Exide Select Orbital ORB75DT-84 SLA Battery

by Jeff Lucius

The information presented here is gathered from the documents listed in the References section below.

The Exide Technologies Exide Select Orbital battery is a sealed lead acid battery using absorbent glass-mat and valve-regulated, lead-acid recombinant techology. It is available at many automotive supply stores, such as Checker Auto Parts, and sometimes at a discount on eBay. The ORB75DT-84 is pictured below. Model ORB84DT-84 is similar, including the dual terminal design and fold-away handles; however, it is about 1" longer. These batteries have a 24-month free replacement period, with a total warranty period of 84 months. Typical prices are from $120 to $140.

Sealed lead acid batteries share a common chemistry with flooded lead-acid batteries. Flooded lead-acid (FLA) batteries are the type usually found in automobiles for the last 100 years. Flooded batteries have a liquid electrolyte between cells that can spill, that can be "boiled off", and that must be replenished periodically. FLA batteries readily emit oxygen gas and some sulfuric acid vapor as they charge.

Unlike flooded batteries, sealed lead-acid (SLA) batteries are designed to recombine the oxygen gas produced on the positive electrode plates by absorption onto the negative electrode plates. This permits SLA batteries to be sealed with one or more one-way, safety valves (6 valves for the Exide Select Orbital). The safety valve is required in the case of overcharging (to let gas escape from the battery to prevent an explosion) and required to prevent oxygen gas in the atmosphere from entering the battery and causing corrosion. Because of the safety valve, SLA batteries are also referred to as valve-regulated lead-acid (VRLA) batteries.

The recombinant technology and "dry" classification are achieved by absorbing the electrolyte, which is dilute sulfuric acid just like in flooded batteries, into the separator (sometimes called absorbent glass mat, AGM, technology). SLA batteries cannot leak even if punctured or cracked open, and can be installed in any orientation.

SLA electrode plates are pure lead grids with small amounts of alloy material (tin for the Exide Select Orbital) used to strengthen the plate. The Select Orbital batteries employ an tightly spiral-wound design for alternating layers of the grids and the AGM ("acid-permeated vitreous separators"). This design gives the battery very high resistance to vibration.

The Exide Select Orbital battery, like other top-quality SLA batteries such as the Hawker Energy Odyssey models and the Optima batteries, is extremely rugged, can tolerate both very cold and hot weather, is capable of high discharge rates, stores well for extended periods, recharges faster than conventional flooded batteries, and is completely maintenance free.

Exide Select Orbital Battery Specifications
  ORB75DT-84 ORB78DT-84
Type 12 volt, Sealed VRLA, AGM
BCI Group Size 75DT 78DT
Length 9-1/8" 10-1/8"
Width 7-1/8" 7-1/8"
Height 8-1/8" 8-1/8"
Weight 36 lb 38 lb
Case material polypropylene
Terminals Top: SAE/BCI auto post; Side: GM 3/8-16 threaded nut
Plate composition lead-tin
Plate design spiral wound
Internal resistance less than 0.003 Ohm
Capacity (20 hr) 45 Ah 50 Ah
Reserve Capacity 80 minutes 95 minutes
CCA (1) 690 A 770 A
CA (2) 850 A 950 A
(1) Cranking amps delivered for 30 seconds at 0F and not drop below 7.2 volts
(2) Cranking amps delivered for 30 seconds at 32F and not drop below 7.2 volts


Exide Technologies' web page: http://www.exideworld.com/products/automotive/exide_select_orbital.html
Exide Technologies' Features and Specifications Chart: misc/exide_orbital_specs.pdf
Bill Darden's web site: http://www.batteryfaq.org/
My web page devoted to sealed lead acid batteries: 2-dynabatt.htm
My comparison of some popular SLA batteries: misc/sla-batts.xls (30 KB)

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Page last updated December 19, 2003.