What has changed in our documents and specifications since publication, and the limitations you should know about, by device.
Change log
Newest first. Dates are when the change went live on this site.
HXB-V1
Date
What changed
Handbook
Voltage and current setting rules now given in figures
Added the rule for choosing the voltage setting, the maximum current for each voltage setting, and why the unit can switch off when the current is lowered and how to avoid it.
Battery-limits drawing and troubleshooting flow added
Figure 3-1 in the installation chapter shows what is inside the unit, what your site provides, the clearances and the discharge points; the troubleshooting chapter opens with a where-to-start flow. The maintenance chapter's figure is renumbered 7-1 to match its chapter.
Downstream chapter widened to upstream and downstream
The DI water, electrolyte, power and control PC going into the unit are now gathered in a first section, What goes in, and Figure 8-1 is redrawn to show upstream and the downstream build-ups on one page. Figure 7-1 in the maintenance chapter is redrawn as a trend against your baseline.
Figure 8-1 shows three build-ups on one page (just preventing condensation; process feed or analysis; fuel cells, refuelling or storage) and whether to order 0 or 10 barg for each, including where a compressor's minimum suction makes 10 barg necessary.
Hydrogen outlet pressure is now chosen at order (0 / 10 barg; 35 barg by agreement)
The pressure mode that let you pick 0 or 10 barg in the control app has been removed. We now fit the relief valve for the pressure you choose when ordering, and a 10 barg unit always builds to 10 barg in operation. 35 barg is under verification and supplied by agreement. To depressurise before decommissioning, press Emergency STOP in the control app to open H2 VENT. The handbook, product specification, FAQ and related articles are updated.
What to do Units delivered earlier may still show the pressure mode in the app. Contact us if you want to change the pressure.
The PLC and SCADA integration section of the Operation and control chapter now lists what each of the four areas (coils, discrete inputs, input and holding registers) holds, their function codes and the float format (IEEE-754 32-bit, high word first). The full register map with every address will be published there once final.
Safety messages: consequences added and signal words corrected
Danger and warning boxes now say what happens if you ignore them (a blocked H2 VENT, electric shock, hot electrolyte, powering the stack without circulation and so on). Oxygen fire, which can injure people, moves up from notice to warning; equipment, warranty and record issues (freezing, make-up water, opening the enclosure, Logging, Clear All) move down to notice. Minor injuries such as lifting use caution. A line now says never to use oil or grease on oxygen lines and fittings.
Stopping before maintenance, DRAIN connection, electrolyte concentration, hydrogen leak check, hydrogen-in-oxygen limit, voltage at 50 A
The first warning in the maintenance chapter is now split by task: isolate mains for wiring and covers, switch off only Electrolyte Control and follow the replacement steps for an electrolyte change, and confirm zero pressure before opening hydrogen lines. DRAIN is the same 1/4″ ferrule fitting as the other ports with no valve, so it flows the moment the cap is off (it used to say it flows once the hose is on). Electrolyte from 0.1 to 1 M can be used; 0.1 M is recommended. The quick-start acceptance now includes a hydrogen leak check. The 2 vol% hydrogen-in-oxygen stop limit is now a warning in the safety and operation chapters. Stack voltage at 50 A is about 38 V new (datasheet 37.8 V) and typically about 40 V in service (same for the HXS-2).
What to do When you review your logs, 38–40 V at 50 A is normal. If you have not been measuring hydrogen in oxygen, consider fitting an analyser or detector after O2 OUT.
The maintenance chapter said when to change the electrolyte but not how. We added the procedure: stop electrolysis, switch Electrolyte Control off, drain through DRAIN, fill and prime as in the quick-start chapter, then take a new baseline and record it. DRAIN is the same ferrule fitting as the other ports, has no valve, flows the moment the cap is off and connects only to the electrolyte loop, so mains power and the pressure mode can stay as they are. The decommissioning chapter now has you confirm hydrogen pressure in the app before powering down.
The PLC and SCADA section of the operation chapter describes Modbus TCP, but the specification still said Modbus was not supported. The specification now reads Modbus TCP supported (not RTU), as do the FAQ and the product page.
The quick-start chapter has you enter 46 V in Power Control, while the setpoint table in the operation chapter said 40 V recommended. 46 V is the upper setting you enter in Power Control; 40 V is the voltage you actually see at 50 A. The table now reads set 46 V, about 40 V in operation.
What to do If you entered 40 V in Power Control, raise it to 46 V. With a 40 V limit the stack may not reach 50 A.
The emergency steps in the safety chapter said to activate the E-stop if there is one. The unit has no emergency-stop button and no external emergency-stop input; the only manual emergency stop is Emergency STOP in the control app. The red button on the front is Reset. The emergency steps, the PLC integration warning and the specification now say so.
What to do If your site needs an emergency stop, build it as an external circuit that cuts power to the unit.
On a circulation alarm, first take the current to 0 A
The actions for alarms EFM201 (Electrolyte circulation lost) and P201 (Circulation pump fault) now begin with “take the current to 0 A first (Power Control OFF)”. Symptom D gains two rows: make-up more frequent than usual with liquid at O2 OUT, and make-up overdue but never ran.
What to do On a circulation alarm, bring the current down before looking for the cause.
Change the electrolyte when its conductivity falls below half the baseline (measured right after a fresh fill). This widens the earlier ±20% band; the reason (about 1.1 V more stack voltage at 50 A) is now in the text. There is no longer an upper limit. More frequent make-up than usual is a sign that KOH is escaping — check for crossover or a leak first. Four printable forms (first start-up, routine checks, maintenance record, electrolyte log) use the same rule.
What to do Keep the baseline you have recorded; only move the decision line to half.
The alarm list now has one row per code, each with its own link, pairing the app message with its sensor label. Typing a code (for example EFM201) into search goes straight to its row.
Chapter references to the old manual now point to the current handbook and manual (chapter 3, Quick start; chapter 5, Maintenance), and the DC cable basis for running up to 80 A (80 A continuous) is added. No design values changed.
A 0–45 V, 0–50 A supply and 50 A cable are for rated operation at 50 A. We now add that running up to the stack maximum (80 A, 50.6 V) needs a 0–51 V, 0–80 A supply or larger and cable rated for 80 A continuous. The symptom “a single cell voltage shoots up” gains a line separating it from the supply hitting its voltage limit.
What to do If you run on a 45 V supply and the current falls by itself, check whether the supply has switched to constant voltage before suspecting a cell.
Added “raising the flow makes the pump noisy or the flow unsteady” to the symptom table. The cause is narrow suction or return tubing or an abrupt change in bore; use larger tubing and put any change in bore close to the tank.
HXS-30 drawings added: ports, DC terminals and lifting points, and the electrolyte loop
The quick-start chapter now has Figure 3-1 (the three ports on the end plate, the M12 lifting holes on top and the M10 DC terminals sticking up) and Figure 3-2 (tank, pump, heat exchanger, stack and hydrogen line). Front-view positions come from the end-plate 3D model.
Lifting points, flow, voltage limit, minimum current, heat and draining filled in
Values that said ask us are now filled in. Lift at four points with eyebolts (supplied by you) in the four M12 tapped holes on top of the end plates. Recommended electrolyte flow is 40 L/min and the stack voltage limit is 101.2 V (2.2 V per cell). We added how to calculate the minimum current from hydrogen in oxygen measured at rated current, and a formula and table for heat versus stack voltage. The decommissioning chapter now gives a draining sequence: out through the bottom inlet, then the remainder pushed out with low-pressure gas (0.3 bar or less).
What to do If you sized the cooling for the first-run voltage, check it again against the highest voltage you will keep running to.
Figure 3-1 in the formats chapter compares the three standard formats in size and thickness at one scale, and Figure 4-1 now marks the HXP-ca catalyst face toward the membrane.
Measurement comparison wording corrected (half-cell vs cell voltage, current limit, temperature and concentration)
Three explanations in the performance chapter were corrected. A half-cell test measures the potential of one working electrode, while a cell voltage contains the equilibrium voltage, the overpotentials of both electrodes and the resistive losses. Where current stops rising before 1.8 V, the text no longer says it is not a fault; it asks you to check the instrument's current-limit indication and the actual current first. 'Lower temperature or concentration raises the cell voltage' now reads that a different temperature or concentration changes the cell voltage, and the HXP-ca Tafel slope is described by the quantity it measures.
We previously wrote that both faces of every HXP electrode are identical. Only HXP-an (anode) is. HXP-ca (cathode) carries a catalyst layer on carbon paper, so the catalyst-layer face must face the membrane and the carbon-paper (GDL) face the cell hardware. The receiving chapter, the cell assembly sequence, the symptom table and the electrode operation note are corrected.
What to do If your cell voltage came out higher than the datasheet, first check that HXP-ca is not upside down.
HXD-V1 installation and HXB-V1 connection chapter published
On the pre-release design basis: what to decide first, the site, the port table, the line from the HXB-V1, vents and drain, power and network, and first start. The other chapters open at launch.
About 240 awkward or literal-translation sentences in the Korean edition of all four handbooks were rewritten. No values or procedures changed.
Handbook
Key steps now say how to check them and what to do if they fail
Under the key steps of the HXB-V1 quick start, daily start-up and electrolyte change, and of the HXS-2 and HXS-30 quick starts, one line now says how to tell it worked (LED colour, ONLINE, flow, temperature, voltage) and one says what to do if it did not (where to look, with links to the alarm table and symptoms).
Handbook
Warnings moved ahead of their steps; static ignition and hot-surface warnings added
In the HXS-2 and HXS-30 quick-start chapters, the warnings on corrosive KOH, never joining hydrogen and oxygen lines, keeping load off the ports and loose terminals now come before the steps they apply to rather than after. The hydrogen boxes in the HXB-V1, HXS-2 and HXS-30 safety chapters now note that even a static spark can ignite it, and a caution says the electrolyte, lines and stack get hot in operation (up to 70 °C on the HXB-V1, 80 °C on the stacks).
Handbook
Stack and electrode safety messages reworked; nitrogen asphyxiation and blocked vent added for the HXS-30
Danger and warning boxes in the HXS-2, HXS-30 and HXP handbooks now say what happens if you ignore them (shock, arcing, KOH burns, transport damage, trapped pressure, 2% hydrogen in oxygen and so on). Equipment-only matters such as freezing, service life, line resistance, solvents and opening the stack are now notices. The HXS-30 decommissioning chapter now warns of asphyxiation when purging with nitrogen, and its safety chapter gains a section on a blocked or iced vent.
Sub-heading links, in-text links, search lands on the section, wording fixes
Every sub-heading now has its own address; the # next to a heading copies the link. Handbook search now takes you to the section where the words were found, not the top of the chapter. Cross-references such as 'see Symptom D' are now links. HXS-2 troubleshooting symptom A has five causes, not four, and the HXS-30 heat example uses the measured daily averages (about 360 A, 76.8 to 81.5 V over six days). The contact form has an 'Existing customer support' option with a serial field, and accepts csv and txt log files.
Document
User manuals are now a direct download
The HXB-V1 and HXS-2 user manuals ver3.0, the HXS-30 user manual ver1.0 and the HXP electrode handling and operation guide ver1.0 can now be downloaded without a request. Each manual is this handbook bound for print, so the content is the same. The HXB-V1 EU declaration of conformity (CE) is also available.
What to do If you hold an older manual (ver2.x), replace it with the new edition.
All four products gain a chapter collecting intended and prohibited use, product views, specifications, electrical ratings and environment, markings on the unit, terms and manufacturer details. It sits just before Troubleshooting.
These are known conditions of the product and its documents, not faults. Each entry links to the relevant chapter.
HXB-V1
IV curves and tests on other stacks may not reach the voltage and current you set
Condition
The HXB-V1 power supply is set up to run the rated stack it ships with at a constant current. Everyday hydrogen production is not affected. This only applies when you use the unit as a test rig: IV curves that sweep the voltage widely, low-current tests on a short stack or another maker's stack, and running well below or above the recommended current.
What to do
Set the voltage above the stack voltage but below 1.25 times the stack voltage. If the stack voltage stays below 80% of the setting for more than 5 seconds the power supply shuts off, and with the voltage set at 43.2 V or less the maximum current falls to 53.6 A. Operation with a stack voltage below 19.2 V is not possible. If you plan tests like these, send us the voltages and currents you want to reach and your test sequence before ordering.
The HXB-V1 is not certified for explosive atmospheres.
What to do
Keep it out of areas classified as hazardous and place it in a general area kept free of explosion risk by ventilation. Establish first whether the location needs explosion-protected equipment in your country.
Connecting a PLC means the desktop control app cannot be used
Condition
The HXB-V1 is normally run by connecting a PC to the Ethernet port on its front panel and operating it with our desktop control app installed on that PC. If you want to control the unit from your plant PLC or SCADA, you connect the PLC to that LAN port instead of the PC. As there is only one LAN port, the desktop control app cannot be used in that case: you lose the app's operating screens, and the app's operating log (csv) is no longer recorded. Safety functions are unchanged: alarms, fault stops and emergency stops are decided by the controller inside the unit and work the same without the app.
What to do
Build the operating screens and logging on the PLC or SCADA side. Logging current, voltage, temperature, flow and alarms every second lets us find the cause if something goes wrong. Ask us for the latest register map, which lists what to read and where.