Outer Limits 4x4 Board

ok pokin around under the bonnet of the 40, the voltage (with car off) across the two battery terminals is 12V

now this is where it gets interesting, the voltage if i put the probes on the plastic case of the battery below the terminals is still 12 volts... if i put one probe next to the (-ve) terminal and one on the side of the battery (plastic) it reads 9 volts

if i do the same, but put the probe on the battery tray it reads 6 volts.

is this bad?

bad_religion_au wrote:ok pokin around under the bonnet of the 40, the voltage (with car off) across the two battery terminals is 12V

now this is where it gets interesting, the voltage if i put the probes on the plastic case of the battery below the terminals is still 12 volts... if i put one probe next to the (-ve) terminal and one on the side of the battery (plastic) it reads 9 volts

if i do the same, but put the probe on the battery tray it reads 6 volts.

is this bad?

Is it all clean and dry?

it's dry, a little dusty but dry

thats a strange one never seen that before have ya got the meter on the right circuit ac/dc maybe evn ya meter could be stuffed ,borrow a mates and retry it

meters on dc voltage, and it does it with a mates meter as well...

should i be scared

Nothing to worry about.

The digital meters only need bugger-all current to measure a voltage. What happens is with a bit of moisture and battery acid mist the ions in the acid act as a bit of a conductor (a resistor) down the side of the battery case, and across the top of the case too, (in reality a couple of megohms resistance - nowhere near enough to discharge you battery). Running one lead of the meter down the side of the battery essentially "taps" that resistance about half way down giving a voltage proportional to the resistance it is measuring.

Essentially like a demister fan speed controller on a very "lite" scale

Should be able to find strange voltages across all surfaces of the battery.