Top 5 Battery Bank Mistakes!

Battery banks are becoming a popular choice for off-grid power however there are a plethora of mistakes being made in the maintenance of these battery banks.  Here are the top 5 mistakes I am finding.

1)  Over discharging your batteries.

Batteries use chemical reactions to produce power.  During recharging, the chemical reaction is reversed.  Over discharging a battery can make the reactions permanent.  A good guideline is to only use 70% to 50% of your batteries capacity also referred to as the Depth of Discharge.  If you use your batteries daily, a 50% Depth of Discharge is appropriate for you. Whereas, a weekend use or occasional use system you can maintain your battery life with a 70% DOD or Depth of Discharge. 

2)  Not letting your Batteries come to a Full Charge.

When you consume the power stored in your batteries you will need to recharge them.  However, a point that is often overlooked is allowing the batteries to come back to a full charge.  This means you may have to let your battery sit for a day or several days in order to insure they hit that full charge.  Remember that the process of discharging and recharging the battery is a chemical process.  By denying your battery a chance to fully charge you are reducing your battery's capacity, effectively shortening its life.

3)  Equalizing your Batteries too Often (For Flooded Lead-Acid Batteries)

A common practice is to equalize your batteries once a month.  Unfortunately, this is not required.  In fact, when you equalize your batteries you are, in affect, overheating them.  While this is a necessary step to "clean" your battery, too much heat will again shorten battery life.  In reality, a maintained battery bank only requires 2-3 equalizations per year.

4)  Throwing Out a Dead Battery.

Why would you keep a dead battery?  The truth is that a dead battery might not be lifeless.  Just because batteries are not taking a charge does not mean they can’t be reconditioned.  Sometimes a battery can be recovered by setting the float voltage a little higher than normal.  Reconditioning a battery can take a few days up to a few months.  However, if you are dependent on your battery bank, this tip is indispensable.

5)  Not letting your Batteries Breathe (For Flooded Lead-Acid Batteries)

You must vent your batteries.  During the process of discharging, the batteries release hydrogen gas.  While this is not enough to cause a massive explosion it is enough to destroy your batteries and anything near them.  It is critical that your batteries are properly vented to breathe.

Take care of your batteries, and they will take care of you.

Paradigm Shift

Solar arrays consisting of a single module connected into a battery date back to the 1950’s.  A simple setup used by the Telecom companies to provide power in remote locations.  With growing grid instability and preparation for natural disasters, this grass roots design is re-emerging.

Most people are looking for a way to have backup power in the event of a grid outage.  And a simple solar module connected into a battery is a great way to do that.  This grass roots design doesn't require fuel or the utility grid to operate.  With the addition of a battery, you can operate the system at anytime of the day.  Even better, is the quiet peaceful production making it perfect for locations with ordinances.  There is one exception though.  Because most people want a system that can power AC appliances we must introduce one necessary component to our setup.  The modern version of the grass roots design now incorporates an inverter.  This addition greatly increases the versatility of the system.  You can run DC appliances directly off of the battery and AC appliances off of the inverter. 

Choose Solar for your backup generator!

Car Fuses and Solar - Not a Good Mix

Car Fuses and Solar – Not a Good Mix

When it comes to protecting your solar investment, it couldn’t be easier than adding a fuse.  In the event that the current in your solar array goes too high, the fuse opens up.  This removes the current draw on the system and protects it from further damage.  The problem comes from the fact that not all fuses are right for this application.  In this article, we are going to discuss why using just any car fuse isn’t a good idea.

I’ve seen a lot of talk about using car fuses in solar applications.  Why wouldn’t you use them?  They’re rated for up to 32V of DC electricity.  Most small off-grid solar arrays are running at 12V to 24V of DC electricity.  All of our requirements are met so far, aren’t they?

Truth be told, our requirements are not met.  A key component to fuse sizing is the AIC or Amperage Interrupt Capacity.  During a short circuit event, a solar array may produce amperage in the thousands.  This is especially true when talking about the batteries.  It is not uncommon for batteries to have short circuits in the 5000 amp range.  To keep it simple, the AIC rating tells you how much current the fuse can withstand.  If the short circuit of the solar array exceeds the AIC rating of the fuse, the fuse will fail to operate properly, causing damage to the array.

A standard car fuse typically has an AIC rating around 1000 amps.  During a short circuit event, this fuse will fail.  This is why there are specific fuses created for solar arrays.  An example of this is the KLKD Series from Littlefuse.  The KLKD series fuse can handle up to 600V DC with an AIC rating of 100,000 amps.  If you still choose to use a car fuse, be sure to use an ANL type fuse.  An ANL fuse will generally have an AIC rating of at least 2,700 amps.

Protect your investment, use the right fuse.