Connecting Well?

[Bravedan 106]

 

Following Ben's post about checking servo extension leads, here's something else for you to worry about.

 

The red coloured JST RCY plug/socket type is widely used for LiPo batteries. You may well have some cell packs with them on, they are everywhere. It suffers the same potential issues as a servo lead/plug, in that the pin is small and long, so alignment is critical. For this reason the pins "float" a lot in their red plastic body.

 

Usually packs up to 3S 1000mAh ish have this type, going to Deans or EC or XT above that, but recently I have seen it being used for high "C" rated 4S 1500mAh batteries, which prompted me to remind myself on my memory of what I'd checked years ago.

 

Before I go on, bear in mind that the plastic used is low temperature, too low for soldering connections in situ, the manufacturer states that connections should be crimped and heat avoided.

 

The batteries that focussed my attention are rated 21Amps constant with 42Amp burst. Since these are "designed for" race quads with four motors at near full throttle most of the time, it's possibly an extreme example, but many of the cell packs they are being attached to develop in excess of 10 Amps.

 

The manufacturers MAX current rating for a red JST RCY is ONLY THREE AMPS.

 

The max conductor size they specify as max is also small (since they need to float as stated above and housing space is very tight, a bigger cable, and one not visually FAR too large, will stop that float occurring).

 

Even if they don't melt on you, their small contact surface creating a relatively large resistance to current flow must inhibit the cell packs ability to deliver its "C" rated current at well above the Max specified.

 

Even charging is a potential risk. As an example I have some 1000mAh 3S that are rated for 5C charging, but if you did, you would be subjecting the plug/socket to a 60% overload.

 

Given the packs using them, "Not fit for purpose sold" springs to mind, but if you had an incident causing injury, and were found by a legal eagle to be using these connectors at well above their rated Max, it would likely not go well for you, so be careful out there!!