two fxr's two 3amp bec's why run an external

[Harley]

Originally Posted by bigemike

There obviously is not much manufacturer support on this site. I have a message into the president of tekin, I am sure I can get a legit answer from him I will post it up on here when I am get a reply.

Please don't clog up my thread, your opinion are on here. Hopefully someone who actually works for the company can post a good reply.

There is actually a lot of manufacturer support here. However one of the main reasons they are here is to LEARN FROM US about their products and how to improve them. Even big R&D teams couldn't put in as much testing as this community does. If you had any idea how many changes the feedback from members of this forum has caused you would you would reword your smartass posts and learn from those of us that have been doing this for a lot longer then you.

All of us would love to not have to run an external BEC. Maybe you haven't seen that some of us are shaving the rubber off the tires to help lose another 2g of weight. If simply getting rid of a BEC was possible we would do it for a shear weight factor

Originally Posted by SMR 510RR

Its also important to note that the amp rating of a BEC changes with the input voltage, higher the voltage the lower the amp output the BEC is capable of.

A CC 10A BEC is rated at 7a with a 12v input (roughly operational voltage of a 3s lipo). I dont want to know what a 3 or 5a BEC would actually put out when running a 3s pack, this is the reason why there is a need for a better BEC when you increase input voltage.

The reason why your boat is fine running on 4s with the internal BEC is because there is a lot less load on the servo. When is the last time your rudder got stuck between two rocks and you had to wiggle it free?

Don't speak this gibberish! He has an electronics degree!

[The Violator]

I say connect them both together. You will be fine. A BEC is over rated. Just make sure when you do connect them and fire up this bad boy please use a go pro and get the video of you proving your theory right. No video, no proof it worked.

[bigstu]

I still want to know what he had for dinner.

I agree with Violator, plug both red wires in and take your XR10 for a drive. See how long it lasts.
But I want to see the video and see the reaction on your face when you let the smoke out..

I love $50 discussions for a $20 part..
Hope you can get a refund on that electronics degree...

[bigemike]

Man you guys take it all wrong, i wasn't trying to be a smartass and wasnt bragging about a degree. I was simply asking why and it seems i have offended the people that could answer it with intelligence. It just seems alot of people here do what the top guys do without thinking for themselves. Harley i respect your knowledge. There where a few other posts that made sense. But the guys who say it doesnt give 6amps of output dont know what they are talking about.

So to summarize in theory i do get 6amps, but it is not advised because one esc could pick up the load and burn it out. Pretty straight forward. Why we had to go through all 4 pages to get to a real answer is beyond me.

Its like hey there is a new guy asking a real question lets jump up and down on it and see if he will leave.

Also if the manufacter built the bec circuits in a way they would join together it would make the bec circuit stronger thusly eliminating the need for the castle bec and saving weight. Maybe tekin could chime in and let us know how thiers is built. Because i think everyone would benefit if it worked.

Again i apologize if i pissed anyone off.

Sent from my SGH-T989 using Tapatalk 2

[bigemike]

From my inbox at rctech from Randy Pike at Tekin

Bigemike wrote:
I am running dual fxr in my new crawler and I have a question regarding bec's

if both esc have a 3 amp bec does that give me 6 amp of bec current. If I had to 5 amp power supplies i could parallel them and get 10 amps of current.

also is it needed to pull the red wire from one esc? if so can you explain why this is, it kinda goes against everything I have ever learned about electrics and current. Just trying to understand what needs to happen and why. Thanks a bunch.

Randy Pike wrote:
Mike in theory you're correct. Two 3 amp bec's would be 6 amps.

What are your actual concerns though?

Bigemike wrote:
will I need a castle bec to run a strong servo in my crawler, will I burn something out if my draw goes over 3 amps

Randy Pike wrote:

Well look at it this way. 6 amps has to be spread across the entire rig. So radio, servo, esc,etc.

Most go to a separate BEC for JUST the servo since it's so important to the performance of the crawler...

[bigemike]

So two fxr's = 6 amps of bec power

The only need for an external bec is when you want to raise the voltage for the servo. So everyone running an external bec set to factory defualts and running 2 fxr speedo's are carring extra weight for nothing.

rofl, lol lol lol

And you guys give me a hard time. I just saved you a bunch of weight.

[AreCee]

I just disconnect my power leads to the ESCs and run 7.5V to everything via the external BEC. I'm using both a High Voltage receiver and servo so even with the combined ESC BECs I wouldn't have the voltage desired.

Also using a 3 cell reduces the current output of the ESC's BEC.

[Ty@Tekin]

Originally Posted by bigemike

how do you come up with that, if you have two 3a power sources hooked in parallel then your total capacity for current draw is 6amps, sorry duuuuuuude but you are just plain wrong go back to electronics 101.

I can't believe how backwards some people are on here about electronics.

Also it is a regulated power source so no external bec is needed for 3s. I run 4s with speedo's in my boats with no external bec.

Just put a bec on everything, don't worry about it.

There obviously is not much manufacturer support on this site. I have a message into the president of tekin, I am sure I can get a legit answer from him I will post it up on here when I am get a reply.

Please don't clog up my thread, your opinion are on here. Hopefully someone who actually works for the company can post a good reply.

We are on here most of the time, just not at 7-10pm.

Theoretically the two BECs will work together and always be balancing each other out. Plugging them both into the receiver won't give anymore voltage than just one or the other. But, the proper thing to do is put the external BEC on anyways. It's easier on the ESCs, plus if the BEC fails (which they do) it is more easily replaced and cheaper than a new FXR.

Yes they are regulated, but as voltage goes up, the amperage the BEC can supply goes down. If you're running 3S, no question you need an external that can provide a higher amperage.

[Ty@Tekin]

Originally Posted by AreCee

I just disconnect my power leads to the ESCs and run 7.5V to everything via the external BEC. I'm using both a High Voltage receiver and servo so even with the combined ESC BECs I wouldn't have the voltage desired.

Also using a 3 cell reduces the current output of the ESC's BEC.

On paper it equals 6 amps, but that drops quite a bit when you up the voltage to 3S. So you really aren't getting full potential, you've got two mediocre power supply's at best.

[klabeaume]

Originally Posted by Ty@Tekin

We are on here most of the time, just not at 7-10pm.

Theoretically the two BECs will work together and always be balancing each other out. Plugging them both into the receiver won't give anymore voltage than just one or the other. But, the proper thing to do is put the external BEC on anyways. It's easier on the ESCs, plus if the BEC fails (which they do) it is more easily replaced and cheaper than a new FXR.

Yes they are regulated, but as voltage goes up, the amperage the BEC can supply goes down. If you're running 3S, no question you need an external that can provide a higher amperage.

Wait, But he just told me I wasted my money and added unnecessary weight. And he has a degree.

[bigemike]

Ok, so you are working with roughly 2 amps ea at 3s

And why is everyone such an a$$ on here, I was simply trying to understand, and I was stating I had a degree so that if someone wanted to be technical in thier response they new I could understand what they are saying.

I got annoyed when the first person called me an idiot basically for saying that the amperage added when you plugged both in at the same time.

Then you get people talking out thier ass and I get more annoyed, It has been stated that it is fine to run with both plugged in. It was stated early on in here that that was a no no.

It is stated that it does double the bec when you plug in two esc

All of the people that stated I was crazy on the first page of this now what, I was simply trying to help you guys out, because obviously not everyone has a good understanding and is just adding a bec.

I like to know why I am adding every part that I buy for my stuff. Not just buy it because someone told me to.

do you know how many times I have seen a kid at a hobby shop waste a racers money selling him a bunch of stuff they don't need.

[klabeaume]

Originally Posted by bigemike

I am thinking people are just doing as they have always done, lol

I have a degree in electronics, so I am 100% sure on my logic.

Originally Posted by bigemike

I could be 100% wrong but still 100% sure, lol

Originally Posted by bigemike

sorry duuuuuuude but you are just plain wrong go back to electronics 101.

I can't believe how backwards some people are on here about electronics.

Just put a bec on everything, don't worry about it.

There obviously is not much manufacturer support on this site.

Please don't clog up my thread, your opinion are on here. Hopefully someone who actually works for the company can post a good reply.

Originally Posted by bigemike

wow why even clog the thread with all the useless posts

Originally Posted by bigemike

running 2 fxr speedo's are carring extra weight for nothing.

rofl, lol lol lol

And you guys give me a hard time. I just saved you a bunch of weight.

Originally Posted by bigemike

And why is everyone such an a$$ on here.

Good question...

[Duuuuuuuude]

Originally Posted by bigemike

And why is everyone such an a$$ on here, I was simply trying to understand, and I was stating I had a degree so that if someone wanted to be technical in thier response they new I could understand what they are saying.

I got annoyed when the first person called me an idiot basically for saying that the amperage added when you plugged both in at the same time.

Then you get people talking out thier ass and I get more annoyed, It has been stated that it is fine to run with both plugged in. It was stated early on in here that that was a no no.

It is stated that it does double the bec when you plug in two esc

All of the people that stated I was crazy on the first page of this now what, I was simply trying to help you guys out, because obviously not everyone has a good understanding and is just adding a bec.

I like to know why I am adding every part that I buy for my stuff. Not just buy it because someone told me to.

do you know how many times I have seen a kid at a hobby shop waste a racers money selling him a bunch of stuff they don't need.

First, and to be fair, there is nothing wrong with asking questions. It is reasonable to wonder why we need becs when there is (theoretically) twice the power available when running two escs.

Second, people are being asses because you are under the assumption that we don't know what we're doing, but you do because you know theory. Also because there is quite a bit of overblown self importance in your posts. An email to the President of Tekin? Really?

Can you connect two becs together? Sure. Will they work happily together? No. Not unless they were designed to do so. There are more that a few threads where people have tried it and it has caused nothing but problems.

Something you will find here is that most people do not have the wanna-be racer mentality. People use things that work because they work, not because Mr. Superstar Crawler Guy won Nats with it last year. Products gain popularity here because they do their job and have value, not because they are flashy. If that weren't true we'd all be running MaxAmps batteries and Integy alloy bling.

When you enter the crawler world, its best to leave all prior experiences at the door. Race cars, boats, helicopters, and planes have very little in common with our rigs.

[SMR 510RR]

From my experience of being on here for a while a BEC is just required unless your servo is 200oz or under (general guideline). This has been proven by countless threads where the resolution was adding a BEC.

I dont think anyone here is giving you a hard time about asking, at first it was going smoothly then it took a turn for the worst when you said that we dont know what we are talking about. You have to remember that you have a higher proficiency with electronics than we do and while we know something wont work we may not be able to explain to you in enough detail to satisfy your desire for an answer.

From the information I have read and that has been already posted it still seems that two 3a bec's that are not working together would still only provide you with 3a of power. If one BEC is taking all the load and the other is doing nothing because it is sensing the proper voltage then the second BEC is not adding any additional amperage to the equation. I could be wrong but it makes sense to me.

Also I think what complicates the BEC equation even more is mixing brands. If you plug a CC BEC in and dont pull the red wire from your esc (assuming it is a different brand and the BEC is setup differently) then they really have a power struggle and typically the ESC takes a dump on you. I could be persuaded that two of the same ESC's BECs would have less of a fight becuase some people are not pulling one of the red wires even though for piece of mind I still suggest it.

[AreCee]

Originally Posted by Ty@Tekin

On paper it equals 6 amps, but that drops quite a bit when you up the voltage to 3S. So you really aren't getting full potential, you've got two mediocre power supply's at best.

Precisely why I use an external BEC to pump up the voltage to 7+Volts which the internal BECs cannot do especially on 3S.

[ninja turtle]

i think my sig belongs here.

[bigemike]

again sorry if I come off being an ass, I have been accused of that before, I was really just trying to help.

I still feel that you could prolly get by with powering any 1 servo at 6volts with the dual esc's. I am just going to try it and find out.

There are alot of problems with for example the MMP that you would never see out of a tekin product. But if the Tekin guys say you can run it together, then it should be ok.

Eventually this will all be a non issue I want one of the big dog futaba high voltage servos.

Hopefully no hard feelings, sorry I come off wrong with my posts, not really my intention.

[bigstu]

I will say this, it takes a big person to admit when they were wrong and I personally appreciate the humility it takes to do that.
Second thing to be said, when you come on this forum, you are going to get the personal experience of people that have been crawling since before there were crawler kits. They have years of practical experience that can not be measured.
There are tons and tons of threads on this forum that talk about what worked when crawling.
There are even more that tell you what someone tried and didn't work, in fact there are some impressive pictures of the fails on here.
So when you express your opinion you have to keep that in mind.

I have a Bachaelors of Science in Mechanical Engineering and have been working as an engineer for more than 10 years.
That means I can calculate the strength of materials, and tell you how something is going to fail, before it does.
The things people accomplish on this forum defy some of those calculations and they are accomplishing things that analytical science would simply shake their head at. The analytical and practical experience must blend together to make something that works. Either will fail on their own.
And why do I suddenly sound like confusious?
So, Kevin what did you end of having for dinner last night?

[bigemike]

lol, I don't know about keving but I went to pappadueax and had a food orgasm eating king crab and bananna pudding

[klabeaume]

Originally Posted by bigstu

So, Kevin what did you end of having for dinner last night?

Well put Stu!

Oh and I had a pepperoni and bacon pizza, chicken wings and breaded and fried cheddar cheese balls with ranch.

In all seriousness, I don't consider myself an "ass" there are a few people on here that take stuff too seriously but I was trying to help and maybe learn a thing or two myself. After all this was a tech thread and you can't tell people the can't post their opinion. I pay $100 bucks a site to this year and I'll post up if I want to. People here want to help but you came off as a jerk. I respect your apology and I hold zero hard feelings. I know first hand that it's really hard to read into text with no tones. Happy crawling.