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FAQ - Batteries explained (Cranking and Deep cycle)

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FAQ - Batteries explained (Cranking and Deep cycle)

Postby Pissy » Wed May 20, 2009 2:20 pm

NOTE: Lead-acid batteries contain a diluted sulfuric acid electrolyte, which is a highly corrosive poison and will produce flammable and toxic gasses when recharged and explode if ignited. For this reason NEVER place a battery inside a car cabin, camper trailer or Caravan without the advice of a battery professional, failure to do so may result in DEATH!

Car batteries are essential to operate your vehicle. They start your engine and provide extra power to the ignition, lighting and accessories. They also give power to the electrical system of your vehicle when the charging system is not operational.

Selecting a Car battery can be confusing as they are many types and styles to research and consider. I will not recommend any brands in this FAQ but I will try and discuss the all the different battery types. A lot of this info has been taken off the web from many different sites, so I can’t really reference where I got the info from.

Normal Alternator charging rates should be over 14 volt but no more than 14.7 volts, anything below or above this, could be an alternator related issue and therefore you should consult an Auto electrician ASAP or you do damage to your battery, cars electric and/or alternator. Above 14.7 and you risk killing your battery and electrical system.

Normal Healthy Battery at rest should be just over 12 volts, below this, could indicate that your battery maybe undercharged or dyeing. At rest means when the battery has not been recently charged, this could be several minutes to hours after driving or charger. If your alternator is producing the correct voltage 14.2-14.7 and your battery’s voltage continues to drop into the 11s after a good drive, it is fair to say that your battery is NOT HOLDING CHARGE and needs replacing. Please check with your auto electrician and ask for a LOAD TEST before buying a new on, this tests the batteries ability accept and hold a charge.
Also, silly as it may seem, measure and check your batteries dimensions before buying a new one!

As this FAQ is an attempt to simplify a huge subject, I’ll try and break up the battery types and makes separately.

When considering a new battery, there are 2 types of batteries you should keep in mind before purchasing, is the battery for “Starting the car” or is it a second battery used to “Power” your accessories and or camping needs. There is also a “Dual Purpose” battery also known as the Marine/RV battery incorporates the 2 types mentioned above.

A Starting or Cranking Battery is measured in CCA “Cold Cranking Amps”. CCA is the measure of a battery’s ability to start your vehicle in cold weather conditions. The size of the battery CCA rating should meet or exceed the car’s OEM (original equipment manufacturer) cranking rate. Note: If you are not sure what this rating is, check out your owner’s manual. If you live in cold climates, it is best to get a battery with a high CCA rating since a sluggish, chilled engine requires more power to start it up. A normal CCA rating is anywhere from 500 – 1000 plus CCA. Once the engine starts, the alternator provides all the power that the car needs.

A Deep cycle Battery is designed to deliver a consistent voltage as the battery discharges and therefore usually does not have the ability to act a Starting/Cranking battery.
These batteries are also designed to be deeply discharged (up to 80% although I have heard 50% is preferred) over and over again. Deep Cycle batteries are measured in Amps per hour and range from 50 – 130 plus amp/hours. Theses batteries are usually the second batteries in a dual battery sets. In these set up the Deep cycle battery is charged by the alternator, but it’s only able to charge it to around 80% of its true capacity. The only way to fully charge these batteries is by using a smart 3 phase charger.

There is also a “Dual Purpose” battery also known as the Marine/RV battery incorporates a high CCA with the ability to deeply discharge, The Marine/RV battery is basically a wet car (or starting) battery with studs or combination terminals and designed for high current and shallow discharges. The wet "dual purpose" marine/RV battery is a compromise between a starting and deep cycle battery that is specially designed for high vibrations in marine/RV applications.

Starting and deep cycle Batteries can be divided into different types by how they are made and by the Technology they use to create there power. Different types of batteries have different capacities, charge rates, CCA, amp/hours, etc and therefore, they all have different Pros and cons. The divisions are as follows:

1. Wet/Flooded, Standard (lead acid battery)

Standard wet flooded batteries are (Sb/Sb) non-sealed lead-acid batteries (with filler caps) have Lead-Antimony (Sb) positive and Lead-Antimony (Sb) negative plates.
• Lower initial cost than other types the same capacity
• Tolerance for a wide range of charging current (to 25% of the battery's capacity) and voltage
• More forgiving when accidentally overcharged
• Long service life (if properly maintained)
• Increased water consumption and production of gas requiring more ventilation
• Highest self-discharge rate (typically 1% per day and on hot days, up to 2%)
Charging losses of 15%-20% and maximum continuous discharge rate of 25% of their capacity

2. Low Maintenance Free (Lead acid)

The (Sb/CA) are non-sealed Low Maintenance batteries (with filler caps) have Lead-Antimony (Sb) positive and Lead-Calcium (Ca) negative dual alloy or hybrid plate formulations. These batteries have the same Pros and Cons as the Sb/Sb but are better at copying with under bonnet heat.

3. Maintenance Free Battery (lead acid)
These are normally a wet battery where the design keeps gassing to a minimum and includes a battery box that is sealed to keep the gases in place. An ample amount of acid means the fluid can last for the entire service life of the battery without being topped up. They have a Lead-Calcium (Ca) positive and Lead-Calcium (Ca) negative plate chemistry or formulation. They are available in non-sealed sealed (with removable filler caps) and sealed (with non-removable filler caps) versions. The non-sealed versions are recommended for use in hot climates, so lost water can be replaced.
Less preventive maintenance due to less water loss
• More forgiving when accidentally overcharged
• Require a slightly higher (.45 VDC) absorption charging voltage
• Reduced terminal corrosion and ventilation
• Smaller self-discharge rate
• Less risk to consumers because there is less to service

The Valve Regulated Lead Acid (VRLA) battery is one of many types of lead-acid batteries. In a VRLA battery the hydrogen and oxygen produced in the cells largely recombine back into water. In this way there is minimal leakage, though some electrolyte still escapes if the recombination cannot keep up with gas evolution. Since VRLA batteries do not require (and make impossible) regular checking of the electrolyte levels.

Sealed Gel Cell
Seal Gel Cells are (Ca/Ca) VRLA deep cycle batteries which also uses GRT (Gas Recombinant Technology). They use a thickening agent like fumed silica gel to immobilize the electrolyte instead of a liquid electrolyte like wet batteries
A gel battery (also known as a "gel cell") does not need to be kept upright. Gel cells virtually eliminate evaporation of the electrolyte, spillage (and subsequent corrosion issues) common to the flooded lead acid battery, and boast greater resistance to extreme temperatures, shock, and vibration.
• Have greater ability to withstand a deep discharge, but not temperatures over 100°F (37.8° C) because of the possibility of "thermal runaway"
• Need a 10 to 15 cycle preconditioning or "break-in" period
• Supply less Cold Cranking Amps
• Have 80% of the capacity of a similar sized AGM (Ca/Ca) battery and physically larger
• Require longer recharging times and lower currents
• More forgiving when accidentally overcharged
• Are intolerant of incorrect charging voltages which require special gel cell chargers or gel cell settings
• Produce lower capacity in cold temperatures
• Provide up to 20% more life cycles than AGM VRLA batteries
• Costs more because more expensive to manufacture
• Can loose capacity due to voids between the plates when overcharged
• Sustain charging losses of 4% and maximum continuous discharge rate 25% of their capacity

Absorbent glass mat (AGM) is a class of lead-acid battery in which the electrolyte is absorbed into very fine fiber Boron-Silicate glass mat between their flat Lead-Calcium positive and Lead-Calcium negative plates. They are also known as "starved electrolyte" or "dry. They have all of the advantages of the Maintenance Free (Ca/Ca) batteries plus:
• Much safer then wet batteries (due the hydrogen gas recombination during charging)
• Do not require water
• Lower self-discharge rate (typically 1%-2% per month)
• Longer service life
• Higher resistance to vibration
• Lower deep discharge failure
• Less forgiving when accidentally overcharged
• Higher bulk charge acceptance rate (which means up to a 15% shorter recharge time and reduced cost)
• Lower tolerance for heat
• Do not require special hazardous shipping
• Can be used in saltwater applications
• Spill proof and can be mounted in virtually any position (because they are sealed)
• Can be used inside a semi-enclosed area, like the passenger compartment or trunk
• Greater terminal corrosion resistance
• Less charging voltage tolerance
• Not subject to sulfation from electrolyte stratification or water loss
• Charging losses of 4% and maximum continuous discharge rate 33% of their capacity

Spiral batteries (Optima barnd) are a type of AGM battery with the lead plates tightly compressed into spiral wound cells. Spiral batteries are smaller in size, lighter, sealed and maintenance-free. Spiral batteries are reported to have a high cranking performance, a longer shelf life (when not in use), a higher charge acceptance rate during recharging and more robust to withstand vibrations. Some spiral batteries can be installed in any position making for more flexible installation. These batteries are for excessive vibration applications, in off-road operation, or extreme conditions. have all of the characteristics of the AGM (Ca/Ca) VRLA batteries with Lead-Calcium positives and Lead-Calcium spiral wound plates plus:
• Withstand up to 15 times more vibration
• Up to twice the number of cycles than a wet lead-acid battery
• Smaller
• Recharges faster reducing charging cost
• Wider absorption and float charging voltage variance
• Withstand heat better
• Charging losses of 4% and maximum continuous discharge rate 33% of their capacity

Before you even think about a Dual Battery System, you should consider if you really need one in the first place, how often you will use it, how much it will cost to complete and finally, whether you have room to fit it all in. Fitting a second battery tray usually requires some modifications in your engine bay. In my case I had the move the fuel filter and power steering reservoir about 20cm plus I removed the EGRs (were not working anyway) to allow for a larger battery, mine is a 130amp hours and is bigger and heavier than a normal N70 battery.

One other thing to remember with Dual Batteries systems and setups is that some systems recommend using identical batteries for starting and auxiliary applications, while others don't, plus some battery types can be mixed with others, while other batteries should not be mixed.
If you have a winch and wish to have a battery purely for it, then you need one with high CCA. Winching can take upto and more than 400 amps, which means even if you have your engine running and a winching battery, you still can use up all the power left in your starting battery if you are winching for too long. Be aware

Best to discuss these points with a battery and dual battery System specialist.

94 3.1L MU,2.5"suspension lift,2"body Lift,33"Bighorns,F&R Autolockers,Rock Sliders,winch bar,240 lightforces,UHF,120amp alternator,dual batteries,snorkel,turbo timer etc
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