{
"node": {
"id": "term:constant-voltage",
"type": "Term",
"label": "Constant voltage",
"properties": {
"id": "constant-voltage",
"name": "Constant voltage",
"abbr": "CV",
"section": "topic-charging",
"definition": "A charge stage in which the terminal voltage is held at a selected limit while the current is allowed to fall. The charge added during this stage and its duration depend on the cell, initial state, voltage limit and termination current.",
"related": [
"cc-cv-charging",
"constant-current",
"taper-current",
"cutoff-voltage"
],
"example": {
"title": "Read the taper correctly",
"text": "In a hypothetical CV stage with a 4.0 V ceiling, the controller holds terminal voltage at that ceiling while current tapers as the cell state changes and its OCV rises. A voltage plateau does not mean the charge session has completed; the current cutoff and dwell still matter."
},
"url": "https://lemonergy.com/learn/glossary/constant-voltage/",
"mentions": [
"voltage"
]
}
},
"edges": [
{
"id": "edge:35",
"source": "term:constant-voltage",
"target": "workflow:cccv",
"type": "usedIn",
"properties": {
"sourceFile": "wiki-blocks.json"
}
},
{
"id": "edge:1079",
"source": "term:constant-voltage",
"target": "topic:topic-charging",
"type": "belongsTo",
"properties": {
"sourceFile": "terms.json"
}
},
{
"id": "edge:1080",
"source": "term:constant-voltage",
"target": "term:cc-cv-charging",
"type": "relatedTo",
"properties": {
"sourceFile": "terms.json",
"meaning": "Related context; not a causal claim"
}
},
{
"id": "edge:1081",
"source": "term:constant-voltage",
"target": "term:constant-current",
"type": "relatedTo",
"properties": {
"sourceFile": "terms.json",
"meaning": "Related context; not a causal claim"
}
},
{
"id": "edge:1082",
"source": "term:constant-voltage",
"target": "term:taper-current",
"type": "relatedTo",
"properties": {
"sourceFile": "terms.json",
"meaning": "Related context; not a causal claim"
}
},
{
"id": "edge:1083",
"source": "term:constant-voltage",
"target": "term:cutoff-voltage",
"type": "relatedTo",
"properties": {
"sourceFile": "terms.json",
"meaning": "Related context; not a causal claim"
}
},
{
"id": "edge:mentions/constant-voltage/voltage",
"source": "term:constant-voltage",
"target": "term:voltage",
"type": "mentions",
"properties": {
"sourceFile": "terms.json",
"method": "build_glossary.mention_index + mentions",
"field": "definition",
"meaning": "Text mention; not a causal claim"
}
},
{
"id": "edge:1085",
"source": "term:constant-voltage",
"target": "visual:charging-cv",
"type": "illustratedBy",
"properties": {
"sourceFile": "visual-pages.json"
}
},
{
"id": "edge:1086",
"source": "term:constant-voltage",
"target": "reference:tomaszewska-charging",
"type": "cites",
"properties": {
"sourceFile": "wiki-references.json",
"scope": "direct technical reference"
}
}
],
"neighbors": [
{
"id": "workflow:cccv",
"type": "Workflow",
"label": "Build CC–CV charging",
"properties": {
"id": "cccv",
"title": "Build CC–CV charging",
"kind": "studio",
"summary": "Native current and voltage regulation act against an explicit battery.",
"steps": [
"Open home charging and inspect settings.",
"Choose immediate charging; inspect mode and completion."
],
"example": "An illustrative 100 Ah battery with a 420 V ceiling can use a 32 A cap. At the ceiling, current falls as OCV rises.",
"observe": "Completion needs current below cutoff at the CV ceiling for the configured dwell. Site-limited low current is different.",
"limits": "The battery uses linear OCV and fixed resistance. It does not automatically add aging, thermal dynamics or balancing.",
"url": "https://design.lemonergy.com/cosim.html?example=charging-home",
"label": "Open the Studio example",
"evidence": [
"js/charging-control.js",
"js/charging-scenarios.js",
"docs/CHARGING_BLOCKS_SPEC.md"
]
}
},
{
"id": "topic:topic-charging",
"type": "Topic",
"label": "Charging and discharging",
"properties": {
"id": "topic-charging",
"name": "Charging and discharging",
"lede": "How current goes in and comes out, and the limits that stop it.",
"context": "Separate regulation from availability.",
"example": "The same CC–CV law can operate overnight or during a short depot stop.",
"lesson_url": "https://lemonergy.com/learn/fundamentals/capacity-and-c-rate/",
"lesson_label": "Open charging quantities"
}
},
{
"id": "term:cc-cv-charging",
"type": "Term",
"label": "CC-CV charging",
"properties": {
"id": "cc-cv-charging",
"name": "CC-CV charging",
"aka": [
"constant current constant voltage"
],
"section": "topic-charging",
"definition": "The standard lithium-ion charge protocol: constant current until the cell reaches its upper cutoff voltage, then that voltage held constant while the current tapers. The charge ends when the current falls to a set fraction, often C/20.",
"related": [
"constant-current",
"constant-voltage",
"cutoff-voltage",
"taper-current",
"fast-charging",
"cp-cv"
],
"lesson": "fundamentals/capacity-and-c-rate/#real-cells",
"example": {
"title": "Follow a two-stage charge",
"text": "For an illustrative 5 Ah cell, a 2.5 A current request is 0.5C. During CC the voltage rises. At the selected upper voltage, CV regulation holds voltage while current tapers. Completion requires the taper current to fall below the selected cutoff for the configured dwell."
},
"notes": [
"Choose voltage, current and temperature limits from the actual cell specification. These example values do not define a charging recipe."
],
"url": "https://lemonergy.com/learn/glossary/cc-cv-charging/",
"mentions": []
}
},
{
"id": "term:constant-current",
"type": "Term",
"label": "Constant current",
"properties": {
"id": "constant-current",
"name": "Constant current",
"abbr": "CC",
"section": "topic-charging",
"definition": "A charge or discharge at a fixed current, so capacity is simply current times time. It is the first stage of a CC-CV charge and the normal way to run a capacity test.",
"related": [
"cc-cv-charging",
"constant-voltage",
"c-rate",
"capacity-test"
],
"example": {
"title": "Compare two cell capacities",
"text": "A 2 A current is 1C for a 2 Ah cell and 0.4C for a 5 Ah cell. A constant-current step holds amperes fixed, so a fair comparison between differently sized cells also records C-rate."
},
"url": "https://lemonergy.com/learn/glossary/constant-current/",
"mentions": []
}
},
{
"id": "term:taper-current",
"type": "Term",
"label": "Taper current",
"properties": {
"id": "taper-current",
"name": "Taper current",
"aka": [
"termination current",
"cutoff current"
],
"section": "topic-charging",
"definition": "The current at which a constant-voltage charge stage is declared finished, often C/20 or C/50. A higher taper current ends the charge sooner and leaves the cell slightly less than full.",
"unit": "A",
"related": [
"constant-voltage",
"cc-cv-charging",
"state-of-charge"
],
"url": "https://lemonergy.com/learn/glossary/taper-current/",
"mentions": []
}
},
{
"id": "term:cutoff-voltage",
"type": "Term",
"label": "Cutoff voltage",
"properties": {
"id": "cutoff-voltage",
"name": "Cutoff voltage",
"section": "topic-charging",
"definition": "The terminal-voltage limit that ends a discharge, or caps a charge — in constant-current, constant-voltage (CC-CV) charging the cell is then held at that voltage until the current falls to a cutoff. A real discharge ends at the lower cutoff, which is why actual runtime can differ from the ideal duration.",
"unit": "V",
"related": [
"voltage-window",
"cc-cv-charging",
"ideal-duration",
"over-discharge",
"overcharge"
],
"lesson": "fundamentals/capacity-and-c-rate/#real-cells",
"url": "https://lemonergy.com/learn/glossary/cutoff-voltage/",
"mentions": [
"service-life"
]
}
},
{
"id": "term:voltage",
"type": "Term",
"label": "Voltage",
"properties": {
"id": "voltage",
"name": "Voltage",
"aka": [
"terminal voltage"
],
"section": "topic-units",
"definition": "The potential difference between a cell’s two terminals. It comes from the chemical difference between the electrodes, moves with state of charge, and sags under load because of internal resistance.",
"unit": "V",
"related": [
"open-circuit-voltage",
"nominal-voltage",
"internal-resistance",
"ir-drop"
],
"lesson": "fundamentals/cell-anatomy/#voltage",
"url": "https://lemonergy.com/learn/glossary/voltage/",
"mentions": [
"state-of-charge"
]
}
},
{
"id": "visual:charging-cv",
"type": "Visual",
"label": "Compare charging profiles",
"properties": {
"title": "Compare charging profiles",
"summary": "See which quantity is held constant, when the phase changes and how charging ends.",
"readout": "Voltage holds at an illustrative 4.15 V while current tapers. Real controllers must limit initial current and define termination.",
"formula": "CC: I = I_set · CV: V = V_limit",
"note": "Positive current charges the cell. Time is normalized; selected thresholds are not cell-specific recommendations. The voltage trace ends at termination; post-stop relaxation is excluded.",
"software": {
"status": "studio",
"label": "Lemonergy Studio charging controller",
"body": "The native controller regulates CC-CV charging. Its battery model uses charge balance, linear OCV and constant resistance. These authored profiles are explanatory, not its simulation output.",
"href": "https://design.lemonergy.com/cosim.html?example=charging-home"
},
"html": "Current profile
Charge current
\nVoltage profile
Cell voltage
"
}
},
{
"id": "reference:tomaszewska-charging",
"type": "Reference",
"label": "Lithium-ion battery fast charging: A review",
"properties": {
"title": "Lithium-ion battery fast charging: A review",
"publisher": "eTransportation",
"url": "https://doi.org/10.1016/j.etran.2019.100011",
"type": "Review article",
"scope": "CC-CV and alternative charging protocols, transport limitations, degradation and thermal implications; results depend on cell and test conditions. Software behavior is documented separately in Lemonergy block references.",
"year": 2019,
"authors": [
"Anna Tomaszewska et al."
],
"accessed": "2026-10-27"
}
}
]
}