New battery already drained?

[Cheap6]

I bought a new multimeter from there today so i wanted to see how much DCA i was getting only to realize i had blown the fuse by first connecting the pins then turning it on (NEVER DO THAT) so i still don't know if my DCA is under .70 or over.

If I read that correctly you tried to read the current from the battery and blew the fuse in the DMM. Maybe that's a clue. Most of those DMM's are rated to read 10A, maybe 15A max. so what was 'on' that was drawing more than that current? (That's a lot of current to be drawn without anything switched on.)

If you do need to measure a current greater than that which the DMM can handle, Jaycar (and others) sell shunts. You temporarily wire that in between the +ve wire that supplies the power to the fuse box and measure the voltage drop across it. (The shunt is a very low value calibrated resistance and the voltage drop is converted to a current flow using Ohm's law: V=IR or I=V/R.)

The current drawn with ignition off should be something like 150mA (=0.015A), maybe not even that much. It's basically just to keep the memory alive in the electronic modules and to run the anti-theft monitoring. With the ignition off, it shouldn't be anywhere near enough to blow the DMM fuse.

If it is more than that, the diagnosis starts with removing each fuse one by one until the current drain disappears. Then you know that's the circuit to look at.

 

[oska]

Have you checked the water level?

Unless your battery says it maintenance free and sealed you need to top it up with distilled water

 

[gossie]

Why don't you just go to a "sparks" and spend some money with him to fix your problems?

 

[acarmody]

If I read that correctly you tried to read the current from the battery and blew the fuse in the DMM. Maybe that's a clue. Most of those DMM's are rated to read 10A, maybe 15A max. so what was 'on' that was drawing more than that current? (That's a lot of current to be drawn without anything switched on.)

Depends how he measured it. I (in a moment of sheer stupidity) put the DMM on current and put it across the positive and negative terminals. Instantly the wires started melting and DMM shut off. I don't know how but the damn thing still works.

 

[Cheap6]

That would do it .

Even measuring current the "right way" i.e. inline between the battery terminal and the terminal connector to the car it doesn't take very many things to be drawing current to exceed 10A. That method is valid way to detect how much current is being drawn without anything switched on, because the current draw under that circumstance should be very small. To measure current on a running engine, or even with anything more than one or maybe two electrical items switched on, requires the use of the shunt. An alternative would be using a clamp meter but they're a bit more expensive.

I have a shunt made up with old DMM leads, cut down, and some eye terminals so it's easy to use. Jaycar QP-5412 (50A, $12.95) or QP-5415 (100A, $19.95) are suitable. You are unlikely to get a current draw or feed over 100A but do watch the total current if using the 50A shunt. (Add up all the circuits' fuse values to get some idea.) Possibly it's better just to pay the extra and use the 100A but the 50A allows more precision.

To use it, wire the shunt in series between the battery terminal and the positive wire that feeds electrical power to the fuse box. Set the DMM to read 200 or 400mV, depending on what the meter will read and read the voltage dropped across the shunt i.e. connect the meter leads either side of the shunt, with whatever it is you want to measure switched on. With the 100A shunt, 10A is 5mV drop, 20A, 10mV and so on up to 100A and 50mV. With the 50A, 10A is 10mV etc.

The polarity of the voltage drop will tell you whether current is being drawn from the battery or if the alternator is feeding it. The latter should be the case with the engine running.