Hoverboard Circuit short?

[Mortoney]

Hi,

I have hoverboard with disconnected battery. Where I try to connect I get sparks. I tested battery positive and negative terminals on a circuit for continuity with the multimeter and I get a result that in fact there is continuity.

I know that connecting the battery to such a circuit may cause a spark and its normal. But is it normal to have continuity on a circuit? The circuit does not have on of switch, it has more like PC On switch.

thanks for your help.

 

[audioguru]

A battery is never tested for continuity. Instead it is loaded then has its voltage measured.
Maybe you are connecting the battery with backwards polarity? Then that might have damaged the circuit.

 

[Mortoney]

Thanks for your reply, I have not tested battery for continuity, I tested circuit cables, the segway main logic board. The battery is fine, I have checked the voltage.

And the connectors are different for positive and negative, so its not possible to connect it the wrong way.

Should circuit have continuity?

 

[JonSea]

The circuit probably has some large capacitors that need to charge when the battery is connected. Connect the battery; if the wires get hot to the touch, disconnent it. If it doesn't work properly after a few seconds, it may be broken. Disconnect the battery if it doesn't work correctly.

 

[Mortoney]

Thanks JonSea. I tried to connect battery again, got a big spark and new fuse (which I just installed a few minutes prior) blown right away. So I am certain now that there is short.

What component most likely to cause short?

 

[alec_t]

The power semiconductors (diodes, MOSFETS) are components which can go short-circuit, but their failure may be due to failure of something else (such as a shorted motor coil, stalled motor, excessive ESR of a capacitor, or ....).

 

[JonSea]

If the hoverboard is new there are too many possibilities to count. A good first step would be to look for a loose screw or metal debris shorting out the circuit board somewhere; during shipping, parts can work loose and create problems.

Next, look for any discolored/burned areas on the circuit board, loose components, bulging capacitors. But like alec said, a burned up part may be the result of some less obvious failure.

 

[Mortoney]

The hoverboard is not new, I bought it as used - not working (visually looks that it has been used only for a short period, almost no scratches). When I unscrewed plastic covers I found battery disconnected from circuit and both circuits (left and right wheel) had blown fuses.

I could not see obvious signs of any failed component. I will do more investigation later this week. Circuits have many MOSFETS, maybe that could be a cause.

I will make a couple of high-resolution pictures of those circuits and I will upload here in case you can spot something.

Thanks

 

[audioguru]

Maybe previously the battery was connected with backwards polarity that destroyed the circuit?

 

[JimB]

Old thread revived by a spammer (now deleted).
JimB