Category: Maintenance

Battery Maintenance Tips: How To Care For Your Deep-Cycle Batteries

Battery Maintenance Tips: How To Care For Your Deep-Cycle Batteries

How Do I Maintain Deep-Cycle Batteries?

  • Program your voltage set points so that the battery bank charges at the proper voltage.
  • Refill flooded lead-acid batteries with distilled water every 2-4 weeks as needed.
  • Regularly check battery state of charge. Apply an equalization charge to flooded batteries every 90 days. (Do not equalize sealed lead-acid or lithium batteries.)
  • Clean terminal connections and cables to prevent corrosion.

Solar batteries are the most costly component of any off-grid solar system. It’s important to program them properly and stick to a regular battery maintenance schedule to keep them running efficiently for years. Neglecting the proper setup and maintenance routine can shorten the lifespan of your batteries and void the product warranty.

Some battery types, like Lithium-ion, require little to no maintenance after the initial setup. Other battery types (especially flooded lead-acid) need regular upkeep to stay in good condition.

No matter what type of batteries you own, this article will help you program your battery bank and give some battery maintenance tips to keep your system running smoothly.

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Initial Programming

The first time you bring your system online, you’ll need to program your battery chargers to the proper charging settings for your battery bank. These settings dictate parameters like charging voltage and current.

This is where you program voltage set points, the charging voltages applied to the battery during each stage of the charging cycle. Batteries typically charge in 3 phases—bulk, absorb, and float, which can be summarized as follows:

  • Bulk: High current to replenish charge and bring voltage up as quickly as possible (below 80%)
  • Absorb: Charge rate slows as batteries approach full state of charge (~80-100%)
  • Float: Batteries receive a trickle charge at 100% to stay fully charged

Each stage requires the charger to be set at a specific voltage, which is based on the requirements of your battery.

Programming the voltage set points accurately is critical to ensuring the long-term health of your batteries. Setting the wrong charge parameters will make your batteries charge improperly, shortening their lifespan.

There are other values to set during the initial programming phase as well:

  • Absorb time: The amount of time the charger spends in the absorb phase.
  • AC input amps: Maximum input current from grid or generator, to ensure the combined current from the battery charger and loads doesn’t exceed the rating of the generator. Depends on generator size or grid input breaker. See manual for details.
  • Max charge rate or charge current limit: Maximum charging current, either expressed as a percentage of the charger output or total maximum charging amps. This setting is used to limit charger output, to make sure your batteries are not overcharged with too much current.
  • Temperature compensation: Adjusts the battery charger for operation in various temperature ranges. Most chargers include a battery temperature sensor.

These settings are different for every battery and charger. Check the spec sheets or installation manuals for your batteries and chargers to find the specific values for each of the above settings.

Programming your equipment according to the settings recommended in the manual is the first step toward ensuring the long-term health of your battery bank.

Flooded Lead-Acid Battery Maintenance Tips

Flooded lead-acid batteries require regular maintenance to function properly. We recommend checks every 2-4 weeks to keep the battery bank tuned up.

Note: always follow proper safety procedures when working around batteries. Wear eye protection and gloves, remove any jewelry, and secure loose clothing and long hair.

Add distilled water every 2-4 weeks

Flooded lead-acid batteries lose water during the charge cycle. They must be refilled regularly with distilled water to function properly and stay healthy.

Note that you should only use distilled water. Non-distilled water (like tap water) will introduce small particles and contaminants, which weakens the battery chemistry.

Check water levels every 15-30 days and refill as necessary. Your watering schedule depends on your local climate, charge settings and specific application. It may be useful to keep a log to track how often your batteries need to be refilled.

  1. Check water level when batteries are fully charged.
  2. Open the vent well to check the water level.
  3. Add water to just below the maximum water level line. DO NOT overfill past this line. The battery installation manual should indicate where to find the maximum water level line.

Check battery state of charge (SoC):

Use a refractometer to keep an eye on how charged your batteries are. The refractometer measures the specific gravity of your batteries. This video explains how to use a refractometer:

Consult the charts published by your battery manufacturer to find your battery state of charge based on their specific gravity reading. An example chart is shown below.

If your batteries are not holding charge even after a full charge cycle and equalization, they are likely defective, damaged, or have reached the end of their lifespan and are starting to lose some capacity.

Some inverters use a battery monitor to measure state of charge. These battery monitors typically rely on a shunt for measuring the total current coming in and out of the battery bank.

Battery monitors are a useful tool for daily monitoring, but they require proper setup. If they aren’t installed or programmed correctly they can provide false readings.

Even if you have a battery monitor, we still recommend checking the specific gravity with a refractometer on a regular basis. It helps verify the battery monitor is accurate and ensures your batteries reach a full charge.

Use a refractometer to check the specific gravity of your flooded lead-acid batteries.

Equalization Charges

Batteries should be equalized occasionally to make sure each cell is equally charged. Apply a controlled overcharge once every 30-90 days, or whenever individual batteries are imbalanced (reading a different voltage or specific gravity).

  1. Check water level before initiating an equalize charge.
  2. Turn off any loads.
  3. Set your charger at the Equalize voltage specified in your battery manual.
  4. Start the Equalize charge. Gassing and bubbling is normal during this process.
  5. Stop charging and take specific gravity readings every hour. The EQ process is complete when the specific gravity stops rising.

Other Routine Flooded Lead-Acid Battery Maintenance

  • Tighten the battery cable connections as needed. Wear gloves/eye protection and use insulated tools.
  • Clean terminal connections & cables to prevent corrosion. Mix baking soda and distilled water into a paste and apply with a wire brush. Rinse cleaning residue and dry with a cloth or paper towel.
  • Keep the top of the batteries clean from dust and debris to avoid creating a current pathway or electrical leakage across the top of the battery.

Sealed Lead-Acid Battery Maintenance

Sealed lead-acid batteries do not need to be filled with water or equalized. They require very little maintenance other than the occasional check-up on the battery’s state of charge.

Check Battery State of Charge (SoC):

Use a multimeter to keep an eye on how charged your sealed lead-acid batteries are based on the voltage. A multimeter is equipped with positive and negative probes which allows the meter to get a DC voltage reading from the battery.

Your battery manual should contain a chart that estimates the battery’s state of charge based on these voltage readings (like the one in the previous section).

To get the most accurate reading, your batteries should be tested in a resting state. Let your batteries rest for at least 2 hours (no charging/discharging) before taking the voltage reading. Attempting to use the multimeter when batteries are being charged or discharged is going to result in a higher or lower voltage, depending on the load.

If your batteries fail to approach 100% SoC even after a full charge cycle, they are likely defective, damaged, or have reached the end of their lifespan.

Equalization Charges

DO NOT equalize sealed batteries! This applies to flooded lead-acid batteries only.

Other Maintenance

  • Tighten the battery cable connections as needed. Wear gloves/eye protection and use insulated tools.
  • Keep the top of the batteries clean to prevent them from getting dusty and grimy.

Lithium-Ion Battery Maintenance

Fortunately, lithium batteries require little to no maintenance (one of the main appeals when comparing lithium vs. lead-acid batteries). Once they are set up properly, they don’t need any checks aside from the occasional state-of-charge reading to ensure they are holding a charge.

Lithium battery manufacturers sell a tool to gauge the battery’s state of charge (SoC). The tool typically communicates with the built-in Battery Management System (BMS) to get an accurate SoC reading. Simply hook the monitoring tool up to the battery and read the SoC value from the display screen.

Discover Battery makes their own monitoring tool called a Battery Discharge Indicator, while Simpliphi recommends Victron battery monitors for their batteries.

Other Maintenance

  • Tighten the battery cable connections as needed. Wear gloves/eye protection and use insulated tools.
  • Keep the top of the batteries clean to prevent them from getting dusty and grimy.

A Note About System Design

That’s it for our maintenance tips, but it’s worth pointing out that maintenance is only effective if your system is well-designed and your battery bank has been properly sized.

In our experience, many cases of battery bank failure can be attributed to poor system design. People buy the wrong size battery bank or solar array, not taking into account key factors like temperature, local sun hours, and discharge depth. If you simply don’t have enough panels to fully charge your batteries, they’re destined to fail at some point.

The solar array, battery bank and inverter all need to be the proper sizes for the batteries to stay healthy. You also need enough amperage left over to charge the battery bank after accounting for loads that need to be powered (15 charging amps per 100ah is recommended for lead acid batteries). Take a look at our off-grid system sizing guide for more info.

Stuck on system design? Get in touch for a free consultation with one of our solar designers. We provide design advice that is tailored to your application, and our in-house tech team closely reviews proposed plans to avoid the common pitfalls outlined above.

More Battery Maintenance Resources

If you follow this guide, you’re well on your way to ensuring a long lifespan and peak performance from your battery bank. For more battery advice, grab our free Solar Battery Guide linked below.

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Solar How To: Taking Care of Your System in Winter

Solar How To: Taking Care of Your System in Winter

Preparing Solar System for Winter

Winter is the most demanding time for solar power systems. Not only does winter mean more severe conditions, it also means that people are spending more time indoors, and therefore using more electricity. Especially people with electric heating.

However, if you take the proper precautions you can be sure your solar energy system will function properly even during the harshest winter weather.

Even though your solar system doesn’t require any additional maintenance to run smoothly in snowy weather,  it may need more frequent attention and upkeep. All you need to do is keep these simple tips in mind and you will keep your system operating safely all winter long!

It Starts With Energy Conservation

You may see your solar system’s production decrease during the winter months. That’s because the days are shorter, sunlight strikes the panels at a “lower angle,” and accumulated snowfall can cover panels and temporarily halt production.

Therefore, it’s best to know how to minimize your electricity usage in order to maximize your savings. Using energy more efficiently this winter can help keep your utility bills under control.

Wholesale Solar's 53 ways you can lower energy use green cfl lightbulb graphic
Click for more ways you can lower your home’s energy use right now.

Tips to make the most of your clean electricity :

  • Ensure that your house has proper insulation to conserve heat. If it doesn’t, investigate the cost of adding insulation to exterior walls and attic.
  • Before turning on your heater, check your ducts for leaks.
  • Use a heating system that automatically maintains a preset temperature with the help of a digital thermostat.
  • Make sure to close your damper when the fireplace is not in use.
  • Take advantage of sunny days to heat your house.
  • Open the curtains on your south-facing windows during the day and close them at night to lock the warmth in. Thermal curtains help insulate windows even better than regular curtains.
  • Make sure you only use necessary loads.
  • Turn off excessive lighting when not needed.
  • Disconnect ghost loads that consume power even when off as long as they are plugged in. Over a period of 24 hours, a plugged in TV consumes the same power as when it is ON for thirty minutes.
  • Replace all the high wattage bulbs with energy efficient ones. You could save about 75% of energy consumed by a 60 watt bulb by replacing it with a 15 watt energy efficient CFL, without sacrificing your light output.

Snow On Your Solar Panels

Snow Melting on Solar Panels
In most areas, sun will melt the snow from your panels on its own.

After heavy snowfall, snow or ice may accumulate on your rooftop and cover your solar panels. If you have a rooftop array that is out of reach, we don’t recommend trying to get on your roof to shovel snow off your solar panels. Their dark surface will gather sun and actually help melt the snow, causing it to slide off the system’s glass surface.

Raking snow off rooftop arrays could harm the panels by scratching them or worse, harm you, if you slip and fall or get caught under snow and ice falling from your roof.

If you have a ground-mount array that is easily accessible, and you do choose to brush snow off your panels, use a soft brush or broom so you don’t scratch the panels. Also, be mindful of your footing, and beware of falling ice or heavy snow loads from the panels.

If you’re living in a country where you get plenty of snow and wind during the winter, it’s highly recommended to purchase solar panel that have been tested to withstand a certain snow load. Wholesale Solar recommends the strong and durable SolarWorld SW270 Protect Solar Panel.

Most IEC / UL certified solar panels can withstand 50 psf (pounds per square foot) of snow load and wind load. However if you expect several feet of snow every winter, it’s highly recommended to go with a more robust version, such as panels that withstand 113 psf snow load.

Nowadays there are even panels on the market that withstand 150 psf of snow load. That may seem excessive, but when snow builds up, and it starts raining snow starts melting, the pressure from the snow will be very extensive.

Maintaining Your Battery Bank During Winter Months

Adding fluid to offgrid battery banks
Warning: If fluid levels are low, replenish prior to charging batteries!

Extreme cold temperatures can be very hard on your deep cycle batteries. Make sure your batteries are installed indoors, and if they are outdoors, make sure that the compartment is properly insulated. Lead acid batteries freeze at below zero temperatures and will be destroyed.

Make sure that you have all the diagnostic tools ready at your disposal. This includes a digital multi-meter, a set of clampers and cutters, and a handheld battery refractometer.

If a constant power supply is crucial, make sure that you have a backup generator ready and tested for functionality in advance. Some fuel supply would be handy as well.

For Off-Grid solar system owners, have enough supply of anti-freeze distilled water for your batteries. The battery fluid level should be checked regularly. The fluid level should be at the plastic fill port lower ring. If the level is low, add distilled water.

Battery output voltage and battery capacity both decrease with temperature. Check battery voltage often. If battery level is at or below 12 volts DC, you should charge the batteries. Use a 45 amp or greater capacity 12 volt DC battery charger.

If possible, the batteries should receive an equalizing battery charge from a high capacity battery charger about once a year to keep the plates free of sulfate buildup.

Most batteries do not fail instantaneously, but over time. Regularly checking the voltages identifies a potential problem earlier than later.

The Final Word

During the severe winter months, it’s essential that you maximize your electricity generation, minimize your electricity consumption, and be diligent about maintaining your solar system.

Following the above tips can help you and your solar system fare a little better this winter when the inevitable “Snowmaggeddon” comes barreling through your city.

Have questions? Need help choosing the right solar system for your needs? Call the solar experts at Wholesale Solar at 1-800-472-1142. After all, we don’t just sell solar, we live it.

Related Links:

Energy Conservation Tips
Solar Panels
SolarWorld SW270 Protect Solar Panels
Battery Backup Power Systems
Grid-Tie with Battery Backup Solar Systems
Off-Grid Solar Systems

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