Solar Charge Controller Battery Profiles, Low-Temperature Charging and BMS Compatibility: RFQ Guide

A controller described only as “12/24/48 V, lead-acid and lithium compatible” is not ready for purchase. The same label can hide materially different absorption voltages, absorption exit rules, float behavior, temperature compensation, cold-charge protection and battery-management-system interfaces. A selectable “lithium” preset may still be wrong for the exact battery, while a controller that regulates bank voltage accurately may have no knowledge of an individual cell that is already at its limit.

A defensible request for quotation therefore starts with the battery manufacturer’s current charging envelope and maps every requirement to one exact controller model, firmware and sensing arrangement. The returned evidence must show what happens during bulk, absorption, float, re-bulk, equalization, low temperature, loss of a temperature sensor, loss of communications and a BMS request to stop charging. Commissioning then proves the configured values at the battery, not merely on an app screen.

This guide is a procurement and evidence method. It is not a battery-design approval, a universal charging recipe or permission to copy settings between products. The battery, controller and BMS manufacturers, the responsible system designer and applicable installation rules remain controlling. It makes no unverified claim about a SINAWATTS controller, battery, BMS, certification, programming service, test capability, stock, price, MOQ, lead time or project result.

Direct answer: what should a buyer require?

For every controller-battery combination, require the bidder to return one completed battery-side settings schedule containing:

• exact controller manufacturer, model, hardware revision and firmware;
• exact battery manufacturer, model, chemistry, series/parallel configuration, capacity and BMS version;
• battery-manufacturer limits for charge voltage, continuous and conditional charge current, absorption or charge-hold time, float policy, equalization policy and allowed charge-temperature range;
• controller values for absorption, maximum absorption time, tail-current logic, float, re-bulk, equalization, temperature compensation, low-temperature cut-off or foldback and maximum charge current;
• the temperature and voltage measurement source actually used, its placement, wiring, communication path and failure behavior;
• the BMS-to-controller interface, including signal type, normal and stop states, thresholds, delays, restart rules and response to a broken wire or lost network;
• coordination with every other charging source connected to the same battery;
• a configuration export, version-controlled settings sheet and photographs or screenshots identifying the commissioned equipment; and
• a functional test record demonstrating normal charging, a simulated or manufacturer-approved charge-disable command, sensor-fault response and restoration without defeating battery protection.

Treat any blank or ambiguous field as an engineering hold point. A battery logo beside a controller logo is not compatibility evidence. Neither is a statement that “the BMS will protect it” unless the proposed architecture shows how the BMS can stop every charging source under the relevant abnormal conditions.

Keep this battery-side review separate from PV-input limits

This article addresses what the controller delivers to and learns from the battery. It does not repeat the array-side checks in the solar charge controller PV input-limits guide. That separate review covers cold-adjusted PV open-circuit voltage, startup and tracking voltage, PV short-circuit current, parallel strings, input current and array power. Passing the battery profile review does not approve the PV input, and passing the PV input review does not approve the battery profile.

Keep the two acceptance sheets connected by exact controller model and firmware. A substitute controller can change both sides at once. It may accept the same array but offer different charge-stage logic, sensing options or BMS inputs. Conversely, a new battery may leave the array calculation unchanged while invalidating absorption, float, temperature and charge-current settings.

IEC 62509:2010, whose official record was checked on 2026-09-24, establishes minimum functioning and performance requirements for photovoltaic battery charge controllers used with lead-acid batteries. Its stated aims include controller reliability and maximizing battery life. Its scope is useful context for lead-acid controller procurement, but it does not certify a specific product pairing and it does not extend automatically to a lithium battery. IEC 62509 official publication record.

Freeze the exact battery, controller and control architecture

Start with a controlled one-line and a device register. “48 V lithium” is too broad: nominal voltage does not disclose series cell count, permitted charge ceiling, current at cold temperature, internal contactor behavior or communications protocol. Record complete order codes and document revisions before comparing settings.

On small screens, swipe or scroll sideways to read every column. Keyboard users can focus the table and use the arrow keys.

Draw signal paths separately from power paths. Show whether the BMS opens a main contactor, sends a dedicated “allow to charge” signal, commands a networked charger, or depends only on its own internal charge MOSFETs. State which equipment remains powered when charging is prohibited. If the controller must remain awake to receive a restart command, an architecture that removes its control power may not recover as intended.

Also identify the source of truth. In one system, fixed controller settings govern all stages. In another, a compatible battery or supervisory device sends dynamic voltage and current limits. In a third, a BMS supplies only a binary permission while the controller retains its own profile. Do not combine descriptions from these architectures into a single “BMS compatible” check box.

Translate the battery manual into a controlled charge profile

Create the battery requirements row before opening the controller configuration screen. Use the exact battery manual, integration guide and BMS instructions for the supplied revision. Record values with units, temperature basis, bank scaling and any current-versus-temperature or state-of-charge conditions.

A complete profile normally resolves the following functions even when the manufacturer uses different names:

1. Bulk or maximum-current stage: the charger supplies available current up to the lower of its configured limit, the battery limit, the BMS limit and available solar power. “Bulk voltage” is often a transition target rather than a separate constant-voltage plateau.
2. Absorption or constant-voltage stage: the controller regulates at a specified voltage. The exit can depend on time, tail current, state information or a combination. Record the maximum duration and the rule that can end it early.
3. Float or maintenance stage: the controller reduces voltage after absorption. Some batteries require float, some permit a specific value, and others require the stage to be disabled or treated differently. Use the exact battery instruction.
4. Re-bulk or recharge condition: a voltage offset, elapsed time, state of charge or load event can restart the cycle. A poor threshold can cause repeated cycling or insufficient return to full charge.
5. Equalization: this intentionally raises voltage for certain lead-acid maintenance regimes. It must be disabled unless the exact battery manufacturer requires it and defines the conditions.
6. Current limit: record both the controller maximum and the battery/BMS limit. For a parallel bank, include the battery manufacturer’s permitted sharing assumptions rather than multiplying a label automatically.

The current Victron SmartSolar MPPT 150/35 and 150/45 configuration manual, checked on 2026-09-24, illustrates why a profile is more than two voltages. Its custom settings include absorption voltage, adaptive or fixed absorption behavior, maximum absorption time, tail current, float voltage, re-bulk offset, equalization controls, temperature compensation and low-temperature cut-off. The manual says tail current can end absorption after current remains below the threshold for one minute, while the maximum time remains a separate limit. Those behaviors apply to the named controller family and configuration; they are not universal controller logic. Victron SmartSolar MPPT 150/35 and 150/45 configuration manual.

Ask the bidder to return both the human-readable schedule and the controller export or screenshots. A screenshot without the battery requirement column proves only what was entered. A battery datasheet without the commissioned configuration proves only what should have been entered.

Do not borrow charge settings from a chemistry label

Chemistry is a starting category, not a completed profile. Two lead-acid products can require different absorption, float, equalization and temperature-compensation behavior. Two lithium iron phosphate batteries can use different cell counts, charge limits, balancing strategies, BMS thresholds and permitted cold-charge behavior. A preset name such as “AGM,” “flooded” or “LiFePO4” does not establish compatibility with the exact model.

For a named example, the current Victron Lithium Battery Smart manual checked on 2026-09-24 publishes a product-specific profile: 14.2 V absorption and 13.5 V float for its 12.8 V battery, with scaled values for its stated 24 V and 48 V arrangements, plus its specified absorption-time guidance. It also says temperature-compensated charging is not required and should be disabled or set to 0 mV/°C for that battery. These values are evidence for the named Victron battery system, not a generic “12 V lithium” recipe and not SINAWATTS specifications. Victron Lithium Battery Smart charging guidance.

Equalization deserves an explicit line even when the answer is “disabled.” The SmartSolar configuration manual warns that equalization can damage a battery that is unsuitable for it, and its lithium preset does not make equalization available. A commissioning sheet should record the disabled state rather than assuming a preset keeps it disabled forever.

If the battery supplier issues a revised profile, preserve both versions and the effective serial or firmware range. Do not silently update a fleet based on a support email for one unit. Request a controlled document or written project disposition that identifies the affected products.

Separate lead-acid temperature compensation from lithium cold-charge protection

These functions both use temperature, but they solve different problems.

Temperature compensation changes charge-voltage setpoints with temperature. For lead-acid batteries, a manufacturer may specify a coefficient and reference temperature. The coefficient can be stated per cell or for the whole bank; confusing those bases creates a large error. The sensor, allowed compensation range and any upper/lower voltage clamps are part of the setting.

Low-temperature charge protection reduces or stops charge current when a battery, commonly a lithium battery, is too cold for the permitted charge regime. It is a current-permission boundary, not a reason to raise charge voltage. A BMS may enforce it, a controller may enforce it using a verified battery-temperature input, or both may provide coordinated layers.

The current SmartSolar manual says its configurable temperature-compensation coefficient is for the whole battery bank and uses 25°C as the base temperature. It also says its low-temperature cut-off is active only when the controller receives battery temperature through the specified VE.Smart sensing arrangement. The setting is disabled by default; the manual’s 5°C default when enabled is described as suitable for LFP, but it expressly directs the user to check the lithium battery supplier. It resumes charging 0.5°C above the configured cut-off. These details are model-specific examples of the evidence an RFQ should request, not project settings to copy. Victron controller configuration and low-temperature cut-off.

Morningstar documents a different mechanism for its named ProStar family: Low Temperature Foldback. The current official manual says a configurable high limit defines the lowest temperature for 100% rated charging current, a low limit defines the temperature at which charge current stops, and current tapers linearly between them. That is not the same response as a single cut-off with restart hysteresis. The offered model, meter/configuration capability and exact thresholds must therefore appear in the bid. Morningstar ProStar operator manual.

Build a temperature-state matrix rather than one “minimum operating temperature” field:

On small screens, swipe or scroll sideways to read every column. Keyboard users can focus the table and use the arrow keys.

Do not infer battery temperature from outside air or controller heatsink temperature. A battery inside an insulated box can lag ambient temperature by hours. Charging current and nearby equipment can create gradients. Define sensor attachment, location, cable routing and the rule for banks with multiple modules.

Specify remote temperature sensing as an evidence chain

A temperature sensor is not complete merely because it appears in the bill of materials. Require the exact sensor part number, compatibility with the controller revision, mounting instruction, measurement accuracy where published, lead limits, connector and monitored failure modes. The commissioning record should show the sensor installed on the battery location required by the manufacturer and compare its reading with an appropriate reference under stable conditions.

Victron’s current SmartSolar 150/60 through 250/70 manual explains that the controller’s internal sensor uses a “cold” controller reading as an estimate of ambient and battery temperature. For more accurate battery information, its supported external arrangement can send battery temperature and voltage through VE.Smart Networking. The same manual states that the external voltage value is used to compensate for cable losses. This is evidence for those named products and supported accessories; it does not prove that every Bluetooth sensor or battery monitor works with another controller. Victron SmartSolar external temperature and voltage sensing.

Morningstar’s current Remote Temperature Sensor page says its RTS measures temperature at the battery and recommends remote sensing when battery temperature will differ from controller temperature by more than 5°C. It also states that the TriStar has no onboard temperature compensation and requires the RTS for temperature-compensated charging. Those statements apply to the listed Morningstar products and sensing architecture. Morningstar Remote Temperature Sensor product page.

Ask what occurs if the sensor is unplugged, shorted, reports an impossible value or loses its network path. A displayed temperature before commissioning is not proof that the controller will behave safely after a fault. The test can use the manufacturer’s approved simulation method rather than exposing a real battery to a prohibited temperature.

Use remote voltage sensing without hiding cable problems

The voltage at a controller’s power terminals can differ from the voltage at the battery because current flows through cables, fuses, disconnects, busbars and connections. If the controller regulates only its local voltage, cable drop can leave the battery below the intended absorption voltage. A proper remote-sense input measures close to the battery with a very low-current pair, allowing the controller to regulate against a more representative value.

Remote sensing does not make an undersized, hot or loose power path acceptable. It can cause the controller to increase its output-terminal voltage to overcome drop, which may increase stress at other equipment connected near the controller. The compensation range and maximum output limits still apply. The buyer should require both a conductor/connection voltage-drop review and a sense-wire design.

The current Morningstar TriStar MPPT 150 V manual, checked on 2026-09-24, explains that its battery-sense terminals measure battery-terminal voltage with small-gauge, very-low-current wires. It recommends the connection for best performance, requires the positive sense lead to be fused near the battery, identifies 16–24 AWG (1.0–0.25 mm²) and gives a maximum sense-wire length of 30 m for that model. Those details must not be transferred to an unrelated controller. Morningstar TriStar MPPT 150 V operator manual.

For first article, record four synchronized values at a meaningful charge current: controller power-terminal voltage, battery-terminal voltage, controller remote-sense reading and an appropriate reference meter reading. Record current, conductor temperature and measurement locations. A difference should trigger investigation, not an arbitrary calibration offset.

Use the battery-cable voltage-drop guide to define the power-path calculation and the Kelvin resistance testing guide when a connection-resistance investigation is required. Remote sensing supports regulation; it does not replace sound cable and joint evidence.

Map BMS compatibility by signals and failure states

A controller can have the right voltages yet remain incompatible with the battery’s protection architecture. The BMS observes individual cell voltages and battery temperatures that the controller may not see. If the BMS detects a high cell or prohibited temperature, it must be able to stop charging by a method the exact controller accepts.

Classify the proposed integration:

On small screens, swipe or scroll sideways to read every column. Keyboard users can focus the table and use the arrow keys.

The current Victron SmartSolar 150/60 through 250/70 manual identifies a remote on/off interface that can be controlled by an external device such as a lithium BMS, and publishes model-specific electrical options for its H and L terminals. Separately, the current Victron Lithium Battery Smart system-design guide says the battery communicates high cell voltage and low/high battery-temperature conditions to a compatible BMS, which then sends a charge-disconnect signal or controls supported chargers. These two documents illustrate the required end-to-end chain: battery detection, BMS decision, electrical or communications interface, and charger response. They do not establish cross-brand compatibility. Victron controller remote on/off description and Victron Lithium Battery Smart BMS selection guide.

Morningstar’s current lithium-battery guidance makes another boundary explicit: Morningstar controllers do not themselves include a lithium BMS, and voltage regulation alone does not protect against individual-cell overvoltage or undervoltage. Its page calls for attention to external charge/load disabling and coordination with the battery BMS. This is a useful purchasing distinction between battery charging and cell-level battery protection. Morningstar lithium battery controller guidance.

Require the bidder to state the normal state and de-energized state of every control output. A normally closed permission loop can stop charging when the wire breaks, while another interface may fail in the opposite direction. The preferred behavior depends on the approved equipment architecture, but it must be deliberate and tested. Also record whether a BMS stop is latched, whether manual acknowledgement is required and what temperature or cell conditions permit restart.

Coordinate all charging sources and current limits

Solar is often only one source. An RV, marine, telecom or backup system may also have an alternator charger, shore charger, inverter/charger or generator. A controller set to the battery’s maximum current can exceed the bank limit when another charger starts. Prepare an operating-state table with the worst credible simultaneous sources.

On small screens, swipe or scroll sideways to read every column. Keyboard users can focus the table and use the arrow keys.

Where dynamic current limits are communicated, define update interval, timeout and conservative fallback. Where only fixed limits are available, set them for the credible simultaneous-source condition or provide interlocking. Do not assume two chargers will naturally share current in a safe ratio.

The BMS’s emergency high-cell disconnect should not be the normal end-of-charge mechanism. Normal regulation should remain within the approved profile so the BMS protection acts as a last line of defense. Repeated charge-disconnect events can indicate an incorrect profile, cell imbalance, failed sensing, excessive charge current or incompatible control behavior and should create an alarm and investigation record.

Use bounded calculations to review a proposal

The following examples are hypothetical procurement arithmetic only. They are not settings for a real battery or approval of any product.

Example 1: controller-terminal voltage versus battery voltage

Assume a fictional battery instruction requires 14.20 V at the battery during a defined absorption condition. At 40 A, a fictional measured round-trip power-path resistance is 8 mΩ. The simple drop is:

Vdrop = I × R = 40 A × 0.008 Ω = 0.32 V.

If a controller regulates 14.20 V only at its own terminals, the battery could see about 13.88 V under that assumed steady condition. A valid remote-sense arrangement might command the controller higher to compensate, but only within the controller’s stated compensation and output limits and only after the cable path is accepted for ampacity, temperature and voltage drop. The example shows why the measurement point belongs in the RFQ; it does not prescribe 14.52 V at a controller terminal.

Example 2: lead-acid temperature compensation basis

Assume a fictional 12 V lead-acid bank has a manufacturer-approved coefficient of −24 mV/°C for the whole bank, referenced to 25°C. At a measured battery temperature of 15°C, the temperature difference is −10°C. The hypothetical adjustment is:

−0.024 V/°C × (15 − 25)°C = +0.24 V.

That result applies only if the coefficient is truly for the whole bank, the battery manufacturer authorizes it, and the controller applies the same sign convention and reference. If −24 mV/°C were a per-cell figure or if the controller expected a bank-level entry, the result would be very different. The schedule must therefore record coefficient basis and units, not just “temperature compensation on.”

Example 3: simultaneous charging current

Assume a fictional bank permits 80 A charge current at normal temperature and only 20 A in a cold reduced-current band. A solar controller can provide 50 A and an AC charger 40 A. The normal maximum sum is 90 A, already above 80 A. In the cold band it is more than four times the fictional 20 A limit. Choosing a 20 A solar setting alone does not solve the cold case if the AC charger can still supply 40 A. The control plan must constrain the combined sources or prevent their simultaneous operation.

No example substitutes for the exact battery and controller manuals. Its purpose is to expose missing units, measurement locations and coordination logic before award.

Build a bidder comparison matrix

Compare one exact combination per row. Mark “provided,” “applicable,” “configured” and “functionally verified” separately.

On small screens, swipe or scroll sideways to read every column. Keyboard users can focus the table and use the arrow keys.

Score documentation completeness separately from attractive headline ratings. A lower-current controller with a fully documented BMS stop path can be lower integration risk than a higher-current model whose “lithium mode” cannot be mapped to the battery.

Commission a first article before releasing the batch

Use a representative first installation or bench assembly under an approved safe procedure. Do not force a production battery into damaging conditions to test protection. The manufacturer may provide a simulator, service mode or approved signal-injection method for BMS and sensor tests.

At minimum, the first-article record should include:

1. controller, battery, BMS, sensor and communications serial/model identities;
2. firmware versions and configuration-tool version;
3. exported charge settings with a checksum or controlled file name;
4. verified power and sense wiring, polarity, protection and connection torque records;
5. comparison of controller, BMS and reference battery-voltage and temperature readings;
6. normal progression through the permitted charge stages under meaningful conditions;
7. configured maximum current and any dynamic-limit behavior;
8. BMS charge-disable response and confirmation that all charging sources stop;
9. sensor or communications fault response using an approved method;
10. controlled recovery and confirmation that protection is not bypassed;
11. alarms, event logs and timestamps synchronized across devices; and
12. deviations, corrective actions and final acceptance signatures.

Confirm that a settings change persists after an ordinary restart and that access control prevents casual alteration. If a rotary switch, display menu, mobile application and network controller can each change settings, document precedence. The Victron SmartSolar manual, for example, notes that changing settings through its application or display can override a rotary-switch selection for the named products. Other controllers can use different precedence.

Do not call a BMS test complete after observing an icon change. Measure that battery charge current falls to the required safe state within the documented response, and verify what each other charger does. Do not submit the website RFQ form as part of this technical commissioning; the eventual commercial inquiry should use project data, not a test message.

Preserve operating evidence and investigate repeated protection events

Define the minimum log set and retention period in the RFQ. Useful records include battery-terminal voltage, controller-terminal voltage, charge current, battery temperature, controller temperature, charge stage, BMS permission, dynamic voltage/current limits, alarms, communications status and energy counters. State sampling interval and clock source. A daily maximum/minimum can hide a short BMS stop or sensor dropout.

Trend stage duration as well as voltage. Persistent maximum-time absorption, failure to reach absorption, repeated re-bulk, unexpected float cancellation or frequent BMS charge disable can each point to a different issue. Possible causes include insufficient PV energy, excessive load, cable drop, incorrect battery capacity entry, wrong temperature data, a settings reset, cell imbalance or another charger holding the bus at a conflicting voltage.

Do not diagnose battery state of charge from voltage alone unless the battery manufacturer supports that method under the measured rest/load condition. Do not use a normal controller temperature as proof that the battery is warm enough to charge. Do not clear BMS event history before capturing it.

When a protection event occurs, preserve controller and BMS logs, time correlation, environmental data and the configuration export. Record whether the event stopped all sources and whether it restarted automatically. Repeated safety-layer operation is a reliability signal, not evidence that the system “protects itself successfully.”

Control substitutions, firmware and settings changes

Require advance review for changes to controller model, hardware, firmware, battery model, bank topology, BMS, sensor, communications gateway, charge source, conductor length, fuse/disconnect, ambient enclosure or software profile. A firmware update can change menu ranges, default settings, communications timeouts or compatibility. A battery substitution can change every charge boundary while retaining the same nominal voltage.

For an approved change, repeat only the affected analyses and tests, but do not skip the end-to-end charge-disable path. Preserve the old settings export, new export, release notes, reason for change and reviewer. If a field replacement falls back to factory defaults, the service procedure must require loading and verifying the controlled profile before reconnecting the battery.

Keep editable configuration files under revision control and provide a readable PDF or table for long-term service. A proprietary binary file alone may become unusable when an application changes. Conversely, a typed table alone can contain transcription errors. Retain both and map them to serial numbers.

Send a complete solar controller battery-profile RFQ

Issue the one-line diagram, battery schedule, charger-source table, environmental range, cable/sense arrangement, applicable rules and required evidence matrix. Ask the supplier to return exact manufacturer documents and a line-by-line deviation list. Include the destination market and responsible party for final design approval.

Request pricing, MOQ, sample availability and lead time as supplier responses for the exact order codes. Request certification or laboratory evidence only where applicable to the project and require documents that resolve to the offered model. Do not assume any commercial term, inventory, certification or production capability from this guide.

For a focused inquiry, attach:

• battery model, quantity, series/parallel bank diagram and BMS manual;
• controller and all other charger candidates;
• required charge voltage/current/temperature table from the battery manufacturer;
• minimum and maximum battery-location temperatures;
• power-cable path, remote-sense and temperature-sensor plan;
• BMS signal or protocol interface and fail-state requirement;
• desired logs, commissioning tests and document language;
• change-control and warranty-impact questions; and
• quantity, destination, target schedule and requested quotation validity.

Use the SINAWATTS knowledge center to prepare the related cable, terminal, fuse and disconnect evidence. When the technical package is complete, send the project-specific RFQ with the battery and controller manuals attached or linked. Ask for written confirmation of compatibility and deviations rather than a general “suitable for lithium” statement.

Buyer FAQ

Is a controller’s lithium preset enough to approve the battery?

No. Compare every preset value and behavior with the exact battery and BMS manuals: charge voltage, current, absorption duration and exit, float, re-bulk, equalization, temperature compensation, low-temperature response and charge-disable interface. Record the controller firmware because available settings can change.

Are absorption voltage and float voltage the only settings that matter?

No. Stage duration, tail-current exit, re-bulk logic, equalization, charge-current limits and temperature behavior can materially change the result. The controller must also stop when the BMS removes charge permission.

Should temperature compensation be enabled for every battery?

No. Use the exact battery instruction. Many lead-acid batteries require a defined compensation coefficient, while the cited Victron Lithium Battery Smart manual instructs users to disable temperature compensation for that named lithium battery. Do not generalize either rule across all products.

Is low-temperature cut-off the same as temperature compensation?

No. Compensation adjusts a voltage setpoint with temperature. Low-temperature protection reduces or stops charge current when charging is prohibited or restricted. The temperature source, thresholds, hysteresis and failure response must be documented separately.

Can the BMS simply disconnect the battery whenever charge voltage is high?

Only if the exact battery/BMS architecture and switching device are designed and rated for that response. BMS protection should not replace normal controller regulation. Prefer a documented charge-disable interface when the manufacturers support it, and verify the entire signal chain.

Does remote voltage sensing allow smaller battery cables?

No. It can help the controller account for voltage difference between its terminals and the battery, within stated limits. Cable ampacity, temperature, protection, connection quality and acceptable voltage drop remain separate requirements.

Where should the temperature sensor be installed?

Follow the exact battery and sensor manufacturer instructions. The RFQ should name the location, attachment, bank-module selection and cable route. Controller temperature or outside air is not automatically an acceptable substitute for battery temperature.

What happens if the temperature sensor or BMS communications fail?

The supplier must state and demonstrate the exact fault response: charge limit, stop state, alarm, timeout and restart. Do not assume a missing reading automatically produces a safe result.

How should multiple chargers share the battery current limit?

Calculate the credible simultaneous total and coordinate all sources through fixed limits, interlocks or a compatible supervisory system. A BMS cold-current limit or charge-disable decision must reach the solar controller, AC charger, alternator charger and any other active source.

What evidence should accompany the first article?

Retain exact product identities, firmware, configuration exports, wiring and sensor records, calibrated comparison measurements, normal charge-stage logs, current-limit evidence, BMS stop and fault-response tests, restart behavior, alarms, deviations and approval signatures. The evidence must resolve to the delivered hardware rather than a family brochure.

When must the compatibility review be repeated?

Repeat the affected review after changes to battery model or topology, controller, firmware, BMS, sensor, communications gateway, charge source, cable path, environment or profile. Always recheck the complete BMS-to-all-chargers stop path after a control change.