bobbyb
Active member
Very Good Topic =D> Purching the right battery is confusing for a lot of people - incl me..........lol
Here's a handy little guide that I came across. Found it useful when I needed a conclusion for battery choices.
bobby
Choose the right battery chemistry
Marine batteries are available in three chemical types: flooded, Gel and AGM (Absorbed Glass Mat). Which type you choose is based on your needs (deep cycle vs. starting), the capacity and lifespan you are looking for, and your budget.
Flooded batteries, unlike other types, use a reservoir of liquid sulfuric acid to act as a pathway between positive and negative plates, which produce hydrogen and oxygen when the battery is being charged. Vented wet cell batteries allow the gases to escape into the atmosphere, unlike gel and AGM batteries, which recombine the gases and re-introduce them to the system. Vented hydrogen is an explosive gas, so battery boxes and compartments must be vented to let the gas escape safely outside the boat. Flooded deep-cycle batteries require maintenance-periodic inspection and topping-off with distilled water.
Flooded batteries handle overcharging better than gel and AGM batteries, because of this hydrogen venting and because they are not sealed like the other types. They self-discharge at a higher rate (6 to 7% per month) and thus require off-season charging. Wet cells must be installed in an upright position and do not tolerate high amounts of vibration. Their initial cost is lower than similarly sized AGM or gel batteries. Properly charged and maintained, our premium wet cell deep-cycle batteries are capable of between a few hundred and over a thousand discharge cycles, which can translate to many years of dependable service.
Gel Batteries: The SVR design nearly eliminates gassing, so they are safer to install around people and sensitive electronics (but gel and AGM batteries still need to be vented). Gel batteries are manufactured to very high standards of quality and consistency, since it is not possible to add water or gain access to the interior. The "gel" is a combination of sulfuric acid, fumed silica, pure water and phosphoric acid. After mixing during manufacturing to a thin liquid form, it is sucked into each cell by vacuum pressure up to six times, eliminating voids and air pockets on the plates that would cause dead spots and reduce performance. Once it is in place, the gel becomes quite viscous, which prevents leaks if the battery is inverted or the case is damaged.
Charging causes a small amount of hydrogen and oxygen to be generated at the plates, like a flooded battery, but the pressure inside the cells combines the gasses to create water (so they are called "recombinant" batteries). This keeps the battery from drying out due to charging, but it also requires that the vessel’s charging system be very carefully regulated to prevent high voltage over-charging.
AGM batteries: Sealed Valve-Regulated AGM (Absorbed Glass Mat) batteries feature fine, highly porous microfiber glass separators compressed tightly between the battery’s positive and negative plates, which are saturated with just enough acid electrolyte to activate the battery. During charging, precision pressure valves allow oxygen produced on the positive plate to migrate to the negative plate and recombine with the hydrogen, producing water. In addition to providing equal saturation across the entire surface of the battery’s positive and negative plates, the fibers in the dense glass mats embed themselves into the plates’ surface like reinforcing rods in concrete, providing more plate support and better shock and vibration protection than in conventional batteries.
High-density AGM batteries have lower internal resistance, allowing greater starting power and charge acceptance, and quicker recharging than other types of deep cycle batteries. High acceptance means that AGM batteries can accept the highest charging current, up to 40% of the amp hour capacity of the battery, compared to about 25% for the other two battery chemistries. Long life, a low 3% self-discharge rate and outstanding performance make AGM batteries excellent dual-purpose batteries for boaters who require quick starting power and reliable deep cycle ability.
Battery tips for best performance
No matter what kind of battery chemistry you choose, follow these recommendations to get the best performance:
•Stay with one battery chemistry (flooded, gel, or AGM.) Each battery type requires specific charging voltages. Mixing battery types can result in under- or over-charging. This may mean replacing all batteries on board at the same time.
•Never mix old batteries with new ones in the same bank. While it seems like this would increase your overall capacity, old batteries tend to pull down the new ones to their deteriorated level.
•Regulate charge voltages based on battery temperature and acceptance (manually or with sensing) to maximize battery life and reduce charge time. Ensure that your charging system is capable of delivering sufficient amperage to charge battery banks efficiently. This generally means an alternator with 25% to 40% as many amperes as the capacity of your entire battery bank.
•Keep batteries clean, cool and dry.
•Check terminal connectors regularly to avoid loss of conductivity.
•Add distilled water to flooded lead acid batteries when needed. Keep them charged. Leaving them in a discharged state for any length of time will damage them and lower their capacity.
•Clean corrosion with a paste of baking soda and water.
--------------------------------------------------------------------------------
Need more juice?
If your boat came from the factory with only one battery, or with two batteries of inadequate size, consider installing a second battery bank. Boats often need two banks to have a second "reserve" bank to be sure the engine will start, or to have a large "house" bank so you can run bigger DC loads for longer time periods. If you are installing a reserve starting battery, you can usually ensure enough amps of cranking power by duplicating the type and size of your original battery. To install a "house" bank, you should probably invest in a quality deep cycle battery.
Marine Batteries
Starting batteries are similar to automotive batteries. They can supply lots of current for a short period of time, but like to be recharged almost immediately and are not tolerant of deep discharges. They are appropriate as the single battery for ski boats, runabouts, personal watercraft, and other boats with minimal DC loads where the engine is always running.
Deep–cycle batteries can endure repeated deep discharging and recharging without damage. They are appropriate for sailboats, fishing boats, and all other boats with larger DC power requirements. Any battery used to power onboard DC loads (lighting, trolling motors, inverters, etc.) should be a quality deep–cycle battery.
Here's a handy little guide that I came across. Found it useful when I needed a conclusion for battery choices.
bobby
Choose the right battery chemistry
Marine batteries are available in three chemical types: flooded, Gel and AGM (Absorbed Glass Mat). Which type you choose is based on your needs (deep cycle vs. starting), the capacity and lifespan you are looking for, and your budget.
Flooded batteries, unlike other types, use a reservoir of liquid sulfuric acid to act as a pathway between positive and negative plates, which produce hydrogen and oxygen when the battery is being charged. Vented wet cell batteries allow the gases to escape into the atmosphere, unlike gel and AGM batteries, which recombine the gases and re-introduce them to the system. Vented hydrogen is an explosive gas, so battery boxes and compartments must be vented to let the gas escape safely outside the boat. Flooded deep-cycle batteries require maintenance-periodic inspection and topping-off with distilled water.
Flooded batteries handle overcharging better than gel and AGM batteries, because of this hydrogen venting and because they are not sealed like the other types. They self-discharge at a higher rate (6 to 7% per month) and thus require off-season charging. Wet cells must be installed in an upright position and do not tolerate high amounts of vibration. Their initial cost is lower than similarly sized AGM or gel batteries. Properly charged and maintained, our premium wet cell deep-cycle batteries are capable of between a few hundred and over a thousand discharge cycles, which can translate to many years of dependable service.
Gel Batteries: The SVR design nearly eliminates gassing, so they are safer to install around people and sensitive electronics (but gel and AGM batteries still need to be vented). Gel batteries are manufactured to very high standards of quality and consistency, since it is not possible to add water or gain access to the interior. The "gel" is a combination of sulfuric acid, fumed silica, pure water and phosphoric acid. After mixing during manufacturing to a thin liquid form, it is sucked into each cell by vacuum pressure up to six times, eliminating voids and air pockets on the plates that would cause dead spots and reduce performance. Once it is in place, the gel becomes quite viscous, which prevents leaks if the battery is inverted or the case is damaged.
Charging causes a small amount of hydrogen and oxygen to be generated at the plates, like a flooded battery, but the pressure inside the cells combines the gasses to create water (so they are called "recombinant" batteries). This keeps the battery from drying out due to charging, but it also requires that the vessel’s charging system be very carefully regulated to prevent high voltage over-charging.
AGM batteries: Sealed Valve-Regulated AGM (Absorbed Glass Mat) batteries feature fine, highly porous microfiber glass separators compressed tightly between the battery’s positive and negative plates, which are saturated with just enough acid electrolyte to activate the battery. During charging, precision pressure valves allow oxygen produced on the positive plate to migrate to the negative plate and recombine with the hydrogen, producing water. In addition to providing equal saturation across the entire surface of the battery’s positive and negative plates, the fibers in the dense glass mats embed themselves into the plates’ surface like reinforcing rods in concrete, providing more plate support and better shock and vibration protection than in conventional batteries.
High-density AGM batteries have lower internal resistance, allowing greater starting power and charge acceptance, and quicker recharging than other types of deep cycle batteries. High acceptance means that AGM batteries can accept the highest charging current, up to 40% of the amp hour capacity of the battery, compared to about 25% for the other two battery chemistries. Long life, a low 3% self-discharge rate and outstanding performance make AGM batteries excellent dual-purpose batteries for boaters who require quick starting power and reliable deep cycle ability.
Battery tips for best performance
No matter what kind of battery chemistry you choose, follow these recommendations to get the best performance:
•Stay with one battery chemistry (flooded, gel, or AGM.) Each battery type requires specific charging voltages. Mixing battery types can result in under- or over-charging. This may mean replacing all batteries on board at the same time.
•Never mix old batteries with new ones in the same bank. While it seems like this would increase your overall capacity, old batteries tend to pull down the new ones to their deteriorated level.
•Regulate charge voltages based on battery temperature and acceptance (manually or with sensing) to maximize battery life and reduce charge time. Ensure that your charging system is capable of delivering sufficient amperage to charge battery banks efficiently. This generally means an alternator with 25% to 40% as many amperes as the capacity of your entire battery bank.
•Keep batteries clean, cool and dry.
•Check terminal connectors regularly to avoid loss of conductivity.
•Add distilled water to flooded lead acid batteries when needed. Keep them charged. Leaving them in a discharged state for any length of time will damage them and lower their capacity.
•Clean corrosion with a paste of baking soda and water.
--------------------------------------------------------------------------------
Need more juice?
If your boat came from the factory with only one battery, or with two batteries of inadequate size, consider installing a second battery bank. Boats often need two banks to have a second "reserve" bank to be sure the engine will start, or to have a large "house" bank so you can run bigger DC loads for longer time periods. If you are installing a reserve starting battery, you can usually ensure enough amps of cranking power by duplicating the type and size of your original battery. To install a "house" bank, you should probably invest in a quality deep cycle battery.
Marine Batteries
Starting batteries are similar to automotive batteries. They can supply lots of current for a short period of time, but like to be recharged almost immediately and are not tolerant of deep discharges. They are appropriate as the single battery for ski boats, runabouts, personal watercraft, and other boats with minimal DC loads where the engine is always running.
Deep–cycle batteries can endure repeated deep discharging and recharging without damage. They are appropriate for sailboats, fishing boats, and all other boats with larger DC power requirements. Any battery used to power onboard DC loads (lighting, trolling motors, inverters, etc.) should be a quality deep–cycle battery.
