Bench Power Supply Buying Guide: 60V 5A vs 60V 20A — How Much Current Do You Actually Need?

Bench Power Supply Buying Guide: 60V 5A vs 60V 20A — How Much Current Do You Actually Need?

So you’re setting up your bench and staring at two power supplies that look nearly identical except for one number: the current rating. The 60V 5A and the 60V 20A. The voltage is the same, so what’s the big deal? Well, that current rating is the difference between a supply that politely taps out when you push it and one that keeps on giving. But do you actually need 20A? Or is 5A plenty? Let’s cut through the spec-sheet noise and figure out how much current you really need for battery testing, motor drivers, and general lab work.

Why Current Rating Matters More Than You Think

Voltage gets all the glory, but current is what does the work. A power supply’s current rating tells you the maximum amps it can deliver before it either limits the current (in CC mode) or shuts down. If your load tries to pull more than the supply can give, you’ll hit that ceiling fast. For some tasks, that’s fine—you just need a little juice. For others, it’s a brick wall.

Think of it like a water pipe: voltage is the pressure, current is the flow rate. A 5A supply is a garden hose; a 20A supply is a fire hose. Both can fill a bucket, but only one can blast out a clogged drain.

Battery Testing: How Many Amps Do You Really Need?

Battery testing is where current demands can sneak up on you. If you’re charging small Li-ion cells or lead-acid batteries at a gentle 1C rate, 5A is often enough. For example, a 12V 5Ah battery charges at 5A in about an hour—perfect for a 60V 5A bench power supply. But if you’re testing larger packs, like 12V 20Ah or 24V systems, you’ll want more headroom. A 20A supply lets you charge at higher rates or run capacity tests without waiting all day.

And if you’re diagnosing a car battery’s health, you don’t necessarily need a high-current supply—you need a proper tester. The FNIRSI BTM-24 2000A CCA Multi-Function 12V/24V Car Battery Tester is a dedicated tool that measures cold cranking amps and battery condition without stressing your bench supply. Pair it with a 5A supply for charging and you’re covered for most automotive battery work.

Tip: Always check your battery’s max charge current. Pushing too many amps can damage cells or cause overheating—even if your supply can handle it.

Motor Drivers: Where 20A Shines

Motor drivers are a different beast. When a motor starts up, it can draw a massive inrush current—often several times its rated running current. A 5A supply might handle small hobby motors, but for anything with real torque, you’ll hit current limiting instantly. That’s where the Power Supply 60V 20A earns its keep. It gives you the grunt to spin up larger motors, run drivers at full load, and avoid frustrating brownouts.

Even if your motor only draws 10A continuous, having 20A on tap means you won’t trip the supply during acceleration. And if you’re testing stepper or servo drivers, that extra headroom is a lifesaver.

Lab Work: General-Purpose Power

For everyday breadboarding, powering sensors, or running small DC-DC converters, 5A is usually plenty. The Power Supply 60V 5A is a compact, affordable workhorse that handles most low-power projects with ease. It’s also great for powering the ZK-4KX DC-DC Adjustable Step Up / Step Down Converter CC CV 4A, which itself tops out at 4A. Using a 5A supply with this converter gives you a clean, regulated input without wasting money on amps you’ll never use.

But if your lab work involves testing power amplifiers, large LED arrays, or charging big battery banks, the 20A model future-proofs your bench. It’s better to have and not need than need and not have.

So, Which One Should You Buy?

Here’s a quick cheat sheet:

• Go with 60V 5A if: You mostly work with small electronics, charge batteries up to ~5Ah, use DC-DC converters, and want to save money and bench space.
• Go with 60V 20A if: You test motors, drive high-power LEDs, charge larger battery packs, or want a supply that won’t flinch under heavy loads.

And remember: you can always add a dedicated battery tester like the FNIRSI BTM-24 to your kit for accurate battery diagnostics, regardless of which supply you choose.

Final Thoughts

Don’t overbuy current you’ll never use, but don’t undersize and frustrate yourself either. Match the supply to the work you actually do—and if you’re unsure, the 20A model gives you room to grow. Ready to power up your bench? Browse our full selection of power supplies and test gear at Electra Store and find the perfect match for your projects.

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