Connector Fail!

[Onoff]

After a few nights of constant printing the Anycubic i3 Mega S just stopped mid print. I was in bed but my lad had left a note when I got up. Apparently neither the bed or extrude were heating up.

We had a look last night. Powered it up and there was no voltage coming from the retro fitted MOSFET boards. On the 12VDC "in" (the two yellow crimps at the bottom), my lad was only getting about 5V.

I figured high resistance joint somewhere, so using the magic finger started prodding. Problem is the Molex style connectors where we sited the power supply remotely! A wiggle on this and it all fired up. You can just the the scorch mark inside the housing on the negative wire number 6. A pity as it was all properly crimped and done well. Just not man enough.

 

[8ob]

I figured high resistance joint somewhere, so using the magic finger started prodding. Problem is the Molex style connectors where we sited the power supply remotely! A wiggle on this and it all fired up. You can just the the scorch mark inside the housing on the negative wire number 6. A pity as it was all properly crimped and done well. Just not man enough.

That's why I am nervous about leaving stuff like this unattended.

Bob

 

[carbon]

The printer I have has a common issue with the heated bed connector, after some use they get hot and melt. So best if not left unattended. The fix for mine is remove the connector and solder the wires directly to the bed

 

[Screwdriver]

Another option would be to use higher rated connectors more suited to the power requirements.

 

[Onoff]

Another option would be to use higher rated connectors more suited to the power requirements.

I did look at the time but struggled to find any. Suggestions welcome!

 

[awemawson]

Parallel up several pins - share the current

 

[Onoff]

Parallel up several pins - share the current

That was my first thought. Only trouble is I don't think I'd get two cables in one pin or even two cable diameters into the hole in the housing.

 

[knighty]

just join the wires outside of the connector?

6 pins so 3 +ve and 3 -ve?

join them all together outside of the connector and split for the bed and hot end

personally I'd probably use big waggos inside the printer, but you probably have room on the screw connectors for 2 crimps, so do 1 wire each then 1 wire with 2 crimps on joining the 2 screw terminals together?

 

[Jack_K]

What is the rating on the connector?

 

[hotponyshoes]

What is the rating on the connector?

You get different pin sizes for molex connectors, Range from 5a to 8.5a I think

 

[Onoff]

What is the rating on the connector?

I seem to recall 12.5A but I can't remember. I was dubious when I used them in this application and asked on here a few months ago. Someone on here reckoned take that with a pinch of salt and halve it.

 

[ukracer]

Try these..

 

[Onoff]

Try these..View attachment 410335

Cheers for that you've saved the day. I've just ordered them.

 

[m_c]

50A Anderson connectors are a bit overkill.
Just for reference, they're 35mm wide, and two coupled together are over 80mm long.

I'd probably go for 15A Anderson Power Pole connectors, however things like Deans or XT30/60 will be more compact and handle higher currents.

 

[Onoff]

50A Anderson connectors are a bit overkill.
Just for reference, they're 35mm wide, and two coupled together are over 80mm long.

I'd probably go for 15A Anderson Power Pole connectors, however things like Deans or XT30/60 will be more compact and handle higher currents.

Whoops...that's £12 down the drain!

 

[Onoff]

I've ordered these:

Genuine Amass XT30U Upgraded Male & Female Plug Connectors 5 Pairs. UK Stock | eBay

Find many great new & used options and get the best deals for Genuine Amass XT30U Upgraded Male & Female Plug Connectors 5 Pairs. UK Stock at the best online prices at eBay! Free delivery for many products.

www.ebay.co.uk

 

[Onoff]

50A Anderson connectors are a bit overkill.
Just for reference, they're 35mm wide, and two coupled together are over 80mm long.

I'd probably go for 15A Anderson Power Pole connectors, however things like Deans or XT30/60 will be more compact and handle higher currents.

Do you solder this type of connector to the incoming wire? Then heat shrink to insulate?

Thanks.

 

[m_c]

Do you solder this type of connector to the incoming wire? Then heat shrink to insulate?

Thanks.

Most of the connectors used by the RC crowd are solder.
You do need quite a high output solder iron, and to be fairly quick, as you can melt the housing if you don't get the wire soldered quick enough.

And yes, a bit heatshrink is normally used.

 

[Onoff]

I got the 50A Anderson connectors as recommended by @ukracer and yes they are indeed massive. I've not used them before so am unsure how they assemble though granted it should be obvious.

They come as a plastic housing that has two spring blades in, then a solderable "finger" connector I guess you push in from the rear and is held in place by the sprung blade?

https://flic.kr/p/2oUBKJx

From the rear with them seemingly properly seated:

https://flic.kr/p/2oUBKJC

Have I got this correct?

https://flic.kr/p/2oUCNpJ

https://flic.kr/p/2oUCNpZ

The trouble is, when I push the two connectors together it can dislodge and push one of the fingers back out. See the one on the left has been pushed back out:

https://flic.kr/p/2oUBKKQ

 

[hotponyshoes]

Pins in upside-down?

They have a sharp edge on one side. That side clicks into the spring to lock them in place.
Spring can be pushed down to remove them again.
The other side has a rounded hump, that's the mating face.

The specs say crimp them but they solder fine.