Introduction
Yuasa began development of the NP Series of valve regulated lead acid batteries in 1958. Today's NP battery is the culmination of over 75 years of battery manufacturing experience.
The high energy density, advanced plate technology sealed construction, efficient performance and service life combine to make Yuasa NP batteries the most reliable and versatile valve regulated lead acid batteries available.
Advancements
With the progress of modern technology and the specific development of application requirements, Yuasa has designed generic NP's to be application specific with the introduction of NPC, NPH and NPL product ranges.
NPC is specifically designed to suit the arduous requirements of cyclic applications allowing increased cycle life (at least double the cyclic life of conventional types).
NPH These high performance batteries are specifically designed for applications requiring high rate discharge and offer much improved power densities up to 50% more watts per kilo than conventional NP models when operated at the 10 minute discharge rate.
NPL Offers up to double the float service life of the conventional NP type battery. Note, these models are available to BS6290pt4 (1997).
The generic types utilise identical physical designs and characteristics to the standard NP type in all aspects except their specific application advancement. This in many cases allows users to upgrade without major redesign.
Glossary
1. Ampere (A)
The unit for measuring the flow of electric current.
2. Ampere hour (Ah)
The current in (A amperes) multiplied by time in (h hours). Used to indicate the capacity of a battery.
3. Capacity (C)
Ampere hours that can be discharged from a battery.
4. Cell
The minimum unit of which a battery is composed, consisting of positive and negative plates, separators, electrolyte, etc. In valve regulated lead acid batteries, the nominal voltage is 2 volts per cell.
5. Charging
The process of storing electrical energy in a battery in a chemical form.
6. Cyclic Service
The use of a battery with alternate repetition of charging and discharging.
7. Cycle Service Life
The total number of cycles expected at a given depth of discharge.
8. Deep Discharge
(a) Discharge of a battery until 100% of the capacity is exhausted
(b) Discharge of a battery until the voltage under load drops below the specified final discharge voltage. (Over discharge).
9. Depth of Discharge
The ratio of discharge capacity vs. the rated capacity of a battery.
10. Discharge
The process of drawing stored energy out of a battery in the form of electrical power
11. Energy Density
The ratio of energy that can be discharged from a battery to the volume of that battery measured in Watt Hours (WH) per cubic inch, or litre.
12. Float Service
Method of use in which the battery and the load are connected in parallel to a float charger (or rectifier) so the constant voltage is applied to the battery continuously, maintaining the battery in a fully charged state and to supply power to the load from battery the without interruption or load variation.
13. Gas Recombination
The process by which oxygen gas generated from the positive plates during the final stage of charging is absorbed into the negative plates, reducing the potential at the negative plates, so suppressing the generation of hydrogen.
14. Impedance
The ratio of voltage variation vs. current variation in alternating (a.c.) supply.
15. Internal Resistance
The term given to the resistance inside a battery, consisting of the sum of resistance of the electrolyte, the positive and negative plates & separators, etc.
16. Life Expectancy
Expected service life of a battery expressed in total cycles or time in float service in relation to a specified application.
17. Nominal Capacity
The nominal value of rated capacity. In valve regulated lead acid batteries nominal capacity is usually measured at the 20 hour rate, although higher rate discharge types have their nominal capacities given at the 10 hour rate.
18. Nominal Voltage
The nominal value of rated voltage. In lead acid batteries, nominal voltage is 2 volts per cell.
19. Open circuit Volts
The voltage of a battery which is isolated electrically from any external circuit, i.e. the voltage is measured in a no load condition.
20. Parallel Connection
Connection of a group of batteries by interconnecting all terminals of the same polarity, thereby increasing the capacity of the battery group but not increasing voltage.
21. Recovery Charge
The process of charging a discharged battery to restore its capacity in preparation for subsequent discharge.
22. Sealed
The word "Sealed" is used as a relative term when referring to cells in NP batteries compared with open vented free electrolyte types.
23. Self Discharge
Loss of capacity without external current drain.
24. Series Connection
Connection of a group of batteries by sequentially interconnecting the terminals of opposite polarity thereby increasing the voltage of the battery group but not increasing capacity.
25. Shallow Discharge
Discharge of a battery in which discharge is less than 50% depth of discharge. (D.O.D.)
26. Shelf Life
The maximum period of time a battery can be stored, under specified conditions, without needing supplementary charging.
27. Standby Service
General term for an application in which the battery is maintained in a fully charged condition by trickle or float charging. Synonymous with Float Service.
28. Trickle Charge
Continuous charging by means of a small current designed to compensate for self discharge in a battery which is isolated from any load. For valve regulated lead acid batteries, constant voltage charging is common.
29. Charged Volume
The power returned to the battery by charging as a percentage of the power taken out during discharge.
30. VPC (vpc)
Term for volts per cell.