Limitless First time speed build.

[chris adams]

@LegacyIV Goodluck with your endeavor. I hope you don't regret nit starting on lower volts. Maybe just gear for 120 or so first to get the car tracking straight and get used to how it drives. Always be gentle on the trigger, especially with all the power your trying to put down. One quick squeeze and you could be picking up pieces off the road.

 

[mat60]

@LegacyIV Goodluck with your endeavor. I hope you don't regret nit starting on lower volts. Maybe just gear for 120 or so first to get the car tracking straight and get used to how it drives. Always be gentle on the trigger, especially with all the power your trying to put down. One quick squeeze and you could be picking up pieces off the road.

Just my opinion here so no offence. I think even at 80 may be a crash on the first run but it doesn't matter what myself or anyone says to try to help. You guys have all offered him good advice. I hope he doesn't burn his house down and I hope he doesn't post his stuff on u tube for others to see.

 

[vwturbowolf]

I used qs8’s for a while but the anti sparks inside of them tend to blow out causing the plug to get corroded in there. I find it far simpler to use bullets, and just made simple jumper anti spark harnesses from a 5$ part and some alligator clips, during your last connection, you bridge the connection with it for a split second then make your connection. No spark.

 

[aroberson77]

I like the 8mm bullet idea, I am running QS8 and have been satisfied other than how hard they are to unmate. I have personally only made it to 81 mph and did crash so I also recommend starting out slow.

 

[Dan B.]

In the picture you can see that the positive wire from one battery and the negative wire from another battery are soldered to the same qs8 plug while the other positive and negative are joined by what it seems to be qs8 bullets which means that two different batteries are in fact wired together and must be charged somehow because I don't think he's unsoldering them to charge them individually.

Nope, nope, nope. Under no circumstances does one ever solder two LiPo’s together. You’re not seeing what you think you are here, he’s using jumpers. I guess I’m going to be the bad guy here….
@LegacyIV I mean absolutely no disrespect here, but you should really back up three paces, take a couple deep breaths, and reconsider your path. You have a lot of research to do, especially in regard to LiPo’s and electronics, and as @dure16 said, you absolutely can burn your house down by improper handling, storage, charging, and use of LiPo’s. This is not hyperbole or dramatics. It’s also really easy to roast some very expensive electronics the minute you power them up if you’ve botched the wiring. You have a lot more to learn before you’ll even be able to ask the right questions.
Where you stand right now, the best case scenario may be that you manage to get this thing together without causing property damage first and promptly wreck it into oblivion on its maiden voyage. That’s the course you’re on.
Go slow, man! Have fun with the journey, with the learning process, and progress when you can. Everyone is here to help, and most are more than happy to do so. There are some very gracious and knowledgeable people here, and some super experienced speed runners. (I’m not one of those, lol, an experienced speed runner I mean.)
I totally get the argument that it makes sense to buy the best in the beginning without having to upgrade as you progress, but this is one of those rare instances where it actually doesn’t make that much sense at all. The guys hitting the numbers you aspire to have literally taken years to do so.

 

[LibertyMKiii]

Raz offers alot of good setup tips, but I don't agree with his wiring of LiPos. There are some minor benefits of shortening your wires, but James ran 200+ with very long wires in a more standard configuration. I don't think the risks and complications of Raz's wiring setup is worth it.

 

[Dan B.]

Raz offers alot of good setup tips, but I don't agree with his wiring of LiPos. There are some minor benefits of shortening your wires, but James ran 200+ with very long wires in a more standard configuration. I don't think the risks and complications of Raz's wiring setup is worth it.

I’ve also been questioning the real world benefits of making the power leads shorter by inches. I can’t imagine that voltage drop might even be measurable at those already short lengths. It ain’t like the LiPo’s are feet from the ESC. I’ve also wondered the same about cap-packs. In a theoretical sense it makes perfect sense that they should be as close to the ESC as possible, like everyone says. But a quality cap-pack that is three or four more inches upstream wouldn’t negate its use, right? In the build I’m doing now I have one of Phil’s 8S Ripple Killers that just simply won’t fit closer than about 4” from the ESC. Perhaps not the ideal scenario, but it still must be well worth its inclusion anyway, right?

 

[LibertyMKiii]

I’ve also been questioning the real world benefits of making the power leads shorter by inches. I can’t imagine that voltage drop might even be measurable at those already short lengths. It ain’t like the LiPo’s are feet from the ESC. I’ve also wondered the same about cap-packs. In a theoretical sense it makes perfect sense that they should be as close to the ESC as possible, like everyone says. But a quality cap-pack that is three or four more inches upstream wouldn’t negate its use, right? In the build I’m doing now I have one of Phil’s 8S Ripple Killers that just simply won’t fit closer than about 4” from the ESC. Perhaps not the ideal scenario, but it still must be well worth its inclusion anyway, right?

Exactly.... it will be fine.

James does not show the inside of his cars often, but you can see the wiring could be shorter by inches and is still performing at the top level.

 

[Killacam]

I wasn't planning on taking short cuts.

everything you're doing- watching raz's videos, copying his builds, asking for gearing- those are all shortcuts, because you're not the one pulling the trigger. it's like copying your friend's homework.

 

[LegacyIV]

Raz's wiring looks like a single battery but it's not. It's just super clean.

In the first picture he has connection from first battery to the second battery with an 8mm Bullet connector. He has showed this before where just uses bullets. He probably has a special charging cable for that setup.
View attachment 270632

The second picture is a series configuration with a jumper. He has two jumpers on the side of the batteries.
View attachment 270640

Another shot of his bullets (on his latest build). The bullets are on the ESC and the QS8 on the battery. There is another QS8 hidden in the shadows. It's still a series circuit.
View attachment 270639

The idea is to have the least resistance possible. More wires add, smaller (thicker) gauge wires and connectors all add resistance to the system. It's only miliohms but it adds up when you are on the ragged edge. Realistically, I wouldn't worry about it until you're running 180 in an open wheel.

If you look at the last picture he could actually clean this up even more. Start by placing the batteries 180, where the connectors are closer to the ESC. Then shorten the ESC wires and upgrade to a smaller (thicker) gauge wire. I also suspect the QS8 connectors are a weak link and maybe two connector pairs in parallel might help lower the impedance?

Would it make a difference in the real world? The math says it does, but in reality there are so many variables it's hard to say. It's all theory and to conclusively say what works and doesn't work you need a highly controlled environment with high precision instruments. For all I know he might get better performance by removing all of the stickers?

Thank you for responding to my question and not getting side tracked by your personal opinion on how I should go about my build. I'm just gonna go with this wiring setup its clean and it doesn't look like a mess that was my main goal with choosing one of these wiring setups. The other technical benefits were just a byproduct for me and the other choices are a little complex to pull off and from most responses seems to be more work than worth.

Nope, nope, nope. Under no circumstances does one ever solder two LiPo’s together. You’re not seeing what you think you are here, he’s using jumpers. I guess I’m going to be the bad guy here….
@LegacyIV I mean absolutely no disrespect here, but you should really back up three paces, take a couple deep breaths, and reconsider your path. You have a lot of research to do, especially in regard to LiPo’s and electronics, and as @dure16 said, you absolutely can burn your house down by improper handling, storage, charging, and use of LiPo’s. This is not hyperbole or dramatics. It’s also really easy to roast some very expensive electronics the minute you power them up if you’ve botched the wiring. You have a lot more to learn before you’ll even be able to ask the right questions.
Where you stand right now, the best case scenario may be that you manage to get this thing together without causing property damage first and promptly wreck it into oblivion on its maiden voyage. That’s the course you’re on.
Go slow, man! Have fun with the journey, with the learning process, and progress when you can. Everyone is here to help, and most are more than happy to do so. There are some very gracious and knowledgeable people here, and some super experienced speed runners. (I’m not one of those, lol, an experienced speed runner I mean.)
I totally get the argument that it makes sense to buy the best in the beginning without having to upgrade as you progress, but this is one of those rare instances where it actually doesn’t make that much sense at all. The guys hitting the numbers you aspire to have literally taken years to do so.

From what I see with most of the responses everyone is jumping to conclusions when I clearly stated in my first post my goal. I have common sense and just because I asked for the 150/180mph gearing and also a "bashing gearing setup" (that everyone so conveniently ignored) doesn't mean first day im gonna go out and send it until I hit these numbers or crash. I planned to go "slow" this isn't my first rc car I grew up driving them. There's a learning curve to these kinds of things. My passion may not be the same as you all where im getting the joy of starting from the bottom (80mph) going from 2s,3s,4s,6s etc and going out every day with new gearing, batteries etc and making my way up. Just because Im not doing it the way you all did it doesn't mean im doing it wrong. Im doing my research and coming to a forum where I ask a question and I should get a response to that question not a long drawn out explanation on why I shouldn't do it my way.

There should be guidance not deterence... that's what a forum is for. Helping people along their way. Not stopping them to do it your way.

 

[Dan B.]

From what I see with most of the responses everyone is jumping to conclusions when I clearly stated in my first post my goal. I have common sense and just because I asked for the 150/180mph gearing and also a "bashing gearing setup" (that everyone so conveniently ignored) doesn't mean first day im gonna go out and send it until I hit these numbers or crash. I planned to go "slow" this isn't my first rc car I grew up driving them. There's a learning curve to these kinds of things. My passion may not be the same as you all where im getting the joy of starting from the bottom (80mph) going from 2s,3s,4s,6s etc and going out every day with new gearing, batteries etc and making my way up. Just because Im not doing it the way you all did it doesn't mean im doing it wrong. Im doing my research and coming to a forum where I ask a question and I should get a response to that question not a long drawn out explanation on why I shouldn't do it my way.

There should be guidance not deterence... that's what a forum is for. Helping people along their way. Not stopping them to do it your way.

Fair enough, man. You’re absolutely correct. Good luck, and keep us posted. I doubt if anyone here wants to see you fail. I don’t. In fairness though, if you grew up driving these things as you said and start asking people about soldering LiPo’s together, then the neighborly thing to do is to try to keep you from making that kind of mistake, which could certainly be catastrophic.
And as others have said, no question is a dumb question so keep on asking if you’re going to do this. Maybe you’ll surprise all of us.
And start a build thread. That will be the place where everyone can address your questions and we can all share in your progress. Plus, you get a groovy banner.
Welcome to the forum, man!

 

[vwturbowolf]

I’ll try to be constructive and just say that most all of the gearing “apps” are more of a reference tool and are only really able to be accurately used when you e already made passes to compare it with.
Your logs are way more important to use as a tool.

I’ve made hundreds of passes with different cars and setups and know what speeds I’ve run with the speed that I’m geared to in the calculators. So using my average numbers as a reference it helps me gear other setups.
If you want a starting point fill in the missing info:
Motors 2400kv
Voltage 8s
Tire diameter: ?
Diff ratios: 13/43 or 15/42?

Give me the info missing and I’ll get you a starting point

 

[LegacyIV]

Fair enough, man. You’re absolutely correct. Good luck, and keep us posted. I doubt if anyone here wants to see you fail. I don’t. In fairness though, if you grew up driving these things as you said and start asking people about soldering LiPo’s together, then the neighborly thing to do is to try to keep you from making that kind of mistake, which could certainly be catastrophic.
And as others have said, no question is a dumb question so keep on asking if you’re going to do this. Maybe you’ll surprise all of us.
And start a build thread. That will be the place where everyone can address your questions and we can all share in your progress. Plus, you get a groovy banner.
Welcome to the forum, man!

I think we both know what I meant by soldering two different lipos together. I was very clear and explained what I meant. As you can see below positive and negative cables from two different batteries have been soldered together. One part connected by qs8 plug other connected by just the cord. Soldering was used to achieve this.

 

[Diem Turner]

I think we both know what I meant by soldering two different lipos together. I was very clear and explained what I meant. As you can see below positive and negative cables from two different batteries have been soldered together. One part connected by qs8 plug other connected by just the cord. Soldering was used to achieve this.

View attachment 271419

FWIW, they haven't been soldered together. If you look closely you can see the heat shrink and 8mm bullet connectors.

 

[Dan B.]

I think we both know what I meant by soldering two different lipos together. I was very clear and explained what I meant. As you can see below positive and negative cables from two different batteries have been soldered together. One part connected by qs8 plug other connected by just the cord. Soldering was used to achieve this.

View attachment 271419

Like others have pointed out in a couple replies here, they are not soldered, they’re 8mm bullets. People do this to add flexibility to your battery options, as it lets one choose a single, series, or parallel connection (done with a short QS8 harness downstream of the bullets) without being “married” to any single power configuration.
Check out post 17 in this thread, @Jerold provided a really good explanation of how to do it.
Practice with your soldering station, too. 8mm connections are a little trickier to avoid a cold joint just because of the size of them. I’ve always been apprehensive when I do it, it’s definitely challenging. Stresses me out and gives me a headache, lol.

 

[Jerold]

Practice with your soldering station, too. 8mm connections are a little trickier to avoid a cold joint just because of the size of them. I’ve always been apprehensive when I do it, it’s definitely challenging. Stresses me out and gives me a headache, lol.

Straight up bullets are way easier than QS8s. Solder flux helps tremendously for any of the big stuff. For 8mm bullets, just tin your wires with a big soldering tip on the highest heat setting. Then stuff a bunch of solder into the cup, get out your Bernzomatic Butane torch (thanks to @WoodiE for that tip) and go to town. Continue going to town and stuff your wire in there. I have blurb in my build log.
https://www.arrmaforum.com/threads/jerolds-limitless-build.49292/post-703067

The QS8s you have be careful not to melt your plastic. I also use a mating pair to keep it from deforming as well.

 

[LegacyIV]

Ok im back car fully built been driving it the past two days 4s only!! Worked out the kinks i ran into and now ready to go 8s. I was a little hesitant because I'm paranoid about positive and negative connections.

I used the wiring from my charger to make the shorty connecting wires as seen below.

I had already tried this connection and turned on the esc for a few seconds but quickly turned it off because i was nervous and thought it just needed some time to blow up so before it happened i turned it off

As you can see something weird happened on the second attempt and a spark flew out. It happened as soon as i touched the “negative” side of the shorty plug to the battery, didnt get a chance to turn it on this time.

My question is, just because its colored as positive or negative does that mean that cord is now forever that. Or once it's been cut its just wiring with no distinction of being positive or negative regardless of what color it is.

And if this was just a onetime weird occurrence, is it safe to try to connect it again or just resolder a new qs8 plug on it.

 

[Killacam]

Sparks are normal

 

[MLyons]

My question is, just because its colored as positive or negative does that mean that cord is now forever that. Or once it's been cut its just wiring with no distinction of being positive or negative regardless of what color it is.

OP, I beg you do some research on electronics and wiring before you continue. If you continue with this level of knowledge you're going to at best detonate an ESC and worst your house.

 

[chris adams]

That's a very nice build. If you plug somthing in "wrong" you will know immediately. I vaporized a 8mm bullet myself. There is no delay just instant bright light if you do any speed over 100 I wouldn't use hoons. I understand that those are probably there just for the bench.