Electronics meltdown

[SSnowman]

I have a Notorious that I’ve been building for a long time . I installed a spectrum firma 160 amp ESC. I’ve installed a reefs rc Raw 800 Lp servo. This was part of a warranty covered by Horizon , they treated me really well upgrading me for free because the original melted down . I also have a program card for the ESC and I have the programmer for the servo as well. The internal BEC is 8.4v capable and the servo runs on 8.4v . My question is … Do I need to run an external BEC ?

 

[Doom!]

I have a Notorious that I’ve been building for a long time . I installed a spectrum firma 160 amp ESC. I’ve installed a reefs rc Raw 800 Lp servo. This was part of a warranty covered by Horizon , they treated me really well upgrading me for free because the original melted down . I also have a program card for the ESC and I have the programmer for the servo as well. The internal BEC is 8.4v capable and the servo runs on 8.4v . My question is … Do I need to run an external BEC ?

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Me personally, I like a little extra overhead just in case, lets see what the others think.

 

[Dan B.]

It looks like you already have a 10amp UBEC? Set your jumper on it to 8.4v (looks like it’s set to 7.4v now) and connect it to any open slot on your receiver. Be certain to unpin or cut the red power wire from the ESC plug that goes to channel 2 on your receiver. The UBEC will then power your entire receiver and everything that’s plugged into it.
That said, you’d be better off running a separate, dedicated battery for the servo and direct powering it. Servos benefit greatly from a “clean” power source, i.e. a battery, instead of a digitally processed source from a BEC. That servo pulls roughly 7.5amps at 8.4v, and that could tax a 10 amp BEC if you have other things plugged into your receiver like additional fans, lights, etc. Plus, the servo will perform to the potential that you paid for. If you’re interested in taking that route, a simple harness and a very small battery (easy to tuck into the rig) is required. This is what I use, but there are many other options available.
https://www.promodeler.com/HV2SV-X
https://www.amazon.com/BETAFPV-Batt...lipo+2s+receiver+battery+xt30,aps,129&sr=8-19

 

[WickedFog]

I love how Spektrum stuff notoriously doesn't have the required info for stuff like this. But I would run that 10A BEC no problem with that servo. It's only going to hit the 7.5A for short periods, as long as your end points are set correctly. And I best at most, with standard use, it isn't even hitting that under typical load. That 7.5A rating is max load. And since that Spektrum ESC doesn't say what amperage the BEC in it is, all you can do it test it and see what it can handle. But you should be fine with that 10A BEC. Just make sure your endpoint adjustment is set correctly.

Your BEC doesn't currently have any jumper on it, so it is currently set to 6v.

 

[SSnowman]

It looks like you already have a 10amp UBEC? Set your jumper on it to 8.4v (looks like it’s set to 7.4v now) and connect it to any open slot on your receiver. Be certain to unpin or cut the red power wire from the ESC plug that goes to channel 2 on your receiver. The UBEC will then power your entire receiver and everything that’s plugged into it.
That said, you’d be better off running a separate, dedicated battery for the servo and direct powering it. Servos benefit greatly from a “clean” power source, i.e. a battery, instead of a digitally processed source from a BEC. That servo pulls roughly 7.5amps at 8.4v, and that could tax a 10 amp BEC if you have other things plugged into your receiver like additional fans, lights, etc. Plus, the servo will perform to the potential that you paid for. If you’re interested in taking that route, a simple harness and a very small battery (easy to tuck into the rig) is required. This is what I use, but there are many other options available.
https://www.promodeler.com/HV2SV-X
https://www.amazon.com/BETAFPV-Battery-Brushless-Quadcopter-Meteor85/dp/B0BR3K4DJY/ref=sr_1_19?crid=A46FBICOA1NG&dib=eyJ2IjoiMSJ9.zjZMVfoWoWa9_QGYjLWZFzzyEMLrFp2wsMYtGwgP7X7z3BIT0MQcyhqtqFP8g3Zl4X-LZrOsIhyvmhZ-Pspj0WQcyCdu3ulL4o8DBEwRK8H1nWSKbAqW7OfH0-NXCbVLpr5vI03ESjpQfkPbRVxYLwoVc7t3jhn8KL2kTRn-9qYamkj3-Nyj2f3eE5-TRORzL4ayHZarpMwSNW3yKFuQUUhBe6GE-uz7LwHyxTLQS1iayKdcsYh5XAZ3r9tMzyoFAwsPGJyI8TaLAXeZ8w0w_-mdQ659V9Bslh30RE4OlhxsQBgf65vGjPx1KxhgNpSj9Fu7_LqRko2q18d1L269TFYVxJ3va5ydlL3IyTJJhkHK9LYkUJsrh3qizx8CM5tJqneu5lS4nDkBrrWPYJOrrkjLH_CjceFqgDuRyTnjgqs_8YjPAb4vu5uVj3x24Omq.Ei2jNaPsGUlKu-bumpwGfyfBhRgP0c3uQAj6KY2JtCI&dib_tag=se&keywords=LiPo+2s+receiver+battery+xt30&qid=1741131354&sprefix=lipo+2s+receiver+battery+xt30,aps,129&sr=8-19

I like that idea…. Beingi use 2 3s batteries stacked so using a ubec would be complicated because it would only draw power from one battery so they would have to be rotated constantly. This is why I was sceptical running it in the first place . I plan on in the future grabbing a couple 6s batteries but I have lots of 3s so why spend more money. Just to but the wire and the IC5 connectors is more expensive than a pair of 2s batteries and I already have a bunch . Thanks man!

 

[SSnowman]

I love how Spektrum stuff notoriously doesn't have the required info for stuff like this. But I would run that 10A BEC no problem with that servo. It's only going to hit the 7.5A for short periods, as long as your end points are set correctly. And I best at most, with standard use, it isn't even hitting that under typical load. That 7.5A rating is max load. And since that Spektrum ESC doesn't say what amperage the BEC in it is, all you can do it test it and see what it can handle. But you should be fine with that 10A BEC. Just make sure your endpoint adjustment is set correctly.

Your BEC doesn't currently have any jumper on it, so it is currently set to 6v.

The jumper pin is in the bottom of the box

 

[Dan B.]

I like that idea…. Beingi use 2 3s batteries stacked so using a ubec would be complicated because it would only draw power from one battery so they would have to be rotated constantly. This is why I was sceptical running it in the first place . I plan on in the future grabbing a couple 6s batteries but I have lots of 3s so why spend more money. Just to but the wire and the IC5 connectors is more expensive than a pair of 2s batteries and I already have a bunch . Thanks man!

Just something else, every time I use a UBEC to power a receiver I always solder the UBEC power inputs directly to the battery inputs of the ESC. As long as you run a UBEC that can take 6 or 8s input voltages you’re golden and don’t need to worry about flipping batteries around or (worse) powering it or anything else from the balance leads of your LiPo’s.

 

[SSnowman]

It looks like you already have a 10amp UBEC? Set your jumper on it to 8.4v (looks like it’s set to 7.4v now) and connect it to any open slot on your receiver. Be certain to unpin or cut the red power wire from the ESC plug that goes to channel 2 on your receiver. The UBEC will then power your entire receiver and everything that’s plugged into it.
That said, you’d be better off running a separate, dedicated battery for the servo and direct powering it. Servos benefit greatly from a “clean” power source, i.e. a battery, instead of a digitally processed source from a BEC. That servo pulls roughly 7.5amps at 8.4v, and that could tax a 10 amp BEC if you have other things plugged into your receiver like additional fans, lights, etc. Plus, the servo will perform to the potential that you paid for. If you’re interested in taking that route, a simple harness and a very small battery (easy to tuck into the rig) is required. This is what I use, but there are many other options available.
https://www.promodeler.com/HV2SV-X
https://www.amazon.com/BETAFPV-Battery-Brushless-Quadcopter-Meteor85/dp/B0BR3K4DJY/ref=sr_1_19?crid=A46FBICOA1NG&dib=eyJ2IjoiMSJ9.zjZMVfoWoWa9_QGYjLWZFzzyEMLrFp2wsMYtGwgP7X7z3BIT0MQcyhqtqFP8g3Zl4X-LZrOsIhyvmhZ-Pspj0WQcyCdu3ulL4o8DBEwRK8H1nWSKbAqW7OfH0-NXCbVLpr5vI03ESjpQfkPbRVxYLwoVc7t3jhn8KL2kTRn-9qYamkj3-Nyj2f3eE5-TRORzL4ayHZarpMwSNW3yKFuQUUhBe6GE-uz7LwHyxTLQS1iayKdcsYh5XAZ3r9tMzyoFAwsPGJyI8TaLAXeZ8w0w_-mdQ659V9Bslh30RE4OlhxsQBgf65vGjPx1KxhgNpSj9Fu7_LqRko2q18d1L269TFYVxJ3va5ydlL3IyTJJhkHK9LYkUJsrh3qizx8CM5tJqneu5lS4nDkBrrWPYJOrrkjLH_CjceFqgDuRyTnjgqs_8YjPAb4vu5uVj3x24Omq.Ei2jNaPsGUlKu-bumpwGfyfBhRgP0c3uQAj6KY2JtCI&dib_tag=se&keywords=LiPo+2s+receiver+battery+xt30&qid=1741131354&sprefix=lipo+2s+receiver+battery+xt30,aps,129&sr=8-19

So if I get the harness and a separate power supply there is no need for the UBEC correct?

 

[Dan B.]

So if I get the harness and a separate power supply there is no need for the UBEC correct?

Yes, the direct power servo harness and any 2s battery with an EC3 connector. And most of those batteries I use are much smaller that a pack of smokes and last for three or more packs before you have to recharge them.

 

[WickedFog]

So if I get the harness and a separate power supply there is no need for the UBEC correct?

If I am understanding this correctly, you're running that on 6S? And you're thinking you can run the servo off one pack? If so, there is no way for you to wire that servo into one of the batteries. Without the built-in BEC powering the servo, or an external BEC doing so, you'll fry that servo almost instantly running it on 3s power (12.6v). You have everything you need to power that servo perfectly with either the ESC's internal BEC (if it can deliver 8A at least) or use the external BEC. Remove the + Pin from the JR connector of the lead going from the ESC to the Rx. Tape that removed wire back onto itself in the lead so it doesn't contact anything. Then connect the positive lesd from the BEC to your + battery wire, or the + battery input on the ESC. Same for negative wire. Connect it the negative lead.

You don't even need a new connector. Just cut a little portion of the input leads' shielding out and solder the BEC in, then covery your surgery with liquid tape.

 

[SSnowman]

Yes, the direct power servo harness and any 2s battery with an EC3 connector. And most of those batteries I use are much smaller that a pack of smokes and last for three or more packs before you have to recharge them.

Thanks dude

 

[SSnowman]

If I am understanding this correctly, you're running that on 6S? And you're thinking you can run the servo off one pack? If so, there is no way for you to wire that servo into one of the batteries. Without the built-in BEC powering the servo, or an external BEC doing so, as you'll fry that servo almost instantly running it on 3s power (12.6v). You have everything you need to power that servo perfectly with either the ESC's internal BEC (if it can deliver 8A at least) or use the external BEC. Remove the + Pin from the JR connector of the lead going from the ESC to the Rx. Tape that removed wire back onto itself in the lead so it doesn't contact anything. Then connect the positive lesd from the BEC to your + battery wire, or the + battery input on the ESC. Same for negative wire. Connect it the negative lead.

You don't even need a new connector. Just cut a little portion of the input leads' shielding out and solder the BEC in, then covery your surgery with liquid tape.

if you were me exactly what would you do ?

 

[Dan B.]

Thanks dude

You’re welcome, man. Anytime.

 

[WickedFog]

So you're going to get at best 8.2v for a very short period running that servo on a 2s battery, then the battery voltage will drop quickly and level off somewhere in the 7+v range.

Or you could do as I suggested and simply wire in the BEC you already have and get a consistant 8.4v across the run time

 

[WickedFog]

if you were me exactly what would you do ?

Run the external BEC and be done with it.

 

[SSnowman]

You’re welcome, man. Anytime.

So just to clarify you would run a harness and batteries to power the servo and don’t bother hooking up the UBEC?

 

[SSnowman]

So you're going to get at best 8.2v for a very short period running that servo on a 2s battery, then the battery voltage will drop quickly and level off somewhere in the 7+v range.

Or you could do as I suggested and simply wire in the BEC you already have and get a consistant 8.4v across the run time

You’re right . To wire it would you just simply slice into the wires going into the ESC ? That seems to be the simplest.

 

[Dan B.]

So just to clarify you would run a harness and batteries to power the servo and don’t bother hooking up the UBEC?

That’s my preferred way to do it. I just let the ESC’s built in BEC power the fans and lights through the receiver, as they are pretty low amp-draw items. For the amp-hungry servos, I direct power the servo only with a small dedicated battery. Not only does the servo perform much better on that clean power source, it also eliminates the possibility of brownouts on your receiver.

 

[SSnowman]

That’s my preferred way to do it. I just let the ESC’s built in BEC power the fans and lights through the receiver, as they are pretty low amp-draw items. For the amp-hungry servos, I direct power the servo only with a small dedicated battery. Not only does the servo perform much better on that clean power source, it also eliminates the possibility of brownouts on your receiver.

Thanks , everyone has different opinions , some guys are saying a separate power supply will only run a very short time and use a Bec , Too many chiefs not enough natives , lol. I hear what you’re saying dude. I’m gonna try it.

 

[WickedFog]

You’re right . To wire it would you just simply slice into the wires going into the ESC ? That seems to be the simplest.

Yes.

Even if you're running 3 fans (.1A each maybe), and 10 LED's (.02A typically), and that servo (7.5A), at most you're pulling maybe .3A + .2A + 7.5A = 8.0A. You're still well within that external BEC's amp draw rating.