I’ve seen people say that they do not let their battery go below 3V per cell (for 13s 48v battery that’s 13*3=39V; for a 14s 52V battery = 14*3= 42V). However some BMS low voltage cut off is higher than 3V. Others use 3.2V or 3.3V.
What should the voltage be when the battery is off?
But, once the surface charge (immediately after being charged) is off of the battery, the voltage should be stable around 12.5v to 12.7v. Therefore, after its stopped over night, this is what you should have.
What should I do if my battery voltage drop is too low?
If the voltage drop exceeds specification, check for corrosion, frayed strands of wire, loose connections or a battery cable gauge that is too small. Ensure the vehicle’s batteries have been tested and that the terminals have been cleaned and tightened.
What is a good low voltage cut off for low voltage batteries?
However some BMS low voltage cut off is higher than 3V. Others use 3.2V or 3.3V. And yet I’ve heard others use as low as 2.7V. And yes I do know that is somewhat variable depending on the type of battery and chemistry you are using. However I’m trying to come up with some minimum standard that would be acceptable for the vast majority of batteries.
What is voltage drop in a battery?
The voltage “drop”, is the voltage lost across the internal resistance of the battery.: As you can see, the higher the internal resistance of the battery (Rint), the greater the voltage drop will occur across Rint for a given load current Is, and the less voltage you’ll have available across the load (VL).
How low can a battery voltage go?
So, how low are we talking? A typical 12-volt auto battery will have around 12.6 volts when fully charged. It only needs to drop down to around 10.5 volts to be considered fully discharged. If it drops down below that, the battery will become damaged due to excessive sulfation.
What is the lowest voltage for a lead acid battery?
The truth is that any lead acid battery, be it a Gel Cell, AGM or flooded batteries such as DCBs, should be cut-off at 11.6 volts. Not doing so increases the risk of damage to the battery and if taken down deep enough into the batteries charge, will ruin the battery.
How low can you drain a 12V battery?
Rule of thumb, don’t go below 50% – for best battery life on a 12V battery don’t go below 70%.
How low can you discharge a 12V lead acid battery?
Do I need to completely discharge my lead acid battery before recharging it? No, in fact you should never discharge your lead acid battery below 80% of its rated capacity. Discharging it below this point or 10.5 volts can damage it.
At what voltage is a 12V battery low?
12.0 volts or below – At 12.0 volts your battery is considered to be fully discharged or ‘flat’ and should be recharged as soon as possible. The lifespan of your battery will be severely affected if it remains within this voltage range for extended periods of time.
What is the minimum voltage of a 12V lead acid battery?
Minimum voltage This also means than nothing below 2.15 volts per cell will do any charging (12.9V for a 12V battery) However, most of the time a higher voltage than this is used because it forces the charging reaction at a higher rate. Charging at the miminum voltage will take a long long time.
What to do if voltage drop exceeds specification?
If the voltage drop exceeds specification, check for corrosion, frayed strands of wire, loose connections or a battery cable gauge that is too small.
What voltage is required to remove surface charge?
2) If the voltage is greater than 12.6 volts (AGM batteries 12.8 volts), surface charge must be removed.
How many volts should a battery have?
1) With the voltmeter connected to battery, and key and engine off, record a “base” voltage reading. (Your battery should have a minimum of 12.4 volts.) If it is less than 12.4 volts, charge the battery and repeat the test.
What is voltage drop test?
This is why the concept of voltage drop testing is the only sure method of determining if there is an adequate current delivery path for optimum starting, charging, battery performance and life.
What causes cranking and charging problems?
High or unwanted resistance is one contributing factor that leads to cranking and charging system problems. High resistance is often caused by one of these four main issues:
What is voltage drop?
The voltage “drop”, is the voltage lost across the internal resistance of the battery.: As you can see, the higher the internal resistance Rint, the greater the voltage drop there will be across Rint for a given load current Is, and the less voltage you’ll have available across the load (VL).
Why do my batteries drop volts?
An excessive resistance of your high amperage circuit is an overlooked problem that can cause your volts to drop in your batteries.
Why do batteries use voltage regulators?
Most of the time, in order to compensate for how the battery voltage changes over its discharge cycle, the electronics will utilize a voltage regulator set to somewhat below the battery’s supplied voltage.
How to calculate watts?
Watts = volts x amps, so by using watt-hours instead of amp-hours, you have one number that says how much capacity the battery has. Kilowatt-hours are a more convenient measurement for very large batteries (a kilowatt-hour is 1,000 watt-hours). Most people don’t know or care about the actual voltage or amperage – they just want to know how far they can drive on a charge,
Why does cell voltage change with age?
So there is cell voltage changing as a function of age and there is a series resistance voltage drop caused by current discharge that also increases with age. 6.4K views.
Why does the voltage go back up when you charge a battery?
This happens due to the fact that as the reactants in the battery get less concentrated less reactions happen per second, decreasing the voltage. When you charge the battery you reverse the reactions bringing the reactants back to the original concentrations (or at least close) the voltage goes back up to what is originally was.
How does the potential of a battery change?
As the electrons pass from one end of the battery to the other the potential on the negative end starts lowering (compared to earth) while the positive end starts going up (again, relative to earth). Then the difference in potential (voltage) goes down aswell
What is the low voltage on a Samsung controller?
I have my controller Low Battery Cutoff set to 39v using a 48v battery which is down to approximately 22.5% of total allowable according to Samsung specifications. So down to 3v where Samsung specs 2.65V per cell low V cut off.
What is the ideal storage voltage for a cell?
Ideal storage voltage where cells age the least is about 3.85V per cell. If you go much below that you should charge right away up to that if you are not going to ride right away.
How many volts does a 14s battery have?
I’ve seen people say that they do not let their battery go below 3V per cell (for 13s 48v battery that’s 13*3=39V; for a 14s 52V battery = 14*3= 42V). However some BMS low voltage cut off is higher than 3V. Others use 3.2V or 3.3V. And yet I’ve heard others use as low as 2.7V.
What temperature should a battery charger be?
Not a very good idea to charge at those low temperatures either. Best practice is battery and charger should be near 70° F to charge.
How many cycles are bare cells?
Since bare cells are rated at their 800-1000 cycles when tested down to 2.5V, that means most of us are already being nicer to our batteries than we realize. If you charge to 90%, then you are doing even better.
How many volts does a bike controller use?
Bike controllers, at least mine, are set for about 3.1V/cell for the lower limit. Battery controllers, at least the ones where I’ve looked at the specs, are set for around 2.5 volts, the lower limit of a lithium cell. The bike manufacturers are looking out for us by setting the cutoff that high.
Is a longer battery run more whimsical?
The longer runs are generally not as whimsical. They are more something that are planned at least a day ahead of time, allowing plenty of time to charge the battery, no matter it’s current voltage. Agree on the pretty grey. Battery power still in it’s infancy to my way of thinking.
How many cycles does a deep discharge battery last?
Many a battery tech sheet says a deep cycle battery discharged to 20% state of charge will only last 500 cycles.
What is a cycle in a battery?
A cycle is defined as a period of discharge followed by a period of charge, ideally to full capacity. While a battery is discharging, the sulphuric acid, which is the electrolyte, chemically reacts with the lead plates to create lead sulphate, which builds up on the surface of the plates.
Is 60% a cycle?
When looking at amount of energy stored and delivered, two cycles of 60% are equivalent to one cycle of 20%. Every charge and recharge incident degrades the battery by some small amount.
Does a recharged battery have less lead sulphate?
Yes, during each recharge event, a little less lead sulphate is converted, as I explained above. The rate at which the degradation occurs is pretty well linear to the amount of conversion that occurs during a single event where the battery is discharged from some charge level.
Why is my car battery voltage low?
Another common cause of low voltage is due to prolonged time in a state where the battery isn’t being used. When a battery sits for long periods of time (generally a year or more) sulfation occurs which causes the battery to lose its charge internally. There are also cases when car battery voltage can become too high.
How many volts does a car battery have?
A fully charged car battery voltage for a vehicle that isn’t running should fall between 12.4 volts and 12.6 volts. Each battery is complete with 6 separate cells that each contains 2.1 volts, for a total of 12.6 volts. If your car battery voltage is discharged, or has less than 12.4 volts, the power decreases dramatically.
How long does a car battery last?
A car battery life expectancy can range from between four and five years before it will no longer hold a charge. However, depending on the climate where you live, it can be even shorter.
How long does it take for a battery to drop to 12.7?
If you measure the voltage immediately after the end of a drive, it should be more like 13.2, and drop to 12.7 within a few minutes as the chemical reactions in the battery slow down and stop when you stop charging it.
How much current does a car battery need to charge?
With the battery in that poor condition, the regulated 14.4V from the car alternator will be barely enough to charge it at all. You might be able to get some more life out of it by disconnecting it from the car electronics and putting it on a high power charger that can apply 15 or 16V if necessary to force a reasonable charging current (5 to 10 amps) through it for a few hours.
What is a fully charged battery?
Technically speaking, 12.6V at rest is considered a fully charged battery. When a battery has just finished charging (or when you just shut off your car after driving for a bit), the battery will typically have a “surface charge” so its voltage will be in the upper 12s or possibly even low 13s, and it takes the battery a while (couple hours, perhaps) for its voltage to drop down to its true resting voltage. The battery in my Cobra shows mid-12s immediately after being charged, and its resting voltage is usually in the low-12V range, so it’s definitely not performing optimally.
How many miles does a PA 130A alternator have?
The current alternator is a PA Performance 130A model that I bought in May 2016, and it has only about 1500 miles on it. (As you can guess from the low miles, my Mustang only sees 1500-2000 miles per year.
Can an alternator put out good voltage?
While probably rare alternators can put out good voltage and current at low RPMs but fall on their face when spun hard.