In inverters with battery selection switches, TT and FT usually refer to settings optimized for different types of lead-acid batteries: TT (Tall Tubular) and FT (Flat Tubular). These settings primarily adjust the charging parameters to best suit the specific battery technology, optimizing battery life and performance.
Understanding TT (Tall Tubular) and FT (Flat Tubular) Battery Settings
Many inverters offer a switch or setting to choose between TT (Tall Tubular) and FT (Flat Tubular) battery types. This is crucial because different battery chemistries and constructions have slightly different charging voltage requirements. Using the wrong setting can lead to undercharging (reducing battery capacity and lifespan) or overcharging (damaging the battery).
Key Differences and Parameters
Here's a breakdown of the typical differences in charging parameters between TT and FT settings:
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Battery Type:
- TT (Tall Tubular): Designed for tall tubular batteries. These batteries generally have a longer lifespan and can handle deeper discharge cycles better than flat plate batteries.
- FT (Flat Tubular): Designed for flat tubular batteries.
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Charging Voltages: The most significant difference is in the charging voltage profiles.
Parameter TT (Tall Tubular) FT (Flat Tubular) Notes High Cut Voltage ~14.5-14.7 V ~14.2 V The voltage at which the inverter stops charging to prevent overcharging. Float Voltage ~13.8 V ~13.5 V The voltage the inverter maintains after the battery is fully charged, for maintenance.
Why These Differences Matter
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High Cut Voltage: Setting the high cut voltage too high for an FT battery can lead to gassing and premature failure. Setting it too low for a TT battery can lead to the battery not reaching a full charge.
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Float Voltage: The float voltage is critical for maintaining a fully charged battery without overcharging it over long periods. Again, these voltages need to match the battery type for optimal performance.
Practical Implications
- Selecting the Correct Setting: Always consult your battery manufacturer's specifications to determine the appropriate charging parameters and then select the corresponding TT or FT setting on your inverter.
- Battery Life: Using the wrong setting can significantly reduce battery lifespan and capacity.
- Performance: Optimized charging leads to better battery performance and longer backup times.
In summary, TT and FT settings on an inverter allow it to optimize the charging process for different types of tubular batteries. Correctly matching the inverter setting to the battery type is crucial for maximizing battery life and performance.
