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Marine Battery Technology


Some key benefits:

When choosing a battery for a runabout, don't make the mistake of using a car battery in your boat -- it simply isn't built to withstand the vibrations and shocks of boating in New Zealand's seas and lakes. Enjoy your boating in safety with a reliable, purpose-built marine battery. However, if your vessel is a larger launch or yacht, the vibrations, crashing and banging are softer and many automotive and commercal batteries are used.
Another common mistake is believing any marine battery can perform all jobs. It simply can't unless it is 'Dual Purpose' and then with limitations.

We offer a choice of starting, Dual Purpose and deep cycle batteries. Starting batteries are designed to dump high cranking current you need to start your boat engine first time every time. Dual Purpose is used in Runabouts when you have only one battery and need light cyclic loads for the radio, fishfinder or GPS. Deep cycle batteries are designed to cycle many times (500 ~ 800) and to achieve this the plates are very dense but have less ability to dump high current - a must if your are running a fridge.

We bring you four famous world-renowned names in marine batteries, and each one's a winner. 

Hella Endurant, a good reliable unit manufactured in the USA.

Bosch manufactured in the USA, 

Trojan, arguably the most popular marine battery in the USA.

Powersonic, one of the biggest battery manufacturer and sourced from America featuring sealed AGM Deep Cycle and High discharge technology at affordable prices.

We have many brands of batteries for one reason - no two manufacturers make the same battery and all differ in the technology. When the correct battery for any application is identified, you may be left with one or two manufacturers and then it may come down to price. 

When you choose to go to a distributor who has one brand only, that's what you will get - right or wrong. And that is our difference. We can choose which battery brand suits your application and supply it.

Read about Chargers

Which technology should I use ?

There are four lead acid technologies available to us today: Flooded, Maintenance free (Calcium), AGM or Gel.

The flooded battery (wet), you know, the one we have to top up the electrolyte from time to time. Another pair of jeans and another T shirt. However, its not all bad, they are cost effective and by far the most common battery used in most applications.
The charging voltages are accommodated by almost all off the shelf alternators and AC powered chargers. In applications where multiple banks are use, such as boats and motor homes, the flooded start battery is used almost exclusively for the start bank. However, a deep cycle version is used in many house bank applications.

Lead Antinomy Range - flooded
Is your older equipment keeping up with new battery technology?
The Lead Antinomy range utilises resilient Lead Antinomy plate compounds. They are more suited to lower voltage systems found in early model commercial vehicles. The product overcomes issues where later calcium/calcium batteries go flat due to low charge rates of those earlier vehicles.

Commercial vehicles with low charge voltages including some 12V trucks, stationery operating roadside service trucks, low revving line haul with large lighting loads and low RPM vehicles.
The lead antinomy plates are robust and durable ensuring long life. Vibration resistant to minimise damage caused by shock and vibration.. Low water loss allows accurate service procedures. listings.. Identified with LA in the product code

Dual Purpose flooded
Where a the dual purpose of start and cycle are needed. The product delivers good cranking ability while providing cyclic operation. A good option where space and or budget does not allow multiple batteries but semi cyclic use is required. Dual terminals afford start and house connections. The lead plates are robust and durable ensuring long life. Vibration resistant to minimise damage caused by shock and vibration.. Low or nil water loss due to maintenance free technology. A good option for the smaller 'trailered' runabout listings.. Identified with DP in the product code

The AGM battery. (absorbed glass matting) also referred to as SLA (Sealed lead acid) or VRLA (Valve regulated lead acid) remains a lead acid battery. The electrolyte is absorbed by glass matting between the plates (a bit like a sponge). The unit is held in a slight positive pressure and because it is sealed has a regulating valve to relieve excess pressure when over charged, (at a voltage too high) or over overheated through other circumstances.
An advantage if the correct AGM is used has may have longer cyclic life than the flooded unit because there is no need to top up the electrolyte level - it is sealed. Another plus, generally, the required charging voltage is compatible with the flooded unit. 

A slight down side to the AGM is lack of tolerance to high ambient temperatures. Some makers will halve the warranty period if the unit is to be housed in temperatures exceeding 25 deg C for more than 10 consecutive days. Something to consider in the tropics or high temperature engine bays.

The Gel battery. Again, a lead acid battery but the electrolyte is held in a jelly consistency. The advantage of a gel battery is extended cyclic life over the flooded and AGM. No toping up and is also protected by valve regulation. It is considered a superior technology and is found in important rolls such as buses, trucks, the military and higher valued boats. It is more tolerable to high ambient temperatures and complete discharge without damage.
Perhaps a down side, the gel battery will not tolerate gassing, therefore demanding a lower charging voltage and is therefore not compatible with the other two technologies. Off the shelf alternators must have the internal regulator extracted and an adjustable external regulator installed and adjusted not to exceed say 14.2 volts. (Refer makers recommendation) AC powered chargers are available with a "switchable" Gel option.

Models of AGM and Gel batteries are available for cyclic duty (as in house, golfcart, forklift) and standby duty (as used in UPS applications in the telecommunication Industries and many other)
They can be mounted in almost any orientation. I say almost as you must avoid horizontal installation where the plates are also horizontal. You can mount the battery on its side but spun around so the plates are vertical.
This will eliminate a problem caused by stratification whereby the specific gravity of the electrolyte diminishes on the upper most plate and reduces its ability to produce voltage.

Exide. stowaway starting battery range is purpose-built for smaller outboard motors up to larger-size V8 units and medium-size inboard cruisers, whether petrol or diesel. They are constructed with robust heavy-duty plates and each is wrapped in glass mat separators with "NoVibe" bonding to further resist any plate vibration - the No.1 cause of battery failure.
The protected plates are also resistant to paste shedding, ensuring maximum energy output at all times. Stowaway starting batteries are built to do just that - provide the starting power you need to get going, first time, every time.
Exide also feature heavy duty commercial batteries common in larger vessels such as the N150 and N200 in both start and cyclic technologies.

Trojan batteries are renowned for their long running time and longer life. Now with Alpha Plus, Trojan's exclusive deep cycle paste formula, for added product life. Large heavy grids provide maximum run time in demanding motive power and heavy service equipment applications. Exclusive multi-rib Flexsil® separators reduce water consumption and resulting maintenance. Double thick glass mats reduce plate wear to extend cycle life.

Endurant offer a great range encompassing not only Marine applications but also automotive including race cars and heavy commercial equipment. Endurant Start and Deep Cycle batteries are used throughout New Zealand waters and generally are extremely cost effective.

Vision AGM and Gel batteries are VRLA (valve regulated Lead Acid). The sealed units are pressurised to one or two pounds which will reconstitute the electrolyte from the evaporation process. This means it never needs to be topped up. Vision is one of the biggest AGM and Gel Battery manufacturers in the world and offer high tech batteries at prices often well below alternative brands

Sizing the house bank

A battery bank is a storage device and the duration of use before recharging must be determined before the bank can be sized.
If you intend recharging every 24 hours, the battery bank capacity will be expected to provide power for that 24 hour period.
DoD (depth of discharge) of the bank should not exceed 50%. This is to protect the battery from premature failure. Gel technologies can cope with deep discharge more than others but 50% is a good rule of thumb.
This means that the bank needs to be twice that required for the 24 hour period.

Next, determine your current draw over that time frame. The total lights may draw 4 amps and be on say 5 hours of the 24 hour period. This is 4 x 5 = 20 amp hours. Add all the consumers and multiply by the time you will run them to find a total amp-hour requirement. You may need say 120 amp/hours and therefore the battery bank needs to be twice that - 240 amp/hour bank.

The next consideration is the size of charger. Again using a general rule, the engine alternator needs to have a least 25% of the capacity of the bank. In our boat with 240 amp/hour batteries, the alternator should be 60 amp or more. A shore powered adaptive charger needs to be 10% of the bank and again in this case, a 25amp charger or more would be chosen.
So from this simple exercise, you can see that the battery bank sizing is a balance of consumption over time and charger size.

To recap

  1. Determine the consumption in amp hours
  2. Double that for the battery bank size
  3. Ensure the re charging device size is adequate

Typical and approximate house bank sizes:

  • Yacht 30 ~ 40 feet with basic needs 110 a/h
  • Yacht 30 ~ 40 feet with electronic devices such as wind, plotters and autopilot 225 ah
  • Launch 30 ~ 40 feet with basic needs - 225 ah
  • Launch 40 feet plus with entertainment and electronic devices 450 ah plus
  • Yacht or Launch 50 feet plus often use banks of 675 ~ 900 ah

Points to remember:

  1. The longer the time between charging, the bigger the bank needs to be.
  2. Consumption while motoring will be supplied by the alternator and not drawn from the battery bank
  3. Consumption drawn from the alternator or charger will detract from available current for battery charging.

A word on battery connection and mixing

Mixing batteries on the same charging system must be done with consideration as does multi battery configuration.
'Charging voltages' is generally common with flooded and AGM but varies with a gel battery. One often sees AGM and flooded used in boats. The flooded battery is a good economical start battery and the AGM, a convenient house storage battery. These two banks can be charged off the same alternator but ideally connected through a voltage sensitive relay. With the start battery prioritized, it will be charged first and then the less important house batteries is bought in parallel to receive its share of the charge. As soon as the bank voltages vary, ie, the house bank used, the relay will open and leave the start battery isolated and fully charged.
If a gel battery is to be introduced to the system, it must have a dedicated charging system ie, its own alternator etc..

When increasing the voltage of a bank (12V to 24V) two twelve volt banks will be connected in series (+ to -) This configuration will maintain the battery capacity but increase the voltage. To increase the capacity but maintain the voltage, the batteries are to be connected in parallel (+ to + and - to -) The capacities will be added but the voltage remain.

Another word on multi battery connections.

With a series connection, it is important to use two identical batteries in both model and age. As the charging and discharging current flows through both batteries, they must be compatible.

Only connect batteries in parallel when you must. It is very tempting to just add a battery to increase capacity but as they will be permanently connected together, and batteries (as are people) are never identical, the lesser one will forever be drawing current from the better and the end result will be two flat batteries.
The preferential method when an increase in capacity is needed in a 12 volt system, use two larger 6 volt units and connect them in series. The 'parallel' problem will then not exist.


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