4. Operation
4.1. Charge algorithm
The Smart IP43 Charger range are intelligent multi-stage battery chargers, specifically engineered to optimise each recharge cycle and charge maintenance over extended periods.
The multi-stage charge algorithm includes the individual charge stages described below:
Bulk
The battery is charged at maximum charge current until the voltage increases to the configured absorption voltage.
The bulk stage duration is dependent on the battery’s level of discharge, the battery capacity and the charge current.
Once the bulk stage is complete, the battery will be approximately 80% charged (or >95% for Li-ion batteries) and may be returned into service if required.
Absorption
The battery is charged at the configured absorption voltage, with the charge current slowly decreasing as the battery approaches full charge.
The default absorption stage duration is adaptive and intelligently varied depending on the battery’s level of discharge (determined from the duration of the bulk charge stage).
Adaptive absorption stage duration can vary between a minimum of 30 minutes, up to a maximum limit of 8 hours (or as configured) for a deeply discharged battery.
Alternatively, fixed absorption duration can be selected; fixed absorption duration is the automatic default when Li-ion mode is selected.
Absorption stage can also be ended early based on the tail current condition (if enabled), which is when the charge current drops below the tail current threshold.
Recondition
The battery voltage is attempted to be increased to the configured recondition voltage, while the charger output current is regulated to 8% of the nominal charge current (for example: 1.2A maximum for a 15A charger).
Recondition is an optional charge stage for lead acid batteries and not recommended for regular/cyclic use; use only if required, as unnecessary or overuse will reduce battery life due to excessive gassing.
The higher charge voltage during recondition stage can partially recover/reverse battery degradation due to sulfation, typically caused by inadequate charging or if the battery is left in a deeply discharged state for an extended period (if performed in time).
The recondition stage may also be applied to flooded batteries occasionally to equalise individual cell voltages and prevent acid stratification.
Recondition stage is terminated as soon as the battery voltage increases to the configured recondition voltage or after a maximum duration of 1 hour (or as configured).
Note that in certain conditions it is possible for the recondition state to end before the configured recondition voltage is achieved, such as when the charger is simultaneously powering loads, if the battery was not fully charged before recondition stage commenced, if the recondition duration is too short (set to less than one hour) or if the charger output current is insufficient in proportion to the capacity of the battery/battery bank.
Float
The battery voltage is maintained at the configured float voltage to prevent discharge.
Once float stage is commenced the battery is fully charged and ready for use.
The float stage duration is also adaptive and varied between 4 to 8 hours depending on the duration of the absorption charge stage, at which point the charger determines the battery to be in storage stage.
Storage
The battery voltage is maintained at the configured storage voltage, which is slightly reduced compared to the float voltage to minimise gassing and extend battery life whilst the battery is unused and on continuous charge.
Repeated absorption
To refresh the battery and prevent slow self-discharge while in storage stage over an extended period, a 1 hour absorption charge will automatically occur every 7 days (or as configured).
The indicator LEDs display the active charge state; refer to the image below:
Alternatively, a Bluetooth enabled device (such as a mobile phone or tablet) with the VictronConnect app can be used to view the active charge state; refer to the 'Monitoring > VictronConnect > Status screen' and 'Monitoring > VictronConnect > Graph screen' sections for more information.
4.2. Charge modes
There are 3 integrated charge modes (Normal, High and Li-Ion), as well as an optional Recondition stage that can be included (except for Li-ion mode).
The integrated charge modes combined with adaptive charge logic are well suited for most common battery types; such as flooded lead-acid, AGM, Gel and LiFePO4.
The required charge mode can be selected via the MODE button on the charger or a Bluetooth enabled device (such as a mobile phone or tablet) with the VictronConnect app; refer to the 'Setup > Setup using the charger' or 'Setup > Setup using Bluetooth' section for more information.
If necessary, advanced configuration with user defined settings is also possible using a Bluetooth enabled device (such as a mobile phone or tablet) with the VictronConnect app; refer to the 'Advanced configuration > Advanced settings' and 'Advanced configuration > Expert mode settings' sections for more information.
Any settings made are stored and will not be lost when the charger is disconnected from mains power or the battery.
4.2.1. Charge voltage
The charge voltage settings for each charge stage are altered depending on integrated charge mode selected; refer to the table below:
Notice
To ensure proper charging, battery longevity and safe operation it is important to select a charge mode appropriate for the battery type and capacity being charged; refer to the battery manufacturer’s recommendations.
The Smart IP43 Charger range feature temperature compensation, which will automatically optimise the nominal/configured charge voltage based on ambient temperature (except for Li-ion mode or if manually disabled); refer to the 'Operation > Temperature compensation’ section for more information.
4.2.2. Recondition mode
If enabled the recondition stage is included in the charge cycle; use only if required as a corrective/maintenance action - refer to the 'Operation > Charge algorithm' section for more information.
When the recondition mode is enabled the RECONDITION LED will be illuminated and blink during recondition stage.
Recondition mode can be enabled and disabled via the MODE button on the charger or a Bluetooth enabled device (such as a mobile phone or tablet) with the VictronConnect app; refer to the 'Setup > Setup using the charger' or 'Setup > Setup using Bluetooth' section for more information.
4.2.3. Low current mode
If enabled the maximum charge current is limited to 50% of the maximum rated charge current; refer to the 'Technical Specifications' section for more information.
Low current mode is recommended when charging lower capacity batteries with a high current charger; charging at an excessive charge current can cause premature battery degradation and overheating.
Typically the maximum charge current for lead acid based batteries should not exceed ~0.3C (more than 30% of the battery capacity in Ah) and the maximum charge current for LiFePO4 batteries should not exceed ~0.5C (more than 50% of the battery capacity in Ah).
When low current mode is enabled the LOW LED will blink.
Low current mode can be enabled and disabled via the MODE button on the charger or a Bluetooth enabled device (such as a mobile phone or tablet) with the VictronConnect app; refer to the 'Setup > Setup using the charger' or 'Setup > Setup using Bluetooth' section for more information.
Notice
It is also possible to set the charge current limit to a user defined value between the maximum rated charge current and the minimum charge current limit (25% of maximum) using a Bluetooth enabled device (such as a mobile phone or tablet) with the VictronConnect app; refer to the 'Advanced Configuration > Advanced settings' section for more information.
When the charge current limit is set to or below 50% of the maximum rated charge current the LOW LED will blink.
4.3. Temperature compensation
The Smart IP43 Charger range feature temperature compensation, which will automatically optimise the nominal/configured charge voltage based on ambient temperature (except for Li-ion mode or if manually disabled).
The optimal charge voltage of a lead-acid battery varies inversely with battery temperature; automatic temperature-based charge voltage compensation avoids the need for special charge voltage settings in hot or cold environments.
During power up the charger will measure its internal temperature and use that temperature as the reference for temperature compensation, however the initial temperature measurement is limited to 25°C as it’s unknown if the charger is still warm from earlier operation.
Since the charger generates some heat during operation, the internal temperature measurement is only used dynamically if the internal temperature measurement is considered reliable; when the charge current has decreased to a low/negligible level and adequate time has elapsed for the charger’s temperature to stabilise.
For more accurate temperature compensation, battery temperature data can be sourced from a compatible battery monitor (such as a BMV, SmartShunt, Smart Battery Sense or VE.Bus Smart Dongle) via VE.Smart Networking; refer to the 'Operation > VE.Smart Networking’ section for more information.
The configured charge voltage is related to a nominal temperature of 25°C and linear temperature compensation occurs between the limits of 6°C and 50°C based on the default temperature compensation coefficient of -16.2mV/°C for 12V chargers (-32.4mV/°C for 24V chargers) or as configured.
Refer to the graph below for the default temperature vs charge voltage curve for 12V chargers:
Notice
The temperature compensation coefficient is specified in mV/°C and applies to the entire battery/battery bank (not per battery cell).
If the battery manufacturer specifies a temperature compensation coefficient per cell, it will need to be multiplied by the total number of cells in series (there are typically 6 cells in series within a 12V lead-acid based battery).
4.4. VE.Smart Networking
The Smart IP43 Charger range feature VE.Smart Networking capability, which enables Bluetooth connectivity and communication between multiple Victron products.
This powerful feature enables chargers to receive accurate battery voltage (Volt-sense), charge current (Current-sense) and battery temperature (Temp-sense) data from a compatible battery monitor (such as a BMV, SmartShunt, Smart Battery Sense or VE.Bus Smart Dongle) and/or multiple chargers to operate in unison with synchronised charging to further enhance the charge cycle.
A single compatible battery monitor (such as a BMV, SmartShunt, Smart Battery Sense or VE.Bus Smart Dongle) will provide voltage, temperature and/or current sense data to all (a single or multiple) chargers withing the common VE.Smart network.
Multiple compatible chargers in a common VE.Smart network (with or without a battery monitor) will also syncronise their charge algorithm (known as synchronised charging).
Notice
Only one battery monitor (BMV, SmartShunt, Smart Battery Sense or VE.Bus Smart Dongle) can be included in a VE.Smart network.
All battery monitor connections (voltage sensing cables, temperature sensor and current shunt) and chargers in a common VE.Smart network must be connected to the same battery / battery bank.
The maximum number of devices permitted in a VE.Smart network is 10.
Communication via VE.Smart networking requires all devices to be located within Bluetooth range of each other. Systems with poor or intermittent Bluetooth signal between devices will experience connection issues. Signal strength between devices can be checked in the VictronConnect VE.Smart networking page.
Multiple chargers in a common VE.Smart network must have the same charge settings, since the 'master' can change dynamically any charger could become the 'master'.
Multiple chargers in a common VE.Smart network do not need to be the same type or model, they just need to be VE.Smart Networking compatible (this includes VE.Smart Networking compatible Blue Smart chargers, Smart IP43 chargers and MPPT solar chargers).
Some older devices may not be VE.Smart networking compatible or have limitations; refer to the 'VE.Smart Networking Product Compatibility' table in the VE.Smart Networking manual to confirm.
4.4.1. Voltage sense
Voltage Sense uses battery voltage data that is accurately measured directly at the battery terminals (or very close) and provides it to the charger, the charger then uses this voltage data to dynamically increase the output voltage and precisely compensate for voltage drop in the cabling and connections between the charger and battery.
This enables the battery to be charged with the exact voltage as configured in the charger, instead of a lower voltage due to voltage drop in the cabling and connections.
Voltage drop is proportional to the charge current and cabling/connection resistance (V=IxR), so voltage drop will vary during a charge cycle and can be quite significant when charging at higher charge currents through cabling and connections with higher than optimal resistance; in this scenario voltage sense will be particularly beneficial.
Note that voltage sense does not allow inadequately rated cabling/connections to be used or compensate for excessively high voltage drop; for reliable and safe operation cabling and connections must all be suitably rated and appropriately sized for the application; refer to the 'Installation > Wiring' section for more information.
4.4.2. Synchronised charging
Synchronised charging capability enables multiple compatible chargers to be combined together in a common VE.Smart network, allowing the chargers to operate in unison as if they were one large charger.
The chargers will synchronise the charge algorithm between themselves with no further hardware or physical connections required, and simultaneously change charge states.
Synchronised charging works by systematically prioritising all chargers and assigning one as the 'master', this charger then controls the charge stage of all other 'slave' chargers. In case the initial 'master' is disconnected from the VE.Smart Network for any reason (out of Bluetooth range for example), another charger will be systematically reassigned as the 'master' and take over control; this can also be reversed if communication with the initial 'master' (that has a higher priority) is re-established. The 'master' charger can not be manually selected.
Synchronised charging does not regulate or equalise the current output of multiple chargers, each charger still has total control over it's own current output. Accordingly, current output variation between multiple chargers is normal (primarily dependent on cable resistance and charging conditions) and a total system current output limit cannot be configured; when a total system current output limit is important, consider using a GX device with DVCC (Distributed Voltage and Current Control) instead of VE.Smart Networking.
Synchronised charging can be setup with different charger types, providing they are VE.Smart Networking compatible (this includes compatible Blue Smart IP22 chargers, Smart IP43 chargers and SmartSolar MPPT solar chargers). Charging from solar chargers is not prioritised over mains supply chargers, so in some installations (primarily dependent on cable resistance and charging conditions) it is possible for solar power to be underutilised.
Synchronised charging can also be used in conjunction with a battery monitor (BMV, SmartShunt, Smart Battery Sense or VE.Bus Smart Dongle) to provide voltage, temperature and/or current sense data to the chargers in a common VE.Smart network; refer to the 'Operation > VE.Smart Networking > Voltage sense / Temperature sense / Current sense' sections for more information.
In the absence of a battery monitor providing current-sense data (requires a BMV or SmartShunt), the charge current from each individual charger is combined by the 'master' and referenced against the tail current setting.
4.5. Commencing a new charge cycle
A new charge cycle will commence when:
The configured Re-bulk condition is satisfied (typically due to a large load):
'Re-bulk method' set to 'Current' and 'Re-bulk current' is disabled (default configuration): The current output must be maintained at the maximum current output for four seconds.
'Re-bulk method' is set to 'Current' and 'Re-bulk current' is configured with a user defined value: The current output must exceed the configured 'Re-bulk current' for four seconds while the charger is in float or storage stage.
'Re-bulk method' is set to 'Voltage' and 'Re-bulk voltage offset' is configured with a user defined value: The battery voltage must drop below the configured 'Re-bulk voltage' for one minute.
The MODE button is pressed or used to select a new charge mode.
VictronConnect is used to select a new charge mode or change the function from ‘Power Supply’ to ‘Charger’ mode.
VictronConnect is used to disable and re-enable the charger (via the switch in the settings menu).
The remote terminals are used to disable and re-enable the charger (from an external switch or BMS signal).
The power supply to the AC power supply has been isolated and reconnected.
4.6. Estimating charge time
The time required to recharge a battery to 100% SOC (state of charge) is dependant on the battery capacity, the depth of discharge, the charge current and the battery type/chemistry, which has a significant effect on the charge characteristics.
4.6.1. Lead-acid based chemistry
A lead-acid battery is normally at approximately 80% state of charge (SOC) when the bulk charge stage is completed.
The bulk stage duration Tbulk can be calculated as Tbulk = Ah / I, where I is the charge current (excluding any loads) and Ah is the depleted battery capacity below 80% SOC.
The absorption stage duration Tabs will vary depending on the depth of discharge; up to 8 hours of absorption may be required for a deeply discharged battery to reach 100% SOC.
For example, the time required to recharge a fully discharged Lead-acid based 100Ah battery with a 10A charger would be approximately:
Bulk stage duration, Tbulk = 100Ah x 80% / 10A = 8 hours
Absorption stage duration, Tabs = 8 hours
Total charge duration, Ttotal = Tbulk + Tabs = 8 + 8 = 16 hours
4.6.2. Li-ion based chemistry
A Li-ion based battery is normally well above 95% state of charge (SOC) when the bulk charge stage is completed.
The bulk stage duration Tbulk can be calculated as Tbulk = Ah / I, where I is the charge current (excluding any loads) and Ah is the depleted battery capacity below 95% SOC.
The absorption stage duration Tabs required to reach 100% SOC is typically less than 30 minutes.
For example, the charge time of a fully discharged 100Ah battery when charged with a 10A charger to approximately 95% SOC is Tbulk = 100 x 95% / 10 = 9.5 hours.
For example, the time required to recharge a fully discharged Li-ion based 100Ah battery with a 10A charger would be approximately:
Bulk stage duration, Tbulk = 100Ah x 95% / 10A = 9.5 hours
Absorption stage duration, Tabs = 0.5 hours
Total charge duration, Ttotal = Tbulk + Tabs = 9.5 + 0.5 = 10 hours
4.7. Multiple isolated outputs
The Smart IP43 Charger 1+1 and 3 output models both include an integrated FET battery isolator and multiple isolated outputs.
Multiple isolated outputs make it possible for a single charger to charge multiple individual batteries that are at a different voltage/SOC level without current flow between the batteries, and with the charge current intrinsically distributed between all batteries depending on their voltage/SOC level and capacity.
The 1+1 output charger models can supply the full rated current from the main output, and the starter/auxiliary output is limited to a maximum of 4A; however the combined current of all outputs is limited to the full rated current.
The 3 output charger models can supply the full rated output current from all 3 outputs; however the combined current of all outputs is limited to the full rated output current.
Notice
The multiple isolated outputs are not regulated individually, one charge algorithm (charge cycle and charge voltage) is applied to all outputs; accordingly all batteries will need to be compatible with the common charge algorithm (typically the same chemistry type).