Votronic MPPT 25A Duo (Dual) 350 Solar Charge Controller
Votronic MPPT 25A Duo (Dual) 350 Solar Charge Controller
Dual-battery MPPT charging with AES fridge control and LiFePO4 support
Highlights:Solar Panel Terminals: Connection points for solar panels up to 350Wp or 21A,Battery Terminals: Dual charging outputs for board and starter batteries,30A Protection Fuse: Standard 30 amp blade fuse for circuit protection,Status LEDs: Indicators for AES, Battery Full, Charging and Battery Low,Solar Display Port: RJ12 connection for optional Votronic LCD solar computer,Signal Terminals: Ports for temperature sensor, AES refrigerator control and EBL.
Key features: Dual output for simultaneous main and starter battery charging, Compatible with solar panel capacities up to 350W, Integrated AES output for automatic refrigerator switching, Supports external temperature sensor and LCD display options, Clear wiring instructions for EBL and vehicle chassis grounding.
Comprehensive technical data comparison for the Votronic MPP Duo Digital range, specifying solar power limits, charging voltages for lead-acid and LiFePO4 batteries, and physical dimensions of 131 by 77 by 40 mm. 
DESCRIPTION
Votronic MPPT 25A Duo 350: Advanced Dual-Battery Solar Regulation for Mobile and Marine Applications
Precision MPPT Charging for Caravans, Campervans, and Boats
The Votronic MPPT 25A Duo 350 Solar Charge Controller is engineered for demanding off-grid energy systems where reliable dual-battery charging is essential. Utilising advanced Maximum Power Point Tracking (MPPT) technology, this controller continuously optimises the power harvest from your solar array, converting excess voltage into higher charging current. This results in up to 30% more charge current compared to conventional PWM controllers, particularly in cooler or overcast conditions when every watt counts.
Designed for 12V lead-acid, gel, AGM, and LiFePO4 batteries, the Duo 350 intelligently manages two battery banks: the main service battery (BOARD I) receives full charging priority, while the starter battery (Start II) is maintained with a regulated trickle charge of up to 1A. This ensures your vehicle is always ready to start, even after extended periods off-grid.
Key Features at a Glance
- Dual-battery charging – Simultaneously charges main and starter batteries with independent regulation
- High-efficiency MPPT tracking – Delivers up to 30% more current than PWM controllers, with >95% conversion efficiency
- Multi-chemistry support – 3 selectable charge profiles for lead-acid/gel/AGM, plus 5 for LiFePO4 batteries with integrated BMS
- IU1oU2 charge algorithm – Prevents harmful acid stratification and ensures full, safe charging without overvoltage
- AES refrigerator control – Automatically switches compatible Dometic/Electrolux fridges to 12V when surplus solar is available
- Temperature sensor input – Optional sensor (Art. 2001) adjusts charging voltage for lead batteries and protects LiFePO4 in extreme temperatures
- Integrated system protection – Safeguards against overload, overheating, reverse polarity, and battery back-discharge at night
- Compact, robust design – 131 x 77 x 40 mm footprint with CE and E-approval for motor vehicle use
Why MPPT Matters for Your Mobile Solar System
Unlike basic PWM regulators that simply connect panels to batteries, the Votronic MPP 350 Duo actively tracks the panel's maximum power point several times per minute. This is especially beneficial when using higher-voltage panels or when light conditions are variable. The high-frequency switching technology transforms voltage surplus into usable charging current, meaning you can extract more energy from the same panel—ideal for space-constrained installations on campervans, caravans, and marine vessels.
Intelligent Battery Management for Longevity
The controller's IU1oU2 characteristic ensures a defined boost phase (U1) to equalise cells and prevent acid stratification in lead batteries, followed by a precise float stage (U2) to maintain full charge without gassing. For LiFePO4 systems, temperature-compensated charging protects against low-temperature damage—a critical feature for Australian conditions where overnight temperatures can drop unexpectedly. Automatic cable loss compensation further ensures accurate voltage delivery at the battery terminals, regardless of cable length.
Seamless Integration with Existing Systems
The Duo 350 is designed to work harmoniously with other onboard power sources, including alternators, mains chargers, and wind generators, thanks to its integrated suppression filter. It also features a measurement output compatible with Schaudt Elektroblocks (EBL), allowing you to monitor solar yield via your existing control panel (compatibility should be verified). For enhanced visibility, the controller is plug-in ready for the optional Votronic LCD Solar Computer S, Bluetooth Connector, or VPC interface.
Built for the Road and the Water
With an operating temperature range of -20 to +45 °C and robust construction, this controller is suited to the harsh environments encountered in mobile and marine applications. The fully encapsulated electronics resist moisture and vibration, while the compact dimensions allow installation in tight electrical lockers. CE and E-mark approval ensures compliance with European automotive electromagnetic compatibility standards, giving you confidence in its reliability.
Take Control of Your Off-Grid Power
Upgrade your solar setup with the Votronic MPPT 25A Duo 350 and experience faster charging, longer battery life, and true set-and-forget operation. Whether you're powering a weekend camper or a liveaboard yacht, this controller delivers the intelligent energy management you need. Add the Votronic MPPT 25A Duo 350 to your system today and maximise every ray of sunshine.
SKU: Vot-1720
SPECIFICATIONS
Specifications
| Model | MPP 350 Duo Dig. |
|---|---|
| Article No. | 1720 |
| Battery Voltage Lead / LiFePO4 | 12 V / 12.0...13.3 V |
| Solar Module Power (Pmax) | 50...350 Wp |
| Solar Module Current Max. | 21 A |
| Solar Module Voltage (Voc) Max. | 50 V |
| Charge Current Board/Starter Battery Max. | 25.5/1.0 A |
| AES Refrigerator Switched Output | 12 V/0.2 A |
| Connection Solar-Computer S, VPC, Bluetooth Connector | Plug-In Ready |
| Dimensions (L x W x H) | 77 x 131 x 40 mm |
| Weight | 285 g |
| Charge Programmes For Lead-Acid/Gel/AGM | 3 |
| Charge Programmes With Temperature Protection For Current LiFePO4 Complete Batteries With BMS | 5 |
| Charge Curve | IU1oU2 |
| Efficiency | > 95 % |
| LED Indicators | 5 |
| Operating Temperature Range | -20 to +45 °C |
| Approvals | CE, E-Approval (EMC/Motor Vehicle Directive) |
| SKU: | Vot-1720 |
| Model #: | Vot-1720 |
| MPN: | Vot-1720 |
WARRANTY
VOTRONIC Warranty Policy
This warranty policy applies to VOTRONIC products supplied by us in Australia. VOTRONIC products supplied by us are covered by a 60 month warranty against defects in materials or manufacture, subject to the product being used, installed and operated correctly and in accordance with the manufacturer's instructions.
This warranty applies to the original end-user purchaser of the product, as evidenced by a valid proof of purchase, and is not transferable unless otherwise agreed in writing.
The benefits given by this warranty are in addition to other rights and remedies available under law.
Warranty Coverage and Periods
This warranty covers VOTRONIC products supplied by us, including charging devices, inverters, converters, monitoring devices, display devices and related accessories. The warranty periods for each product range are set out below.
| VOTRONIC Product Model Range | Warranty Length | Application / Notes |
|---|---|---|
| VOTRONIC Charging Devices | 60 months | Applies to VOTRONIC chargers, charging converters, solar charging controllers and related charging equipment where used as intended and within the product's rated specifications. |
| VOTRONIC Inverters and Power Devices | 60 months | Applies to VOTRONIC inverters, converters and related power electronics where correctly installed and operated within the product's technical ratings. |
| VOTRONIC Measuring and Display Devices | 60 months | Applies to VOTRONIC battery monitors, displays, tank level displays, computers and related monitoring devices where installed and used in accordance with the manufacturer's instructions. |
| VOTRONIC Accessories and Peripheral Devices | 60 months | Applies to VOTRONIC accessories and peripheral devices supplied by us and covered by the applicable manufacturer warranty. |
The warranty period begins on the date of purchase by the original end-user, as shown on the valid proof of purchase. A valid proof of purchase is required for all warranty claims.
Installer Responsibilities and System Design
VOTRONIC products are commonly installed, connected, configured or integrated into a broader electrical system, vehicle, vessel, caravan, motorhome or other operating environment. Once installed, the product may form only one component of a larger system.
We do not provide installation services unless expressly stated in writing, and we do not supervise or control installation practices carried out by dealers, installers, contractors or end-users. The installer, system designer, integrator, dealer or end-user is responsible for ensuring that the product is suitable for the intended application and is installed correctly.
Issues or damage arising from incorrect installation, poor system design, incorrect configuration, incompatible equipment, inadequate protection, unsuitable mounting, unsuitable environmental conditions or failure to follow the manufacturer's instructions are not product defects and are not covered by this warranty.
Appropriate Installation
All VOTRONIC products must be installed in accordance with the product manual, the manufacturer's installation instructions, applicable Australian Standards, relevant electrical, automotive, marine or industry standards, and recognised industry best practice.
The installer must ensure that the product is used in an appropriate environment and within its specified ratings. Improper, unsafe, unlicensed, sub-standard or non-compliant installation may void or limit warranty coverage.
System Compatibility
The installer or integrator is responsible for selecting and using compatible components. This includes ensuring compatibility with batteries, chargers, solar panels, regulators, alternators, inverters, wiring, fuses, circuit breakers, sensors, shunts, displays, power supplies, controllers and any other connected equipment.
Damage or underperformance caused by incompatible, incorrectly configured, undersized, oversized, unsuitable or improperly installed equipment is not covered by this warranty.
System-Wide Performance
Overall system performance depends on design, installation, configuration, usage, maintenance and environmental factors beyond the VOTRONIC product itself. This warranty covers the quality of the individual VOTRONIC product supplied by us only. It does not guarantee the performance of the broader electrical system into which the product is installed or integrated.
Issues such as insufficient charging, incorrect battery management, poor solar performance, nuisance faults, overheating, voltage drop, instability, intermittent operation, inaccurate readings or operational shortfalls caused by system design, installation or configuration are outside the scope of this warranty.
Installation Location and Environmental Suitability
The installer must ensure that VOTRONIC products are mounted, located, supported, ventilated and protected in a manner suitable for the installation environment.
Where relevant, the installer must allow for heat dissipation, ventilation, moisture exposure, dust, vibration, corrosion risk, aggressive battery gases, electrical clearance, mechanical loading, access for inspection and service, and protection from unsuitable environmental conditions.
Damage caused by unsuitable mounting, inadequate ventilation, moisture, dust, corrosion, aggressive battery gases, excessive heat, vibration, insufficient clearance, unsuitable substrate selection or other installation environment issues is not a manufacturing defect and is not covered by this warranty.
System Protection and Fault Isolation
The installer must incorporate suitable protective devices and design measures appropriate to the product and installation type. This may include correctly rated fuses, circuit breakers, isolators, over-current protection, over-voltage protection, low-voltage protection, reverse polarity protection, surge protection, correct cable sizing and other protective devices required by standards or best practice.
The installer is responsible for ensuring that a fault or failure in one component does not cause cascading damage to other components. Damage to VOTRONIC products caused by inadequate system protection, poor fault isolation, incorrect protection settings or missing safety devices is not covered by this warranty.
Service Accessibility Requirement
Products must be installed in a manner that allows reasonable access for inspection, testing, servicing, removal and replacement. We are not responsible for additional labour, structural modification, access equipment, removal of fixtures, cabinetry, panels, flooring, trim, sealants, adhesives or other costs arising from installation methods that restrict reasonable access to the product.
Installation Documentation
We may require documentation of the installation when assessing a warranty claim. This may include photos of the product in its installed location, wiring diagrams, system layout, serial numbers, details of connected equipment, installer details, commissioning records, service history, fault logs, operating settings and maintenance records.
Failure to provide reasonable installation evidence may limit our ability to assess the claim.
Independence of Dealers and Installers
Dealers, resellers, installers and contractors act independently and are not agents, employees or representatives of VOTRONIC or us unless expressly agreed in writing. We are not responsible for the acts, omissions, workmanship, advice, representations, installation practices or system design decisions of independent dealers, resellers, installers, contractors or third parties.
What This Warranty Does Not Cover
This warranty covers manufacturing defects or failures of the product arising from normal use in accordance with the manufacturer's instructions. It does not cover any failure, damage, performance issue, deterioration or loss caused wholly or partly by external factors, misuse, incorrect installation or circumstances outside the manufacturer's control.
- Incorrect installation or wiring
- Incorrect product selection or application
- Use outside the product's intended purpose
- Operation outside the product's rated technical specifications
- Incorrect voltage, current, load, charging profile or configuration
- Improper operation, misuse, abuse or neglect
- Physical impact, accidental damage or mechanical damage
- Unauthorised modification, tampering, disassembly or repair
- Service work carried out by a third party not authorised by the manufacturer
- Use with incompatible, incorrectly rated or improperly configured third-party components
- Damage caused by inadequate fusing, circuit protection, isolation or system protection
- Damage caused by moisture, dust, corrosion, aggressive battery gases or unsuitable installation environments
- Damage caused by excessive heat, inadequate ventilation or installation in an unsuitable location
- Damage caused by vibration, movement, poor mounting or inadequate support
- Normal wear and tear, cosmetic deterioration or gradual degradation consistent with normal use
- Failure to carry out reasonable inspection, cleaning, maintenance or servicing where required
- Products with removed, altered, damaged or illegible serial numbers, rating labels or identification markings
- Products purchased second-hand, from unauthorised channels, auction sites, liquidation sales or grey-market sources
- Labour costs for removal, replacement, reinstallation or diagnosis
- Freight, travel, call-out costs or access costs unless otherwise required by law
- Products not returned for assessment when reasonably required
- Consequential or incidental loss, including damage to other equipment, downtime, loss of use, loss of revenue or economic loss, to the extent permitted by law
Warranty Assessment and Remedy
If a VOTRONIC product supplied by us is found to be defective within the applicable warranty period, we will, at our discretion, arrange a repair, replacement, store credit, refund or another appropriate remedy, depending on the nature of the fault and the requirements of Australian Consumer Law.
Products may need to be returned for assessment before a warranty claim can be approved. Where required, the product must be returned with dated proof of purchase, product details, serial number if available, installation information and a clear description of the fault.
If the product is required to be returned to VOTRONIC or another nominated assessment location for inspection or repair, a return authorisation process may be required before the product is sent. Products sent without the required return authorisation or documentation may not be processed.
Labour costs for removing, replacing, reinstalling or diagnosing a product are not covered by this express warranty unless otherwise required under Australian Consumer Law.
Making a Warranty Claim
If you suspect a fault with a VOTRONIC product supplied by us, do not immediately remove or uninstall the product unless it is unsafe to leave it in place or unless authorised as part of the warranty process. Premature removal may cause further damage or make it difficult to determine the original cause of the issue.
- Contact us: Contact us with your dated proof of purchase, product model, serial number if available, and a description of the fault.
- Provide product and installation information: We may request installation photos, wiring details, connected equipment details, operating settings, fault codes, measurements or service history to assist with assessment.
- Assessment and troubleshooting: We may ask for safe checks, photos, testing information or other details to determine whether the issue appears to be a product fault or is caused by installation, configuration, connected equipment, environment or misuse.
- Return for inspection if required: If the fault cannot be confirmed remotely, the product may need to be returned for inspection, testing, repair or replacement assessment. Return instructions will be provided where required.
- Outcome: If the product is confirmed to be faulty and covered by this warranty, we will advise the available remedy. If the product is found not to be faulty, or the issue is caused by an excluded factor, the claim may be rejected.
Remedies Under Warranty
If a defect covered by this warranty is confirmed, we may provide one or more of the following remedies, subject to the circumstances of the claim and the requirements of Australian Consumer Law:
- repair of the product;
- replacement of the product;
- store credit;
- refund;
- supply of replacement parts; or
- another appropriate remedy required by law.
Repair or replacement under this warranty does not restart or extend the original warranty period. The warranty continues from the original purchase date.
Manufacturer Support
VOTRONIC may provide repair or assessment services through its own service process. Where available, we may assist customers in contacting the manufacturer or arranging assessment, but any manufacturer service is subject to VOTRONIC's own process, requirements and continued availability.
Australian Consumer Law
This warranty is in addition to other rights and remedies available at law. Our goods come with guarantees that cannot be excluded under the Australian Consumer Law. You are entitled to a replacement or refund for a major failure and compensation for any other reasonably foreseeable loss or damage. You are also entitled to have the goods repaired or replaced if the goods fail to be of acceptable quality and the failure does not amount to a major failure.















































