Battery Types
Choosing the Right Battery for Your Application
Up to 85% of the 70 million new batteries sold each year will die before their 5+-year design life is up. *The main reasons for this are...
- Poor maintenance
- Vibration
- Contamination, Overcharging/Undercharging
- Incorrect application - Buying and using the wrong type/size battery for your application
Choosing the right type / size battery:
Whether you have good or bad service from your battery will first and most importantly depend on choosing the right battery for the right job. Unfortunately most mass retail stores don't have the trained personnel to help you with this most important decision. A store specializing in batteries is your best bet. Remember that it's not what you pay for the battery, but how long it will give you good performance that determines the real cost of the battery. Think long term when buying a battery. Each battery has its strengths and weaknesses. No battery is the perfect solution to any application. Reducing the "negatives" of each battery type for your particular need is the process we will help you with.
Starter Battery-Maintenance Type (filler caps)
- Most commonly referred to as automobile/truck starter type. Least expensive (initial cost)
- Not to be used for non-starting type applications such as running lighting, deep cycling (trolling), fish finders, electronics.
- Must not be deeply discharged and should be re-charged immediately after being used.
TIP 1: Never use a battery rated only in Cranking Amps (CCA) for anything but starting.
TIP 2: Always charge a starter battery as soon after using it as possible.
TIP 3: Always purchase a maintenance type battery (w/ filler caps), if you plan to properly maintain your battery and are not concerned about locating/operating the battery in a con-fined area.
TIP 4: Always buy the largest/highest rated battery possible to reduce the depth of discharge in order to maximize its life and reduce total cost.
TIP 5: Always think of the cost of the battery you are going to buy in terms of performance, safety, and convenience. Total cost/cycle is what you should be concerned with, not just initial price.
TIP 6: If you are NOT planning on using your battery on a every day basis, such as in seasonal type equipment, be sure you have a means of keeping it fully charged for long periods with-out ever risking it being over-charged. Batteries kept at full charge at all times without being over-charged will last 3-5 times longer than those that are allowed to self-discharge.
Starter Battery - Maintenance Free Type (no filler caps w/ liquid electrolyte)
- Sold as never needing maintenance i.e. water.
- Good for people who never want to know what is going on "under the hood".
- Satisfactory for most starter applications in frequently used equipment. Disadvantage: Can't determine health of battery without using an accurate digital volt meter or load tester, even if they are equipped with a state-of-charge, aka: Charge Level Indicator window.
TIP 7: Don't rely on the "Charge Level Indicator", aka: "Magic Eye" for accurate state-of-charge. They are notoriously inaccurate, especially in stationary applications like emergency generators.
Starter Battery - Sealed Gelled, AGM, or Dry (no filler caps -electrolyte is "non liquid")
- Much more expensive than non-sealed liquid type.
- Can be operated in any position without risk of spilling.
- Have a lower rate of self-discharge than non-sealed maintenance and/or maintenance-free (liquid) batteries.
- Are considerably more sensitive to overcharging and self-discharge, which can cause serious damage and shortened battery life.
- Recommended for applications where little or no checking and/or maintenance can easily be performed.
TIP 8: Consider the potential benefits vs. cost of these types before making a buying decision.
TIP 9: Check the output of your alternator/generator-voltage regulator settings before replacing your standard liquid type battery with any non-liquid sealed type to be sure your charging system does not overcharge it.
TIP 10: Never allow a sealed "non-liquid" battery to self-discharge below 11.5 volts or permanent damage can occur. Special charging equipment and/or procedures may be needed to recover sealed batteries that have been allowed to self-discharge below 11.5 volts.
TIP 11: To prevent self-discharge during periods of non-use/storage, maintain your battery using a constant voltage type charger with end of charge to prevent over / under charge.
TIP 12: Always use an accurate digital voltmeter or similar device to determine your sealed batteries true state-of-charge. Remember to let your battery "Rest" for 12 hours or longer before testing its voltage.
TIP 13: Knowing the exact voltage of your battery can help you to accurately determine it's state-of-health.
Voltages and Specific Gravity (s.g.) of battery at various levels of charge:
| Voltage | S.G. | Capacity | |
| 12.6 - 12.8 | 1.265 s.g. | = | 100% Charged |
| 12.4 - 12.6 | 1.225 s.g. | = | 75% - 100% |
| 12.2 - 12.4 | 1.190 s.g. | = | 50% - 75% |
| 12.0 - 12.2 | 1.155 s.g. | = | 25% - 50% |
| 11.7 - 12.0 | 1.120 s.g. | = | 0% - 25% |
Deep Cycle Battery - liquid - maintenance type with filler caps
- Designed to deliver maximum capacity through hundreds of full cycles of charge.
- Discharge without damage. Ideal for trolling motor, RV service (house) battery applications.
- Can be left in discharged state for extended periods without serious damage.
- Best used in pairs to maximize capacity, while reducing level of discharge to a minimum in each battery.
- Should not be used in starter type applications where heavy current draw is required over a short time period.
TIP 14: Never mix old and new deep cycle batteries in a series or parallel set-up.
TIP 15: Never combine different type batteries (Gel, AGM, Sealed, vented) in one set-up.
TIP 16: Try never to discharge any deep cycle battery below 50% of capacity, in order to maximize cycle life.
TIP 17: Try to recharge deep cycle batteries as soon after discharging them as possible.
TIP 18: Because most deep cycle batteries are used on an infrequent basis i.e. not ever day or week, self-discharge and plate sulphation can become a serious problem. Maintain at full charge without ever over charging them.
Deep Cycle (non-liquid) Sealed, Gelled and Absorbed Glass Mat (AGM) w/o filler caps
- Can operate in any position and confined areas.
- Have all attributes of maintenance type deep cycle batteries as described above.
- Cannot be checked accurately for state of health, due to being sealed. Use "resting" voltage (see chart) to determine state-of-charge.
- Rate of self-discharge is less than vented, free electrolyte (liquid) batteries, but serious recharge problems can develop if left uncharged for too long. Remember a battery can loose up to 1% of its capacity a day when left uncharged.
TIPS 14-18 apply to these as well.
Battery Chargers/Maintainers/Conditioners
Choosing the right battery for the job is only half the story. Now you need to choose the right device to properly charge, maintain and recondition them, once they start showing signs of aging.
- Battery chargers that do not have an "end of charge control" or too much output current can ruin a battery in just a few hours.
- Avoid charging any battery in a time period of less than 24 hours, unless you need to place the battery back in service in a short time.
- If a battery is charged slower it lasts longer.
- Pulse type chargers with end of charge controls minimize the heat build-up during charging, while decreasing the time needed to fully charge battery.
- Minimizing plate sulphation build-up by keeping your battery at full charge at all times, can extend its life by as much as 300%.
- Using de-sulphation equipped conditioner-chargers early in the life of your battery will guarantee maximum performance, as well as longer life.
TIP 19: Never leave an unregulated or so called "automatic" charger connected to your battery overnight, unless it shuts off completely.
TIP 20: Avoid the use of "trickle rate" chargers that do not have an automatic float mode or current control circuitry that is guaranteed not to overcharge your battery.
TIP 21: Keep your battery at full charge at all times without ever overcharging it. By doing so you will always have maximum power, eliminate additional sulphation build-up, prevent freeze-up (to - 40°F) and extend your battery's useful life.
*Battery Council International, January '98, 12 months - Nov. '95 - Oct. '96