If you plan on doing any work on your electric bicycle yourself then you’re going to need a few tools. One of the most important ebike related tools to add to your shelf is a digital multimeter. You can use a multimeter for all kinds of tests and diagnostics on your ebike. For my bikes, the multimeter I use more than any other is the INNOVA 3320.
The INNOVA 3320 digital multimeter retails for $35, but I picked mine up on sale for less than $20. It’s been perhaps one of the best under $20 ebike purchases I’ve made in a long time.
Full of functions
Right off the bat you’ll see you’ve got all your main functions for measuring voltage (AC and DC), current (AC/DC up to 200mA fused, DC up to 10A unfused), resistance, continuity, diodes, etc. These functions are also auto ranging you don’t have to worry about selecting the right voltage setting (forget the old 2V, 20V, 200V settings). Just choose your function, connect the probes and let the multimeter do the rest.
Each function is also color-coded to show you where the plugs need to be at the bottom. Beginners should find this helpful. You pretty much only need to move the red probe over to the left side socket when you’re measuring large current loads up to 10 amps. Protip: remember to move the red probe back to the right side socket before checking your battery voltage. I vaporized the metal tip on another multimeter once by making that mistake.
A neat feature of the INNOVA 3320 digital multimeter is the battery load test. Connect batteries such as AA’s, AAA’s, C’s, D’s, 6V’s, 9V’s, etc and the load test will determine if the battery holds up during use. The color coded LEDs indicate whether the battery is new, used but still working or in need of replacement. This will obviously be more helpful around the house than on your ebike, but it’s still a nice feature to have.
One of the advantages of this multimeter is the giant screen. This extra large display makes it easy to read all the numbers and symbols even when you’re inevitably cramped in a tough position or trying to do some troubleshooting under poor lighting. I’ve found myself in both of those situations more than once and the generous display on this multimeter has been a huge help in an otherwise frustrating scenario.
The multimeter also comes with impact resistant rubber bumpers for when you eventually drop it. Mine hasn’t taken a tumble yet so I can’t speak to how well they work, but as crowded as my work table gets I’m sure I’ll be able to report back soon on that note. Additionally, integrated into the rubber bumpers are molded holders for the probes. Not a groundbreaking feature, but they certainly help keep cable mess under control.
Most multimeters come with an auto-off feature and this one is no exception. It sure beats grabbing your multimeter when you need it most only to realize the battery is dead because you failed to turn it off last time.
Watch out for the auto-off
There is one disadvantage of this multimeter that has always bothered me. It’s admittedly a small thing, but the auto-off feature is accompanied by a surprisingly loud high pitched succession of five beeps. That’s not a problem per se, except that it has a nasty habit of sneaking up on you during tense situations.
Imagine, you’ve got the guts of your ebike hanging out; high voltage wires and connectors are hanging everywhere. You’re diligently moving from one connection to the next, testing and checking. A bead of sweat forms on your brow and the tension builds as you move from wire to wire, searching for the problem and trying to avoid creating another. The silence is deafening. You reach for the live battery positive cable while simultaneously trying to keep wide berth of anything grounded. Just as you touch the bare connec-BEEEEP!BEEEEP!BEEEEP!BEEEEP!BEEEEP!
It’s happened to me at least a dozen times and you’d think I’d be used to it. Each time though there’s that split second where in the tension-filled moment the multimeter shrieks as it automatically turns off. For that fraction of a second my heart pauses and my brain races to check everything that just happened and make sure I’m not about to witness an explosion or see a few hundred dollars vaporize before my eyes. But then I quickly return to the real world, chuckle at my skittishness, and return to the task at hand. Even so, I could do without the auto-off BEEEEEEP.
Hands free has never felt so good
A nifty feature that makes this multimeter so easy to work with is the dual rear stand/bungee cord. Most multimeters will come with a little kickstand, so that’s nothing to write home about, but the bungee is a nice addition. When you’re measuring things on your ebike you’re often force to use two hands just to hold the probes in place. Finding a place where you can put the multimeter and still see it can be a challenge. Between the large screen and the rear bungee cord, I can always find somewhere to place or hang the multimeter in plain view.
For me, usability is one of the most important aspects of a multimeter. It could have all the features in the world, but if I can’t find a comfortable way to use it, a multimeter is just a hunk of plastic and copper. In my opinion, the INNOVA 3320 digital multimeter is a great combination of functionality and features. And for just $20, it’s a deal that’s hard to beat.