I have to add to this debate and point out that deep cycle chart on page 14 of the battery spec. The graph shows charge cycles from a very deep 10.02 volts. I know it is very unwise, even with a deep cycle battery, to constantly let a battery get down to 10.02v. To me, it looks like the long term damage is being done because the voltage is allowed to get too low not because of the voltage that charges it. The higher voltage charge, after a very deep cycle, only reduces the long term damage from letting your battery run down too low. If you do "accidentally" let the voltage get extremely low, you can recondition the battery using a proper charger that has a high charge voltage recondition program.
I also have to point out the temperature compensation graph on page 15. If the battery is under the bonnet then its temperature is going to rise. The under bonnet heat is the reason why car manufactures make the alternator run at a reduced voltage as temperatures rise. To quote the battery spec, "the voltage MUST be reduced as the temperature rises". Looking at the chart, at 25 degrees the theoretical ideal cycle voltage is 14.7v. At 40 degrees it is 14.4v and reduces to 14.1v and flat lines when temps go above 60. Therefore, the magical 14.7v cyclic charge voltage, and float voltage, should be compensated when temperatures change from 25 degrees.
Yes, a charge voltage of 13.6v is not ideal if the battery is at or below 25 degrees. If the battery is located under bonnet and subject to heat from the engine and radiator, the voltage from the alternator fine and is doing what it should! Therefore, a DC/DC charger only should be used if the battery is not under the bonnet or if the charger has the ability to lower the voltage if it senses the battery temperature is rising.
I also have to point out the temperature compensation graph on page 15. If the battery is under the bonnet then its temperature is going to rise. The under bonnet heat is the reason why car manufactures make the alternator run at a reduced voltage as temperatures rise. To quote the battery spec, "the voltage MUST be reduced as the temperature rises". Looking at the chart, at 25 degrees the theoretical ideal cycle voltage is 14.7v. At 40 degrees it is 14.4v and reduces to 14.1v and flat lines when temps go above 60. Therefore, the magical 14.7v cyclic charge voltage, and float voltage, should be compensated when temperatures change from 25 degrees.
Yes, a charge voltage of 13.6v is not ideal if the battery is at or below 25 degrees. If the battery is located under bonnet and subject to heat from the engine and radiator, the voltage from the alternator fine and is doing what it should! Therefore, a DC/DC charger only should be used if the battery is not under the bonnet or if the charger has the ability to lower the voltage if it senses the battery temperature is rising.
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