1.What is the memory effect of batteries?  
 

Memory effect only happens on NI-CD batteries. As in traditional technology a NI-CD battery’s negative is agglomeration with thick Ni crystal, if NI-CD batteries are recharged before they have been fully discharged, Ni crystal easily gathers to from agglomeration, which makes the primary discharge platform cone into being. The battery stores the platform, which will be considered as the end of discharge for the next cycle even though the capacity decides that the battery can be discharged to a lower platform.

The battery will store this process in its memory so during the next discharge, the battery only remembers this reduced capacity. Similarly any further incomplete discharge in each use will aggravate the effect makes lower capacity.		  
  2.What is the battery self discharge?  
  Primary battery or full charged secondary battery, when put aside for a period, it is capacity will decline or lose, this phenomenon calls “Self discharge” that is electricity flee away. It is decided by the inner electro-chemistry system, similar to water leakage from pond.  
  3.What is the cycle life of rechargeable battery?  
 

When a battery experiences a charge and discharge, we call a cycle or a period. In the stated charge and discharge condition and the capacity decline before a stated standard(Normal 70% of battery), the total cycles it can undergo called rechargeable battery cycle life.

  
  4.What is battery inner impedance?  
 

Battery impedance is the resistance when the current flow through an operating cell, in general the internal resistance in included both d.c. and a.c. resistance. For the rechargeable cell resistance is small and electrode is easy to be polarized along with producing a polarization resistance while measure d.c. resistance, the accurate value can’t be measured.

  
  5.What is the difference between primary and secondary battery?  
 

A primary battery can discharge once only, while a second battery is rechargeable. When discharge a rechargeable battery, its electrode volume and structure cause a reversible change. Therefore the design of a rechargeable battery must be adequate to adjust these changes. Since a primary battery internal structure is more simple, it doesn’t have to accommodate reversible volume changes. The primary battery has bigger quality ratio and volume ratio than rechargeable battery, however it has a far bigger impedance, consequently the load capacity is lower. Furthermore self-discharge of a primary battery is far lower than secondary one.

  
  6.Why do batteries packs with zero voltage or low voltage?  
 

Reason why of batteries packs with zero voltage or low voltage:
1)The batteries packs lead wires are short or over charge and reversed charge
2)Battery continue over charge at high rate big current, it make battery internal     plate has been to expand and short
3)Wrong battery connection or connection tabs are miss or weak weld or broken

  
  7.What is the ambient temperature affects the battery performance?  
 

Low temperature (e.g.-15℃) will obviously reduce NI-CD and NI-MH battery discharge rate. At -20℃ electrolyte is at its freezing point, charge speed will greatly slow down. At low temperature (under -15℃) charge will raise the internal gas pressure and probably unseal the safety vent. Ambient temperature of 5℃ to 30℃ is the best range to get effective charge. Generally with temperature rising charge efficiency will become higher. But when the temperature rises to 45℃ or higher, the materials performance in the battery will be degenerated and battery service life will be shorten greatly.