Traxxas Jato BL Conversion
 

Hey Everyone,

I've just picked up a brand spanker Traxxas Jato 2.5 and am looking to convert it to a BL system after being inspired by BrianG's Jato.

As with Brian, I am looking for very long run time, whilst still being able to get a top speed of at least 55mph. I am keeping the two speed unlike Brian, as engine braking and reverse don't concern me that much.

I am wondering, as I am new to the hobby, what sort of battery/engine/esc combo I should be looking to get? And any set up help would be great too.

Keep in mind, that I do live in Australia so I may not be able to purchase parts from America.

All help would be greatly appreciated.

That would be cool to do! Max Amps 12000 3s lipo, Mamba Maxx 5700!

Welcome! I see you made your way over from the Traxxas forums!

Like we talked about already, much of how it will be set up is dependent on which batteries you get. A set of 2s Lipos from Maxamps will fit in between the dirtguards if you put them on a platform so they clear the screw nibs. The 6Ah or 8Ah packs should give you tons of runtime.

The motor only has one place to go, so that's pretty easy. Because the steering servo horn sticks up, you'll probably have to come up with some type of new top plate.

Once you know where your battery will fit, it's just a matter of finding convenient spots for the receiver and ESC.

You'll find that the Mamba Max ESC is probably by far the best value. You can either use one of the optional Mamba Max motors (I'd suggest the 4600 on 3s lipo or the 5700 on 2s lipo) or another similar size motor from another manufacturer.

i say who needs runtime putin in Lehner 1950 motor with a 1920 on a 5s pack that should easily hold 55mph:005: :027: :004:

I'd say a MM5700 on Maxamps 8K 3S lipo...The 12K's are going to be really heavy...

Yeah, 12Ah would be kinda heavy at 1.2 lbs.

I get close to an hour on a warmish day (45min track time) with my 5.8Ah pack on a 4600. But this setup only does 47ish mph. If he went with the 5700 with the same gearing I'm using (54T/22T), he should easily get 55mph especially considering he's going to stick with the two speed tranny. He could actually gear a little higher since he still has first gear and get close to 65mph if not more. Since the 5700 is a little hotter, 8Ah should get about the same runtime if not a tad more and not be too bad on the weight. With that power on a 2wd, he's gonna want some weight for traction!

Brian are you running 2S or 3S in your Jato?

2s2p emolis

Thanks for everyone's input.

Because I'm new to all this electronic stuff? What does the 4600/5700 mean? Same with 6aH/8aH?

Im assuming the 6/8aH is something to do with the batteries, is the higher the number the better? And the 46/5700 is to do with the motors? Once again is the higher the better?

And do I only need 2s lipo's? Not anymore than that?

The 4600/5700 are the Mamba Max motors and refer to their model numbers and their KV rating. KV is how mnay times the motor spins per volt. 4600 means it spins 4600rpm per volt. 2v=9200rpm, 3v=13800rpm, snf do on.

6Ah/8Ah refers to the battery capacity in amp-hours. Sometimes you'll see it as 6,000mAh; same thing. 6Ah means it supplies 6 amps for one hour, or 12 amps for 1/2 hour, or 24 amps for 15 minutes, and so on. The bigger number is not necessarily better. Sure, it has higher capacity, but weighs more.

The battery voltage you need depends on the motor selected, the gearing, etc. You've already said you want to do ~55mph with long runtimes. The 5700 motor with 2s lipos rated at 8Ah will give you that of not more. Of course, it depends exactly how much runtime you want. It also depends on how you drive (full throttle starts all the time needs more power than reasonable throttle), weight of vehicle (heavy needs more power), terrain (tall grass is harder to go through so it pulls more power), etc.

Thanks Brian, its all making sense now.

My local hobby shop website: www.rchobbies.com.au seems to only sell the mamba motors 2068 and 2088, are they any good? also with the batteries, unless im reading their specs wrong, the highest number they sell in li-po is only about 2200mah, is that really low?

Do I need to shop around for the better motors and batteries or can you recommend an online store that sells what im after and ships to Australia?

The regular mamba motors are too small for use in the Jato. You really want a 540 size "S" can motor. If your LHS carries the Mamba, they most likely can order the Mamba Max system. You don't have to use the Mamba Max system, but it's by far the best value out there right now.

I'm not absolutely sure, but I do believe Mike (the owner of this site) ships his products worldwide. And I will tell you that you'll be hard-pressed to find better customer service. But I understand if you want to stick to local shops.

2200mAh is only 2.2Ah. It may work but your runtime will be short. Mike also carries Maxamps batteries. If you don't see what you want at the storefront, he can order whatever you need.

The batteries in my conversion (emolis) are the cells found in the Milwaukee V28 power tool system. I just tore the pack apart to get the cells and arranged them for my use. You might be able to find that locally (make sure it's the V28 system though). Although, you'll get somewhat less runtime than I do since you'll be running a hotter motor to get the speed you want. They are heavier than lipos (100g per cell), but have metal casings for added protection. Also, they aren't quite as volitaile as lipos.

So if I can get my hands on the 5700 motor and run it with the 8aH 2s Li-Po's how much run time will I be looking at?

Again, it depends a lot on how you drive it, terrain, final weight, etc. But I would say at least 35-45 minutes. If that's not enough, you could get two packs for well over an hour.

Thats sounds great! How long do the packs take to charge? And what sort of charger would I need? Would I be able to have two separate packs so I can charge them both up and use one for 40 mins, then use the second one for 40mins? Or is it better to make the single bigger pack?

Providing your charger can charge at the proper rate, the charging process will take about 1.5 hours give or take.

Most lithium chargers have a power limit. This means that if the charge voltage X the charge current exceeds this limit, it will only charge up to that limit. Example: the Hyperion has a power limit of 120W. If you try to charge a 3s 12Ah pack at 12A, the charger will only charge at 9.5A instead of 12A. This is because 12A * 12.6v (4.2v/cell X 3 cells) is 151W. So, think about that before you buy a charger if you decide to go with a 3s pack at high capacity (over 8Ah).

You can either get two packs for 40 min each and change them out, or get one big pack. It depends what is most important to you. If you really want one long continuous runtime at the expense of a heavy single pack, then go with one big pack. If you don't mind replacing the pack halfway through, then two smaller packs is a better option. The less weight will actually increase total runtime over a large pack of equal total capacity because the truck won't have to haul that extra weight around. I would choose two smaller packs over one big one. Two 8Ah packs should be perfect IMO. Other people would suggest getting three 6Ah packs instead for less weight.

So the MaxAmps Lipoly 8000mah 2S2P 7.4V Pack, along with the Mamba Max 5700 Motor/ESC will give me decent run time of approx. 40mins whilst still being able to hit 55mph?

Is it possible to pull the battery pack apart and reaarange the cells into a more confined hump looking shape? That way it should fit easier?

Do you know if products from RC-M can be shipped to Australia, and how much and how long it would take?

Thanks for everyone's help, I will post up some pics as soon as I get the parts needed and put them all together.

Yes, that combo should give you what you're looking for.

The battery pack consists of stacked flat cells, so you won't gain anything by disassembling them. If you lay the pack across the chassis so the ends are over the dirt guards, they'll fit.

Maybe someone else here can confirm the questions about shipping to Australia...

Don't forget to get a suitable charger and balancer for your lipos.

We ship to Australia all the time. Items typically arrive in 3-5 days, though I have had packages arrive NEXT DAY!! Service to Australia is guaranteed to arrive in 7 days, but typically arrives faster. :)
Shipping cost is based on package weight.

Thanks Mike. Do you know when you will be getting more of the Mamba Max 5700 combo's in stock so I can grab one?

Also does anyone know what plug I will need for the Maxamps li-po?

Tomorrow or Thursday should bring the 7700 and 5700 combos back in stock - though in small quantity for now. Be sure to sign up for notification so you receive an email when they go back in stock as well. They go pretty quick and I haven't been able to get them in very large quantity yet.
You can order whichever plug you want with the Maxamps pack - I use Dean's plugs myself, with the "standard" balancer plug.

Thanks Mike, I received the engine & battery's all in one piece!

I just have a few questions now about the set up.

Since I am keeping the 2 speed and mechanical brake, i believe the wires from the brake join up with those from the engine to the esc? How does the esc know when to apply the mechanical brake?

On the battery there are the two wires that run to the esc, but there are also some smaller thinner wires with a white connector, what are they for? A fan? or something totally different?

Not to jump in, lol, I'm sure Mike will get back to you also, but was on line and figured I'd post it :) You keep the mechnical brakes by using a "Y" connector to attach the ESC and brake servo to the receiver. Simply connect the "Y" to the throttle brake slot in your reciver then plug the ESC lead into one and the servo into the other (hope that made since). You'll need to set your ESC for forward only, what will happen is when you apply the brakes the ESC will do "nothing", but the reciver will still operate the brake servo as if it were normal, applying the brakes and allowing the motor and ESC to "free-wheel" in a since. Works great and is what most of us do when converting our savages, maxxs, etc, etc. As for the white connectors on the batts, those are for a cell balancer. If your using li-pos (and you want to take good care of them), you'll want to pick up a decent balancer. Check with Mike, I know he'll have some recommendations.

Best of luck with that Jato and post up some pics when your done, would love to see it!!

No worries, I don't think it could be any easier.

Mike, can you recommend a good charger and balancer for the Maxamps 8000mah Li-Po?

I would recommend a Hyperion EOS7i with the Hyperion Balancer. I have been looking into lipo for quite some time, and the setup (if I choose to go lipo) I plan to get is that charger setup with the 8000mah 2s2p Lipo's.

If you have a radio with channel mixing, set it up so that the servo only moves when you apply brakes and the ESC only receives signal under throttle. This will make it a little easier to setup.

If not, go and program the ESC to have no brakes and reverse (I'm quite sure its possible) so that way the ESC just gives throttle and nothing else. This will save the ESC alot of work and save battery energy and reduce temperatures.

I like the MRC charger. This can charge both packs at the same time. The LBA10 balancer would also be my choice.
I also agree with Brian - if it were my truck, I would use each 8kmah pack seperately. The extra weight adds a load on everything, and will get slightly less runtime vs. the individual packs. The weight alone would be the determining factor for me - both packs would be heavy for this little truck and would likely cause premature failure on the drive train(and require some beefy springs and heavy shock oil). I use two 8k packs(in series) in my emaxx, which is twice the truck a Jato is(at least).