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Connector sparking and damage due to inrush at "mating" time?

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zenerbjt:
Dear Engineers,

We are using the JST connector of Part number = S2B-XH-A. We are using it to connect our 48V battery to our 5Vout DCDC module. (as attached)
This comprises an 82uF capacitor at its input. Considering the inrush and sparking at the connector contacts due to the 82uF input capacitor, how long do you think this connector will last?
Say, after 10000 connections, what would then be the resistance of this connector?
Circuit attached showing where connector is.

It will be  connected once per day. Every day.

S2B-XH-A connector
https://docs.rs-online.com/f25e/0900766b81357f2f.pdf

NiHaoMike:
Add a small resistor or NTC in series to reduce the inrush. Since your load is small, the additional losses will be minimal.

wizard69:
Silly question but why are you plugging in while powered up.   That seems like asking for trouble on a JST style connector.   You might not get a off by one error due to the shroud but those types of connectors tend to get rocked into place.    Plus you are exposing whomever is plugging in, to voltages over 24 VDC.   That might be a regulatory problem, I just know I've had a enough wire to board connectors, fail to retain the insert contact that I wouldn't like it.


--- Quote from: zenerbjt on August 30, 2020, 09:46:55 pm ---Dear Engineers,

We are using the JST connector of Part number = S2B-XH-A. We are using it to connect our 48V battery to our 5Vout DCDC module. (as attached)
This comprises an 82uF capacitor at its input. Considering the inrush and sparking at the connector contacts due to the 82uF input capacitor, how long do you think this connector will last?
Say, after 10000 connections, what would then be the resistance of this connector?
Circuit attached showing where connector is.   

It will be  connected once per day. Every day.

S2B-XH-A connector
https://docs.rs-online.com/f25e/0900766b81357f2f.pdf

--- End quote ---

Psi:
yeah, JST really aren't designed for hot plugging power, or hot plugging in general.

You could add a mosfet + and RC filter on its gate.
Have the mosfet pass through power after a delay from the connector insert. That way the inrush happens once the connector is fully seated not when a tiny area of the conductors first touch.

temperance:
Just to convince you that a some form of inrush current limiting will be required. The connector is not the only problem.

For aluminium electrolytic and film type capacitors: the pin to foil connection will fail.
For ceramic capacitors: because of electrostriction they will crack and cause a short and burn out your board before the fuse melts.

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