Burn watts on purpose.
Learn what your batteries are hiding.

1 · Mental model A resistor that takes orders and keeps a diary

An electronic load is a resistor that changes its value on command and then confesses exactly what happened. You set one rule (hold this current, hold this power), the BW150's MOSFET turns the source's energy into heat under that rule, and six meters record what the source did while it was being drained. Every test in this guide is one rule plus one honest log.

1.2 · The four rules

Choose which quantity the BW150 pins, and the source has to live with it. Everything else on the device is either a preset recipe built from these four (BRT, PT, CT, the cycle modes) or a way to display them (the curve tiles).

1.3 · The diary: six meters and four tripwires

Every measurement screen on the BW150 has the same anatomy (dissected in §7): the setpoint at the top, six readouts on the left, the stop conditions on the right. The six readouts split into three meters that show right now (Vol, Cur, Pwr), one derived value (Res = V ÷ I, which reads 9999.99 Ω when nothing is connected) and two integrators that accumulate since you pressed start (Ene in Wh and Cap in mAh). The integrators are the product; the meters are how you check the product is being made honestly.

The four tripwires are the rules under which the device stops on its own: a cutoff voltage (the "empty" line for a battery), an over-power limit, an over-temperature limit for the MOSFET, and an optional time limit. They show on the screen as Run Stop: <003.0V >0150W >100°C and Limit time: OFF, and are edited right there by holding Setup (§5.3). Set the cutoff wrong and the device will happily discharge a lithium cell into a paperweight; §9 gives the numbers.

1.4 · What you will be able to do

• Explain which quantity each mode pins and why CV and CP are forbidden for batteries.
• Perform a 4-wire capacity test on any cell from a coin cell to a 12 V lead-acid block and report Wh, mAh and internal resistance with the C-rate and cutoff stated.
• Characterize a USB charger or power bank: rated versus real current, real power at each PD/QC voltage, and cable resistance.
• Run unattended charge-discharge cycles with the charging-control module and read the per-cycle table.
• Debug a test that stopped early, a reading that looks wrong, an app that will not pair, and every alarm the device can raise.

Sources: BW150 User Manual §5 (test modes) · §10 (alarms) · CC-screen capture 2026-09-05.

2 · Prerequisite floor What you need before the first amp

This guide assumes you can use a multimeter and know which end of a battery is which. It assumes nothing about electronic loads. Everything above this floor is taught in place; everything below it is yours to bring.

Hard prerequisites

• Polarity discipline. Red to plus, black to minus, checked twice. The BW150's start-up screen says "Connect positive and negative!" because the terminal block does not forgive.
• Your chemistry's numbers. For every cell you will test, know its nominal voltage, its full-charge voltage and a safe empty voltage. §9 has a table, but you must know which row you are on.
• A 12 V supply you trust. The BW150 ships with no power adapter. A DC 5.5 mm barrel 12 V supply is the least fussy option, and the cycling modes require 12 V (§3.2).
• A phone with Bluetooth and a 2.4 GHz WiFi network if you want the apps. The device will not join 5 GHz networks, full stop.

Soft prerequisites

• A spreadsheet habit. The device records ten groups of results (BAT 01 to BAT 10), but your log is the one you will still have next year.
• A passing familiarity with USB Power Delivery voltages (5, 9, 12, 15, 20, 28 V). §10 introduces what you need.
• Having read a datasheet for at least one battery. Not required, but it makes §9 land faster.

Self-assessment

Tick what you can do without looking anything up. Anything unticked has a section number next to it.

• State why a 3000 mAh 18650 and a 3000 mAh NiMH AA store very different energy. (§1 Level 1)
• Convert "0.5C for a 2600 mAh cell" into amps. (§1 Level 1, §9)
• Explain why a 4-wire measurement reads higher than a 2-wire one at 3 A. (§1 Level 1, §6)
• Name the safe empty voltage for a lithium-ion cell and for a NiMH cell. (§9)
• Say which of CC, CV, CR, CP you would use to test a 65 W USB-C charger. (§1.2, §10)
• Identify the four terminals A+, V+, V−, A− on the board without the manual. (§3, §6)
• Explain what Res: 9999.99 Ω means on the measurement screen. (§1.3, §7)
• List the three power ceilings and the voltages at which they change. (§3.3)

Sources: attention-screen capture · BW150 User Manual §2 (power supply) · §6 (online).

3 · Board tour A bare PCB with a CPU cooler bolted to it

The BW150 is a naked board with a heatsink and fan standing on it. Nothing hides behind a case, which is convenient for wiring and inconvenient for coffee. Learn the six regions once and the rest of the guide reads like a map.

3.1 · The six regions

3.2 · Powering it: three ways, one recommendation

No adapter is in the box. The manual lists three ways to power the board, all of which go into the top-left corner, and then adds in yellow that a DC 12 V supply is "needed to work". Read that as: 5 V will light it up, 12 V is what it was designed around.

3.3 · The power envelope, and the cliff at 36 V

The BW150 is a 150 W load only while the input voltage stays under 36 V. Above 36 V it limits itself to 60 W, and above 80 V to 45 W. The board says so in silkscreen next to the heatsink, and the device repeats it on a Tips screen at every power-on. The same screen suggests bigger siblings (DL24MP, DL24EW) for high-voltage, high-power work.

3.4 · The four alarms

The manual calls them the "four major alarm functions". Each one stops the load, sounds the buzzer and prints a code on the screen. Three are thresholds you set in the settings menu (§12); the fourth is the external probe.

The probe alarm is the one worth configuring on purpose. Tape the NTC probe to the cell under test, set the Ext.T limit to something a healthy cell never reaches (45 °C for lithium is a sane ceiling), and the BW150 becomes a thermal cutout for the battery, not just for itself.

3.5 · What is in the box, and what is not

Sources: BW150 User Manual §1 (structure) · §2 (power) · §10 (alarms) · §11 (accessories) · Tips-screen capture.

4 · First power-on The four-minute monologue, and how to end it

Power the BW150 and it talks for about four minutes before it lets you do anything. Every screen carries a countdown in the corner and a way to skip it. Here is the whole monologue, screen by screen, so you never have to read it on a 2.4-inch display again.

1. Language selectioncountdown 02 s English, 中文, or Start-up Info OFF. The third choice is not a language: it is the switch that silences the screens that follow on every future boot. +/− move, OK confirms.
2. Download screen58 s A QR code to the manual and software download page. OK skips it.
3. Hardware self-testruns on its own Software init, voltage sampling ✓, current sampling ✓, WiFi chip ✓, Bluetooth chip ✓, "Start WIFI program", then "About to enter the network program or function program". Hold + to skip.
4. Attention19 s Six rules: do not disassemble, mind polarity, 2.4 GHz only, phone Bluetooth on, phone GPS permission on, and "power-on information can be closed through background set". OK for Next.
5. Key Tip19 s The entire button grammar in one dense paragraph. Decoded properly in §5.
6. Online Tip24 s Download Smart Life or Tuya, 2.4 GHz only, Bluetooth and location permissions on.
7. Waiting network…60 s A Tuya pairing QR code and a progress bar while the WiFi chip looks for a network. Next skips it; no network is required to use the load.
8. Tips: maximum power13 s The derating rules from §3.3. OK dismisses.
9. Main menu Twelve tiles on page one, six more on page two. You are in.

4.1 · The main menu, decoded

Sources: nine boot-sequence captures 2026-09-05 · BW150 User Manual §3 (main functional interface) · §9 (background introduction).

5 · The four buttons Two press lengths, eight verbs

Four buttons and two press lengths give you eight verbs, and every screen on the device reads with the same grammar. Learn it once here, then practise on the virtual front panel below until the real board feels obvious.

5.1 · The grammar

"Short" is a tap. "Long" is holding until the screen reacts, about a second. The device makes no sound to tell you the long press registered; watch the display.

5.2 · Editing a number, digit by digit

Setpoints are edited one digit at a time. The magenta underline on the screen (visible in the CC capture in §7 under the second digit of 01.0000) marks the digit that +/− will change. Each digit wraps on its own: + on a 9 gives 0, − on a 0 gives 9, and nothing carries into the neighbour. Setup moves the underline to the next digit and wraps around. To set 2.500 A from 1.000 A: tap Setup until the units digit is underlined, tap + once, tap Setup to reach the first decimal, tap + five times, then OK.

5.3 · Cursor mode: the recording group, the tripwires and the timer

The cutoff voltage, the power and temperature limits, the time limit and the BAT recording group are all edited on the measurement screen itself. Hold Setup and the BAT number in the footer lights up: +/− pick the group, 01 to 10. Each further tap of Setup moves the cursor one place along the right-hand panel: through the digits of the Run Stop voltage (<003.0V), then the wattage (>0150W), then the temperature (>100°C), then the hours and the minutes of Limit time, and finally to Save. OK does the same as Setup here: it steps to the next field, it does not start the load. At every stop, +/− change the value under the cursor, and every field wraps at its ends: a digit goes 9 → 0, BAT goes 10 → 01, minutes go 59 → 00.

Two ways out. Step onto Save and press once more, and the device leaves cursor mode with the new values. Or leave the buttons alone for five seconds, and it exits and saves whatever is on the screen by itself. That second exit is also the trap: if you are interrupted mid-edit, whatever was showing at the five-second mark is what got saved. Read the panel back before you start the load.

5.4 · Virtual front panel

A working replica of the navigation, with a pretend battery on the terminals so the meters move. Click a button for a short press, hold it for a long press. Keyboard: ← → are − and +, Enter is OK, S is Setup; hold a key for a long press. The simulation runs sixty times faster than real life, so a capacity test takes minutes, not hours.

Sources: Key Tip capture · button-cluster photo · CC and UREG captures 2026-09-05 · cursor-mode behaviour observed on the unit 2026-09-06 · BW150 User Manual §9.

6 · Wiring Where every wrong number begins

Every wrong number this device will ever show you starts at the terminal block. Polarity, lead resistance and the choice between two wires and four decide whether the log you get is about the battery or about your clips.

6.1 · Two wires or four

The rule: 2-wire for a look, 4-wire for anything you write down. Under 1 A on a large cell the error is a rounding error; at 0.5C on an 18650 it is a real capacity error; on a 12 V block at 5 A it is the difference between a good battery and a condemned one.

6.2 · Hooking up

1. Load off, source disconnected. Never wire live. Hold OK to return to the menu if a mode is open.
2. Current pair first. Red clip or wire to A+, black to A−. The manual: the cell "must be connected to the 2 terminals [A+] and [A−]". Tighten the screws; a loose terminal is a resistor.
3. Sense pair second, one of two ways. 2-wire: two short jumper wires at the block, A+ to V+ and A− to V−, as in the manual's diagram. 4-wire: no jumpers; a second red lead from the battery's positive terminal to V+, a second black lead from the negative terminal to V−, clipped on the cell terminals themselves, not on the current clips. Either way V+/V− must be connected to something, or the voltmeter has nothing to read.
4. Probe. Tape the NTC probe to the cell body. ETS:Wait.. becomes a temperature within a few seconds.
5. Check before you press. Open the mode. With the load still OFF, Vol should show the cell's resting voltage. If it shows zero, V+/V− are open: a jumper or a sense lead is missing or loose. If it is negative or the buzzer complains, polarity is reversed. Expect: a rested 18650 reads 3.6 to 4.2 V; a 12 V lead-acid block 12.4 to 12.9 V; a NiMH AA 1.25 to 1.4 V.

6.3 · Fixtures and adapter boards

Three kinds of thing plug into the terminal block, and each has its own wiring habit:

• Bare cells go in a 4-wire fixture (the 20 A battery box or the 5-in-1 holder). Both bring out four wires: two thick for current, two thin for sense. Match colour to terminal and you are done.
• USB sources (chargers, power banks, cables) go through the measuring line adapter board: plug the source in on one side, run its two output wires to A+ and A−, and keep the A+→V+ and A−→V− jumpers in place. It is a 2-wire connection by nature; USB testing lives at currents where that is acceptable (§10).
• Fast-charge negotiation goes through the trigger board, which hands the negotiated voltage to the load over four wires: A+, V+, V−, A− (§10.3).

Sources: BW150 User Manual §4 (wiring method) · §11 (accessories) · Attention-screen capture.

7 · CC & the measurement screen Thirteen things on a 2.4-inch display

Constant current is the mode you will use nine times out of ten, and its screen is the template for every other mode. Learn the thirteen things on it once and you can read any BW150 screen, in any mode, at a glance from across the bench.

1. Mode and setpoint. CC and Is=01.0000A: the rule and its value. In CV this reads Vs=, in CP Ps=, in CR Rs=. The magenta underline is the edit cursor (§5.2).
2. Vol (yellow): voltage at the V terminals, in volts, 1 mV resolution.
3. Cur (lime): current through the A terminals, 1 mA resolution.
4. Pwr (cyan): V × I, computed.
5. Res (orange): V ÷ I, computed. 9999.99 Ω means no current is flowing.
6. Ene (white): energy integrated since start, in Wh. The honest number.
7. Cap (cyan): charge integrated since start, in mAh. The label number.
8. Run Stop. The tripwires: <003.0V stop below this voltage, >0150W stop above this power, >100°C stop above this MOSFET temperature. Edited in place: hold Setup (§5.3).
9. Limit time. OFF, or a countdown in hours and minutes after which the load stops on its own (Settings 05, or cursor mode, §5.3).
10. CPU.T / MOS.T. Processor and MOSFET temperatures. MOS.T is the one that matters under load.
11. FAN.Speed. RPM. It rises with MOS.T; a sudden drop to zero is a fan failure and a reason to stop.
12. ON / OFF. Whether the load is sinking current right now. Magenta OFF, yellow ON.
13. Footer. BAT 02 is the recording group (ten exist; chosen in cursor mode, §5.3), 000:00:00 is elapsed run time in h:mm:ss, ETS:Wait.. is the external probe status (a temperature once a probe is plugged in).

7.1 · Running a constant-current discharge

1. Wire the source (4-wire for a battery, §6). From the main menu open CC. Expect: Vol shows the resting voltage, OFF in magenta.
2. Set the current: Setup to enter edit, Setup to walk the digits, +/− to change, OK to confirm.
3. Hold Setup for cursor mode (§5.3). Pick the BAT group the run should be filed under, tap Setup onto the Run Stop voltage and set the cutoff for your chemistry (§9.1). Tap on to Save and press OK, or wait five seconds. Expect: the highlight clears and Run Stop shows your cutoff.
4. Tap OK. Watch the first ten seconds. Expect: ON, Cur equals the setpoint, Vol dips and settles, the fan speeds up, Cap starts counting.
5. Leave it. The load stops itself at the cutoff and the integrators freeze. Read Cap, Ene and the elapsed time from the footer, and write all three down with the current and the cutoff.

7.2 · UREG: the load is on, but nothing is home

UREG is not in the manual. On this unit it appears the moment you start the load with no source on the terminals, and disappears when you stop it. Read it as unregulated: the load is switched on but cannot reach its setpoint, because there is no voltage to draw current from. This matches what bench loads from other makers display as UNREG. By the same logic it should also appear mid-test if the source collapses or hits its own current limit below the setpoint, which makes it a useful sign that a charger has given up, but that case has not been captured on this unit and is marked as an inference.

7.3 · The curve tiles

The tiles on the menu with a wave symbol (CC~, CV~, CR~, CP~ and, with the module, CDC~ and CDCDC~) run the same modes but replace the numeric screen with a live plot of voltage and current against time. They are the right choice when the shape matters more than the total: a battery's discharge knee, a charger's droop under a step, a supply's recovery. The vendor's photographs show a green grid with voltage in yellow and current in magenta. No capture of the curve screen was made for this guide, so treat the details above as the manual's description rather than a verified observation.

Sources: CC and UREG captures 2026-09-05 · BW150 User Manual §1 (structure), §3, §5 (CC), §8 (curves).

8 · CV · CR · CP Three other rules, and what they are for

The other three rules exist because not every source is a battery. A supply with a current limit wants CV; a gadget you are imitating wants CR; a charger rated in watts wants CP. Pick by asking what the source can do, not by what sounds precise.

8.1 · The wrong question and the right one

The wrong question is "which mode is most accurate?". They are all the same meters. The right question is "what does my source do when I ask for more than it has?" A battery gives more current and sags; that is fine for CC and lethal for CV and CP, which chase the sag. A regulated supply hits its current limit and drops voltage; CV maps that limit exactly. A charger negotiates a voltage and has a wattage on the label; CP checks the label.

Sources: BW150 User Manual §5 (CV, CP, CR) · §1.2 of this guide.

9 · Battery labs Capacity, resistance, and the numbers you must not guess

A capacity test is a discharge at a stated current to a stated cutoff, with the voltage measured at the cell and the temperature watched. Get any of those four wrong and the mAh you write down describes the test, not the battery. This section gives you the numbers, the recipe and a health check that takes ninety seconds.

9.1 · Chemistry table: the voltages you set

The "rating" cutoffs are what manufacturers use; the "to set" cutoffs are what a hobbyist who wants the cell back should use. The difference is a few percent of capacity and a great deal of cycle life.

9.2 · BRT: internal resistance in ninety seconds

BRT is a recipe, not a rule. Select it, wire the cell 4-wire, tap OK, and the BW150 steps the current up through a ladder (the manual's screen shows 0.1, 0.2, 0.4 … 1.8 A), records the voltage at each step, fits the slope and prints a single number: "Analog AC integrated average internal resistance", 53 mΩ in the vendor's example. The manual's guidance: "small battery tests low current internal resistance, big battery tests high current internal resistance", which is its way of saying the ladder scales with what the cell can supply.

These bands are hobbyist rules of thumb for 18650-class cells measured this way, not vendor specifications; a large prismatic cell or a lead-acid block has its own scale. The value depends on temperature and on state of charge, so compare BRT numbers only between cells tested the same way on the same afternoon.

9.3 · The capacity test, done properly

Sources: BW150 User Manual §5 (BRT) · §11, §12 (fixtures and cell types) · chemistry voltages are standard values, not from the manual.

10 · Charger & cable labs PT, CT and the trigger board

USB chargers, power banks and cables are where marketing meets the terminal block. The BW150 has two automatic recipes for them, PT and CT, and with the trigger board it can ask a fast charger for every voltage it claims to offer and then lean on each one.

10.1 · PT: what a supply can really deliver

PT ("power tester") ramps the load up on a DC source and reports four numbers: rated output current, rated output power, maximum output current, maximum output power. The vendor's screen shows the ramp as a table of voltage against current and power (e.g. 5.05 V at 0.5 A, 4.98 V at 1.0 A, 4.62 V at 3.0 A) followed by the four results. The manual's own caveat is worth quoting: "This result is not an absolute value, but as a relative value." PT tells you where a charger starts to sag and where it quits; the exact watt figure is an estimate of that, not a certification.

1. Plug the charger into the measuring line adapter board (USB-A, micro, mini or Type-C socket). Run its two output wires to A+ and A−.
2. From the main menu open PT. Expect: the charger's open-circuit voltage in the header, about 5.1–5.2 V for a USB-A charger, and a "Start" cue.
3. Tap OK and wait for the ramp. Expect: rows filling in as current rises, then four result lines: rated current, rated power, max current, max power.

10.2 · CT: cable resistance from a voltage drop

CT measures a cable by putting it between a stiff 5 V source and the load, then drawing current until the voltage at the load end has dropped by a set amount. The vendor's screen shows steps of 0.1 to 0.7 V of drop, the current that caused each, and the resistance that implies (R = ΔV ÷ I). It ends with four numbers: an average cable resistance and the current the cable can pass at 0.3 V, 0.5 V and 0.7 V of drop. That last trio is the practical one: a cable that only carries 1 A before it drops half a volt is a cable that will make a fast charger fall back to 5 W.

1. Source: a USB-A charger you trust (its PT result from 10.1 tells you it is stiff). Cable under test from the charger to the adapter board's matching socket. Adapter board wires to A+ / A−.
2. Open CT. Tap OK. Expect: the empty (no-load) voltage, then one row per drop step, then "Cable average resistance assessment" in mΩ and the three current-at-drop lines.
3. Repeat with a second cable. The difference between a good and a bad cable is usually 3× or more, which is why this test is worth doing once on every cable you own.

10.3 · The trigger board: asking for 9, 12, 15, 20 or 28 V

A USB-C charger sits at 5 V until a device asks for more using the Power Delivery protocol. The DL24B-XSP16 trigger board does the asking. It has four inputs (DC 5.5 barrel, mini-USB, micro-USB, and Type-C for PD/QC/AFC/FCP), two buttons (V− and V+) to step through the voltages the charger offers, and four output wires to the load's A+, V+, V−, A−. Once the charger has agreed to a voltage, the load sees it as a plain DC source and any mode applies; CP is the natural one.

Sources: BW150 User Manual §5 (PT, CT) · §11 (adapter board, trigger board) · DL24B-XSP16 operation page in the manual.

11 · Cycling CDC · CDCDC · CDxN with the charging-control module

A capacity test tells you where a cell is today. A cycle test tells you where it is going. The charging-control module lets the BW150 hand the cell to a charger, take it back, discharge it, and repeat, unattended, for up to 99 rounds, logging each one.

11.1 · The three cycle modes

11.2 · Wiring the module

The module is a switch board. Its four-pin lead goes to the BW150's header (S, GND, CTL+, D), the battery connects to the module, the charger connects to the module, and the module's other side goes to the load's terminals. During a charge phase the BW150 closes the charger onto the battery and idles; during a discharge phase it opens the charger and sinks current itself. Two requirements from the manual are not optional:

• "Insert DC12V power supply for power supply." The module's relay wants 12 V on the barrel jack; USB 5 V board power is not enough.
• "Must be connect Battery Dedicated charger!!!" The charger in the loop must be a proper charger for that chemistry with its own termination. The BW150's charge-cutoff settings (§12, items 10 and 11) decide when the load hands over; the charger decides how the cell is actually charged. A bench supply is not a charger.

11.3 · Settings that govern a cycle

Charge cutoff by current is the honest one: a charger tapers current as the cell fills, and "under 50 mA at 4.2 V" is what "full" means. The voltage cutoff alone would end the phase at the start of the taper, with the cell at 80–90 %.

Sources: BW150 User Manual §5 (CDC, CDCDC, CDxN), CDC wiring photograph, §9 (settings map), §11 (charging control switch board warning).

12 · Settings menu Twenty-three items behind the gear

Everything the measurement screens do not let you set lives behind the gear tile: alarms, cutoffs, calibration, brightness, the boot monologue, and the two buttons that erase things. The manual calls it the "background" and warns that its layout "may change". On firmware 1.1.0 it has twenty-three rows.

12.1 · Getting there and back

1. From any measurement screen hold OK to return to the main menu.
2. Tap + or − until the Settings gear turns green. Tap OK. Expect: "BenFang Sys Settings" with a numbered list; the first page shows items 01 to 06.
3. Tap +/− to move down and up the list (it scrolls through further pages). Tap OK to open an item. Expect: a single-value page for that item, edited with +/− and confirmed with OK.
4. Move to 23 · Exit and tap OK, or hold OK, to leave.

12.2 · All twenty-three, with opinions

The "value seen" column is read from the low-resolution settings map in the manual and from the measurement screens; treat the figures as the vendor's example state rather than a promise of your unit's defaults.

Sources: BW150 User Manual §9 (product background introduction, settings map) · main-menu and CC captures 2026-09-05.

13 · Going online Bluetooth, WiFi, Windows, and a Mac

The BW150 talks to three kinds of software and none of them is the one you want. The PC program does everything and runs only on Windows. The Bluetooth app runs on your phone and the manual tells you not to rely on it. The WiFi app works from anywhere and cannot export. Know what each is for and you will stop fighting them.

13.1 · On a Mac

The PC software is Windows-only and nothing in the manual suggests otherwise. Your options, in order of effort: use the phone apps and your own spreadsheet (this guide's labs assume that); keep an old Windows laptop on the bench for XLS export and firmware; or run Windows in a virtual machine with the HID device passed through to it. The last option is not tested for this guide and USB passthrough of HID devices varies between VM products; treat it as an experiment, not a plan.

13.2 · Bluetooth from an iPhone

The device advertises two Bluetooth names, one ending in _BLE and one in _SPP. The manual is explicit: do not pair in the phone's Bluetooth settings. Open the app, tap its Bluetooth symbol, and pick the _BLE name from the app's own list. _SPP is classic Bluetooth for a PC, where the pairing code is 0000 or 1234.

13.3 · WiFi through Smart Life or Tuya

The WiFi path uses the Tuya cloud, so the phone app is Tuya's own (Smart Life) or the Tuya-branded twin. Pairing is the usual Tuya dance: 2.4 GHz network, phone on that network, phone Bluetooth on (Tuya uses it for the handshake), add device, and either scan the QR code the BW150 shows on its "Waiting network…" boot screen or let the app discover it. If it will not pair, Settings 18 · WIFI Device Reset forgets the old pairing and the boot screen shows the QR again.

What the app shows once paired, from the manual's screenshot: a RunMode row of buttons (CC, CV, CR, CP, BRT, PT, CT, CDC, CDCDC), the setpoint with − and + controls, the discharge stop voltage, the charging stop voltage, the fan-open temperature, and live voltage, current, power, capacity and the three temperatures. Because it goes through the cloud, it works from anywhere, which is the one thing the other two channels cannot offer.

13.4 · Firmware upgrades

Two channels: over the HID cable from the PC software's firmware window, or remotely over WiFi. The vendor publishes the .bin on its website; the manual gives the software download and a link to a zip that the PC program updates from. The rules that matter: board on a power supply you trust, nothing on the terminals, and do not touch anything until the bar is full and the device has rebooted to the language screen. A firmware upgrade that is interrupted is the one repair this guide cannot help you with.

Sources: BW150 User Manual §6 (online instructions, software FAQ), §7 (firmware upgrade) · Product-upgrading capture 2026-09-05 · PC software: vendor zip · Android APK: vendor link (both as printed in the manual; not verified for this guide).

14 · Capstone One cell, fully characterized

Take one cell you care about and produce its datasheet: resting voltage, internal resistance, capacity at two rates, energy, temperature behaviour, and a verdict. Every phase uses something taught above, and the deliverable is a card you would be happy to tape to the cell.

Phase A · Intake (10 minutes)

1. Label the cell. Note the printed capacity and chemistry. Charge it fully on its dedicated charger and rest it 30 minutes.
2. 4-wire fixture, probe taped on. Open CC, load off, read Vol and ETS. Record both as "resting".
3. Open BRT, tap OK, record the averaged mΩ figure.

Phase B · Rated capacity at 0.2C (about 5 hours, unattended)

1. Settings: 09 Discharge Cutoff 3.0 V, 14 Ext.T 45 °C, 12 OCP at your cable rating.
2. CC, Is = 0.2C from the planner. Tap OK. Watch two minutes, then leave it.
3. When it stops: record Cap, Ene, elapsed time, peak ETS.

Phase C · Recharge and rest (charger time + 30 minutes)

1. Dedicated charger to full. Rest 30 minutes. Record the resting voltage again; it should match Phase A to within 20 mV.

Phase D · Working capacity at 1C (about 1 hour)

1. Same wiring, same cutoff, Is = 1C. Tap OK. This run heats the cell; check ETS at 10 and 30 minutes.
2. When it stops: record Cap, Ene, elapsed time, peak ETS, and the Vol reading ten seconds after start (the sag).

Phase E · The card

Rubric

Phase F, if you own the module: CDxN with N = 3 at 0.5C, rest time 15 minutes, and read the CD-Cyclic table. A cell whose capacity drops more than 1–2 % per cycle over three cycles is telling you something the single test could not.

15 · Troubleshooting Symptom, cause, fix

Most BW150 problems are wiring, most of the rest are settings, and the remainder are the apps. Find the symptom, apply the fix, and if the fix is "check the clips" do it before reading further.

Sources: BW150 User Manual §6 (software FAQ), §10 (alarms) · captures 2026-09-05 · the rest is general electronic-load and wiring practice rather than observation of this unit.

16 · Cheat sheet One page to tape to the bench

Everything you need at the terminal block, with the section that explains it in brackets.

17 · Glossary Every term of art, with where it was taught

Measuring line adapter board

The kit's small PCB with USB-A, mini-USB, micro-USB and Type-C sockets and two output wires. It is how a USB source reaches the terminal block. (§6.3, §10.1)

BenFang System

The firmware's name for itself, shown on the second menu page and in the settings title. Version 1.1.0 on the unit captured. (§4.1)

BRT

Battery resistance test. An automatic current ladder that reports an averaged internal resistance in mΩ. (§9.2)

C-rate

Current expressed as a multiple of the capacity per hour. 1C empties the rated capacity in one hour; 0.2C in five. (§1 Level 1)

CC · CV · CR · CP

Constant current, constant voltage, constant resistance, constant power: the four rules, each pinning one quantity and leaving the source the rest. (§1.2, §8)

CC port

The Type-C socket that powers the BW150 from a USB or QC/PD charger. Unrelated to CC mode and not a test input. (§3.2)

CDC · CDCDC · CDxN

Cycle modes: charge-discharge-charge (3 phases), five phases, and N cycles from 1 to 99. All need the charging-control module. (§11.1)

Charging-control module

A separately sold relay board on the S/GND/CTL+/D header that switches the cell between a dedicated charger and the load during cycle modes. Needs 12 V board power. (§11.2)

Cursor mode

The in-place editor for the BAT group, the Run Stop values and Limit time: hold Setup; tap Setup or OK to move; end at Save, or wait five seconds. (§5.3)

CT

Cable test. Draws current through a cable until the load-end voltage has dropped by set steps, reporting resistance and the current at 0.3, 0.5 and 0.7 V of drop. (§10.2)

Cutoff voltage

The voltage at which a discharge stops on its own; shown as <003.0V under Run Stop. The setting that decides whether a cell survives the test. (§1.3, §9.1)

Derating

The load's self-imposed power ceiling that falls with input voltage: 150 W under 36 V, 60 W above, 45 W above 80 V. (§3.3)

DUT

Device under test: whatever is on the terminal block. (§1.2)

E-marker

A chip inside a USB-C cable that declares its current and voltage rating; required for PD 3.1's 28 V. (§10.3)

ETS

External temperature sensor: the NTC probe on the ETS socket. ETS:Wait.. means none is plugged in. Its alarm is Settings 14. (§3.4)

E-test / E_test

The vendor's Bluetooth app for Android and iOS. Connect from inside the app to the _BLE name. The manual calls it a switch controller, not a logger. (§13.2)

HID

The Type-C "PC-USB" data port and the USB device class the BW150 uses to talk to the Windows software and to receive firmware. (§13)

Internal resistance

The series resistance inside a cell; causes the voltage sag under load and rises with age. Measured by BRT. (§1 Level 1, §9.2)

Kelvin (4-wire) sensing

Measuring voltage on a second pair of wires that carry no current, so lead resistance does not pollute the reading. The V+ / V− terminals. (§6.1)

mAh · Wh

Milliamp-hours count charge; watt-hours count energy. Compare cells in Wh at a stated rate and cutoff. (§1 Level 1)

MOS.T · CPU.T

MOSFET and processor temperatures on the screen. MOS.T is the one that trips OTP!(t Mos). (§7)

OPP · OCP · OTP

Over-power, over-current and over-temperature protection: the alarms. (§3.4)

PD · QC · AFC · FCP

Fast-charging protocols (USB Power Delivery, Qualcomm Quick Charge, Samsung Adaptive Fast Charging, Huawei Fast Charge Protocol) that the trigger board can negotiate. (§10.3)

PT

Power tester. Ramps the load on a DC source and reports rated and maximum current and power, as relative figures. (§10.1)

Recording group

BAT 01 to BAT 10 in the footer: one of ten result slots, chosen in cursor mode. Cleared by Settings 19. (§5.3, §7.1)

Res 9999.99 Ω

The resistance readout when no current flows: the device's spelling of "open circuit". (§1.3)

Setpoint

The value of the pinned quantity: Is, Vs, Rs or Ps at the top of the screen. Edited digit by digit. (§5.2)

Smart Life · Tuya

The cloud app (two brandings of the same thing) for the BW150's 2.4 GHz WiFi channel: remote view and control, no export. (§13.3)

Trigger board (DL24B-XSP16)

A separately sold board that requests PD/QC/AFC/FCP voltages from a charger and feeds the result to the load over four wires. (§10.3)

UREG

Screen title when the load is on but cannot regulate: no source connected, or (inferred) a source that cannot deliver the setpoint. Not in the manual. (§7.2)

18 · Index Terms, screens, settings and buttons

19 · Quiz Sixteen flashcards, self-scored

Reveal, then be honest. Aim for 13 of 16 before you trust yourself with a cell you cannot replace. Your score persists in this browser; the reset button below clears it.

20 · Sources Where every claim came from

Written against the vendor's BW150 User Manual (a 19-page Microsoft Print-to-PDF export of "BW150 User Manual.docx", dated 2024-12-24) and fourteen photographs of one unit running firmware 1.1.0 "BenFang System", taken 2026-09-05. The author of this file did not operate the hardware. Every "Expect" line is traced to a capture, to the manual, or to arithmetic, and is labelled Observed when it comes from a capture and Expected when it is an inference rather than a documented fact. Battery chemistry voltages, resistance bands and C-rate practice are standard hobbyist values, not the vendor's. External links require a network; the guide itself works offline.

• BW150 User Manual (PDF, ATorch, Dec 2024). The primary source: structure diagram, power options, wiring diagram, mode descriptions, settings map, alarm table, accessory list, DL24B-XSP16 page. Best used for the photographs this guide could only redraw.
• en.atorch.cn — the vendor site the manual's download links point to. Best used for the firmware .bin and the current PC software. Domain as printed in the manual; not verified for this guide.
• PC software zip — Windows 7 / 10+ program for live data, XLS export and HID firmware upgrade, as linked in manual §6.
• E-test Android APK — as linked in manual §6; the manual also says to search "E-test" on Google Play and "E_test" on the App Store.
• Battery University — best used for chemistry-by-chemistry discharge characteristics, C-rate practice and what "state of health" means.
• Peukert's law (Wikipedia) — best used for why capacity falls with discharge rate, the effect Lab 7 and the capstone measure.
• Four-terminal sensing (Wikipedia) — best used for the Kelvin-wiring principle behind V+ / V−.
• USB Power Delivery specification (USB-IF) — best used for the PD voltage levels and the E-marker requirement the trigger board relies on.

A guide is a snapshot, not a subscription. The manual warns that the settings layout "may change"; firmware later than 1.1.0 may move rows, rename tiles or add screens. Cross-check anything load-bearing against the screen in front of you.