• Never let the electrolyte level of a wet battery fall below the plates. Lack of maintaining the electrolyte in a wet battery causes damage (sulfation) to the exposed portion of the plate which reduces capacity.
• Never store a battery in a discharged state. The sulfate that forms during discharge should not be ignored for an extended time period because severe sulfation will take place sometimes, making the battery impossible to recharge fully. Sulfation starts at voltages less than 12.4(6.2) and at specific gravity less than 1.225.
• Always fill your serviceable, wet batteries with water (preferably distilled)...after they have been charged (provided the plates are covered). If the electrolyte level is at least above the plates, do not fill the battery until after recharge. The electrolyte expands during charging and if you fill them before recharging, the electrolyte will possibly bubble out of the battery. The plates must be covered with electrolyte for recharge but be careful not to overfill.
• Don't use battery strap that locks onto the battery posts for transporting battery. This type of device can physically damage the battery's internal connections.
• Don't hammer battery cable clamps down on battery posts. This damages internal parts of the battery.
• Don't add acid to a battery low on electrolyte solution. This increases the % acid above acceptable limits and causes pre-mature failure. Add only distilled water.
• Don't use a fast charger that increases voltage across the battery terminals above 16 volts, especially when connected to the electrical system of the vehicle. A fast charger can damage sensitive electronic components.
• Don't disconnect a battery cable while engine is running. This causes the charging voltage to rise since the voltage regulator loses its reference and cannot regulate the charging voltage. The higher voltage and voltage spikes can damage electronic components.
• Always allow batteries to 'cool off' after charging. The cooling time is very important because heat is generated during the recharge and discharge cycles. Without the cooling time the heat grows, accelerating grid corrosion which is one of the major causes of battery failure.
• Never charge a wet battery with a sealed (gel cell) battery charger. The wet battery needs the higher voltages to finish the charge and without it the batteries never come back to 100% and sulfation can occur.
• Never charge a sealed (gel cell) battery with a wet battery charger. The higher voltages (above 14.8 volts) that a wet battery charger generates cause excessive gassing too fast for the sealed battery to recombine, causing dry-out and battery failure.
• Always keep the tops and terminals of batteries clean and free of corrosion. The film on top of the battery can cause the current to migrate between the posts, accelerating self-discharge.
• A fully charged battery will give you the best and longest service. Be sure the batteries are fully charged before testing or using in your vehicles. Even a perfectly new battery that is discharged only will fail load testing. Various states of charge of a battery, without a drain or load, after the surface charge has dissipated, are:

1. 12.66 volts = 100% charged
2. 12.54 volts = 90% charged
3. 12.45 volts = 80% charged
4. 12.39 volts = 75% charged
5. 12.27 volts = 60 % charged
6. 12.18 volts = 50 % charged
7. 11.97 volts = 25 % charged
8. 11.76 volts = completely discharged

• In situations where multiple batteries are connected in parallel, series or series1parallel, a replacement battery(s) should be of the same size, age and usage level as the companion.
• As batteries age, their maintenance requirements change. Generally their specific gravity is higher. Gassing voltage goes up. This means longer charging time and/or higher finish rate (higher amperage at the end of charge). Usually, older batteries need to be watered more often. And, their capacity decreases.
• Inactivity can be harmful to batteries. If they sit for several months, a 'boost' charge should be given; more frequently in warm climate (about once a month) than in cold (every 2-3 months). This is because batteries discharge faster at higher temperatures than at colder temperatures.
• Monitoring either stabilized open circuit voltage or specific gravity will tell you when to charge and how much to charge batteries that are being stored. Battery voltage should not be allowed to drop below 12.4 for 12-volt batteries or 6.2 for 6-volt batteries. Specific gravity should not be allowed to drop below 1.225.

• Cycle the battery lightly (20% or less depth of discharge) the first few cycles. This helps complete the forming process of the plates (in case they are not completely finished forming).
• Always allow batteries to "cool off" after charging. The cooling time is very important because heat is generated during the recharge and discharge cycles. Without the cooling time the heat grows, accelerating grid corrosion, which is one of the major causes of battery failure.
• Opportunity charging (quick charging between uses) is detrimental to battery life. While it is true that the shallower the cycle, the more cycles the battery can deliver, opportunity charging is not good because the cooling time is eliminated, shortening life. (I.e. One charge cycle per day is preferable.)
• Never charge a wet battery with a sealed (gel cell) battery charger.The wet battery needs the higher voltages to finish the charge and without it the batteries never come back to 100% and sulfation can occur.
• Never charge a sealed (gel cell) battery with a wet battery charger. The higher voltages (above 14.8 volts) that a wet battery charger generates causes excessive gassing too fast for the sealed battery to recombine, causing dry-out and battery failure.
• Never let the electrolyte level of a wet battery fall below the plates. Lack of maintaining the electrolyte in a wet battery causes damage (sulfation) to the exposed portion of the plate that reduces capacity.
• Never store a battery in a discharged state. The sulfate that forms during discharge should not be ignored for an extended time period because severe sulfation will take place sometimes, making the battery impossible to recharge fully.
• Always fill your serviceable, wet batteries with water (preferably distilled) after they have been charged). If the electrolyte level is at least above the plates, do not fill the battery until after recharge. The electrolyte expands during charging and if you fill them before recharging, the electrolyte will possibly bubble out of the battery. The plates must be covered with electrolyte for recharge but be careful not to overfill.
• Always keep the tops and terminals of batteries clean and free of corrosion. The film on top of the battery can cause the current to migrate between the posts, accelerating self-discharge.
• A fully charged battery will give you the best and longest service. Be sure the batteries are fully charged before testing or using your R..Vs. A fully charged battery, without a drain or load, after the surface charge has dissipated, is 12.63 volts for a 12 volt battery. Other states of charge are: 12.60 volts = 93% charged 12.55 volts = 89% charged 12.50 volts = 85% charged 12.45 volts = 80 % charged 12.18 volts = 50 % charged.
• An overly discharged battery may need to be cycled a few times before it can recover fully. If a battery begins to heat before coming up to a full state of charge, it may be necessary to discharge the battery and recharge it a few times. This charge and discharge cycle may help the current acceptance of the battery and facilitate its recovery to a usable condition.
• In situations where multiple batteries are connected in parallel, series or series/parallel, a replacement battery(s) should be of the same size, age and usage level as the companion batteries. Do not put a new battery in a pack that has 50 or more cycles. Either replace with all new or use a good used battery(s).
• Deepcycle batteries need to be equalized periodically. Equalizing is an extended, low current charge performed after the normal charge cycle. It helps keeps cells in balance. Actively used batteries should be equalized once per week. Manually timed chargers should have the charge time extended about 3 hours. Automatically controlled chargers should be unplugged and reconnected after completing a charge cycle.
• As batteries age, their maintenance requirements change. Generally their specific gravity is higher. Gassing voltage goes up. This means longer charging time and/or higher finish rate (higher amperage at the end of charge). Usually, older batteries need to be watered more often. And, their capacity decreases.
• Inactivity can be harmful to deep cycle batteries. If they sit for several months, a "boost" charge should be given; more frequently in warm climate (about once a month) than in cold (every 2-3 months). This is because batteries discharge faster at higher temperatures than at colder temperatures.

• Physical Condition: Sediment accumulates under the plates and can short out a cell. Plate separators fail to insulate the positive and negative plates in a cell and the cell becomes shorted, ruining the battery.
• Insufficient Electrolyte: Allows top exposed portion of plates to sulfate rapidly. This reduces the battery's ability to accept recharge. Accelerated erosion of lower portions of plates in a higher than normal acid content electrolyte may also occur when the electrolyte solution is low. The battery also has a higher internal resistance when low on water. High resistance means heat which mean shorter battery life.
• Sulfation: When a battery is allowed to remain discharged too long the accumulated lead sulfate on the plates hardens. The sulfate from the plate is not able to reconstitute the electrolyte to the higher specific gravity, or to restore the plate material to a more active composition.
• Overheating: A battery operated when the electrolyte temperature reaches 125 F, increases chemical action. This increases corrosion of the plates and reduces battery life. When overheated, the battery plates tend to buckle and destroy the structural integrity of the battery.
• Freezing: When the electrolyte freezes, the ice formed will dislodge active material from the plates. Battery case may crack and electrolyte will leak out when thawed.
• Corrosion: Corrosion from spilled or splashed electrolyte forms deposits that can conduct electricity and cause battery drain. Clean off all corrosion. Prevent its accumulation by coating terminals and exposed metal cable connectors with high temperature grease.
• Vibration: Vibration from an improperly installed battery shakes off active material from the positive plate and reduces battery life. When installing a battery, always insure the battery is securely fastened down.
• Overcharging: Overcharging rapidly converts water to gas and decreases the electrolyte water content. The electrolyte level drops, and becomes more acid in content. This subjects the plates to a higher concentration of acid and results in some plate area not being covered with electrolyte. Prolonged overcharging generates excessive heat inside the battery which buckles the plates and destroys the battery. About 58% of battery failures are caused by overcharging.

We are frequently asked "What are the differences between sealed or gel batteries and the more conventional wet, lead acid batteries?"

Below are some general differences for the consumer to consider.

• GEL - Requires stabilized, regulated charging system Conventional charging system OK, 1.5 to 2.3 more expensive (Less expensive_
• Maintenance free, may operate in any position. Requires maintenance (water) upright operation only
• May be shipped UPS FFA approved with restrictions. Shipped common carrier only Cannot use for air travel
• Float charging voltage 13.5 to 13.8. Float charging voltage 13.0 to 13.5.
• Cycle charging voltage 14.4 to 14.8. Cycle charging voltage 14.5 to 15.0.
• Does not deliver high CCA; better suited for long duration discharges. Delivers high CCA and can deliver long duration discharges
• Lower capacities given dimensions. Better capacities given dimensions.
• Slightly less AH per pound than wet Excellent AH per pound.
• Less ability to dissipate heat. Excellent ability to dissipate heat.
• Less readily available for warranty More readily available for warranty.
• State of Charge and Sulfation 
• To ensure proper testing of batteries and to avoid premature battery replacement, the consumer should be aware of some critical information based upon the "state of charge". Nationally, between 30% to 50% of all batteries picked up as "junk" batteries are actually good, useable batteries (taken from Battery Council International source). There are many reasons for this alarming statistic but as a consumer, if you know some "rules" about battery testing and battery state of charge, you’ll be informed and will avoid the pitfalls that many fall unto.
• Below is a very important table which compares battery "state of charge", "specific gravity" and "voltage". The line passing through the "75%", "1.225", and "12.40" represents important information for the consumer. If your battery has a measured specific gravity of less than 1.225 and a voltage less than 12.4, it usually will fail the prescribed "load test" that battery specialists use as their most important diagnostic test. As a consumer, if the battery does not have a "dead cell", you should insist that it be charged to a level above 1.225 specific gravity (where it can be measured) and then tested before purchasing a new battery. We recommend that you focus on specific gravity (for serviceable batteries) as this measurement provides a more accurate reading of state of charge than open circuit voltage. Accurate voltage readings require that the battery sit up to 2 hours before measurements can be made. Why buy a new battery just to simply replace a discharged one?
• For those of you who store your batteries or let them sit without use, be aware that a process called "sulfation" occurs if the battery’s specific gravity falls below 1.225 or below 12.4 volts. Sulfation is actually a hardening of the battery’s internal plates which need to remain soft and porous so that acid can flow through them. If the flow of acid is reduced, the battery performance is greatly reduced regardless of how much you attempt to charge the battery. Monitoring your batteries for these parameters, particularly specific gravity as it changes less rapidly than voltage, will ensure you get maximum life from them.

STATE OF CHARGE VS SPECIFIC GRAVITY VS VOLTAGE

100% 1.265 12.62(6.3)

90% 1.251 12.54

80% 1.236 12.45

75% 1.225 12.40(6.2)

60% 1.206 12.27

50% 1.190 12.18

25% 1.155 11.97(6.0)

DISCHARGED 1.120 11.76

When batteries are connected in parallel, as in most R.V’s, the positive terminals are connected together and the negative terminals are connected together as shown below:

• The main advantage of these parallel connections is that the total current delivering capacity is the sum of each battery’s current. The total current is equal to the sum of both batteries. The main disadvantage of this type of connection is that the total voltage available cannot exceed the voltage of the weakest battery.
• Unfortunately, too often we see parallel connections that may be less efficient. For example, the diagram below shows the traditional way to connect the cables to a dual-battery pack.
• The positive and negative cables are connected to the terminals on the same battery, battery #1. This puts more of the load on battery #1 for the cranking mode and it also gets a higher charging voltage when the dual-battery pack is being charged. Battery #2 doesn’t work as hard because it has extra resistance to overcome in the cables that connect it to Batt #1. Battery #1 doesn’t see that resistance so it is not affected. The cable and connection resistances reduce the efficiency of battery #2 when cranking or charging especially if corrosion develops. The figures shown below demonstrate more efficient ways to connect the battery cables to a dual and triple-battery pack.

When one amp of current passes through a circuit with zero ohms (the unit of measure for resistance) of resistance, no voltage drop occurs. Even when the circuit current increases to 200 amps through zero ohms, still no voltage drop occurs. The amount of resistance encountered by a current causes a voltage drop. Ohm's Law explains how small resistance values can cause severe voltage drops. The basic form of Ohm's Law is E = I x R, where the current, I in amps, is multiplied by the resistance, R in ohms, to equal the voltage drop, E in volts. To see the affect resistance has on voltage we use Ohm's Law and solve for voltage as shown here by the following equation: I(Amps) X R(Ohms) = E(Voltage).

• By substituting different values for resistance, we can see small resistances can cause significant voltage drop problems, especially in high amperage systems as shown below:

1 Amp X 0(Ohms) = 0 (no voltage drop)

200 Amp X 0(Ohms) = 0 (no voltage drop)

1 Amp X 1 Ohm = 1.0 volt dropped

200 Amp X 0.01 Ohm = 2.0 volt dropped

200 Amp X 0.02 Ohm = 4.0 volt dropped

The Society of Automotive Engineers, S.A.E., has established the maximum voltage drops for common electrical circuit cables and connections. The acceptable voltage drops are shown below:

Voltage Drop (Volts) American Wire Size Current Component Application

0.01-.09 16 - 20 1-20 Computer Connections, Low Current Accessories

0.1-.2 4 - 14 20-100 Alternators, High Current Accessories

0.2 00 - 4 100+ Battery/Starter Cables

0.2-.3 N/A 100+ Heavy Duty Switches, Solenoids

For years, “Cold Cranking Amps (CCA tested at 0 F) have been the industry standard of battery amp rating, but in recent years some battery marketers began testing their products at different temperatures, which result in different ratings.  “Cranking amps”(CA), sometimes called “Marine Cranking Amps”(MCA), for example, test battery performance at 32 F or 0 C, so the rating numbers will be higher than a CCA rating.  Since manufacturers’ specifications are based on 0 F, you may want to base your buying decision on the CCA rating.

That’s why it is important to remember, batteries displaying higher rating numbers don’t necessarily deliver more performance.  Check your battery catalog/replacement guide or your auto’s owner manual to make sure you are buying a product that meets your vehicle’s requirements-and be sure to take a good look at the temperature at which a battery has been tested and the reserve capacity.  If you don’t examine the battery label closely, you could end up with a product that is not really powerful enough to serve your vehicle.  With today’s electronically-sophisticated equipment, your vehicle depends on your battery more than ever.

You also may see a battery rated with “Hot Cranking Amps”(HCA) or some other unfamiliar rating.  Most products marketed with an HCA rating promise better performance in warm climates, but beware! Only CCA and CA ratings are approved by the Battery Council

International(BCI).  In fact, the BCI requires that “CA”-rated products carry a “CCA” rating with equal prominence so that proper comparisons can be made. You can’t really be sure of a rating that is not approved by the BCI.

Presented below is a table which shows the differences between CCA’s, CA’s and HCA’s.

CCA’s CA’s HCA’s

0 F 32 F 80 F

275 340 400

345 430 500

415 520 550

450 560 650

520 650 750

590 740 850

625 780 900

660 825 950

695 870 1000

765 960 1100

To avoid the trap of such marketing gimmicks, you can calculate the approximate CCA from other ratings by the following formulas:

CA (@32  ) X .80 = CCA  and  HCA (@80) X 0.60 = CCA

Below is a table showing the specifications of popular Centennial and Batteries Northwest wet-lead acid, deep cycle batteries and some Trojan group sizes also.  Measurements are “overall dimensions” and therefore include any handles, ridges, etc.

GROUP SIZE CCA(0 deg) RES. CAP / WEIGHT 20 HR. CAPACITY DIMENSIONS

Length Width Height

DP24(CEN) 550 125/41 85 11 1/4 6 3/4 9 3/4

DC24(CEN) 600 150/46 87 11 1/4 6 3/4 9 3/4

DC2 (CEN) 650 160/52 105 12 3/4 6 3/4 9 3/4

DC31MF(CEN) 800 225/61 135 13 1/4 6 13/16 9 1/4

B2200 (BatNW)* 500 220/63 225 10 3/8 7 1/8 11 3/16

B24DC(BatNW) 600 110/41 80 11 1/4 6 3 /4 9 3/4

B27DC(BatNW) 650 145/52 87 12 3/4 6 3/4 9 3/4

SCS150(Trogan) ----- 150/50 100 11 1/4 6 3/4 9 3/4

SCS200(Trojan) ----- 200/60 115 12 3/4 6 3/4 9 3/4

SCS225(Trojan) ----- 225/66 130 14 6 3/4 9 3/4

T-105(Trojan)* ----- 447/62 225 10 3/8 7 1/8 10 7/8

T-125(Trojan)* ----- 488/66 235 10 3/8 7 1/8 10 7/8

T-145(Trojan)* ----- 530/72   260 10 3/8 7 1/8 11 5/8

*Please note that these are 6 Volt batteries and two of them, connected in series, are required to produce 12 volts.

The deep cycle batteries shown above have plate designs that consist of a higher density active material than standard automotive batteries.  This higher density material enables the plates to withstand the stresses of repetitive cycling better. 

The grid alloy in a deep cycle is specially formulated to increase the active material adhesion to the grid thereby providing additional protection against the stresses and abuses of cycling and vibration.

One significant advantage of using the grid alloy (antimony) in deep cycle batteries is that it allows the user to cycle(discharge and recharge) the battery over 250 to 2200 cycles, depending on the type and depth of cycle.   One disadvantage is that while “extra” cycling is enhanced, this battery gasses more and water levels must be checked routinely. The atimoney alloy also increases the “self-discharge rate” when compared to automotive, absorbed glass mat (AGM) or gel batteries.

The Plates designed for GC2200, T-105 , T-125 and T-145 use the same active material and alloy of the other deep cycle batteries but both negative and positive plates are up to 60% thicker than those found in a 24DC or 27DC. The significance of this is that these 6 Volt batteries should have life span up to 60 to 70% longer than the other batteries listed.

Those RV-ers who prefer to stay in campgrounds with full hookups have different requirements than those who enjoy primitive camping without hookups. 

• If you never boondock and always stay in places with electrical hookups, you probably can get by with one good quality deep-cycle battery.  However, those RV-ers who sometimes or regularly depend on battery power for the house systems need to do some calculating in order to have enough batteries of the proper size to meet their requirements.

1. The first step is to figure a typical day’s ampere-hour consumption.  It is easy to do:  

• Simply multiply the amperage draw of each item of equipment in the RV by the number of hours it will be used each day.  
• Amperage draw is found on equipment labels, stamped into the casings, or in the instruction booklets.  
• If your RV manual list only lists watts, watts can be converted to amperage by dividing by voltage (12 volts).  
• Amperage draws can be directly measured also with an appropriate “amp meter”. Typical amperage draws of common RV equipment are listed in the table* below:
• Three lights for 4 hours(4 hrs. x 4.5 amps) = 18.00 Ah

Water pump for 45 minutes; includes two showers (.75 hrs. x 5 amps) = 3.75 Ah

TV, color for 2 hours(2 hrs. x 4 amps) = 8.00 Ah

Miscellaneous (clock, LED pilot lights, etc) 2.00 Ah

Total 31.75 Ah

The total daily consumption of 31.75 may not seem like much, but, in relation to battery capacity, it can be considerable.  If the RV has only one Group 24 battery with a rating of 90 Ah, using 31.75 Ah would deplete 32% of the battery’s capacity.  Two Group 24’s connected in parallel have the capacity of 180 Ah (90 Ah + 90 Ah).  A daily consumption of 31.75 Ah would deplete 17% of the capacity available.  If you dry camped for 3 day (31.75 x 3 days= 95.25 Ah), 52% of your battery capacity would be depleted.  The more Ah capacity that is available to your DC accessories, the longer your systems will run.  You can increase more Ah by using either higher capacity batteries or connecting multiple batteries (2 or 3 or 4) in parallel, if you have room in the battery tray.

* This information is taken from “RV ELECTRICAL SYSTEMS-A Basic Guide to Troubleshooting, Repair and Improvement” by Bill and Jan Moeller, 1994, Ragged Mountain Press, Camden, Maine.

Specific charging rates or times cannot be specified for batteries due to several factors that can vary, such electrical capacity of battery, temperature of electrolyte, state of charge and battery age and condition. We recommend the use of a hydrometer which measures specific gravity to monitor "how much" to charge.

These following tips can be used as a general guide for safe charging.

1. Charge batteries in well ventilated area. Don't smoke around charging batteries, they can explode.
2. Wear protective goggles and clothing. The National Society to Prevent Blindness reports, for instance, that in 1984, 14,238 people suffered serious eye damage mishandling batteries. Most were "Do it Yourself-ers".
3. Always assume that explosive mixtures of hydrogen and oxygen gases are present near the battery at all times.
4. Don't remove caps when charging a battery. Most vent caps are now designed to be flame resistant.
5. Cover the vent cap area of battery with a wet cloth to inhibit sparks from igniting escaping gas.
6. Connect charger to battery terminals while charger is turned off. The turn on the charger. This reduces the chance of sparks being generated.
7. Charge single batteries at a specific rate for a specific time determined by the battery's Reserve Capacity Rating:

Reserve Capacity Slow Charge Fast Charge

80 minutes 10 hrs at 5 amps 2.5 hrs at 20 amps

80-125 minutes 15 hrs at 5 amps 4.0 hrs at 20 amps

125-170 minutes 20 hrs at 5 amps 5.0 hrs at 20 amps

*(If batteries are connected in parallel for charging, the output of the charger will be divided equally among the number of batteries being charged and the charging time will increase).

Recharging at the slower rate will prolong battery life.

If a battery fails to test "good" after two charging and load test cycles, replace the battery.

The best way to determine when a battery is fully charged is to check specific gravity of each cell with a hydrometer. (background--As the battery discharges, the sulfuric acid content of the electrolyte solution is reduced, leaving water. Therefore, the specific gravity decreases as the battery is discharged).

Specific gravity measurements show the state of charge of a battery according to the following chart.

State of Charge Specific Gravity

100% 1.265

75% 1.225

50% 1.190

25% 1.155

Discharged 1.120

When a battery is below 75% of full charge, sulfation (or hardening) of the plates begins to occur and permanent battery damage may result. It is important to keep batteries as fully charged as possible.

1. Hold the hydrometer vertically so the float is free and does not touch the inner walls of the barrel.
2. To increase accuracy of the hydrometer, draw electrolyte into the bulb a few times until the hydrometer parts reach the same temperature as the electrolyte.
3. Hold the hydrometer so that liquid is level in barrel and at eye level.
4. Read specific gravity from the scale on the calibrated float at the point where the surface of the liquid crosses the float.
5. Check each individual battery cell. Specific gravity should not vary more than .050 or "50", points between cells. If a cell varies more than 50 points, charge again. If this difference still remains, replace the battery.
6. Measure the electrolyte temperature with a thermometer for best accuracy. Then correct hydrometer readings for electrolyte temperature (see hydrometer instructions for details on temperature compensation ... normally, in the summer this does not have to be done given our climate in the Northwest).

• It is frustrating to find our batteries discharged, particularly in the spring after our boats, R.V.'s, motorcycles, personal watercrafts, etc. have been in storage for the fall and winter.
• With a little maintenance and information, you can avoid the frustrations of "discharged batteries" and the cost of buying new batteries as well.
• Did you know that a battery starts to discharge once it is filled with electrolyte. Here in the Northwest, most boat and car batteries left unattended (and assuming no "parasitic drains" from computers, etc) will not start the engine after about 3 months. For smaller batteries such as personal watercraft and motorcycles, it takes only about a month to discharge the battery to 75%, which usually will prevent the engine from starting. In hotter climates, this can occur in less time than those specified above.
• Discharged batteries not only won't start your vehicle but will become ruined and in need of replacement if left without any maintenance. A process called "sulfation" occurs if the battery voltage drops below 12.4 volts or if specific gravity drops below 1.225 as measured by hydrometer. Sulfation actually hardens the battery's internal plates, which need to remain soft and porous so that the electrolyte can flow through them.
• Monitoring your batteries for these parameters, voltage and specific gravity, can be done easily and cheaply and will ensure maximum life from your batteries. All you need is a voltmeter and hydrometer.
• Armed with this information you can then determine if you need to charge your battery.
• For those applications where batteries are stored for over 2-3 months "without use", an excellent option to maintain your batteries are the "completely automatic, complete shut off "chargers that are now available. These chargers have computer chips that sense when the battery needs charging and automatically turns itself on. After the battery is charge it automatically turns itself off and therefore never overcharges or undercharges your batteries. They can be left connected to an AC outlet indefinitely. Contact us for more information.

Answer: In the SERIES CONNECTION, batteries of like voltage and Amp-Hr capacity are connected to increase the Voltage of the battery bank. The positive terminal of the first battery is connected to the negative terminal of the second battery and so on, until the desired voltage is reached. The final Voltage is the sum of all the battery voltages added together while the final Amp-Hr, Cranking Performance and Reserve Capacity remain unchanged.

Battery System: 12 Volt, 225 AH 

Using Two T-105 Deep Cycle Batteries 

(6 Volts, 225 AH each)

Answer: In PARALLEL CONNECTION, batteries of like voltages and capacities are connected to increase the capacity of the battery bank. The positive terminals of all batteries are connected together, or to a common conductor, and all negative terminals are connected in the same manner. The final voltage remains unchanged while the capacity of the bank is the sum of the capacities of the individual batteries of this connection. Amp-Hrs, Cranking Performance and Reserve Capacity increases while Voltage does not.

Battery System: 6 Volt, 450 AH 

Using Two T-105 Deep Cycle Batteries 

(6 Volts, 225 AH each)

DEFINITIONS

• COLD CRANKING AMPS (CCA):  The maximum amperes that can be continuously removed from a battery for 30 seconds at zero degrees F before the voltage drops too low to use (7.2 volts).  This term is used only for engine starting batteries, and has little to do with the amp-hour capacity or deep cycle batteries.  This rating will also appear on many deep cycle marine batteries.
• CRANKING AMPS (CA):  A rather optimistic market driven rating, especially for “economy” or “value priced” batteries.  The same CCA, but a 32 degrees F (0 C) temperature.  The standard Battery Council International rating is CCA, at 0 degrees F (about -18 C).  The MCA, or Marine Cranking Amps is basically the same at CA.  CCA is about 20% less than CA or MCA.
• RESERVE CAPACITY (RC): Reserve capacity is sometime used to rate deep cycle batteries.  It is the number of minutes that a battery can maintain a useful voltage at a constant 25 amp discharge rate at 80 degrees that run heavy loads, although most batteries also have tables that show the AH capacity at different discharge rates.  AH is approximately equal to RC X 0.60)

1. Before attempting to jump start the car, it is important to use safety glasses. 
2. Measure battery terminal post voltage with a volt meter to determine if battery has a shorted cell. 
3. A car should not be jump started if the battery has a shorted cell. 
4. The voltage at the shorted battery remains about two volts low even with the jumper cables connected. 
5. Attempts to jump start the car could result in damaged computer memories or alternator damage from voltage spikes from the source battery. 
6. Using jumper cables and jump starting should be the last resort.

Background:  A reading of 11.89 volts(0% charge) indicates the battery state of charge and a shorted cell may not exist in the battery. Compare the actual reading obtained to the BATTERY VOLTAGE vs. STATE OF CHARGE CHART to determine the battery’s state of charge shown below. Readings below 12.45 volts indicate low state of charge and might be the reason the battery cannot crank the engine. A reading of about 10.55 volts(4.22 for six volt batteries), indicates the battery may have a shorted cell and should be replaced.

OPEN CIRCUIT VOLTAGE vs. STATE OF CHARGE

12.66 VOLTS 100% CHARGED

12.45 75

12.18 50

11.97 25

11.76 0

Place the source car (good battery) close enough to the dead car so that jumper cables can reach between the batteries without stretching too tight.  The jumper cables should be long enough and the cars close enough so the jumper cables have plenty of slack.  Do not let car bumpers touch each other. Wear protective eye glasses. Do not attempt to jump start a car if gasoline fumes are present around either the source car or the car with the dead battery.

Turn the source car off before making any jumper cable connections between the two batteries. Having the source car OFF lowers the voltage on the source battery voltage. The lower voltage helps reduce the amplitude of voltage spikes generated when jumper cables are connected to the dead battery. Make your last connection be the ground on the car being jumped and maximize the distance of this connection from the positive terminal.

Background:  Avoid voltage spikes at the battery terminals. Voltage spikes are generated when jumper cables or battery charger cables are connected to the battery terminals of a weak or dead battery.  These voltage spikes can shock computers memories and alter information stored in sensitive memory chips inside computers.  The most sensitive memory chips are called EEPROMs (Electrically-Erasable PROMs) or NVM chips (Non-Volatile Memory).

1. Winter is the hardest on your car.  
2. Colder temperatures make your engine harder to crank and your battery less able to crank the engine over. 
3. There are services that should be performed now to maintain vehicle reliability.  

• If you believe out-of-sight, out-of-mind is acceptable for vehicle maintenance, it’s time for a reality check.  
• Good vehicle performance is directly linked to the care it receives.
• Visually inspect your battery for clean surfaces, loose connections, and corrosion. Dirt, corrosion and moisture provide a path for energy to escape from the battery. 
• When corrosion or dirt accumulates, use a weak solution of baking soda and water to clean the battery’s exterior. 
• You may need a wire brush to scrub the terminals.  Loose connections also may result in an explosion!  Battery cables are important as defective cables and poor connections are two of the top reasons for cranking problems.  Keep cable and connections “bright and tight”.  Play close attention to ground connections.
• Make sure you maintain the electrolyte levels (for serviceable batteries) between above the battery’s plates and below the vent well cap opening. Plates exposed to air will sulfate, become hard and brittle and you’ll loose battery power. Be careful not to overfill.  Adding too much water not only dilutes the electrolytes sulfuric acid but can cause a drop in voltage.  Never add acid to the battery!
• Measure the “state of charge” with preferable a hydrometer.  If the battery is sealed, let the voltage equilibrate and determine “state of charge” with an accurate volt meter.  Appropriate charge levels (1.265 specific gravity as measured by a hydrometer and 12.6 volts as measured with a volt meter) are very important component of year around maintenance.  A discharged battery will lead to a starting failure.  A battery stored in a discharged state is susceptible to sulfation and freezing.
• Have your battery tested by a mechanic or battery specialist to ensure that it meets manufacturing specs for its power.  Not all batteries are created equal. You need a load tester or other digital battery testing equipment to accurately test the battery.  If the battery does not met manufacturer’s specs, then replace the battery with one that does.
• If you are storing batteries be sure to charge the battery before storage and store them in a cool, dry location.  Once a battery is filled with electrolyte, it discharges at 1% a day at 70 degree Fahrenheit. Cooler temperatures, from 40 to 60 degrees F are ideal. Discharged batteries can freeze at 18 degrees F.  Batteries stored in cars newer than 1981 have parasitic drains that will further discharge the batteries.  Check with a specialist before disconnecting the battery from the car’s electrical system.  Charge automotive, R.V. batteries every 3 months.  Charge motorcycle and ATV batteries once every month.  For vehicles left in storage including cars, R.V’s,  trucks, motorcycles, personal water craft, etc, there are several very good manufacturers (i.e. Interactor, VDC Electronics, Battery Tender, etc) that have perfected “completely automatic” chargers that will maintain your batteries at a “full state of charge” but not overcharge. 
• Advantages and Disadvantages of using two 12 volt batteries connected in parallel or two 6 volt batteries connected in series. 
• It would appear that there is no significant difference in capacity and voltage between these two examples. But this really is not the case. The plates designed for the T-105 use the same active material and alloy of the group 27 deep cycle batteries but both the T-105 negative and positive plates are 60% thicker than those found in the deep cycle 27 group sizes. The significance of this is that these 6 Volt batteries should have a longer lifespan than the two deep cycle 27 group sizes, if properly cared for. While the capacities are similar (220 versus 225 Amp Hrs.), battery longevity favors the two 6 Volt batteries. Why? Because a major cause of deep cycle battery failure is the shedding of active material from the battery plates.

Presented below are the “basic” testing procedures used by professionals to determine if your battery is “good” or “bad”.  These are presented in a “bullet format” for ease of reading and interpreting.  More detailed discussion can be found on the internet should you want to pursue it.

STEP 1:  VISUAL INSPECTION

• Check the battery case for breaks and leaks
• Clean corrosion off battery and terminals if present
• Check to see if electrolyte levels (if low maintenance battery) are above plates
• Check electrolyte color (if low maintenance battery) A dark color indicates overcharging)
• If the battery is sealed, check for cracks or corrosion

STEP 2:  STATE OF CHARGE

• Check with hydrometer (if low maintenance battery)
• If readings are less than 50 specific gravity points between highest and lowest cell, go to step 3; if not, continue
• Recharge if one or more cells are below 1.225 specific gravity
• Remove surface charge with a load tester if battery has been on charge
• If the battery is sealed, determine “state of charge” with an accurate volt meter
• If voltage for sealed battery is below 12.6 charge the battery with automatic charger and then proceed to step 3.

STEP 3:  LOAD TEST THE BATTERY

• Apply ½ the CCA rating for 15 seconds and compare resulting voltage with voltage chart
• At 70 degrees the voltage should remain above 9.6 volts to pass; at 60 degrees passing voltage is 9.5; at 50 degrees passing voltage is 9.4; at 30 degrees passing voltage is 9.1 volts.

STEP 4:  ANALYZE RESULTS

• Continue to observe bounce back voltage after load is removed.
• If battery voltage fails to bounce back to 12.4 volts for 12-volt batteries and 6.2 volts for 6-volt batteries, recharge and recheck.