Tag: Power Supplies

VRLA – Valve Regulated Lead Acid Batteries

In VRLA batteries the hydrogen generated at negative plates is mixed with oxygen generated at positive plates and turned back to water thus avoiding the need to replenish distilled water to electrolyte like in open vented lead acid batteries.

12 volt 12 ampere hour sealed lead acid battery
12 volt 12 ampere hour sealed lead acid battery (Photo credit: Steven Vance)

VRLA batteries have a pressure release mechanism to avoid rupture during charging at high voltage.

The biggest advantage of VRLA batteries over normal lead acid battery is no spillage in any position.

Since lead acid battery contains acid transport regulation classifies batteries under Class 8 (Corrosive substances).

12V 7.0Ah Lead-acid Battery.
12V 7.0Ah Lead-acid Battery. (Photo credit: Wikipedia)

Entries in IMDG Code for Lead acid batteries

NICKEL-METAL HYDRIDE BATTERIES

For NiMH AA batteries.
NiMH AA Cells

Nickel-Metal Hydride Batteries are rechargeable batteries. These batteries have equivalent energy density as lithium-ion batteries but looses its charge more quickly in shelf than lithium-ion batteries.

During transport these batteries do not pose much danger however they can be a concern sometimes.

APL Peru during a voyage experienced fire in cargo hold attributed to two containers carrying Nickel-Metal Hydride Batteries. These containers were said-to-contain merely 46 cartons of NiMH batteries only!

There are further cases involving fire due to NiMH batteries, one in a non-live reefer. Considering these experiences and facts IMO DSC agreed to include Nickel-Metal Hydride Batteries as Dangerous Goods.

Requirement as per IMDG Code 35th Amendment

35th amendment of IMDG Code came with new entry UN 3496 BATTERIES, NICKEL-METAL HYDRIDE, Class 9 with Special Provision 117 and 963 assigned.

Though not subject to any other provisions of IMDG Code these batteries  require to meet following provisions

  • Shall be securely packed and protected from short circuit.
  • When gross mass of nickel-metal hydride batteries per container is 100 Kg of more then they shall be subject to below three requirements :
  1. Dangerous Goods Declaration
  2. Inclusion in Dangerous Goods Manifest placed on board vessel
  3. Stowage “Away from” sources of heat

 

Example

Container no. AAAA1234567 Container no. BBBB1234567
Commodity Total Package Weight Requirement Commodity Total Package Weight Requirement
BATTERIES, NICKEL-METAL HYDRIDE  

99 KG

  NIL BATTERIES, NICKEL-METAL HYDRIDE  

100 kg

Or more

 1.DGD,

2.Include in Manifest

3. Stowage away from sources of Heat

 

Now we know that when weight per container is 100 KG or more the changes in requirement is triggered.

However Nickel-metal hydride button cells or nickel-metal hydride cells or batteries packed with or contained in equipment are not subject to any requirement of IMDG Code. Example packed with Radios or Cameras, or Packed inside Radios or Cameras.