'Must Know' Features And Facts; Temperature Compensated Charging - Victron energy Blue Smart IP22 12/15 Manual

2. 'Must know' features and facts

.1 Ultra high efficiency 'green' battery charger
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With up to 95% efficiency, these chargers generate up to four times less heat when compared to the industry
standard.
And once the battery is fully charged, power consumption reduces to 0,5 Watt, some five to ten times better
than the industry standard.
2.2 Durable, safe and silent
- Low thermal stress on the electronic components.
- Protection against overheating: the output current will reduce as temperature increases up to 60°C, but
the charger will not fail.
- When the NIGHT or LOW mode are activated, the maximum output current is reduced to 50% of nominal,
and the fan will be off.

2.3 Temperature compensated charging

The optimal charge voltage of a lead-acid battery varies inversely with temperature. The Blue Power IP22
Charger measures ambient temperature during the test phase and compensates for temperature during the
charge process. The temperature is measured again when the charger is in low current mode during float or
storage. Special settings for a cold or hot environment are therefore not needed.
2.4 Adaptive Battery Management
Lead-acid batteries should be charged in three stages, which are [1] bulk or constant-current charge, [2]
absorption or topping charge and [3] float charge.
Several hours of absorption charge are needed to fully charge the battery and prevent early failure to sulfation¹.
The relatively high voltage during absorption does however accelerate aging due to grid corrosion on the positive
plates.
Adaptive Battery Management limits corrosion by reducing absorption time when possible, that is: when charging
a battery that is already (nearly) fully charged.
2.5 Storage mode: less corrosion of the positive plates
Even the lower float charge voltage that follows the absorption period will cause grid corrosion. It is therefore
essential to reduce the charge voltage even further when the battery remains connected to the charger during
more than 48 hours.
2.6 Reconditioning
A lead-acid battery that has been insufficiently charged or has been left discharged during days or weeks will
deteriorate due to sulfation¹. If caught in time, sulfation can sometimes be partially reversed by charging the
battery with low current up to a higher voltage.
Remarks:
Reconditioning should be applied only occasionally to flat plate VRLA (gel and AGM) batteries because the
a)
resulting gassing will dry out the electrolyte.
Cylindrical cell VRLA batteries build more internal pressure before gassing and will therefore lose less water
b)
when subjected to reconditioning. Some manufacturers of cylindrical cell batteries therefore recommend the
reconditioning setting in case of cyclic application.
Reconditioning can be applied to flooded batteries to 'equalise' the cells and to prevent acid stratification.
c)
Some battery charger manufactures recommend pulse charging to reverse sulfation. However, most battery
d)
experts agree that there is no conclusive proof that pulse charging works any better than low current / high
voltage charging. This is confirmed by our own tests.
2.7 Lithium-ion (LiFePO₄) batteries
NEVER attempt to charge a Li-ion battery when its temperature is below 0°C.
¹ For more information about batteries, please refer to our book 'Energy Unlimited' (downloadable from
www.victronenergy.com),or
² For more information about Li-ion batteries please see
12,8v/
http://batteryuniversity.com/learn/article/sulfation_and_how_to_prevent_it
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http://www.victronenergy.com/batteries/lithium-battery-