 5700 motor and will be able to directly plug into the ESC without a receiver pack or a BEC, right? The MM ESC also has a BEC to only give 6.0V to the receiver, right?

[starluckrc]

I believe the MM esc has a 5V bec, but it will work with the 3S pack. Not sure how well that particular pack will hold up to the current draw since I have not tested 3S on that motor. Personally, I would be thrilled with the 4600 on 3S. Not sure how much battery room you have, but I do have a pair of 3S4350mah packs (162x49x24)in stock that I could make a good deal on.......especially with a MM combo. Just drop me an email for more info.

[TheSteve]

I think that 3S pack will run the 5700 but it will likely be quite hot if you push the system on a track. I recommend the 4600kv motor with a 3S pack but if you require all out insanity and your car is built to handle extreme power get the 5700.

The 3100N Polyquest packs are really good for more like 8C then 12 or 16C