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I want to build a PCB for a charging circuit almost identical to the one shown here.

I plan to hook up the circuit to this battery.

According to the battery's datasheet, there's a 'JST PH 2-pin' connector at the end of its leads which I believe is this one.

Then, on the PCB, I think the corresponding header I would need to purchase is going to be one the parts found on this page (the first row of "Header Right Angle Through Hole.")

As can be seen, most of those parts seem to be out of stock.

In KiCad, the footprint for the JST PH header on the PCB looks like this (horizontal):

2-pin JST PH footprint.

If I am unable to get ahold of the header for the PCB, is possible to just remove the plastic cover on the JST connector coming out of the battery and solder the leads directly to the parts of the footprint with 'MP' written on them?

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  • \$\begingroup\$ That definitely looks like the footprint for a SMD version. \$\endgroup\$
    – vir
    Commented Feb 23, 2022 at 18:13
  • \$\begingroup\$ Just modify the footprint to make the "MP" pads a bit larger outside the plastic frame. Then you can use a soldering iron to attach them without removing the plastic case (which you will probably damage trying to remove/replace). The alternative is that you could do this with hot air (may melt the plastic) or a hot plate. If you wanted to solder the leads directly, you would use the "1" and "2" pads, not the MP ones. Those are for "mechanical" strength of the part, not signals/power. \$\endgroup\$
    – Ron Beyer
    Commented Feb 23, 2022 at 18:18
  • \$\begingroup\$ This is one of the most (if not THE most) popular connectors there is. It has been very widely copied. I am pretty sure you can buy "JST" connectors online through some non-standard source like ali-express or Amazon, etc. They won't be made by JST but they will work well enough. But soldering will work also. Just cut and strip the wires and solder the wires directly to the pads where the header is supposed to go. It can be challenging to avoid shorting the wires together while soldering. Temporarily covering things with electrical tape or kapton tape can help with that. \$\endgroup\$
    – user57037
    Commented Feb 23, 2022 at 18:29
  • \$\begingroup\$ smile.amazon.com/dp/B07SJTLCBR \$\endgroup\$
    – user57037
    Commented Feb 23, 2022 at 18:34
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    \$\begingroup\$ You would solder the wires to the pads marked "1"' and "2" - be sure to check the polarity!! The pads makred "MP" are mounting pads - they will probably have no electrical connection to the board. \$\endgroup\$
    – Peter Bennett
    Commented Feb 23, 2022 at 19:02

4 Answers 4

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If you really need to, then yes, you could remove the plastic and solder the pins directly your board. Or snip the pins off and solder the wire. The MP is not the actual routable connections though. They could be connected to a plane like ground but its normally just mechanical support (solderable wings). You want to connect to pin 1 and 2. Which should match your battery polarity. The connector is only goes in one way (unless you move the terminals on the make end)

Since it's attached to a lithium battery (assuming), just make sure you solder it quickly to avoid any unnecessary heat build up. Soldering wires from a small battery with preattached leads is common.

But as mentioned in the comments, finding the appropriate JST connector is trivial.

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You can solder the wires from the battery to the pads marked "1" and "2". Be sure to connect them with the correct polarity.

The pads marked "MP" are mounting pads to support the connector - they will have no electrical connection to the circuit on the PC board.

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The footprint is for a SMD version of the connector, but manually you can solder the through hole version on the pads too, just mind the polarity. For example this: https://fi.farnell.com/jst-japan-solderless-terminals/s2b-ph-k-s-lf-sn/connector-header-tht-r-a-2mm-2way/dp/9491902

Only pins 1 and 2 make are functional, the other ones are for mechanical support.

Or you could put some other 2-millimeter pitch connector in and cut the shroud enough to fit your connector, but preferrably so that it doesn't fit the wrong way around. Something like this: https://www.digikey.ca/short/052d2bfc

That way you'd be able to disconnect the battery quickly.

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PH is a family of JST connectors that come with both through-hole and SMD. The footprint you got is for a SMD 2-pin side entry header (sometimes also referred to as "right angle" header). So no, you shouldn't use some dirty hack trying to put a through-hole connector there instead, that's a plain bad and expensive idea.

The correct JST part number would be S2B-PH-SM4-TB, see for example Digikey. Digikey are apparently being bad stock-wise, just buy from someone else. There's available parts at for example TME. You could also use some less well-known copycat brand like Neltron 2417RJ.

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