Can someone tell me what this part is? I think it is a diode. The markings say 0830 1Z. It is from an 18v lithium power tool battery. Reading the 5 - 18650 cells shows 3.99v per cell and 19.95v for the pack but going through the BMS is only showing 7.4 ish volts. It is definitely damaged. I don't know if simply replacing this part will solve the problem or if there is another fault that will blow out the new part but it's worth a try.

What is this part?

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    \$\begingroup\$ "It is definitely damaged." Reading that and then looking at that second picture gave me a good chuckle. \$\endgroup\$
    – earl
    Feb 24 at 17:25
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    \$\begingroup\$ Definitly a diode, good chance of it being a TVS. Can you post a photo of it with a bit more PCB in view? Can you see if the power path is in series with this diode or parallel? \$\endgroup\$
    – Bryan
    Feb 24 at 17:30
  • \$\begingroup\$ Welcome! Please trace out the circuit around and connected to it. \$\endgroup\$
    – winny
    Feb 24 at 17:31
  • \$\begingroup\$ Best guess: 30 V Zener diode straight across the rail. Unsolder it and measure if the MOSFET next to it is ok with you DMM diode function. \$\endgroup\$
    – winny
    Feb 25 at 14:41

2 Answers 2


Browsing a lot of online chinese datasheets I've come with this one PDF that looks promising.

It says that it is a 200mW SOD-323 SURFACE MOUNT Small Outline Flat Lead Plastic Package Zener Voltage Regulator. They are available from 2.4V to 75V, depending on the marking. The 1Z states that this is a 2.7V one.

Note that the IZ, OZ and QZ are missing from the table, to avoid confusions with the identification.

The 0830 is maybe the date of manufacture (year 2008, week 30?).


The significant marking is "IZ", in the second picture we can see that it is a "I" and not a "1".

The package is SMA (standard size + J lead shape). With that marking code, on can find that it is a SMAJ24A diode. This is a generic part number, a lot of manufacturers make these parts.

After a search in google I eventually found that the manufacturer of your model is LGE. (No marking in the datasheet unfortunately)

But in the following picture from LCSC you can see that the marking is similar to yours:

enter image description here

By the way someone looked for the same diode here, and didn't find it either.


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