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Test Equipment Buying Guide
🔋 Best DC Electronic Loads
Prove that your ESP32 power supply, buck converter, solar charger or battery pack really delivers what it claims, before your board starts brownout resetting in the field.
✅ 8 Loads Compared
✅ Verified Amazon ASINs
✅ CC, CV, CR and CP Explained
✅ Honest Pros & Cons
An ESP32 looks like a gentle load on paper, but Wi-Fi transmit bursts pull sharp current peaks, and a regulator or battery that sags during those peaks causes random resets, corrupted flash writes and failed OTA updates. A DC electronic load is the tool that finds those weaknesses on the bench. It draws an exact, programmable current (or power, or resistance) from your supply so you can watch the voltage, measure efficiency and see where it gives up.
This guide compares 8 electronic loads from Siglent, Rigol, B&K Precision, Maynuo, Korad and East Tester, from compact 150 W loads to 400 W bench units. We focus on what matters for ESP32 and IoT work: low-voltage performance, current resolution, dynamic (transient) modes for simulating Wi-Fi bursts and battery discharge testing for 18650 and LiPo packs.
💡 Before you buy: An electronic load is not a deep-sleep current meter. These loads resolve current in milliamps, which is perfect for testing regulators, chargers and batteries, but useless for measuring a 10 µA sleep current. For that, use a USB power meter or current profiler. Also check the minimum operating voltage: every load needs some voltage across its input to sink full current, so testing a single 1.2 V cell or a 3.3 V rail at high current is harder than the headline spec suggests.
⚡ Quick Comparison: All 8 Electronic Loads
| Load | Rating | Modes | Best For | Buy |
|---|
| 🥇 Siglent SDL1020X-E | 150 V / 30 A / 200 W | CC, CV, CR, CP, dynamic | Best Overall | Buy Here → |
| 💪 Maynuo M9711 | 150 V / 30 A / 150 W | CC, CV, CR, CW + combos | Best Workhorse | Buy Here → |
| 🔥 Siglent SDL1030X-E | 150 V / 30 A / 300 W | CC, CV, CR, CP, dynamic | Best for Higher Power | Buy Here → |
| 🏛️ B&K Precision 8600 | 120 V / 30 A / 150 W | CC, CV, CR, CW, transient | Best Premium Bench Load | Buy Here → |
| 📦 B&K Precision 8540 | 60 V / 30 A / 150 W | CC, CV, CR | Best Compact Load | Buy Here → |
| 📈 Rigol DL3021 | 150 V / 40 A / 200 W | CC, CV, CR, CP, list | Best for Automated Tests | Buy Here → |
| 🌐 Korad KEL103 | 120 V / 30 A / 300 W | CC, CV, CR, CW | Best Networked Value | Buy Here → |
| 💰 East Tester ET5410A+ | 150 V / 40 A / 400 W | CC, CV, CR, CP | Best Budget High Power | Buy Here → |
Specs come from the manufacturers and the live Amazon listings. Star scores below are our ratings.
🔍 What Matters in an Electronic Load
🎛️
Operating Modes
CC (constant current) tests regulators and batteries, CR mimics a resistor, CP (or CW) mimics a converter downstream, and CV tests chargers and solar panels.
📶
Dynamic Mode
Switching between two currents at a set rate simulates Wi-Fi transmit bursts, so you can see regulator droop and ringing on a scope.
🔋
Battery Test
A discharge mode with a cut-off voltage measures the real capacity of 18650 cells and LiPo packs so you can estimate battery life honestly.
🌡️
Power and Cooling
150 to 200 W covers almost all ESP32 supplies. More watts matter for 12 V and 24 V LED or motor supplies and big battery packs.
🔌
Remote Sense and PC Control
4-wire sense removes lead drop from readings, and USB, RS-232 or LAN control lets you script long tests, even from Python.
🏆 Detailed Reviews: The Top Two
🥇 BEST OVERALL ELECTRONIC LOAD
Siglent SDL1020X-E
⭐ 4.8/5 · Our Rating · The Hobbyist Bench Favourite
Buy on Amazon →
The SDL1020X-E is the load we would put on most ESP32 benches. It sinks up to 150 V, 30 A and 200 W, with static CC, CV, CR and CP modes and a CC dynamic mode up to 25 kHz, which is exactly what you need to hammer a 3.3 V regulator with Wi-Fi style current pulses and watch the result on a scope. A dedicated battery discharge test measures the capacity of 18650 and LiPo packs, 4-wire sense keeps readings honest at high current, and USB, RS-232 and LAN are built in for scripted tests. The color screen and front-panel layout match Siglent’s power supplies and scopes, so it is easy to learn.
✅ Pros- Fast dynamic mode
- Battery discharge test
- USB, RS-232 and LAN
- 4-wire remote sense
❌ Cons- Fan noise at high power
- mA resolution, not µA
- GPIB is optional
🎯 Verdict: The best all-round programmable load for testing regulators, USB supplies and batteries for ESP32 projects.
👉 Check Price on Amazon →
💪 BEST WORKHORSE LOAD
The Maynuo M9711 has been a staple on electronics benches for years, and it is still one of the most practical loads for power-supply work. It handles 150 V, 30 A and 150 W and offers six modes: CC, CR, CV and CW plus the combined CC+CV and CR+CV modes that are handy for testing battery chargers and solar charge controllers. Its compact case fits on a crowded bench, the interface is simple and the remote interface options cover RS-232, RS-485 and USB style connections for logging. The display is a plain segment readout rather than a color screen, but it is easy to read and fast to set.
✅ Pros- Combined CC+CV and CR+CV modes
- Small footprint
- Long track record
- Simple to operate
❌ Cons- Basic display
- 150 W ceiling
- Older-style PC software
🎯 Verdict: A no-nonsense programmable load that is ideal for charger, solar and regulator testing.
👉 Check Price on Amazon →
🔧 More Electronic Loads Worth Buying
🔥 BEST FOR HIGHER POWER · ⭐ 4.7/53. Siglent SDL1030X-E
150 V / 30 A / 300 W · CC, CV, CR, CP · CC dynamic to 25 kHz · battery test · USB, RS-232, LAN
Buy Here →
The SDL1030X-E is the same instrument as our top pick with the power rating raised to 300 W. That headroom matters if you test 12 V or 24 V supplies for LED strips and motors, or discharge larger battery packs, because a 200 W load runs out of power long before it runs out of current at those voltages. Everything else, from the 25 kHz dynamic mode to the battery test, 4-wire sense and USB, RS-232 and LAN interfaces, carries over.
✅ Pros: 300 W headroom; same easy interface; full feature set.
❌ Cons: Costs more; extra power unused on 5 V work.
🎯 Verdict: Pick this over the SDL1020X-E if you regularly test 12 V and 24 V supplies or big packs.
🏛️ BEST PREMIUM BENCH LOAD · ⭐ 4.7/54. B&K Precision 8600
120 V / 30 A / 150 W · CC, CV, CR, CW · transient to 25 kHz · 16-bit measurement · USB, RS-232, GPIB
Buy Here →
B&K Precision is a long-established US test equipment brand, and the 8600 is its entry into a professional programmable load series. It sinks 120 V, 30 A and 150 W in CC, CV, CR and CW modes, adds a transient mode up to 25 kHz and 16-bit measurement, and includes USB, RS-232 and GPIB. B&K backs it with a 3-year warranty, which makes it a sensible pick for a school lab, a small product company or anyone who wants US-based support.
✅ Pros: Professional build; GPIB included; 3-year warranty.
❌ Cons: Expensive for hobby use; 150 W limit.
🎯 Verdict: The load to buy when support, warranty and test automation matter more than price.
📦 BEST COMPACT LOAD · ⭐ 4.5/55. B&K Precision 8540
0 to 60 V · up to 30 A · 150 W · CC, CV, CR · 3 A and 30 A ranges · stores 400 settings
Buy Here →
The 8540 is B&K’s compact, half-width load. Its 0 to 60 V input covers every voltage an ESP32 project normally uses, from single cells to 48 V PoE style rails, and it sinks up to 30 A and 150 W in CC, CV and CR modes. Two current ranges, 3 A and 30 A, give finer control at the low currents ESP32 boards draw, and it can store 400 settings for repeatable tests. The narrow case suits a small bench or a shelf above it.
✅ Pros: Small footprint; 3 A low range; trusted brand.
❌ Cons: 60 V limit; no constant power mode.
🎯 Verdict: The best fit for a compact bench that only tests low-voltage supplies and batteries.
➕ Also Worth Considering
📈 BEST FOR AUTOMATED TESTS · ⭐ 4.7/5
6. Rigol DL3021
Rigol’s popular bench load sinks 150 V, 40 A and 200 W with 0.1 mV / 0.1 mA readback resolution. Beyond CC, CV, CR and CP it has three dynamic modes (continuous, pulsed and toggled), a list function of up to 512 steps and built-in battery, OCP and OPP tests, so it can step a supply through a whole load profile on its own. RS-232 and USB are built in.
Buy Here →🌐 BEST NETWORKED VALUE · ⭐ 4.4/5
7. Korad KEL103
The KEL103 offers 300 W, 30 A and 120 V in CC, CR, CV and CW modes, with USB, RS-232 and LAN interfaces and fine 0.1 mV / 0.1 mA resolution in its low ranges. The LAN port makes it a favourite for makers who log battery discharge curves from a script. Build quality and firmware are simpler than Siglent or Rigol, but the power rating is generous for the class.
Buy Here →💰 BEST BUDGET HIGH POWER · ⭐ 4.3/5
8. East Tester ET5410A+
A single-channel programmable load rated 150 V, 40 A and 400 W, with CC, CV, CR and CP modes, a color screen and battery capacity and internal resistance testing. It delivers a lot of power for the money, which suits big battery packs and 24 V supplies, though independent reviews note that real-world resolution can be coarser than the headline 1 mV / 1 mA figure.
Buy Here →🧪 Which Load for Which ESP32 Job?
| ESP32 Job | Mode to Use | Best Pick |
|---|
| 3.3 V regulator under Wi-Fi bursts | CC dynamic | Siglent SDL1020X-E |
| 18650 and LiPo capacity test | Battery discharge | Siglent SDL1020X-E or Rigol DL3021 |
| Solar charger and MPPT testing | CV, CC+CV | Maynuo M9711 |
| 12 V and 24 V LED strip supplies | CC or CP | Siglent SDL1030X-E or Korad KEL103 |
| Scripted production or class tests | List and remote control | B&K Precision 8600 or Rigol DL3021 |
| Large battery banks on a budget | CC or CP | East Tester ET5410A+ |
🛒 Which One Should You Buy?
🏆
First load for an ESP32 bench
The Siglent SDL1020X-E does everything most makers need.
☀️
Chargers and solar projects
The Maynuo M9711 for its combined CC+CV and CR+CV modes.
⚡
12 V and 24 V power
The Siglent SDL1030X-E, or the East Tester ET5410A+ on a budget.
🏢
Lab, school or small business
The B&K Precision 8600, or the compact 8540 for low-voltage work.
❓ Frequently Asked Questions
Do I need an electronic load if I already have a bench power supply?
They do opposite jobs. A bench supply sources power to your ESP32; an electronic load sinks power from a supply or battery to test it. If you design your own regulators, use battery power or buy cheap converters, a load is how you check them.
How do I simulate an ESP32’s Wi-Fi current peaks?
Use the dynamic (transient) CC mode: set a low level for idle current and a high level for transmit, then switch between them at a fast rate. Watch the regulator output with an oscilloscope to see how far it dips and how quickly it recovers.
Can an electronic load measure ESP32 deep-sleep current?
No. Loads sink a set current; they don’t measure what your board draws, and their resolution is in milliamps. Use a USB power meter, a microamp-capable multimeter or a current profiler for sleep measurements.
How much power rating do I need?
Multiply the highest voltage by the highest current you will test. A 5 V, 3 A USB supply is only 15 W, so any load here is plenty. Testing a 24 V, 10 A LED supply needs 240 W, which calls for a 300 W or 400 W load.
Is it safe to discharge lithium batteries with a load?
Yes, if you set a sensible cut-off voltage and a discharge current within the cell’s rating, and never leave a test unattended. Use the load’s battery test mode so it stops automatically at the cut-off.
🏁 Final Verdict: Best DC Electronic Loads
The right load for each job:
🔥 Best for Higher Power: Siglent SDL1030X-E
Buy Here →📈 Best for Automated Tests: Rigol DL3021
Buy Here →💰 Best Budget High Power: East Tester ET5410A+
Buy Here →For most ESP32 benches, the Siglent SDL1020X-E is the load to buy: fast dynamic mode for Wi-Fi burst testing, a proper battery test and remote control for logging. Choose the Maynuo M9711 for charger and solar work, the SDL1030X-E or ET5410A+ for higher power, and the B&K Precision loads when warranty and support come first. Pair your load with a good source and meters from our bench power supplies, USB power meters and LiPo and 18650 chargers guides, and plan the rest of your bench with our ESP32 electronics lab guide.
💬 What supply or battery are you trying to test? Tell us in the comments below, and we’ll suggest the right load and settings.
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We are a team of experienced Embedded Software Developers with skills in developing Embedded Linux, RTOS, and IoT products from scratch to deployment with a demonstrated history of working in the embedded software industry. Contact us for your projects: admin@esp32tutorials.com
