Hawker Energy Odyssey PC 925 SLA Battery

by Jeff Lucius

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

The Hawker Energy, http://www.hepi.com/ and http://www.hawker.invensys.com/, Odyssey battery (and the similar Genesis model line) is a sealed lead acid battery using absorbent glass-mat and valve-regulated, lead-acid recombinant techology. These batteries are available at many internet stores, such as Battery Mart, BatteryWeb.com, Portable Power Systems, and West Coast Batteries. The PC 925 is pictured below and can be purchased for about $106. These batteries have a 36-month warranty.

Hawker Energy Odyssey PC 925 battery

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. 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 absorbed electrolyte (sometimes called absorbent glass mat, AGM, technology) makes these batteries dry by design. They are classified for US DOT regulated shipping as unregulated "nonspillable wet electric storage batteries". These batteries cannot leak even if broken open by force. Recombination is assured without periodic venting of oxygen gas and acid vapors because of higher vent design pressures (Odyssey valves vent at 50 psi). No maintenance of the electrolyte, which is dilute sulfuric acid just like in flooded batteries, is ever required. External deposits on and near the battery due to outgassing are virtually nonexistant.

The Odyssey and Genesis line of batteries feature rugged construction with strong external packaging. These batteries are highly resistant to shock, high impact, and mechanical vibration, passing the MIL S-901C and MIL S-167-1 tests. The external case is made from non-halogenated, flame-retardant, UL94V-0-approved Noryl plastic, with some models, like the PC 925 shown above, having an additional metal case outside the plastic case to reduce heat absorption by the battery. The terminals are female-threaded, maintenance-free brass that accept SAE automotive terminals. The pure lead-tin plates have a low grid-corrosion rate (providing a long service life), short recharge time, high (99.9%) recombination efficiency, low self-discharge rate, and allow the use of thinner plates. The thin-plate construction promotes fast recharge capabilities and high discharge rates with stable voltage (due to greater surface area and low internal resistance).

The Odyssey and Genesis batteries, like other top-quality SLA batteries such as the Exide Select Orbital and the Optima batteries, are extremely rugged, can tolerate both very cold and hot weather, are capable of high discharge rates, store well for extended periods, recharge faster than conventional flooded batteries, and are completely maintenance free. However, unlike the Exide and Optima batteries, which are starter batteries only, the Odyssey battery can be used for both starter and deep cycle duty since it is rated for 400 deep cycles (100% depth of discharge to 10.02 volts).

Odyssey Battery Specifications
  PC 680 PC 925 PC 1200
Type 12 volt, Sealed VRLA, AGM
BCI Group Size Universal in fit; non-standard size
Length 7.27" 6.69" 7.87"
Width 3.12" 7.05" 7.87"
Height 6.67" 5.04" 7.55"
Weight 14 lb 23 lb 33 lb
Case material Noryl plastic
Terminals M6 female SAE auto post, 3/8-16 internal thread
Plate composition lead-tin
Plate design flat
Internal resistance 0.0075 Ohm 0.005 Ohm 0.0045 Ohm
Capacity (20 hr) 16 Ah 28 Ah 46 Ah
Reserve Capacity 28 minutes 53 minutes 91 minutes
CCA (1) 280 A 470 A 630 A
CA (2) 360 A 590 A 800 A
Temperature range -40F to +140F (-40C to +60C)
Shelf storage @77F 2 years
Float life @77F 10 years
Float charging voltage 13.5 to 13.8
Cycle charging voltage 14.7 to 15.0
Open-circuit voltage 12.84 for 100% charge; 11.58 for 0% charge
(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


Hawker Energy's web pages: http://www.hepi.com/ and http://www.hawker.invensys.com/
The official Hawker Odyssey web site: http://www.odysseyfactory.com/
The odysseybatteries.co.uk web site: http://www.odysseybatteries.co.uk/
The Hawker Genesis Application Manual, 5th ed.: misc/hawker-appl-man.pdf (834 KB)
The Hawker Genesis battery charging guide: misc/hawker-sla-chg-guid.pdf (219 KB)
The Hawker Genesis Selection Guide, 4th ed.: misc/hawker-sla-tech.pdf (1020 KB)
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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Except for the small gif and jpg images, the content, images, photographs, text, and multimedia displayed are Copyright © 2000-2003 by Jeff Lucius and K2 Software. All rights reserved. No part, section, image, photo, article, or whole of this site may be reposted or redisplayed without permission of the author.
Page last updated December 24, 2003.