Newbie: basic stuff

[combatvolcano]

Hello,

I have a Vision Spinner battery that my multi says outputs 5v. It is rated at 1300 MaH but for some reason while I can read the voltage, when I try to read the current the battery flashes the light and turns off as if there were a short. (any tips?)

Assuming it is 1300 Ma at 5v, what sort of circuit might I need to go to standard USB which as I understand it is 500 ma max at 5v?

The idea here is to build an interface that will allow me to emergency charge a cell phone from my eGo battery.

Thank you

CV

 

[Harald Kapp]

I suggest that each plant should have a third connection for common, which should be connected to the 0V rail of the monitoring circuit, to keep the plant and its probes close

Please show us a schematic of your measuring setup. How do you connect battery, meter and lamp?

Assuming it is 1300 Ma at 5v, what sort of circuit might I need to go to standard USB which as I understand it is 500 ma max at 5v?

A pair of wires?
The 500mA rating of USB ports means that such a port shal be able to deliver at least 500mA. It may, and some ports do, limit the current and turn off if more than 500mA are drawn. Many ports, however, do not fully cnform to the standard and deliver >500mA.
If you want to power a USB device from your battery, all you need to ensure is that the 5V are stable.

However, a battery with a 5V output is very unusual. Typical battery voltages would be 4.8V or 6V. Are you sure that this "battery" does not consist of a battery plus an integrated voltage regulator?

 

[combatvolcano]

Well, actually it's a variable-voltage battery you can set up to 4.8 however the calibrated multimeter says it's a stable 5.0. I imagine it has some sort of circuitry to help regulate the voltage but that it's a bit off? Sounds a bit fishy to me?

I'm very technically inclined in other disciplines but electronics itself only seems to come up a couple times a year so I'm really bad at it.

 

[combatvolcano]

Oh and any ideas on testing the current? This is a Li-ion battery with a host of protection circuitry and there's no way to disable that but who knows? Anything might be worth trying.