Charge Controllers, Off-Grid, Remote Living, Cabin, RV, Marine

Charge Controllers, Off-Grid, Solar Battery Chargers. Blue Pacific Solar ships all Charge Controllers for free

Charge controllers are solid-state electronic devices used in nearly every solar and wind energy system that uses batteries. A charge controller is often times used in off-grid solar systems with 12 volt to 48 volt battery banks to keep the voltage to the batteries within acceptable limits. A charge controller automatically tapers, stops, or diverts electrical power when systems batteries become fully charged. Charge controller capacities range from 4 to 80 A and multiple charge controllers can be used in parallel for larger solar battery systems. Some charge controllers offer additional features, like charge status display, data logging, automatic battery equalization charging and generator starting.

The simplest charge controllers cut the power when the battery reaches a set voltage, and turn it on when a low voltage set point is reached. Pulse width modulated (PWM) charge controllers turn on and off very rapidly, maintaining the batteries at full charge with whatever power is available. Maximum power point tracking (MPPT) charge controllers optimize the voltage of the PV array to maximize total power output then convert that to the correct voltage to charge the battery. This process significantly increases the power from a solar array, particularly in low temperatures when battery voltage is significantly below the PV array voltage. Most MPPT charge controllers work with higher array voltages, enabling the use of larger solar modules, which can be more economical on a cost per watt basis. A higher voltage solar array also minimizes the required AWG wire size between the solar panels and the charge controller. While more expensive than PWM controllers, MPPT charge controllers can boost system performance by up to 30%.The Charge controllers Blue Pacific Solar sells employ the latest in power electronics to regulate the battery charge by controlling the charging voltage and current from a solar panel array. Charge controllers regulate the charge of the battery, but also prevent the battery from being over discharged which can damage the battery bank.

Charge controllers has multiple stages of control it uses to regulate different voltage and current levels. The voltage and current of a battery varies over the different stages of battery charge. Though the amount can vary, the bulk charge usually is approximately 80%, the absorption charge is 10% with the float charge representing the balance of the battery charging process.

The bulk charging stage of the charge controllers process is the first stage to used to bring the battery depth of discharge (DOD) back to 100%. The bulk charge stage happens first in in the morning after the batteries DOD has drained down since sunset the previous day. The bulk charging stage pushes as many amps into the battery bank as possible from the solar panels and gets the voltage up in the process. The effect of a charge controller is not unlike trying to fill a glass of water from a faucet. You first turn the faucet on full while the glass if filling, then slowly taper off the pressure until the glass is full. When the battery bank reaches a predetermined level known as the bulk voltage set-point, the charge is then substantially slowed. Because the bulk voltage set point is determined by the type of battery you are using, many charge controllers have to be pre-set to the type of battery which will dictate the rate of charge.

The second state of charge a charge controller employs is the absorption stage. After a battery system has been brought up to the bulk voltage set point, the charge controller slows down the charge rate because the battery bank cannot accept the same rapid charging pace without overheating and damaging the battery bank. At the absorption stage a battery bank is only about 80% full. The absorption charge is the function level in the process that tops off the battery bank. During the absorption stage, the charge controller holds the battery volts constant and reduces the amount of current sent into the battery. When the absorption stage is complete, the battery bank is fully charges.

The final step a charge controller performs is the float charge. Typically a charge controller enters into a float charge state when the other charge levels of the battery bank has been achieved. When the number of peak sun hours is limited, a solar charge controller may not be able to get the battery bank back to the float stage before the next cycle begins.

MorningStar, Outback and Xantrex are adding new and updated charge controllers technology everyday. Various new charge controller models are released every year making what seems like a dilemma at first, but is actually a better solution. There is in fact a right charge controller for every off-grid solar application. Blue Pacific Solars' consultants can help you sort through the different challenges of matching the right charge controllers to your battery bank.