Earth Pigments


Lead acid battery voltage chart

Note that the reading you get while on a charger or even after removing the charger are not valid, until the battery has had a chance to settle. Battery specification sheets, promotional materials, SDS, and more here. 2 volts for a 12-volt lead-acid battery). There are two key things to keep in mind about using voltage to measure state of charge. The chemical reactants in a lead-acid battery consist of lead dioxide or lead peroxide in the positive electrode, sponge lead in the negative electrode and sulfuric acid in a dilute solution, called electrolyte. So between 50F and 80F could have a 10% difference in charge state. Our battery comparison charts allow you to find equivalent batteries in size, voltage, capacity and chemistry, as well as to see the difference between similar makes. The voltage drops below 12 volts when the battery still has 35% of its total capacity remaining, but some electronics may fail to operate with less than a full 12 volt supply. Batteries that are stored for long periods State of Charge and Charging. The capacity doesn't need to be exact.


3 and 1. 19 and rebounding to 12. 2-14. This solution is called electrolyte, which causes a chemical reaction that produces electrons. 5 volts will give you a 100% charge on Lead-Acid batteries. 4 VDC before it is fully charged. 8 out of 5 stars 45 Guide to charging Sealed Lead Acid batteries Another important factor that has to be considered when charging an SLA battery is temperature. 8 volts, but as it is drained the voltage drops steadily. When cranking your motor with a lead battery the voltage can drop down to 9V causing your starter to spin slower.


Here is how it works: When the lead acid battery accepts charge, the sulfuric acid gets heavier, causing the specific gravity (SG) to increase. 6-Volts for Lithium Iron Phosphate Batteries. Q: Can a car battery freeze when it gets too cold? A: When a lead acid battery is fully charged the electrolyte is sulfuric acid with a freezing point of below -40°C. : Consistently charging at 0. This chart was created to be a quick reference to the most common ones. 02 ohms battery is being charge up to boost voltage of 2. Do remember that battery voltage readings are temperature dependent. The following shows the approximate state of charge at various specific gravities at 77ºF / 25ºC. Float voltage for Lead-Acid batteries should be about 2.


You can also checkout The chart is for a Concorde Lifeline battery, but all lead-acid batteries will be similar in the shape of the curve, although the number of cycles will vary. Battery: Specific Gravity Test. charging current at a beginning is 5 AMP. Introduction Lead acid batteries are the most common large-capacity rechargeable batteries. A 12 volt SLA battery can be used for a variety of different applications, with a range in capacity as low as 1 amp to over 200! Our rechargeable batteries are completely sealed and maintenance-free. 1C (10% of the battery capacity). " These numbers are referring to the Battery Council International, or BCI, Group Number of the battery. (For 24 volt systems, double these figures. Some electronic load testers apply a 100 amp load for 10 seconds, and then display battery voltage.


Battery Voltages. The OCV test, however, is the only way to determine the state of charge of a sealed no-maintenance battery. We take the example of a solar installation for a standalone building (Self Sufficient Home). 3-Stage Charging There are two basic types of lead-acid battery charger: FLOAT chargers and 3-STAGE CHARGERS. 8 for a 12 volt battery) when fully charged. For a single cell, the voltage can range from 1. Cell Voltages: Open Circuit, Charging, and Discharging. A battery's ability to sustain a minimum stated electrical load; it is defined as the time (in minutes) that a lead-acid battery at 80 °F (27 °C) will continuously deliver 25 amperes before its voltage drops below 10. Take A properly maintained battery will last many years.


Note that flooded batteries MUST bubble (gas) somewhat to ensure a full charge, and to mix the electrolyte. [citation needed] Group size naturally occurs during normal charging, but when a lead acid battery is overcharged, the electrolyte solution can overheat, causing hydrogen and oxygen gasses to form, increasing pressure inside the battery. g. 5 VDC for a cold 12 Volt lead-acid battery. I don't have a proper lead acid battery charger But I own a small Yuasa 7Ah battery. Measured Voltage: V : The voltage measured across the battery terminals when the battery is not supplying (a significant) current or being charged. 10 V in an open circuit at full charge. Utilize a battery not in perfect health to represent real world. Sealed Lead Acid batteries are one of the most common battery types; however, most people don’t think about them until it's too late.


65 Open Circuit Voltage (OCV) reading for a fully charged (100% SoC), wet Low Maintenance (Sb/Ca) or Standard (Sb/Sb) lead-acid battery at rest, 77° F (25° C), and with the negative terminal disconnected. proposition 65 warning battery posts, terminals and related accessories contain lead and lead compounds, wash hands after handling. 2002 Voltage of lead-acid electrochemical cell vs. . SOC profile, but also its useful Ampere-hour capacity. ) If taken to a lesser voltage level, some of the sulfate deposits that form during discharge will remain on the plates. S. 6 to 12. For really serious work advisable to take temperature of the battery acid for standard lead acid batteries.


1. life. A Smart Battery 12V Lithium Ion Battery has little to no voltage drop while cranking your motor, This provides around 25% faster starting than with a lead battery. The voltage could be held constant for the entire duration of the cell's operation (such as in an automotive battery) or could be held for a particular phase of charging by the charger. Verify charger voltage settings are correct (Table 2). The following graph shows the evolution of battery function as number of cycles and depth of discharge for a shallow-cycle lead acid battery. 77 dropping to 12. 6 volts. If you want to make sure you get the best type of battery for your car, it is essential to know as much as possible about car battery size chart details, group sizes and other details.


Specific gravity is read with a hydrometer. This chart represents the average maximum discharge current ratings for the most common brands of sealed lead acid batteries. lead-acid batteries, both over- and under-charging a Rolls AGM battery will result in shortened service. checking that the charger current and voltage settings are maintained. Lead sulfate is a soft material, which can is reconverted back into lead and sulfuric acid, provided the discharged battery is immediately connected to a battery charger. Our range of battery products includes sealed lead acid (SLA) and lithium iron phosphate (LiFePO4) technologies, chargers and related accessories. 55. 2. First, the battery open circuit voltage is very temperature sensitive.


The application need is summarized in the above table: Measure the open-circuit voltage of the battery using a digital voltmeter or a multimeter. If the battery is not new, it should be charged with a battery charger and then left to sit for several hours to eliminate surface charge. When using lead-acid batteries, one of the most common fatal mistakes is to discharge one's battery bank too deeply. You may have heard common terms like a "group 24 battery" or "type 27 marine battery. Charge Efficiency: When charging a lead acid battery you can lose A rating that is used to define the battery's ability to start an engine under low-temperature conditions. State Of Charge (SOC) State of charge (SOC), or conversely, the depth of discharge (DOD) can be determined by measuring the voltage and/or the specific gravity of the acid with a hydrometer. With your multi-meter, measure the voltage across the battery's two terminals. As the temperature rises, electrochemical activity in a battery increases, so the charging voltage should be reduced to prevent overcharge. Chem.


But which lead acid battery should you use with solar panels? I recommend using sealed AGM lead acid batteries wherever possible and will describe in this post the trade-offs of using different battery types Charging at 15. The lead acid battery used in today's automobile is made of plates, lead, lead oxide, in a solution of electrolyte. I am using a 13volt 1. Use change of voltage as an indicator of changing conditions or relative state-of-charge under similar conditions over time. The graph above shows that the effective battery capacity is reduced at very high continuous discharge rates. Show why using a generic voltage to SOC chart may not work for your battery bank. The following chart shows the time required to give a 100% charge return to a battery from a complete 100% DOD discharge, as a function of applied average voltage and available current. A typical 12-volt lead-acid battery must be taken to approximately 14. 7V.


8 V loaded at full discharge, to 2. Since each cell teledyne battery products dry-charged lead-acid aircraft battery service manual . A load test can only be performed if the battery is at or near a full charge. Educ. These numbers define the physical dimensions of the battery case. Percent Discharged CHART D Gel Percent Cycle Life vs. The following chart illustrates how lead acid and lithium-ion fit into the rechargeable battery world. electrolyte concentration, as predicted by Nernst equation Fully charged Usable range Time to recycle Concorde Battery Corporation manufacturers specialty agm aircraft batteries and is the leading producer of agm batteries for marine, rv, solar, aircraft and wheelchair applications. Charge only in well-ventilated areas.


The internal resistance of AGM batteries CHART C VRLA Battery Voltage During Constant Current Discharge Voltage vs. 4 volts for short periods (8 hours maximum). Lead acid battery technology has been used commercially for over a century. Battery life is directly related to keeping your batteries fully charged. 2 volts per cell (7. It is interesting to note that a charged 12 volt lead acid battery at rest (not powering loads and unused for at least 3 hours) will read about 12. lead acid flooded batteries. IUoU battery charging is a three-stage charging procedure for lead-acid batteries. Discover numerous 12 volt sealed lead acid batteries at Battery Mart.


Often we get asked how to calculate a how many amp hours the customer needs to run a device or multiple devices. Please read the following instructions before using your battery. AGM Batteries - Deep Cycle Battery Types. 1 Basics of Lead Acid Lead acid batteries have been around for more than a century. (e. The basic lead acid battery is ancient and a lot of different charge methods have been used. One basc pi rni cpi al in chemsi try states that as the quantity of reactants or low maintenance is more important than initial cost. 7 and 14. 13.


Configuring a DR Series Inverter for 6V Deep Cycle Batteries: For normal operation, the battery type selector should be set to # 1 – Deep cycle lead acid. Large Screen LCD Display 12V Lead Acid Battery Capacity Meter Battery Voltage Indicator Motorcycle Golf Cart Car. The voltages are different depending on battery chemistry of AGM, Gel, or on eof the three flooded lead acid types of Lead Calcium, Lead Antimony, or pure Lead. Can I select a sealed lead acid battery with a different capacity? When selecting a replacement, the voltage and dimensions should match your original battery. Chart 1 Maintenance of Batteries Flooded Lead-Acid VRLA Voltage Float Range Measurement Measurement Specific Gravity Measurement Not Available Temperature Measurement Measurement Internal Resistance Measurement Measurement Plate Condition Visual Not Available LEAD ACID BATTERIES 1. 9 volts. Conditioning Lead-acid batteries are one of the most common electrochemical energy storage devices. S. The same current may be available but the rate of the reaction decreases, causing a voltage drop.


You don't say how long you left the load on. This charge method is used for starter batt eries in vehicles and in uninterruptible power supplies (UPS). Therefore if your battery is more than 4 years old and car battery voltage drops quickly, it is possible it has reached the peak of its useful service life and requires replacement especially if 7/ Voltage Sag. BATTERY TUTORIAL. A fully-charged 12-volt lead-acid battery should have a voltage of at least 12. Treptow, “The lead-acid battery: its voltage in theory and practice,” J. 4 volts for a 12 volt battery. Optimum charge voltage of Victron VRLA batteries The recommended charge voltage settings for a 12 V battery are shown in table 3. battery’s composition.


R. Valve Regulated Lead Acid Batteries 20 to 200 Ampere Hours Lead Acid Battery Theory of Operation Discharge and Charging Reactions The lead acid battery is a truly unique device - an assembly of the active materials of a lead dioxide (PbO 2) positive plate, sulfuric acid (H 2SO 4) electrolyte and a sponge (porous) lead (Pb) negative plate In order to check the state of charge (SOC) on a lead acid battery the battery should have rested, meaning no input voltage/amps or output/loads, not even the stereo memory, for a considerable amount of time. Basics of Batteries 2. 8ºC) can deliver for 30 seconds and maintain at least 1. BCI defines it as "the number of amps a lead-acid battery at 0ºF (-17. For more accurate state-of-charge readings, a shunt based monitoring system is recommended. While there are many battery chemistries today, and new types becoming commercially viable over time, we deal with the lead acid types, flooded, AGM, and true Gel, as they are widely used in the applications we specialize in. The non-negotiable lowest depth of charge you should EVER let your batteries drop to is 20%. Note: This information applies ONLY to 12 volt single lead acid batteries of the types listed.


They are very popular because they are dependable and inexpensive on a cost-per-watt base. Conversely as temperature falls, I had a heated discussion with a few colleagues today revolving around how low of a voltage was alright for 12 volt lead-acid battery; they were in the opinion that the low voltage warning buzzer and ultimate automatic shutoff was annoying and a safety risk. 5A wall wart to charge it. Each cell of the battery has internal resistance of . 8 volts for long periods and 14. SLI Batteries (UHP and HP range):- Century wet flooded lead acid starting batteries such as the Ultra Hi Performance range can be slow charged, at a rate of 0. For the exact maximum discharge current rating of a specific battery brand contact the distributor or manufacturer of the battery. Battery Capacity Most manufacturers of sealed lead acid batteries have similar battery sizes, which makes product development with SLAs very convenient. If the voltage is below 12.


But they are not good. 4V/cell. Find the Right Car Battery Size Chart and Locate the Ideal Battery for Your Vehicle. 3, Mar. The EMF of lead-acid cells is dependent on chemistry although the actual terminal voltage differs depending on the battery design, this must be taken into account when using a voltmeter to determining the batteries state of charge. Lithium-ion vs Lead-Acid cost analysis. Lead-acid Internal Resistance and SOC In lead-acid cells, the electrolyte a lead acid battery bank having normal voltage of 110 V is to be charge using DC source 160V from initial voltage of 1. See also CA and HCA. The above equations permit electrical monitoring of approximate specific gravity on an occasional basis.


Secondly pulling voltage down to less than 50% remaining capacity permanently devalues the battery. Note for repeated cycles the charge 12V Car Battery Voltage Chart The average duration a car battery can last is 4 to 5 years or even 3 years in hot climates such as Arizona and Florida. Recharge Voltage This chart shows the effect on life of overcharging a gel battery. The best protection from improper charging is the use of a quality charger and routinely. The specific gravity or weight of this solution increases as the battery charges and decreases as the battery discharges. Cross-Reference Battery Charts. Can I recharge my lithium battery from my vehicle alternator? – Yes, but not necessarily to full charge, due to the fact that most Alternators are adjusted for the lower voltage requirements of the vehicle Lead/Acid Battery (approximately 13. Even the weather can play a role. WARNING: Data is not necessarily valid for conditions where multiple 12 volt batteries are connected in strings (series or parallel) See notes below the data table for battery strings.


I do not see molarity used by battery people, but chemists use it all the time. As the battery discharges the voltage will sag down to 10 volts or lower. The figures on this page have been acquired by a various number of sources under different conditions. I cover these formulas in more depth in this post. Specific Gravity Test This test is performed with a hydrometer, which is the most accurate hand held tool for determining the state of charge of a lead acid battery. Unsealed flooded lead acid batteries use venting technology to relieve the pressure and recirculate gas to the battery. 75 maximum. Lead Acid Battery Definition: The battery which uses sponge lead and lead peroxide for the conversion of the chemical energy into electrical power, such type of battery is called a lead acid battery. 8V.


Show the actual rebound voltage after discharging to 50% SOC under controlled conditions. What will be current at the end of charging. 1 vdc 110 ⁰F 10. This chart applies to 12 Volt sealed lead acid (SLA) batteries. This causes permanent damage that impacts performance and reduces the life of the batteries. Frequently Asked Questions about Sealed Lead Acid Batteries. The discharge voltage curves may be depressed by as much as 0. Acid Lead battery restoration recovery 2 of 3 INCLUDES UPDATE 2018 Battery Charge Vs Discharge And Why It Matters The reason there’s not a simple relationship between battery voltage (what a voltmeter reads, or how many of those four idiot lights are illuminated on your display) and state of charge (what the actual storage status of your battery is, 100% being fully charged and 0% being flat dead) is that your RV system is constantly doing different stuff – electricity is coming and going all the time. And I have a volt-meter to check the voltage.


All Lead-Acid batteries supply about 2. The storage capacity for the battery is 50KWh. Accurately monitoring SoC and SoH Both SoC and SoH of the battery can be monitored by accurately measuring: battery voltage, battery temperature, and the charge into and out of the battery. For example, many UPS units use our 12 Volt, 7 Ah battery (Item # SLA-12V7-F2), and TI’s bq34z110, the latest lead-acid gas gauge, uses Impedance Track gauging technology to accurately monitor and report SoC and SoH of the battery [3]. 5 VDC from those shown on the graph. 6 volts across the terminals. 7V rule, treating AGM the same as other lead-acid batteries. PDF Downloads- Access and download U. ), with a 35% sulfuric acid and 65% water solution.


important, however, to limit the maximum battery voltage during charging otherwise the battery will be damaged. Battery Cell Comparison. In the old days, when voltage was difficult to regulate accurately, flooded lead acid batteries were important because the water can be replaced. Century UHP and HP batteries can be charged using any generally available automotive battery charger of appropriate capacity. The ideal car battery voltage range will provide you with a relevant interval according to which you can measure precisely what the voltage says about the battery’s current charge. As well as supplying a wide range of battery products we also provide cutting-edge energy storage solutions for smarter energy management. Gel. Single-cell open circuit voltage = specific gravity + 0. A complete chart for a 12 volt Lead Acid Battery State of Charge for Resting, Discharging, Charging and both Charging and Discharging.


Voltage measurements on to measure SOC on a lead acid battery are useful, but care should be taken to ensure that the results are interpreted correctly. Float voltage is the voltage at which a battery is maintained after being fully charged to maintain that capacity by compensating for self-discharge of the battery. 4 . 8V/cell. Like a deep cycle battery, a gel valve regulated lead acid battery provides dependable long-term power. State of charge 12 volt Standard Batteries Battery state of charge is determined by reading either terminal voltage or the specific gravity of the electrolyte. battery manufacturer can you get a sense of when a battery is good, poor, or will fail. 845. 8 vdc A SLA battery have the same voltage characteristics as a standard lead-acid battery.


Learn About Us This Maximum Voltage should be set for 14. If you value your electronics and your battery, do not bypass the Low Voltage cut-off function of our dew controllers with the use of DC to DC converters which step up voltage to 12 volts dc from voltages lower than 11. 14. Absorbent Glass Mat (AGM) is a type of lead-acid deep cycle battery in which the electrolyte is absorbed into a fibreglass mat. 7 volts above the recommended level reduces life by almost 60%!) Recharge Voltage (12-volt Battery) Figure : Chemical reaction when a battery is being discharged Charge During the recharge phase of the reaction, the cycle is reversed. 9-13. There are few other batteries that deliver bulk power as cheaply as lead acid, and this makes the battery cost-effective for This table has a baseline that assumes that a 12. The lead sulfate (PbSO 4) and water are electrochemically converted to lead (Pb), lead dioxide (PbO 4) and sulfuric acid (2H 2SO ) by an external electrical charging source. However connecting a number of cells together in series results in a battery capable of supplying high-er power demands.


Please click to view: The Typical Charging Time for Single Battery chart is designed to give approximate times for charging and should not be the deciding factor as to whether the battery is finished charging. Proper charging, maintenance, and storage practices are crucial to the life and operation of your battery. 9-Volts). 79 no. Battery voltage state of charge table. The density or specific gravity of the sulphuric acid electrolyte of a lead-acid battery varies with the state of charge (see table below). chemicals known to the state of california to cause cancer and reproductive harm. Lead acid batteries have large capacities and are often available in many places around the world. 5 volts.


The table below shows the voltage and approximate state of charge for each type of battery. Back to top. This solution consists of 65% water and 35% sulfuric acid. The lead acid battery is made up of plates, lead, and lead oxide (various other elements are used to change density, hardness, porosity, etc. Not every manufacturer makes every size, but if you find one you like we can source it for you. com: lead acid battery weight. 15 to 2. To obtain a stable voltage, the battery should not have been used or charged for a minimum of 3 hours before checking the voltage. Battery Voltage The number of cells is determined by the required nominal operating voltage of the equipment.


Hydrometer. They are used in a variety of applications, most people are accustomed to using them in vehicles, where their ability to provide high currents for cranking powe Once a pre -set voltage has been reached the battery is kept at that voltage (the float phase). However with intermittent use the battery has time to recover during quiescent periods when the temperature will also return towards the ambient level. 8 volts it will generally still start the vehicle. Keep sparks or flames away from a charging battery. 23 volts per cell, or about 12. An automatic charger compatible with the battery will look at how the voltage and/or current vary(ies) over time to determine the battery's state of charge . Speaking of correct numbers, the resting Voltage of a 12 Volt flooded lead-acid should be around 12. State of charge does vary a little between a sealed lead acid, flooded, gel and AGM deep cycle battery types and also between brands.


Show the relationship of loaded voltage to SOC on a popular AGM lead acid battery. If the battery stays above 11. 6 volts dc. 14 volts per cell (12. Temperature °F : Ideally this would be the temperature of the battery electrolyte but if the battery has not been charged or used for a few hours the surrounding air temperature will probably be . Amazon. You will find that the plates in an AGM Battery are flat like wet cell lead-acid batteries, or they may be wound into a tight spiral. Lead acid batteries do not develop a memory and do need not be fully discharged before recharging. They seem to be going by the 12.


9 vdc 90 ⁰F 9. However you can get accurate reading SOC voltages on a battery under charge or discharge by making your own chart plotting it with a temperature compensated hydrometer. , vol. In the fully charged state, a 2V electric Lead Acid Battery Charge Reference Chart Thinking out side box. SLA Battery Charging and Maintenance. Voltage readings fluctuate based on various prevailing conditions at the time of measurement. Note. Flooded Lead-Acid Batteries charged will have a terminal voltage of 12. A deep discharge Multi-stage Battery Charging .


The hydrometer offers an alternative to measuring SoC of flooded lead acid batteries. Batteries are more resistant to degradation and freezing when they are fully charged. The truest measure of a battery's state of charge is the SPECIFIC GRAVITY of the battery acid. Battery cell comparisons are tough and any actual comparison should use proven data for a particular model of battery. If a lead acid battery is not immediately recharged, the lead sulfate will begin to form hard crystals, which can not be reconverted by a standard fixed voltage (13. Re: What voltage is 100% SOC for an AGM battery? Here's a really helpful link from the company that manufactured the batteries I'm using (Haze AGM). from the time the battery voltage reaches the boost voltage and the charging current starts to decrease. A fully charged 12-volt lead acid battery starts off around 12. Lead-acid batterieshaving lead calcium grid structures are particularly susceptible to aging due to repeated cycling.


So we prepared some notes on various topics like “How to Calculate Battery Amp Hours” and others Watts = Volts multiplied times Amps Step 1. Recommend boost at or before this SOC before battery use. So the first battery numbers are believable at 12. The lead acid battery is most commonly used in the power stations and substations because it has higher cell voltage and lower cost. DC Battery Meter, DROK Digital Battery Voltage Capacity Percent Monitor Tester DC 8-63V Battery Reader 12V 24V 36V 48V LCD Lead Acid Battery Indicator Electric Quantity Detector for Car Vehicle 3. Concorde also offers a variety of industrial agm batteries in deep cycle and starting batteries. This will NOT tell you how good (capacity in AH) the battery condition is - only a sustained Load Test can do that. A deep-cycle lead acid battery should be able to maintain a cycle life of more than 1,000 even at DOD over 50%. Solar Panels for Lead Acid Batteries.


Teledyne Battery Products is a Stars 2000 Award Recipient. A gel SLA/VRLA battery also offers the greatest number of cycles, making it the ideal choice for heavy, everyday use. battery voltage vs. A lead-acid battery's nominal voltage is 2 V for each cell. For Lead acid batteries the number is typically between 1. Batteries perform differently due to the diverse processes used by various manufacturers. 6 volts How to Revive Old Lead Acid Batteries: If you are like me you probably have old lead acid batteries sitting somewhere probably dischargedIf you dont use lead acid battery always charge it before and recharge it every 3 monts I ve tried this method on maintenance free lead acid, sealed Battery Ratings A single lead-acid cell does not have sufficient power to handle most requirements. 0 vdc 100 ⁰F 9. Here is a chart showing terminal voltage Vs state of charge.


BATTERY LOAD TEST From page 1 Connect Load Tester and Volt Meter to Battery Apply Electrical Load Equal to ½ of CCA Rating for 15 Seconds Determine Battery Temperature With Load Still Applied Read Battery Voltage BATTERY LOAD CHART Battery Temp Acceptable Voltage 120 ⁰F 10. Battery failure rates, as defined by a loss of capacity and the corrosion of the positive plates, increase with the number of discharge cycles and the depth of discharge. Charge voltages will be elevated by as much as 0. A perfect voltage (without any devices or electronic systems plugged in) is between 13. This number is compared to a chart on the tester, based on CCA rating to determine battery condition. As mentioned earlier, specific gravity measurements cannot be taken on sealed lead-acid batteries. 40V, charge the battery in accordance with Section G. Figure 2 shows the terminal voltages experienced by "12 V", 6-cell, lead-acid battery when at different levels of charge and discharge currents. Award winning years: 2005, 2008, 2009, 2010.


Correct the charging voltage to compensate for temperatures above or below 77°F (25°C). Use these Cross Reference Guides to compare battery products with corresponding product numbers from various manufacturers. Hook up a load and the voltage will drop to about 11. The battery voltage should not exceed 13. lead acid battery voltage chart

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