Power Bank Jumpstarter

[PunkyDory]

Hi

I've just bought one of those Li-Ion jumpstarter power banks (RAC one from Wilko).

In the instructions it says to connect the black clamp to the negative terminal of the battery, yet everything I read on the web says to connect it to an unpainted part of the car's body.

Which is correct?

The leads are quite short so I'm not sure it actually reach to an unpainted bit anyway...

cheers

[Filibuster]

This comes from the possibility of oxyhydrogen build up and spark that could ignite those. Which is not going to happen (much less likely) with modern batteries and sparks should be impossible to generate with digital jumpstarters.

So do as told in the manual and connect the jumpstarter directly to the battery.

[Baldchap]

Normal vehicle electrics are 12v negative earth, meaning earth goes to the negative terminal on the battery.

In other words it doesn't matter.

[2 sMoKiN bArReLs]

Really weird you should post this at this time!

Just jump started the Mrs' golf & the negative terminal had a cover over it. When I pulled it back to connect the clamp it too had a big sign telling me to use the bodywork.

The diddy little lead did just reach the bodywork so I followed the instruction. (But I too wondered why)

[col711]

It is possible to use the battery terminal, but if the battery charge is very low it will sap all of the voltage from the donor battery or jumpstarter pack. It you attach the negative lead to part of the engine block or gearbox, that cannot happen.

[2 sMoKiN bArReLs]

col711 said:

It is possible to use the battery terminal, but if the battery charge is very low it will sap all of the voltage from the donor battery or jumpstarter pack. It you attach the negative lead to part of the engine block or gearbox, that cannot happen.

Maybe. But speaking as somebody that's regularly jump started cars over the last 45 years it's the first time I've done it this way! (Or even knew it was a thing)

[fwaggie]

col711 said:

It is possible to use the battery terminal, but if the battery charge is very low it will sap all of the voltage from the donor battery or jumpstarter pack. It you attach the negative lead to part of the engine block or gearbox, that cannot happen.

Oh yes it can.

Get your multimeter and measure the resistance from engine block to battery negative terminal.

Probably a few milli ohms.

Even at 250A that's sod all wattage being consumed compared to going directly to the battery.

[PunkyDory]

Thanks everyone!