louder Posted July 23, 2014 Share Posted July 23, 2014 (edited) Hey, I just wondered how many of you guys run an external BEC opposed to the one in your ESC? I was poking around some servos today and I saw a few that can run at a pretty high voltage and wondered if it's worth running them at that rate as opposed to through the ESC BEC. That way getting the most out of the servo. My main reason for asking is I have never thought about the voltage my servo is running at. It has just never really occurred to me that it might not be running at 6v it might be running at 4v. Edited July 23, 2014 by louder Quote Link to comment Share on other sites More sharing options...
Noj Posted July 23, 2014 Share Posted July 23, 2014 Most receivers run on 6v, as do the majority of servos. Running a separate bec is advisable for certain applications (crawlers, HV set ups, savox servos), however, up the voltage and lesser servos and the Rx will burn out. What vehicle are you proposing to fit the bec to? Quote Link to comment Share on other sites More sharing options...
louder Posted July 23, 2014 Author Share Posted July 23, 2014 (edited) My new D3. I am just looking at a the Savox SC-1252MG. I want the steering to be as quick and responsive as possible so I am thinking it might need a separate one? I am actually looking for new radio gear so I'm now checking all the rx's. Just trying to find the BEC output on my ESC currently. EDIT: My ESC has a 6v BEC. I thought it would do after what you said but I just wanted to make sure. Edited July 23, 2014 by louder Quote Link to comment Share on other sites More sharing options...
Tamiyacowboy Posted July 23, 2014 Share Posted July 23, 2014 (edited) TBH i think these days if your a basher/drifter/largescaler you should be running an external BEC unit if your a racer, weight counts so you maybe able to run without any weight limit extras added using an external bec but 9-10 will just feed from the esc and hope/pray it holds out on the hard throttles. if the esc goes poop so does your rx signal when the receiver has no power. external bec you got no problem. crawlers have servo hold issues, where you just aint got enough amps from the esc to feed the servos needs, this shows as sluggish steering or smokey rx/esc syndrome. so better to run a dedicated bec and draw all the power you need from it. this leaves the esc with less strain on its internal controller and you get the full meat n potates you paid for. ESC is just a oversized voltage regulator/current regulator , BEC is just a smaller version , its real name is a buck converter, it takes a higher voltage and drops it down to a safe voltage at the same time it regulates the voltage and current to safe levels. you may have pulled things apart and notice like on an esc a small black semiconductor looks like a letter D with three legs on it. these are regulators, they take the 12v comming into one leg pin and regulate it to 5v on a second pin , the third pin is a ground. the little regulators have an max in voltage, so here we could use 2s-3s or even 4s battery and it will NOT go above the output voltage of say 5v, but this conversion needs to loose 7v somewhere and they do that via heat, they get hot so have a big heatsink ( your esc is a big heatsink ). Edited July 23, 2014 by Tamiyacowboy Quote Link to comment Share on other sites More sharing options...
Noj Posted July 23, 2014 Share Posted July 23, 2014 Advisable to run a bec for a savox, alternatively, you can run a power cap straight from the Rx. A savox at a full 6v is still a powerful servo, don't get too hung up on 7.4v Rx's... Just ensure you wire the bec in correctly, removing the red pin from the ESC to Rx lead Quote Link to comment Share on other sites More sharing options...
louder Posted July 23, 2014 Author Share Posted July 23, 2014 Ok thank you. Yes I now need to do some research on wiring! Are all BEC's pretty much the same? Will any BEC work? I know very little about them. Quote Link to comment Share on other sites More sharing options...
atom3624 Posted July 23, 2014 Share Posted July 23, 2014 You need to check it can handle your maximum expected voltage and current, or no, there are different ones. Check out the Castle Creations ones for ideas. Al. Quote Link to comment Share on other sites More sharing options...
louder Posted July 23, 2014 Author Share Posted July 23, 2014 Hmmmm OK. I need to go and do some reading up! Thanks guys. Quote Link to comment Share on other sites More sharing options...
Tug Posted July 23, 2014 Share Posted July 23, 2014 HK do one that's fine for 1/10 & 1/8 applications. 5 Amp, 5 and 6 volt output. I use these in quite a few of my rigs, never had an issue with them. Quote Link to comment Share on other sites More sharing options...
louder Posted July 23, 2014 Author Share Posted July 23, 2014 Which one is that? I am currently looking at the CCBEC. They don't seem too difficult to wire in. Quote Link to comment Share on other sites More sharing options...
Tug Posted July 23, 2014 Share Posted July 23, 2014 This one, comes with a switch harness too, which is handy. http://www.hobbyking.com/hobbyking/store/__6320__TURNIGY_5_7_5A_8_42v_HV_UBEC_for_Lipoly.html This is one I recently got, seems fine, no complaints from me. http://www.hobbyking.com/hobbyking/store/__10313__Turnigy_5A_8_40v_SBEC_for_Lipo.html Quote Link to comment Share on other sites More sharing options...
louder Posted July 23, 2014 Author Share Posted July 23, 2014 (edited) Thanks 7.5A would be more than enough. Will the lipo cutoff on my ESC will still function with a BEC installed? Edited July 23, 2014 by louder Quote Link to comment Share on other sites More sharing options...
Tug Posted July 23, 2014 Share Posted July 23, 2014 Yup, that's totally separate. The first one comes with a lead that you can use on OPTO ESCs. These are ESCs with no BEC, the lead has a resistor on the red cable, the resistor keeps the voltage passing through it to 5.75 volts. If you place this lead between the Rx and the ESC and disconnect the red pin from the plug end, this means you don't need to disconnect the red pin on the ESCs Rx plug. This is handy for when you want to plug your ESC into a pit-card, but can't until you've reconnected the red pin. Now you don't have to do that because the ESCs Rx plug still has all three cables attached. Is that making sense? Quote Link to comment Share on other sites More sharing options...
louder Posted July 23, 2014 Author Share Posted July 23, 2014 Yes sort of. I have had to re read it about 4 times but I think I understand. Basically as opposed to pulling the wire out of the ESC RX connector I would be pulling it out of the extension cable. Then just unplug the extension when I want to use a pit card. Seems simple enough. My main concern initially was comparing it to the CCBEC as it only had 2 wires leaving, of course you don't program the BEC through a link like the CC one so it doesn't need that extra power. My other question was, while it has a power switch on it, surely thats only for the receiver and servos? Won't the motor and ESC be turns on all the time? Quote Link to comment Share on other sites More sharing options...
Tug Posted July 23, 2014 Share Posted July 23, 2014 No, the switch allows you to connect cells, lid on and walk or drive to bash spot. Then reach under lid and switch on uBEC first to power up the Rx and servo. Then turn on ESC to power up the car. Quote Link to comment Share on other sites More sharing options...
louder Posted July 23, 2014 Author Share Posted July 23, 2014 Ok, that seems sensible. Thanks for all the advice. It's on my list to order for my new kit. Quote Link to comment Share on other sites More sharing options...
Tug Posted July 23, 2014 Share Posted July 23, 2014 My preferred installation method is to solder some small cables to the main battery cables of the ESC. On the ends of these I solder 2mm female bullets. Colour code accordingly. Job done. On the uBEC itself I solder the male bullets and colour accordingly. This then plugs together and you're good to go. Quote Link to comment Share on other sites More sharing options...
ninjagaiden Posted July 23, 2014 Share Posted July 23, 2014 +4 on the Turnigy 7.5A BEC. I run two in my 1:5 cars because the Castle XL2 BEC is weak, one on my Savage Flux Xl which has an OPTO-ESC with no BEC, and one on my Crawler which has 4WS. Zero issues with them. If you are fond of your Savox'es then maybe pick up a few! Quote Link to comment Share on other sites More sharing options...
louder Posted July 23, 2014 Author Share Posted July 23, 2014 Well I have the Savox on it's way and have ordered 2 BECs. One for my new build and one for my mini revo. I run 2 Savox micros in there and I have noticed latency issues with them responding under full throttle or after the model has been run for a while and starts to get hot. I was planning on just using a Y splitter from the battery. Quickly solder up what is essentially a parallel Y splitter and attach the single side to the battery and one of the splits to the ESC and the other to the BEC. That way I can easily remove it should something go wrong such as either unity fail. Plus I can then use varying lengths so I can move it around, this is especially important on my drift chassis. I am currently thinking about covering large sections of the chassis is velcro and then putting velcro on the underside of the components. That way I can move stuff around till I find it balanced. Also it will be a lot easier for chassis strip downs between events as the electronics just unplug and rip off the chassis. I have never tried it but I remember back when the B2 was popular lots of guys at the club near me doing it. Quote Link to comment Share on other sites More sharing options...
ninjagaiden Posted July 23, 2014 Share Posted July 23, 2014 I usually wire my BEC to the ESC, as it's likely to move with the ESC itself. I strip a small length of wire on the input cables of the ESC and wind the BEC inputs round them, solder them and sleeve them. Keeps the wiring tidy. Quote Link to comment Share on other sites More sharing options...
louder Posted July 23, 2014 Author Share Posted July 23, 2014 Ok brilliant thank you. I still have to wait for my new soldering iron for my birthday off the SO. (At least I think that is what she is getting me) At the moment I only have a 7w touch up I use for PCBs Not too worry though, it gives me time to build the kit! Quote Link to comment Share on other sites More sharing options...
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