battery tender instruction manual
Battery tenders are designed for long-term maintenance, unlike chargers; patience is key, potentially needing up to 72 hours for a full charge.
These devices ensure optimal battery health, preventing sulfation and extending lifespan, crucial for seasonal vehicles or infrequent use.
Deltran offers comprehensive manuals for models like the Battery Tender Plus and JR, detailing safety and operating procedures.
Understanding the difference between a tender and a charger is vital for effective battery care and avoiding premature failure.
What is a Battery Tender?
A battery tender, as detailed in Deltran’s comprehensive guides, isn’t a rapid charger but a sophisticated maintenance device. It’s designed to deliver a low, consistent current, preventing battery degradation over extended periods.
Unlike chargers aiming for a quick voltage boost, tenders focus on keeping a fully charged battery at its peak capacity. This is especially important for vehicles stored seasonally or those with infrequent use.
The Battery Tender Plus, for example, operates on selectable voltages (12V, 6V, 8V) and is ideal for various lead-acid, AGM, and gel cell batteries, as outlined in product manuals.
Benefits of Using a Battery Tender
Employing a battery tender offers significant advantages, primarily preventing battery sulfation – a major cause of failure. Deltran manuals emphasize that consistent maintenance extends battery lifespan, saving costs in the long run.
Tenders ensure vehicles are ready to start immediately, eliminating the need for jump-starts and potential electrical system issues. They are crucial for seasonal equipment like motorcycles and boats, maintaining optimal charge during storage.
Models like the Battery Tender JR provide convenient, reliable power management, as detailed in troubleshooting guides, ensuring consistent performance.
Understanding Battery Tender Lights & Indicators
Battery tender lights signal charging status: red indicates charging, green signifies full charge or maintenance mode, and flashing green suggests potential issues.
Deltran manuals detail these indicators, aiding in troubleshooting and ensuring optimal battery health.
Red Light: Charging Phase
A solid red light on your Battery Tender indicates the charging phase is actively occurring. During this stage, the tender is delivering a controlled current to replenish the battery’s energy reserves.
It’s crucial to remember that this phase can take a considerable amount of time, potentially extending up to 72 hours, depending on the battery’s initial state of discharge.
Do not interrupt the charging process during the red light phase, as this could hinder the battery’s full recovery. Patience is key to achieving optimal results.
Green Light: Full Charge/Maintenance Mode
A solid green light signifies that your battery has reached full charge and the Battery Tender has transitioned to maintenance mode.
In this phase, the tender provides a small, continuous current to counteract self-discharge, keeping the battery at its peak capacity.
The unit can remain connected indefinitely without risk of overcharging, ensuring your battery is always ready for use. This is ideal for seasonal vehicles or long-term storage.
Flashing Green Light: Potential Issues
A flashing green light often indicates a problem with the charging process, requiring investigation. It could signify a deeply discharged battery – below 3 volts – which may struggle to recover.
Ensure all loads are disconnected during charging, as these can interfere with the tender’s ability to properly assess and restore the battery.
Check connections and consider consulting the troubleshooting checklist in your Deltran manual for further guidance.

Setting Up Your Battery Tender
Proper setup involves connecting the positive and negative clamps correctly, ensuring a secure AC power connection, and initiating the charging process.
Always verify polarity before connecting, and allow up to 72 hours for a complete charge cycle.
Connecting to the Battery (Polarity)
Crucially, always connect the red clamp to the positive (+) terminal and the black clamp to the negative (-) terminal of the battery.
Reversing this polarity can cause a blown fuse within the harness or, in severe cases, damage to the battery and the tender itself.
Double-check the connections before plugging in the AC power to avoid potential issues. The Battery Tender JR troubleshooting checklist specifically highlights reversed polarity as a common problem.
Ensure a firm grip on the terminals for optimal charging efficiency and to prevent accidental disconnections during the charging cycle.
AC Power Connection
Before connecting the AC power cord, verify that the battery clamps are securely attached with the correct polarity – red to positive, black to negative.
Plug the tender’s AC cord into a standard wall outlet. The troubleshooting checklist emphasizes ensuring AC power is available if the tender isn’t functioning.
Avoid using extension cords if possible; if necessary, use a heavy-duty cord rated for outdoor use.
Confirm the outlet is properly grounded for safety and optimal performance of the battery tender.
Initial Charging Process ⎼ Expected Timeframe
The initial charging phase can take considerable time, varying based on the battery’s discharge level. Don’t expect an immediate green light; patience is crucial.
A deeply discharged battery may require up to 72 hours to reach full charge and switch to maintenance mode, as indicated by the light change.
If, after 72 hours, the charging light remains red, consult the troubleshooting guide or contact customer support for assistance.
Remember, tenders are for maintenance, not rapid charging.

Troubleshooting Common Issues
Common problems include no AC power, reverse polarity connections, and blown fuses within the harness; always check these first for quick fixes.
A battery below 3 volts may not recover, and disconnecting loads is essential during charging for optimal results.
No AC Power Available
If the battery tender isn’t receiving power, the first step is to insure AC power is actually available at the outlet being used. Verify the outlet functions correctly with another device.
Check the power cord connection to both the tender and the wall outlet, ensuring it’s securely plugged in. A loose connection can easily interrupt the power supply.
Also, examine the power cord itself for any visible damage, such as cuts or frayed wires, which could indicate a safety hazard and prevent operation.
Reverse Polarity Connection
A reverse polarity connection occurs when the red (positive) clamp is connected to the negative battery terminal, and the black (negative) clamp to the positive terminal. Immediately disconnect the clamps if this is detected.
Most battery tenders will not charge with reversed polarity, and some may even be damaged. Correct the connection, ensuring red connects to positive and black to negative.
The Battery Tender JR specifically notes this as a troubleshooting step; reversing clamps is a common error, so double-check before initiating charging.
Blown Fuse in Harness
If your battery tender isn’t functioning, a blown fuse within the ring terminal or alligator clip harness is a potential cause. Check the fuse located in the harness, not the vehicle’s fuse box.
Replace the blown fuse with one of the same amperage rating to avoid further damage. The Battery Tender JR troubleshooting checklist specifically identifies this as a remedy.
A blown fuse often indicates a short circuit or overload, so investigate the cause before replacing it repeatedly; continuous blowing suggests a larger issue.

Low Voltage Battery Concerns
A battery below 3 volts may not recover, even with a tender; disconnecting loads is crucial for successful charging and potential recovery.
Deeply discharged batteries require a longer charging period and may have reduced capacity, impacting overall performance.
Battery Voltage Below 3 Volts ౼ Recovery Chances
If a 12-volt battery has discharged to below 3 volts, the chances of successful recovery are significantly diminished. Deep discharges cause sulfation, a buildup of lead sulfate crystals, hindering the battery’s ability to accept and hold a charge.
While a battery tender can sometimes revitalize a severely depleted battery, it’s not guaranteed. Disconnecting all loads from the battery before attempting to charge is paramount, preventing further drain during the recovery process.
Prolonged tender application may help, but a battery in this state might have permanently lost capacity, even if it appears to charge.
Disconnecting Loads During Charging
Prior to connecting a battery tender, it’s crucial to disconnect all loads or devices drawing power from the battery. This includes interior lights, alarms, or any accessories that might continue to drain the battery during the charging cycle.
Leaving loads connected prevents the tender from effectively delivering a full charge, potentially extending the charging time indefinitely and hindering recovery of a deeply discharged battery.
Disconnecting the battery entirely from the vehicle’s electrical system is also recommended for optimal results.
Specific Battery Tender Models
Deltran offers various models, including the Battery Tender Plus (12V1.25A, 6V1.25A, 8V1.25A) and the Battery Tender JR, each with unique troubleshooting steps.
Refer to the specific manual for your model to understand its features and operating instructions for optimal performance.
Battery Tender Plus (12V1.25A, 6V1.25A, 8V1.25A)
The Battery Tender Plus is a versatile charger suitable for 12V, 6V, and 8V batteries. Ensure AC power is available, and check for correct polarity before connecting clamps.
If the charging light remains red after 72 hours, contact customer support for assistance. A battery below 3 volts may not recover, so disconnect all loads during charging.
Review the troubleshooting checklist in the manual; a blown fuse in the harness is a common issue. This model maintains batteries effectively, preventing sulfation and extending their lifespan.
Battery Tender JR Troubleshooting
For the Battery Tender JR, begin by verifying AC power availability. Incorrect clamp connections (reversed polarity) are a frequent cause of issues, so double-check their placement.
Inspect the ring terminal or alligator clip harness for a blown fuse – replacement is straightforward. Remember, a full charge can take up to 72 hours; patience is crucial.
If problems persist, consult the comprehensive troubleshooting checklist within the user manual. Disconnect loads to optimize charging and assess battery voltage levels.
Deltran Charger Product Groups ⎼ Operating Instructions
Deltran offers various product groups, each with specific operating instructions. The Battery Tender Plus (12V1.25A, 6V1.25A, 8V1.25A) is a popular choice for maintaining multiple battery types.
Always refer to the comprehensive user manual for your specific model, covering safety precautions, setup procedures, and status indicator explanations.
Ensure proper ventilation and avoid water exposure during operation. Understanding the charging phases – red for charging, green for maintenance – is key to optimal battery care.

Advanced Troubleshooting
If the charging light remains red after 72 hours, contact customer support for assistance. A deeply discharged battery may require professional evaluation.
Identifying the root cause ensures proper battery recovery and prevents further damage, extending its overall lifespan.
Charging Light Remains Red After 72 Hours
A persistent red charging light after a full 72 hours indicates a potential issue preventing the battery from reaching a full charge. Don’t assume immediate failure; however, prolonged red illumination signals a need for investigation.
First, re-verify the AC power supply is stable and connected correctly. Then, confirm a secure connection to the battery terminals, ensuring proper polarity. If these checks pass, it’s time to contact Deltran’s customer support team. They can guide you through further diagnostic steps or advise on potential battery replacement if recovery isn’t possible.
Identifying a Deeply Discharged Battery
A deeply discharged battery presents a significant challenge for recovery. If the battery voltage measures below 3 volts, the chances of successful rejuvenation diminish considerably. This level of discharge can cause irreversible sulfation, hindering the battery’s ability to accept a charge.
Before attempting to charge, disconnect all loads drawing power from the battery. A tender may struggle to initiate charging with a parasitic drain. If the tender fails to transition from red to green, professional assessment is recommended.

Battery Tender Maintenance
Regular maintenance ensures optimal performance; Clean terminals to establish a solid connection, and inspect cables for damage, replacing them if frayed or cracked.
Consistent checks prolong the tender’s lifespan and maintain efficient charging, safeguarding your battery investment.
Cleaning the Terminals
Corroded battery terminals impede the charging process, reducing the tender’s effectiveness. Disconnect the battery before cleaning. A mixture of baking soda and water creates a safe, effective cleaning solution; apply it to the terminals and scrub with a wire brush.
Rinse thoroughly with water and dry completely before reconnecting. Ensuring a clean connection is vital for optimal charging and preventing voltage drops. Regularly cleaning terminals extends battery life and maintains tender performance.
This simple maintenance step significantly improves charging efficiency.
Checking the Cables for Damage
Inspect the battery tender cables regularly for cracks, fraying, or exposed wires. Damaged cables pose a safety hazard and reduce charging efficiency. Pay close attention to the points where the cables connect to the clamps and the tender itself.
If damage is detected, replace the cables immediately. Using damaged cables can lead to shorts, fires, or ineffective charging. Ensure replacement cables are of the correct gauge and compatible with your tender model.
Prioritize safety and optimal performance through diligent cable inspection.
Safety Precautions
Ensure proper ventilation during charging to prevent hydrogen gas buildup. Avoid water exposure to the tender and battery to mitigate electrical shock risks.
Always follow the comprehensive safety instructions detailed in your Deltran charger’s user manual.
Proper Ventilation
Battery charging produces explosive hydrogen gas, especially during the initial stages. Adequate ventilation is absolutely critical to dissipate this gas and prevent potential explosions or fires.
Charge batteries in a well-ventilated area, avoiding enclosed spaces like airtight garages or trunks. Ensure airflow is not obstructed, and consider using a fan to circulate air. Refer to your Battery Tender’s manual for specific ventilation recommendations. Ignoring this precaution poses a significant safety hazard, potentially causing severe damage or injury.
Avoiding Water Exposure
Never expose your Battery Tender or the battery being charged to water or moisture. Electrical components and water create a dangerous combination, increasing the risk of electric shock and short circuits.
Use the charger indoors or under a protected shelter. If accidental exposure occurs, immediately disconnect the charger and allow it to dry completely before further use. Inspect cables for damage and replace if necessary. Prioritize safety by keeping all electrical components dry.

Battery Types Compatible with Tenders
Battery tenders effectively maintain lead-acid, AGM, and Gel cell batteries, ensuring optimal performance and longevity for various vehicle types.
Deltran manuals specify compatibility, emphasizing proper settings for each battery chemistry to prevent damage.
Lead-Acid Batteries
Lead-acid batteries are the most common type and widely compatible with Battery Tenders. These batteries benefit significantly from consistent maintenance charging, preventing sulfation – a major cause of capacity loss.
Deltran manuals recommend a standard charging profile for flooded lead-acid batteries, ensuring a safe and effective charge. It’s crucial to ensure the battery is well-ventilated during charging, as lead-acid batteries release hydrogen gas.
Regular tender use extends the lifespan of lead-acid batteries, especially those in seasonal vehicles or infrequently used equipment, maintaining optimal voltage levels.
AGM and Gel Cell Batteries
AGM (Absorbent Glass Mat) and Gel Cell batteries are valve-regulated lead-acid (VRLA) types, also compatible with Battery Tenders, but require specific charging profiles. Deltran manuals detail these differences, emphasizing the importance of selecting the correct mode.
These batteries are sealed and don’t require regular water checks, making them ideal for various applications. Overcharging can damage AGM and Gel cells, so a tender’s maintenance mode is beneficial.
Consistent, low-current charging prevents sulfation and maintains optimal performance, extending their lifespan and ensuring reliable power delivery.

Understanding Charging Time
Charging duration varies; tenders maintain, while chargers rapidly restore. Factors like battery age, depth of discharge, and ambient temperature influence the process.
Allow up to 72 hours for a full charge, as these are tenders, not rapid chargers, prioritizing long-term battery health.
Tender vs. Charger ౼ Key Differences
Battery tenders and chargers serve distinct purposes, despite both delivering power to a battery. A charger aims for a quick, full restoration of charge, ideal for starting a depleted battery. Conversely, a tender provides a low, consistent current to maintain a fully charged battery over extended periods.
Tenders prevent sulfation and extend battery life, crucial for seasonal vehicles. They aren’t designed for rapid charging; patience is required, potentially taking days for initial full charge. Understanding this difference is key to proper battery maintenance and avoiding damage.
Factors Affecting Charging Duration
Several factors influence how long a battery tender takes to fully charge a battery. The initial depth of discharge is paramount; a deeply discharged battery requires significantly more time – potentially up to 72 hours or more – to reach full capacity.
Battery type (lead-acid, AGM, gel) and its capacity (Ah) also play a role. Ambient temperature impacts efficiency, and any loads connected to the battery during charging will prolong the process. Patience is crucial for optimal results.
Contacting Customer Support
If your Battery Tender exhibits issues after troubleshooting, or the charging light remains red beyond 72 hours, contact Deltran’s customer service for assistance.
They offer resources and expert guidance to resolve problems and ensure optimal battery maintenance.
When to Seek Professional Help
Determining when to escalate beyond self-troubleshooting is crucial. If, after following the Battery Tender Plus troubleshooting checklist, the issue persists – particularly a consistently red charging light after 72 hours – professional assistance is recommended.
Similarly, if a battery consistently fails to charge or displays a voltage below 3 volts, indicating a potentially unrecoverable discharge, consult a qualified technician.
Don’t hesitate to seek expert advice if you’re uncomfortable with electrical systems or suspect a more complex problem beyond the scope of the user manual.
Available Support Resources
Deltran provides extensive support for its Battery Tender products. Comprehensive user manuals are available online for models like the Battery Tender Plus (12V1.25A, 6V1.25A, 8V1.25A) and the Battery Tender 4 AMP Charger.
These manuals detail operating instructions, safety precautions, and troubleshooting guides. For specific issues not covered, contacting Deltran’s customer service team directly is advised.
Their website offers a wealth of information, and direct support can assist with complex problems or warranty claims, ensuring optimal battery maintenance.








































































