BATTERY APPLICATIONS NOTES

CHOOSING THE RIGHT BATTERY

To calculate the battery capacity required for any application the current draw and the time duration will be needed.
The following calculation assumes that the battery is dedicated to providing domestic/auxiliary power and is not used for engine starting purposes.

The formula to arrive at the battery capacity required is :-
C = 2 x I x t
where C = Battery capacity in AHr
I = discharge current
t = Time for which the battery can sustain the discharge rate. (normally expressed in hours)

example:- A battery is required that is capable of sustaining a discharge rate of 25 Amps for a period of 2.5Hrs before the battery terminal voltage falls below 11.5 volts.
using calculation above:- C = 2 x I x t
C = 2 x 25 x 2.5
C = 110AHr, from the list on the MAIN page the version BATTERY 3 would be suitable for this application.

When using our range of Batteries to power DC-AC inverters such as our 'X-CELL' range you need to select a bank size that will provide the necessary sustained power. Consider this further example: you need to use a piece of mains driven equipment rated at 100 Watts (a colour television and video player), this will consume approximately 9.5Amps (watts divided by voltage and this example the battery voltage, 10.5 volts, this allows for inefficiencies of the inverter and any voltage drops on the low voltage input cables etc.), assume that you need to run the television for 10 hours over 3 days (assuming no recharge facilities available), this amounts to (using calculation above) C = 2 x 10 x 9.5 // C = 190AHr. In this example a battery bank of 250/300AHr is recommended. This figure does not include any power taken from the battery for lighting etc.

We recommend that the following battery bank sizes for use with DC-AC inverters where the batteries are used for supplying not only the inverters but the normal 12 volts (24 volts) power as well.

 INVERTER SIZE OPTIMUM BATTERY SIZE BATTERY TYPE 500W 220AHr 2 x BATTERY 3 1000W 440AHr 4 x BATTERY 3 or 2 x BATTERY 5 1500W 500AHr 2 x BATTERY 7

RECHARGING THE BATTERY

It should be noted that when recharging batteries in general it will require 1.2 times their discharge capacity to return the batteries to their fully charged state. In most cases a stand alone alternator will not fully charge depleted deep cycle batteries in a short period of time due to their charging characteristics.
When charging our range of batteries it is recommended that if recharging from a battery charger that a 3- stage charger such as our X-Calibre is used or if the battery charger is not a smart charger that the output voltage is set to 14.4 volts and is left connected until the float voltage rises to 14.2 and then reduce the charging voltage to 13.8 volts.Our X-Calibre 3-stage battery charger will provide the correct charging routine without manual intervention. Our range of alternator charge controllers the 'X-ALT',  'X-PORT+' or 'Genie' have special algorithms which cycle the batteries between 14.8 volts and the normal float voltage of the alternator when in boost mode in order to effectively fully recharge heavily depleted batteries in a shorter period of time then stand alone alternators. By using this special algorithm and not exceeding the maximum recommended charging voltage gassing (caused by too high a charge rate) is reduced without extending the recharge period. Our range of battery chargers the "X-Calibre" has the correct charging voltages and 3 stage routine ideally suitable for charging this range of batteries.
When considering implementing or replacing a battery bank it is normally good practice to keep the battery bank to alternator ratio below 5:1, i.e. for a 90A alternator the total battery bank should be 450Ahr, this is to achieve a reasonable charge time period.