Backyard Aquaponics
A place to discuss aquaponics

I just checked a 36v battery and had the positive lead plugged into the 10 amp socket.

I saw a large acr when I touched the probes to the terminal.

Can anyone tell me why?

There is a tiny spark when I connect it normally.

If you look at your meter there is normally different positions you can plug your leads into.
1 set for voltage measurement, and one for current measurement.
If you have it set to measure current and check it against a voltage, it will have a very low resistance by design through the meter and you pretty much have a direct short between the leads. As I=V/R, when your resistance is low you will have a large current flow.

If you had your leads plugged in wrong, that could explain it. More expensive meters will normally be fused, to protect the circuitry but cheaper units may not be, which... may render the meter useless..

Ild check the leads are right, and then check it is still working against a known voltage source.

Out of curiosity, what type of meter was it? Most decent voltage meters should have a high enough internal resistance that there should be no flash at all. If any of mine flashed in the slightest, i wouldn't be trusting it until i gave it a good check over!

Thanks mr water

It's a Digitor Q1467

It seems fine after it's abuse, and voltage reading appear to be accurate. The 10A plug says it's unfused.

I have no idea if it will still read amps.

I have pretty quick reflexes when things that shouldn't, bust into a fireworks display in my face, so it was only in contact for as short a period as I could manage

In fact I think the tip of the probe acted like a fuse by just evaporating so it was probably only in contact for a thousandth of a second:)

Current (amps) is supposed to be read with the meter in series with the load, not short circuited across the power source... no wonder you had sparks!

The leads were probably heated up, but you avoided melting the insulation by quickly disconnecting. It's impossible to say from here as to whether or not you've done any internal damage to the meter though- you'd have to test it in series with a known load to discover that.

If you want to measure voltage, make sure the leads are in the voltage measuring sockets, the 10A socket means that you shouldn't try to measure current in excess of 10A, and a battery of any significant size will easily deliver that when short circuited.

Initiation in to the "Sparky" club. Sounds like you got lucky. Plus one to Gunagulla and Mr Water said.

Thanks people.

For some reason I missed these responses.

It was in series, and I was trying to check a load, but the fuse didnt blow... just sparks.

But since then after leaving my multimeter connected to a lead acid deep cycle battery (backup deep cycle system I was running my pump from) my positive probe grew green and is now a lot shorter.

There's a lesson in there somewhere.

Darn, algae on a multimeter! There’s a first for everything :-)


Just kidding.


Sent from my iPhone using Tapatalk

Actually I did once leave my multimeter probes in the fishtank to see if I could measure pH, and I'd just turn it on every now and again to measure resistance, but I think bio-slime messed up the readings

I've also used it when brining protein to see if I could work out when to take it out of the brine, and put it into a marinade.

Neither worked very well.

I couldn't count how many meters i stuffed bu having the leads in the wrong place