
The circuit design for the proposed battery deep discharge protection circuit can be witnessed in the following diagram: As can be seen, the circuit has a very components, and its working can be understood through the following points: There are a couple of power transistors coupled with each other where, the base of the. . The zener diode decides at what voltage the battery needs to cut off from the load. Therefore, the zener voltage must be approximately equal to the battery voltage at which the cut off needs. . The indicated TIP36 can supply a maximum current of 10 amps to the load. For higher current, the TIP36 could be replaced with a P-Channel MOSFET such as the MTP50P03HDL,. . The above discussed concepts are used to handle the over discharge situation of a connected battery. However, if you want the above circuit to also. [pdf]
A discharge/charge cycle is commonly understood as the full discharge of a charged battery with subsequent recharge, but this is not always the case. Batteries are seldom fully discharged, and manufacturers often use the 80 percent depth-of-discharge (DoD) formula to rate a battery.
For the discharge process to be performed in safe conditions, besides gathering information about the battery’s capacity, SoC and SoH at the beginning of the process it is necessary to monitor the temperature and voltage of individual modules, preferably even groups of cells, as well as to control the discharge current.
High discharge lithium ion batteries are a great way to power any R/C, robotic, or portable project that needs a small battery with a lot of punch. Nominal Voltage - These have a nominal voltage of 7.4V and like the round cell batteries, do NOT have a built in protection circuit.
the flow of discharging current (i.e. current from the battery) into the load. Shown are examples. Irrespective to the protection implementation on high or low side, either source-to-source or drain-to-drain configurations are possible. Inrush currents arise during the turn on, mainly when the battery is first connected to the load.
When being discharged rapidly it can appear that the entire battery energy was consumed when the voltage drops to 0 V, but due to slow chemical reactions within the battery after the load has been disconnected from the battery, minutes to hours later, the voltage on the battery can recover, even over the critical 2.5 V.
Batteries are seldom fully discharged, and manufacturers often use the 80 percent depth-of-discharge (DoD) formula to rate a battery. This means that only 80 percent of the available energy is delivered and 20 percent remains in reserve.

The depth of discharge in conjunction with the battery capacity is a fundamental parameter in the design of a battery bank for a PV system, as the energy which can be extracted from the battery is found by multiplying the battery capacity by the depth of discharge. Batteries are rated either as deep-cycle or shallow-cycle. . Over time, battery capacity degrades due to sulfation of the battery and shedding of active material. The degradation of battery capacity depends most strongly on the interrelationship between. . The production and escape of hydrogen and oxygen gas from a battery cause water loss and water must be regularly replaced in lead acid. . Depending on which one of the above problems is of most concern for a particular application, appropriate modifications to the basic battery configuration improve. . Lead acid batteries typically have coloumbic efficiencies of 85% and energy efficiencies in the order of 70%. Yes, deep discharge can damage a car battery. Frequently allowing a battery to fully discharge harms its lifespan. Car batteries perform best with shallow discharges. [pdf]
To prevent damage while discharging a lead acid battery, it is essential to adhere to recommended discharge levels, monitor the battery’s temperature, maintain proper connections, and ensure consistent maintenance. Recommended discharge levels: Lead acid batteries should not be discharged below 50% of their total capacity.
By understanding and implementing these practices, users can effectively prevent damage while discharging a lead acid battery and ensure its reliable performance. Discharging a lead acid battery too deeply can reduce its lifespan. For best results, do not go below 50% depth of discharge (DOD).
A deep-cycle lead acid battery should be able to maintain a cycle life of more than 1,000 even at DOD over 50%. Figure: Relationship between battery capacity, depth of discharge and cycle life for a shallow-cycle battery. In addition to the DOD, the charging regime also plays an important part in determining battery lifetime.
Specific actions and conditions can contribute to the premature discharge of a lead acid battery. For example, frequent deep discharges, prolonged storage in a discharged state, or operation in extreme temperatures can exacerbate the sulfation process. Regular maintenance and following guidelines for discharge levels are vital.
Personally, I always make sure that anything connected to a lead acid battery is properly fused. The common rule of thumb is that a lead acid battery should not be discharged below 50% of capacity, or ideally not beyond 70% of capacity. This is because lead acid batteries age / wear out faster if you deep discharge them.
For deep cycle lead acid batteries, charging after every discharge is important to extend their lifespan. Avoid letting the battery drop below 20% charge frequently, as this can also damage the battery. In summary, frequent charging at moderate discharge levels maintains the battery’s performance and longevity.

Grounding is the most fundamental technique for protection against lightning damage. You can’t stop a lightning surge, but you can give it a direct path to ground that bypasses your valuable equipment and safely discharges the surge into the earth. An electrical path to ground will constantly discharge static electricity. . The weakest aspect of many installations is the connection to the earth itself. After all, you can’t just bolt a wire to the planet! Instead, you must bury or hammer a rod of conductive, noncorrosive metal (generally copper) into the ground. . For building wiring, the NEC requiresone side of a DC power system to be connected—or “bonded”—to ground. The AC portion of such a system must also be grounded in the conventional manner of any grid-connected. . Array wiring should use minimum lengths of wire tucked into the metal framework. Positive and negative wires should be of equal length and be run. . In addition to extensive grounding measures, specialized surge protection devices, and (possibly) lightning rods are recommended for sites with any of the following conditions: •. [pdf]
To protect solar panels from the devastating effects of lightning, it’s important to implement proper surge protection measures. By ensuring the system is correctly grounded and installing surge protection devices, the risk of damage from lightning strikes can be greatly reduced.
Figure 5 shows an appropriate integrated lightning protection system for a sample solar power system located on a building at roof level, while figure 6 depicts a free field solar panel farm equipped with a lightning protection system. Both examples include the discussed air termination network, SPDs and earthing system.
Regular maintenance and inspections are key to ensuring your system’s longevity. Lightning strikes can damage solar panels directly or indirectly. Direct strikes may melt or shatter system components. Indirect strikes can cause high-voltage surges disrupting system performance. Surge protection devices like Citel DS72-RS-120 are recommended.
Lightning is a common cause of failures in photovoltaic (PV) and wind-electric systems. A damaging surge can occur from lightning that strikes a long distance from the system or between clouds. But most lightning damage is preventable. In this article, you will learn how to protect your solar power system from lightning.
Find out about and download our brochure on “Lightning and surge protection”. When a PV system and an external lightning protection system meet, they often come into conflict: both must share the roof area. The PV system and lightning protection system can be installed at the same time without any problems.
Grounding is a technique to connect a part of the system electrically to the earth by means of a conductive material and is the key technique in Solar Lightning Protection. Earth could be considered as a sea of infinite electricity. Any charge/current that is transmitted to the earth is safely absorbed by it.
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