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JST 4p DC Input Connector (Accidentally ordered 2p)

Posted: Mon Jul 20, 2020 2:51 pm
by gumby4231
Hello,
I'm looking to power my LP Delta 432 with a 12V battery. I'm considering using the JST 4p DC Input Connector. Mistakingly, I ordered these parts [https://www.amazon.com/smseace-connecto ... s9dHJ1ZQ==]. Will they suffice nonetheless if I connect one 2p connector to + and one to -.

Should I integrate Diodes and/or capacitors into the power supply to protect against spikes/reverse polarity.

Thanks for the help

Re: JST 4p DC Input Connector (Accidentally ordered 2p)

Posted: Tue Jul 21, 2020 4:54 am
by ccs_hello
The connector is rated for 1.25A (or 1.5A I forgot, search my old post) per (plus and minus) pair.
This is why 4P connector is chosen. 2P is under spec and is not recommended for a reliable operation.

Re: spikes, surge, reverse polarity, etc.
Invest on a good, high quality power supply is recommened. Life is full of unexpected events. Address potential issues from the source is easier.

Re: JST 4p DC Input Connector (Accidentally ordered 2p)

Posted: Tue Jul 21, 2020 3:18 pm
by gumby4231
@ccs_hello Thanks for the help. Your answers are always helpful.

I need to clarify that I a part of a team that is considering using the Lattepanda for a project. The project involves mounting an apparatus(Lattepanda included) on a tractor. Our goal is to power the apparatus from the tractor battery. If it will be too difficult to in your estimation to power the Lattepanda this way, I defer to your expertise. We're in the beginning phase of the project and nothing is off the table (including alternative power supplies).

Re: JST 4p DC Input Connector (Accidentally ordered 2p)

Posted: Tue Jul 21, 2020 3:22 pm
by ccs_hello
If that is the case, I'd suggest using a
synchronous step up/step down converter and set it to 12V:
LTCC3780 based module (some offers an enclosed module as well), e.g.,
https://usa.banggood.com/Geekcreit-LTC3 ... 51787.html

Re: JST 4p DC Input Connector (Accidentally ordered 2p)

Posted: Wed Jul 22, 2020 1:58 pm
by gumby4231
Luckily enough I already have this guy[https://www.amazon.ca/Yeeco-Converter-1 ... merReviews]. Should work as it has 75W, 5A max current output.

I am about to order the parts to make the JST ph2.0 4P connector parts. https://www.aliexpress.com/item/32848353465.html (JST ph2.0 4pin housing)
https://www.aliexpress.com/item/32888391516.html (JST ph2.0 Female Terminal reed)
They are the ones you share as an example in this forum post.
[https://www.lattepanda.com/topic-f6t16887.html]

You explained, "used a 2-pin 20AWG cable (about 1 ft long)". Do you simply crimp the wire to the terminal? Say you have 20/2 wire. Since it's four pins(two positives and two negatives) do you take the one negative wire and connect it the neg two pins (and do the same for positive)? Or do you feed two 20/2 wires into the connector so that there is one wire for every pin?

Also, I believe the 12V connector is supposed to be rated for 2A but according to this source [https://www.powerstream.com/Wire_Size.htm], 20 gauge is only capable of 1.5A. Would 18 gauge wire fit into those ph2.0 connectors?

I apologize for the number of questions, but there doesn't seem to be a source that explains this specific subject.

Re: JST 4p DC Input Connector (Accidentally ordered 2p)

Posted: Wed Jul 22, 2020 2:19 pm
by ccs_hello
That Powerstream article is written mainly for whole house wiring, typically in the order of 100 ft or more per branch circuit. Use it as a best practice.
The key is resistance-per-meter and how long the cable is.
That 4P connector is tiny and often times the crimped wire used is also thin.

Two methods:
1. (pigtail approach) Buy the pre-wired 4P connector. Cut the cable to be fairly short, say 5 cm. Then solder your normal sized DC cable to that short cable (2 wires for positive and 2 wires for negative) and heatshrink it to protect it.
2. (Improvise way) Just buy the connector only, solder (not crimp) thick DC power wire to two connectors right on the plug. It's ugly but offers the best current carrying capability.