I bought a DBPower 18,000 mAh battery jumper and I wonder if there is anyone else out there with a DBPower unit who might check to see if I have a unique issue with mine.

Because I did not want to go to the trouble of disconnecting my RLX SH battery to test the jumper, I put a voltmeter on the jumper cables, and got 12+ volts, as expected. But I get the same reading with the unit's power switch on or off. The switch does turn on and off the display, but doesn't change the voltage between the jumper cables. Weird. I wonder if anyone else has this unit and if so whether or not it does the same thing, or if mine has a defective switch and should be returned. I guess there is no danger here because the jumper cable is detachable for storage, but still, it seems odd.

Thanks to anyone who might comment.

fsmith, I just checked mine and it reads 12V either its on or off. I guess that is how it is supposed to be......

HTH.

Thanks, pgeorg. 12V with the power switch on or off. Weird. There must be a logic in there somewhere that I am missing.

When jumper kit has power switch OFF, it still has 12V power available to the auxiliary ports (USB, DC) as well as the LED indicators. In order for the jumper cables to become 'live' you have to turn ON the jumper once the cable connections are made to the car battery & ground - completing the circuit (with proper polarity). However, the warnings in the instruction booklet states NEVER touch the jumper cables together when the unit is turned ON. I assume that will spark a short and potentially damage the unit (an potentially give you Tina Turner hair).

Further, in short - the (charged) jumper is always live. However the peak amperage needed to jump the car batter is not delivered until it is turned ON.

Okay, that makes sense. Do you have one of these things, Tampa, or are you surmising based on your general knowledge (which is demonstrably quite significant!)?

thats odd. So you are handling the cables and if they touch they will short. What is the purpose of having the cables live in the off position?

The user guide warns to shut OFF before removing cables and not to cross the cables. But since the amperage is reduced when OFF I would not think there would be a short. If the jumper has a reverse polarity LED warning, that may trigger or perhaps potentially damage it. But I would think you would need to have the unit ON (increased amperage) to create fireworks or a damaging short. Instruction manuals almost always build in extra caution. By warning never crossing the cables, the is no chance of a situation where a malfunctioning OFF switch (actually still ON) could create sparks, short or injury. My guess.

Can you measure the amps in the Off position - would be interesting to know.
Any short is bad to me

I guess I am also still missing what the purpose of such an arrangement might be (as compared to its practical implications). There must be a reason to allow bypassing the switch for even a lower amperage. Why not just have the switch turn off everything? We may be missing something obvious here. Any electrical engineers around?

If the unit is completely OFF, there would be no current for the LED / alert to warn when you reverse connect the cable leads (if so equipped)

Me thinks we are thinking too hard about this.

^^^ Although the DBPower unit doesn't advertise reverse polarity protection, that's a good theory that is likely right on the mark. I agree and promise to stop thinking - and posting - about it.

^^^ slow day, fsmith???

ok so we may be overthinking, but I still see no reason to have live cables in Off. Easy enough to provide Off, Check, On where Check gives polarity on hookup

^^^ Cute, Tampa.