Batteries in General

What is the difference between freshening charge and equalization charge?

Freshening charge implies charging batteries during or after storage, when the voltage or specific gravity falls below a given level. Equalizing charge is given to restore batteries that have been discharged or to restore voltages to batteries whose voltage has fallen outside of the recommended range.

This is general information. For specific information, see the Installation & Operating Instructions manual for the product.

What does VLA stand for?

VLA stand for Vented Lead Acid batteries, sometimes referred to as flooded batteries, or wet cells.

What does VRLA stand for?

VRLA stand for Valve Regulated Lead Acid batteries, sometimes referred to as Sealed batteries or maintenance-free batteries.

How long can batteries be stored?

Batteries should be stored indoors, preferable at 77F (25C) or in a cool (60F to 85F), dry location and placed in service before the date stamped on the shipping carton. The indicated storage time is based on storage at 77F (25C); approximately 6 months for Lead Calcium alloy and approximately 3 months for Lead Antimony and Lead Selenium cells. See product manual for specific details.

Exercise caution when operating or storing batteries at low temperatures because of the possibility of electrolyte freezing. Although the specific gravity of a fully charged battery may present no freezing problem, the discharged specific gravity may. See product manual for more information.

Do you have free software for sizing C&D batteries?

C&D has a web based battery sizing application. You can access the program at Click on REQUEST and the program will take you through the application process. Once your request is approved, you will receive your user name and password. You user name is your email address. Please enter your email address carefully; it will be used to notify you.

What does the name of the Front Terminal VRLA batteries mean?

The first 3 letters represent the intended use of the battery.
TEL – Telecom Applications
UPS – UPS Applications
VRS – Renewable Energy Applications
DCS – Deep Cycle Applications

The next number represents the nominal voltage of the battery (6 or 12)

The number following the dash is an approximation of the commonly used capacity for the application of the battery. These are typically represented in Ampere-Hours (TEL, VRS) or Watts (UPS). See battery label for additional information.

The remaining letters describe characteristics of the battery.
F – Front Terminal
N – Narrow Width
S – Short Depth
W – Wide Width
G – Gas Collection
MR – High Rate Max
C – Cycling Version (TEL Only)

Design Components

How is the battery open circuit voltage related to the electrolyte specific gravity?

The cell open circuit voltage (OCV) is approximately equal to the electrolyte specific gravity (SG) number plus the number 0.84. For example, with an electrolyte SG of 1.300 the OCV will be 2.14 (1.300 + 0.84), or with SG of 1.215 the OCV will be 2.06.


What will happen if I take the battery to a lower end point voltage then that recommended?

Potentially, some of the cells could “reverse”. The active material on the plated could be stressed and sloughed. This over-discharge can reduce the life expectancy of the cell. If over-discharged at a very low rate, the cell could become hydrated resulting in “through separator shorts”.

Hazardous Materials

What materials are used in a battery?

The primary ingredients in a battery are lead and acid.

Where can I get specific information on the volume and weight of sulfuric acid in my battery? (Go to Library /Environmental/Hazmat for this list)


What codes or standards may be involved in the installation of a Lead Acid battery system?

The battery system installation may be subject to local, state and national building, fire and electrical codes. There are also guides as published by the IEEE. Relevant codes and guides may include, among others, the following:

  • National Electric Code (NEC) Section 480 – Storage Batteries
  • Uniform Building Code (UBC) Article 307
  • Uniform Fire Code (UFC) Article 64
  • IEEE – 1187 “Recommended Practice for Installation of Valve Regulated Lead Acid Batteries”
  • IEEE – 484 “Recommended Practice for Installation Design and Installation of Vented Lead Acid Batteries for Stationary Applications”
  • OSHA 1926.403

msEndur II

What is the maximum number of msEndur II (ATP) modules in one stack?

The msEndur II (ATP) modules may be stacked up to 8 modules high.
For systems requiring NEBS qualification, there may be other height restrictions, depending on battery model.

Periodic Maintenance

What codes or standards may be involved in the maintenance of a battery system?

The battery system maintenance may be subject to local, state and national codes depending on the application. These codes and guides may include, among others, the following:

  • IEEE – 1188 “Recommended Practice for Maintenance and Testing of Valve Regulated Lead Acid Batteries”
  • IEEE – 450 “Recommended Practice for Maintenance and Testing of Vented Lead Acid Batteries for Stationary Applications”


What are the replacement parts for RE02069 and RE02070 rail covers?

RE02446 rail cover replaced RE02069 (used on 1-5/8 x 1 rail RD00422). RE02447 rail cover replaced RE02070 (used on 1-5/8 x 1-5/8 rail RD00200).

Can lubricants be used for cell installation?

Do not use oil or grease as a lubricant for cell installation. Lubrication is usually not required due to the low friction interface of the insulation covers. If necessary, a small amount of water, unscented talcum powder or Dow-Corning III can be applied to the rail covers to reduce friction.

What are the part numbers for unistrut rail on racks?

RD00422-L is the C&D part number for 1-5/8 in. x 1 in. unistrut rail and RD00200-L is the C&D part number for 1-5/8 in. x 1-5/8 in. unistrut rail. L is the length in feet.

Do the RDB racks have provisions for grounding?

Rack grounding provisions are integrated into the base of each RDB series frame. Two holes are located at the center of the frames bottom cross members and may be used to secure a standard NEMA lug. These holes are 0.44 inch in diameter and 1 inch between centers.

Renewable Energy

Does C&D offer batteries suited for renewable energy applications?

Yes, C&D has a variety of product designed to meet the demands of on or off grid renewable energy sites. The VR Solar Series is a VRLA solution ranging from 33-178AH. The CPV Series is a 2V Flooded solution designed for higher demand applications.


Where can I get specific information on the volume and weight of sulfuric acid in my battery? (Go to Library /Environmental/Hazmat for this list)

Standby Vented Cells

What is the standard orientation for MCTII cells?

The standard MCTII is installed with plates parallel to the rack rails. The MCTII is also available with plates perpendicular to the rack rails but it requires a different CW battery part number and different rack part number.

When do I need to add water or electrolyte to cells?

CAUTION – Do not add water or electrolyte to cells, particularly before initial charging. Adjust electrolyte levels only when cells are fully charged and stabilized at float voltage.

Before adding water or acid to a battery, you must consider its condition and state of charge. For example, a new battery which has recently experienced vibration during shipment will appear to have a low electrolyte level. Do not add water or acid to cells unless the plates are covered. If the plates are covered by electrolyte, the battery should be placed on charge. (See product manuals for charging instructions). The gases produced by charging will displace the electrolyte and raise it to an acceptable level between the high and low level marks on the container. Had the level been adjusted to the High mark before charging, charging could have caused the electrolyte to rise to a point where it could overflow though the vent or be forced up into the flame arrestor, requiring needless maintenance.

Note: Adding water to a battery to bring the initial electrolyte level up will reduce the specific gravity.

If, after charging, the electrolyte levels have not risen to between the high and low level lines, electrolyte (sulfuric acid and water solution) of the same specific gravity may be added to bring levels to the high mark. Adding electrolyte is a procedure that should be done only after consultation with C&D or performed by a C&D agent.

Storage & Inventory Control

How can I determine the age of a VRLA battery?

Batteries shipped on or after January 1, 2000 have a 4 digit shipping code with the first two digits being the month and the following two being the year in which the battery was shipped from the factory. For example, a code of 1000 would be interpreted as October, 2000.

Technical Support

Where do I call for technical support?

Monday thru Friday, 8AM to 5PM Eastern Time call 1-800-543-8630
After hours Tech Support call 1-800-299-3907