I need to work on the electrical system of my motorcylce and so I need a multimeter (along with various other tools). I can’t afford a Fluke, but Craftsman models appear reasonable, but are they any good?
What should I look for? What should I avoid? That is, what exactly is the difference between $20, $50 and $100+ models?
B+K Precision has a decent line of affordable multimeters. I’ve had a chance to use a few of them over the years, and they’re good stuff for the price–around the same price for similar Radio Shack meters with MUCH better quality and performance.
We use cheap multimeters at school and find that the fuses burn out when measuring higher currents. There are two settings for current. One that is lower and more sensistive and one that is higher and less sensitive. When the lower setting is used with too high a current the fuse blows. When the fuse blows, the lower setting no longer works and we are stuck using the higher setting even though it gives us little precision. I wonder if using more expensive multimeters would solve this problem.
I have a $200 Fluke and a $6.95 no name cheapie. I find that I use the cheapie much more than the Fluke. It is small enough to fit in my pocket, has all of the settings and ranges I need and is accurate enough for most practical uses like checking for voltage present or continuity. Lastly, If I lose it or drop it and break it, it doesn’t bother me, I just plunk down $6.95 for another one. The one upgrade I made was for a better set of leads. The originals are a bit too short and flimsy for my comfort.
I do use the Fluke when dealing with higher voltages or need better accuracy in my measurements, but that’s not very often. YMMV.
You’ll see the difference if you really compare the specs of the meters. More expensive meters will load the circuit less than cheap meters, and will give you a much greater accuracy. If you are working on high resistance circuits, a cheap meter is basically worthless. You end up measuring the internal resistance of the meter more than the circuit you are looking at. The accuracy of the el-cheapo meters isn’t all that great either. It may read 12.65 volts on the meter, but that reading usually isn’t accurate to two places after the decimal. It may be several tenths of a volt off, even though it is displaying values to the hundredth of a volt. A more expensive meter will be accurate down to the hundredths of a volt, and will be calibrated tracable back to NIST standards.
For working on a motorcycle though, you basically just need to be able to measure voltage and continuity. All of the extra precision of an expensive meter usually won’t mean diddley for what you are doing. Let’s say you’ve got a bad connection somewhere between the battery and the headlight. When you turn the light on, the voltage at the light drops to about 3 volts. Do you really care if it’s 3.02 or 3.75 volts? No. All you care is that you’re not getting anywhere near 12 volts to your light. Or, maybe you aren’t getting any voltage at all to your light. A $6 meter measures continuity just as well as a $200 meter.
The $6 cheapie meter will work just fine for most of what you’ll ever do around a motorcycle, but I wouldn’t recommend a $6 cheapie. Find something that is auto ranging and fits in your pocket, but isn’t so small and delicate that it will break easily. Don’t get one where the leads are permenantly attached to the meter, either. Chances are one of the wires will break at some point, and you want to just be able to buy a new set of leads rather than scrap the whole meter or take the darn thing apart and solder new wires to it.
You also want a meter that has a continuity checker on it that beeps when there is continuity.
Fluke also has a less-expensive line called Meterman. The PM series (PM51, PM53, PM55) are all pocket-sized, fairley inexpensive, and more than adequate for what you’ve described.
Fluke also just bought the Amprobe line. They are starting to phase out some of the products that are copies of their Fluke and Meterman products, so you might be able to pick up a discontinued Amprobe multimeter from a dealer at a reduced price.