XT60 or XT90 on 6s
- Thread starter crcr
- Start date
Either should work. Remember what determines connector conductor size is current, not voltage. In a 6S aircraft voltage is high(er), (22.2V), therefore, for a given level of power, (measured in watts), current is halved vs. a lower voltage. I'm certain either connector will stand double or triple their rated current for short bursts, like a rapid climb out. I've seen numerous large aircraft shipped with 60s. I use Anderson Power Poles, which are a another animal all together.
ChrisViperM
Active Member
As a rule of thumb....1S - 4S = XT60, 5S and above = XT90. You can't go wrong with that, and that way it's easy to have LiPos interchangable between different Copters. I do that for a long time now....never ever had a connector related problem. There are people who can write up a 50 pages scientific novel about LiPo connectors.....but I always stay with KISS.... K eep I t Stupid Simple
Chris
Chris
R_Lefebvre
Arducopter Developer
I basically just look at how many amps it's going to draw. The ultimate KISS. 
Those numbers tell you the amps. XT60 is rated at 60, but can spike a little higher. So a quad with 4 20A ESC's, I just use XT60. On my Octo with 8 25A ESC's, I use an XT90. I use an XT90 on my large heli with a 120A ESC.
Those numbers tell you the amps. XT60 is rated at 60, but can spike a little higher. So a quad with 4 20A ESC's, I just use XT60. On my Octo with 8 25A ESC's, I use an XT90. I use an XT90 on my large heli with a 120A ESC.
Bartman
Welcome to MultiRotorForums.com!!
i'm using XT60's with an eight motor heli running at 14 pounds.
power is volts X amps, you only halve the amps if you double the volts which would be the case if you're going from 3S to 6S packs. bigger cell count packs with higher voltages run at lower amps (typically, unless you're running monster heli's and if that's the case then you'd better know what you're doing!! ) so wiring and connectors can stay small saving weight. when i switched to 6S packs from 4S packs I actually reduced wire sizes and went from 40A ESC's to 30A ESC's.
If there's an max amp rating associated with a connector or electrical device you have to know what the corresponding voltage is for the rating or it doesn't really mean anything as it's the total power being transferred that establishes a limit on something and the limit is basically how mush heat it can take without its performance degrading. with wire, for example, the current/voltage limits are going to prevent the wire from heating up which causes resistance of the wire to increase which creates higher voltage drop across the length you're using. abuse the limit too much and the wire can melt or desolder from components.
someone please correct me if I'm wrong but this is how i've come to understand this stuff.
for example, to size wires correctly you have to look at the limits on how much current can be passed for a given size and length of wire but the rating has to also correspond to the voltage you're running. With 6S packs running at 22.2 volts there are 24 volt wire sizing charts that provide the info. For 3S or 4S packs there are 12V charts but since 4S is 14.8 volts you just have to be more conservative than the charts to be able to use them. the connector should be suitable for the size wire you're using, it doesn't make sense to use a 5mm connector with 16 awg wire.
keep in mind also that big connectors weigh more than small connectors and weight matters in every decision you make for you gear so don't use big connectors just because you think you have to for big batteries. take the time to understand what's happening and make smart decisions.
power is volts X amps, you only halve the amps if you double the volts which would be the case if you're going from 3S to 6S packs. bigger cell count packs with higher voltages run at lower amps (typically, unless you're running monster heli's and if that's the case then you'd better know what you're doing!!
) so wiring and connectors can stay small saving weight. when i switched to 6S packs from 4S packs I actually reduced wire sizes and went from 40A ESC's to 30A ESC's. If there's an max amp rating associated with a connector or electrical device you have to know what the corresponding voltage is for the rating or it doesn't really mean anything as it's the total power being transferred that establishes a limit on something and the limit is basically how mush heat it can take without its performance degrading. with wire, for example, the current/voltage limits are going to prevent the wire from heating up which causes resistance of the wire to increase which creates higher voltage drop across the length you're using. abuse the limit too much and the wire can melt or desolder from components.
someone please correct me if I'm wrong but this is how i've come to understand this stuff.
for example, to size wires correctly you have to look at the limits on how much current can be passed for a given size and length of wire but the rating has to also correspond to the voltage you're running. With 6S packs running at 22.2 volts there are 24 volt wire sizing charts that provide the info. For 3S or 4S packs there are 12V charts but since 4S is 14.8 volts you just have to be more conservative than the charts to be able to use them. the connector should be suitable for the size wire you're using, it doesn't make sense to use a 5mm connector with 16 awg wire.
keep in mind also that big connectors weigh more than small connectors and weight matters in every decision you make for you gear so don't use big connectors just because you think you have to for big batteries. take the time to understand what's happening and make smart decisions.
Last edited by a moderator:
R_Lefebvre
Arducopter Developer
Yeah, sorry, that's wrong. For wiring and connectors, amps is what matters, not Watts. Amps are what create heat because of the resistance. The voltage only needs to be considered in terms of the insulation quality. At some voltage, it will allow current to go through, but this is probably very much higher voltage than what we're dealing with. The motor winding insulation will fail much earlier than the power wiring will.
Motors, however, do have Watt limits. This is because they have to deal with heat not only because of current flow, but also because of inductance.
Motors, however, do have Watt limits. This is because they have to deal with heat not only because of current flow, but also because of inductance.
R_Lefebvre
Arducopter Developer
Not for wires. It's simple resistive heating due to current. Volts don't matter.
This is not true for all electrical components. But for wiring and connectors, yes.
This is not true for all electrical components. But for wiring and connectors, yes.
Hi, I agree amps are the important thing regarding wires or connector size, but not necessarily the ESCs' capacity that you are using.
For example the F550 (stock) has 6 x 30 amp ESCs' that equals 180 amps total and bears absolutely not relationship to the actual max. amps the 6 stock motors draw at max. capacity.
Mine at hover (4S) draws about 20 amps, at full throttle about 50 amps. Now 14 AWG cable/wire (at 14 volts) with a 3% loss (voltage drop) over a length of 0.3 mtrs is capable of handling 60 amps and 12 AWG 100 amps.
12 AWG wire fits neatly and easily into an XT60, consider the length of the connector compared to 0.3 mtrs of cable (Length matters).
Without drawing this out too much, what Bartman said is correct "power (Watts) is volts X amps, you only halve the amps if you double the volts" for the same number of watts if you double the volts you halve the amps.
"for example, to size wires correctly you have to look at the limits on how much current can be passed for a given size and length of wire" yes that is correct.
To work out what size cable and connectors are required you need to calculate or test what the total amperage draw of your craft is at the voltage you intend to use (plus a small safety margin) and base your selection on that NOT the capacity of the ESCs' used.
Regards - bruce
For example the F550 (stock) has 6 x 30 amp ESCs' that equals 180 amps total and bears absolutely not relationship to the actual max. amps the 6 stock motors draw at max. capacity.
Mine at hover (4S) draws about 20 amps, at full throttle about 50 amps. Now 14 AWG cable/wire (at 14 volts) with a 3% loss (voltage drop) over a length of 0.3 mtrs is capable of handling 60 amps and 12 AWG 100 amps.
12 AWG wire fits neatly and easily into an XT60, consider the length of the connector compared to 0.3 mtrs of cable (Length matters).
Without drawing this out too much, what Bartman said is correct "power (Watts) is volts X amps, you only halve the amps if you double the volts" for the same number of watts if you double the volts you halve the amps.
"for example, to size wires correctly you have to look at the limits on how much current can be passed for a given size and length of wire" yes that is correct.
To work out what size cable and connectors are required you need to calculate or test what the total amperage draw of your craft is at the voltage you intend to use (plus a small safety margin) and base your selection on that NOT the capacity of the ESCs' used.
Regards - bruce
R_Lefebvre
Arducopter Developer
Yes, I know that the capacity of the ESC is a gross oversimplification, but I only suggest that because most people don't really know how many amps they'll draw. So it's just a guideline, a safe estimate, of how may amps you could draw.