Dyna-Batt and Other Sealed Lead Acid Batteries

by Jeff Lucius

Sealed Lead Acid Batteries
Hawker Genesis G16EP / Odyssey PC 680
Other SLA Batteries
Battery Care


This web page discusses the design, electrical peformance, and mechanical specifications of sealed lead acid (SLA) batteries in general using, as two of the best examples, the Odyssey and Genesis line of batteries manufactured by Hawker Energy. In the Other SLA Batteries section, I list some online sources with the best prices for SLA batteries and also expose the high price markups several companies have for their re-badged SLA batteries. I also document my search for the manufacturer of the battery sold as the Dyna-Batt. At the end of this web page are some tips for caring for your SLA battery.

For many informative web pages, including Car Battery FAQs, Deep Cycle Battery FAQs, Battery Manufacturers & Brand Names List, Battery References & Information List, Popular Battery Myths, Battery Buying Tips, Battery Testing Tips, and much more, please take a look at Bill Darden's web site: http://www.batteryfaq.org/.

The Dyna-Batt "dry cell" battery is sold by Performance Distributors (PD) with a list price of about $155. This is a totally sealed battery that can be mounted in any position and is vibration proof. The exceedingly small size and reduced weight of the Dyna-Batt come with a price though - reduced capacity. While PD rates the Dyna-Batt at 600 cranking amps (at 45F), the capacity is only 16 amp-hours. Listed below are the features that PD claims for this battery.

Key Features of the Dyna-Batt
About six months after buying one of these batteries I became concerned about how to charge the battery while my Dodge Stealth was in "storage" during the winter months. A little bit of reading revealed that the charging method depends on the type of battery. I called PD and was unable to get any usable information concerning the battery type (all they would say is that it is a "dry cell") or the best charging method ("yeah, constant voltage is probably OK"). Not being satisfied with these responses to my questions, I set about to discover exactly what the Dyna-Batt battery is. For information that should concern any current or prospective Dyna-Batt owner, please read the Battery Care section below.

Sealed Lead Acid Batteries

The first thing to determine was exactly what type of battery the Dyna-Batt is. The figure below shows a general classification of battery types with some examples of each in the far right columns. Primary batteries are non-rechargeable batteries like flashlight batteries (typically carbon-zinc dry cells). Rechargeable batteries are called secondary batteries. After examining the characteristics of the various types of secondary batteries, I decided that the Dyna-Batt must be a type of lead acid battery. Because the Dyna-Batt is "dry" and sealed, the final choice was clear. The Dyna-Batt is a sealed lead acid battery.

Battery classifications

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. That acid vapor is what causes those powdery deposits to form near your battery. Unlike flooded batteries, sealed 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 that maintain a 1 to 4 psi pressure within the battery. 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 sealed valve regulated (SVR) and 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 fiberglass-like separator (sometimes called absorbed glass mat, AGM, technology). SLA electrode plates are pure lead grids with small amounts of alloy material (usually tin or calcium) used to strengthen the plate.

While there are many SLA battery manufacturers worldwide, the number of specific SLA batteries commonly available in a size appropriate for use in automobiles is relatively small. The number is even more limited when the actual size and capacity of the Dyna-Batt are considered. The short list of comparable batteries is shown in the table below. The Dyna-Batt I have measures 7.05" long, 2.95" wide, and 6.55" high (without terminals) and weighs 13.5 pounds.

Brand Model Size
LxWxH inches
Plate type Electrolyte
Power Sonic PS-12180 7.13 x 3.00 x 6.59 18 13.1 lead-calcium absorbed
Hawker Energy G16EP 7.15 x 3.01 x 6.65 16 13.5 lead-tin absorbed
MK Battery ES 17-12 7.13 x 2.99 x 6.57 18 14.0 lead-calcium gelled
Panasonic LC-RD1217AP 7.13 x 3.00 x 6.58 17 14.3 lead-calcium absorbed
Odyssey PC 680 7.27 x 3.12 x 6.67 16 15.0 lead-tin absorbed

Besides closely matching the size, weight, and capacity of the Dyna-Batt, the Hawker Energy Genesis G16EP battery is identical in appearance and other design factors to the Dyna-Batt. See the pictures in the next section. The other battery brands look much different than the Dyna-Batt.

Why is this such a big deal? First, Hawker Energy has documented the design, peformance, and mechanical specifications of this battery in excruciating detail. But most importantly for us as budget-minded consumers, the G16EP has a list price of $89.95 and is available at the discount price of

$78 from Portable Power Systems.

If you decide that a battery like the Dyna-Batt is the right battery for you, then consider purchasing the Genesis G16EP or Odyssey PC 680. Peformance Distributors sells the Dyna-Batt at a price ($132 to $155) that is much higher than the list price for the G16EP, which is about $90. The G16EP is available at the discount price of $70 from Portable Power Systems (PPS). PPS also has SAE terminals custom manufactured for Hawker batteries (see their SAE Terminal Kit, part number 30Z101B1, for $11.95). They are identical to those found on the Odyssey line of batteries. SAE terminals for Hawker/Odyssey/Genesis batteries can also be purchased at Battery Mart. The Odyssey PC 680 also suffers from price gouging, often selling at $115 to $145. Battery Mart offers very reasonable prices on a variety of batteries and accessories, including the PC 680 for $86, the PC 925MJT for $106, and the PC 1200MJT for $146. For other reasons to avoid buying the Dyna-Batt, please read the Battery Care section below.

Hawker Genesis G16EP / Odyssey PC 680

Based on the dimensions, weight, capacity and specific design features (some of which are indicated in the pictures below) the Dyna-Batt is certainly a re-badged Genesis G16EP battery made by Hawker Energy. Hawker Energy also makes the Odyssey line of batteries, of which the PC 680 model is a slightly-repackaged Genesis G16EP. The only difference between the the Odyssey and Genesis line of batteries is the external appearance. Internally and functionally the two lines of batteries are identical.

Dyna-Batt Hawker G16EP comparo

Dyna-Batt PC 680 comparo

Dyna-Batt automotive terminal

Once we accept that the Dyna-Batt is a re-badged Genesis G16EP, we can use Hawker Energy's extensive documentation to learn more about the "Dyna-Batt". The information and figures below are from flyers, manuals, and guides that are available as either html or pdf files at the Hawker Energy (an Invensys company) web sites, http://www.hepi.com/ and http://www.hawker.invensys.com/, and from information published about Odyssey batteries (see for example http://www.odysseyfactory.com/ and http://www.odysseybatteries.co.uk/). While much of the information below is for the G16EP/PC680, it is also applicable to the entire line of Genesis and Odyssey batteries and for sealed lead acid batteries in general.

Hawker Energy considers the Genesis battery completely discharged when battery voltage is 10.02 volts, or 1.67 volts per cell (vpc) for each of the six cells. The figure below from Hawker shows the constant current discharge performance of the G16EP (16 Ah) and other models. I extended the 16 Ah curve to reach the 0.01 hr limit (36 seconds).

Hawker Genesis discharge performance

Cranking amps is a general standard for rating the output and capacity of a fully-charged battery. There are three specific standards.
CCA - (cold cranking amps) the number of amps a battery can deliver for 30 seconds at 0F (-17.8C) and not drop below 7.2 volts.
   CA - (cranking amps or sometimes marine cranking amps, MCA) same as CCA except the temperature is 32F (0C).
HCA - (hot cranking amps) same as CCA except the temperature is 80F (26.7C).

For all three of these standards, the minumum battery voltage is far below the level that Hawker states is the end of discharge (EOD) voltage, which is 10.02 volts for the Genesis line of batteries. The Genesis and Odyssety batteries are also rated using this higher standard for discharge performance (that is, 10 volts rather than 7.2 volts). Because the 30 second requirement for the cranking amp standards can be unrealistic for engine starting, a pulse cranking amps (PCA) is sometimes defined. The PCA rating is for a fully-charged battery at 25C (77F) with a constant-current voltage drawdown to 7.2 volts occuring in 5, 10, or 20 seconds. These are considered extreme high-rate discharges and are not recommended for typical or normal battery service. This exceptional high-rate discharge capability is due to the use of thin, flat plates (lots of surface area) and very-low internal resistance (7.5 milli-ohms @ 25C). The nominal short-circuit current for a fully charged G16EP/PC680 battery is 1600 amps or more. The table below summarizes the various cranking amp ratings for the G16EP/PC680 battery.

Genesis G16EP / Odyssey PC 680
  to 7.2 V to 10.02 V
PCA 5 sec 680 510
PCA 10 sec 595 446
PCA 20 sec 525 394
HCA 440 303
CA 360 270
CCA 280 210

This is a good time to note a design difference between starter batteries and deep cycle batteries. Starter batteries have thinner plates and more plates per cell so that there is a large surface area. This promotes a higher discharge rate (better cranking or starting ability) but less tolerance of deep discharges. On the other hand, the thicker and fewer plates found in deep cycle batteries permit a better tolerance of and recovery from deep discharges but reduce the cranking amps available. Nevertheless, a deep cycle battery can be used as a starter as long as it can produce sufficient cranking amps.

The reserve capacity is the number of minutes a fully-charged battery at 80F (26.7C) can discharge 25 amps and not drop below 10.5 volts. The G16EP/PC680 battery has a reserve capacity of 28 minutes. However, a "usable" reserve capacity of only 19 minutes is also listed. I would guess the "usable" rating means the battery should retain enough power to run the engine starter. At 10.5 volts, the battery is discharged and will not turn the starter. The starter in the 3000GT/Stealth, by the way, draws up to 90 amps or more.

The capacity of a battery in amp-hours is determind using constant-current discharge over an extended time period with a drawdown to about 10.2 volts. The time period should always be stated with this rating (usually 20 hours). For the G16EP/PC680 battery the minimum voltage is 10.02 volts. When the drawdown takes 10 hrs, the discharge rate is 1.6 amps, for a 16 Ah rating (1.6 amps times 10 hrs). When the drawdown occurs in less than 8 hours, the amp-hour rating declines as the table below shows for the G16EP (numbers are the same as in the figure above).

Run time to 10.02 v 2 min 5 min 10 min 15 min 20 min 30 min 45 min 1 hr 2 hr 3 hr 4 hr 5 hr 8 hr 10 hr 20 hr
Amps 161.2 90.0 54.8 40.1 32.0 23.0 16.3 12.7 6.9 4.8 3.7 3.0 2.0 1.6 0.8
5.4 7.5 9.1 10.0 10.7 11.5 12.2 12.7 13.8 14.4 14.8 15.0 16.0 16.0 16.0

One thing to consider is that 10.02 volts can be below the recommended operating range of electronic devices. An amp-hour rating to a drawdown to 12 or even 11.5 volts might be more useful for non-motor devices. Hawker does supply a table for the G16EP for drawdown to 11.1 volts.

Run time to 11.10 v 2 min 5 min 10 min 15 min 20 min 30 min 45 min 1 hr 2 hr 3 hr 4 hr 5 hr 8 hr 10 hr 20 hr
Amps 113.2 72.9 47.6 36.0 29.1 21.3 15.3 12.0 6.6 4.6 3.5 2.9 1.9 1.5 0.8
3.8 6.1 7.9 9.0 9.7 10.65 11.5 12.0 13.2 13.8 140 14.5 15.2 15.0 16.0

Genesis/Odyssey batteries may be charged using either a constant-voltage (CV) or constant-current (CC) method, or a mixture of the two. Hawker Energy recommends constant-voltage as the most suitable method. There is no current restriction with a constant-voltage charger. The battery itself regulates the current in the charging circuit. The low internal resistance of the Genesis/Odyssey batteries allows for large inrush current without damage (the very low resistance leads to low temperature levels) and for rapid recharging (comparable to recharge times of nickel-cadmium batteries). If constant-current charging is used, care must be excerised to switch current levels at the correct times.

The way the battery is used determines the voltage level for constant-voltage charging. There are two general types of usage for a battery, cyclic and standby (also called float). The battery application is considered cyclic if the average time on charge is less than 30 days and there is less than 14 days between discharges. In other words, if the battery is recharged at all during a 2-week period, the application is cyclic. Typical automotive use (starting the engine, recharge while the engine is running, and running accesories with the engine off) indicates both cyclic and float-like usage. When the battery starts the engine, the discharge and subsequent recharge is typical of a cyclic use. When the engine is running and the battery is not discharging, a standby (float) use is suggested. The recommended constant voltage charging ranges are as follows.

There are no current limits for the CV charging method. Hawker recommends the highest current that is both practical and economical (high-current chargers are more expensive). For automotive applications, if the engine is not recharging the battery over a prolonged period, which can be days, weeks, or months depending on parasitic losses, a 6-amp Deltran Corporation Battery Tender automatic charger is recommended by Hawker to recharge the G16EP and PC 680. Low-power trickle chargers such as the 1.5-amp Battery Tender from Deltran should be used only for continuous compensation of parasitic losses and not for recharging deeply discharged batteries. If you are not using a Deltran Battery Tender charger, then be sure to check the charging voltage with a hand-held voltmeter. It is very important that charging voltage does not exceed 15 volts. Do not use a battery charger that allows charging voltage to exceed 15 volts. A charging voltage higher than 15 volts at any current level will promote corrosion, which is non-reversible, on the positive plates of the battery and reduce battery life.

Here are some online sources for Deltran battery chargers:

In order to improve charge acceptance in cold conditions and to avoid over-heating the battery in warm conditions, the CV charger float and cyclic voltages should be compensated as indicated in the figure below. Modern automotive alternators already do this to some degree.

Hawker Genesis float charge temp compensation

Any battery loses charge when it is being stored, that is, when no load is attached to the terminals. This phenomenon is called self-discharge. Self-discharge rates are much lower for sealed lead acid batteries than for flooded lead acid batteries. Nevertheless, high temperatures and infrequent freshening charges will ruin a SLA battery. The figure below shows that with cool ambient temperatures, the Genesis and Odyssey batteries can be stored for 8 to 10 years. However, with hot temperatures, storage time is reduced to months or even weeks. Batteries should always be fully charged before storage and have no electrical loads during storage (disconnect the negative battery cable in your car). The Genesis/Odyssey batteries cannot freeze down to a temperature of -40C (-40F).

Hawker Genesis storage time as function of temp

If the Genesis/Odyssey battery has been in an open circuit condition (no charge or discharge) for at least 24 hours, the remaining battery capacity can be estimated by measuring the voltage across the terminals, as summarized in the figure below. This method of estimating capacity may not work well for flooded lead acid batteries (measuring the electrolyte specific gravity is preferred). The battery is at a 100% state of charge if the open-circuit voltage (OCV) reading is 12.84 volts. There is 0% capacity if the reading is 11.58 volts. Care should be taken to never let the battery drop below 11.58 volts. If the battery is at or below 11.58 volts, then it should be charged immediately. Recharging is recommended whenever the battery is at less than 12 volts or at least every 24 months.

Hawker Genesis charged state

There are two types of life expectancy for a battery - float life and cycle life, reflecting the two uses for a battery. For standby (float) applications, a battery can be considered to be at its end-of-life when it fails to deliver 80% of its rated capacity. In automotive applications, this limit could be when the battery can no longer perform above the 80% level of its cranking amp or reserve capacity rating. Because the life expectancy of a battery is of critical importance, the factors affecting the float life and cycle life of a battery must be known and understood.

Factors affecting float life
In automotive use, the battery is in a float application when the engine is running, the alternator is supplying all power needs, and the battery is at full charge. In this situation, the battery is essentially being overcharged using an approximate 13.6 volts so that it remains fully charged. If the battery is not allowed to regulate the current in the charging circuit, as may be the case in an automobile, or if the charging voltage is above the recommended float values, life expectancy can be reduced. Reduced life expectance can be expected also if the battery is subjected to repeated deep discharges, such as leaving the headlights on over night or anytime OCV is below 11.58 volts. The factor that affects life expectancy the most is operating temperature of the battery. The grid corrosion rate increases at higher temperatures regardless of the charge current flowing into the battery. Reduced float charge at higher temperatures can only partially compensate for this effect. The figure below shows the float life of Genesis/Odessey batteries at 13.62 charging volts (2.27 vpc) as a function of internal battery operating temperature. At a continuous 25C (77F) operating temperature, the battery should last 10 years. However, if internal battery temperatures are always above 53C (127.4F), life expectancy will be less than one year.

Hawker Genesis float life expectancy

Factors affecting cycle life
If the discharge and charge times are about the same length, the battery application is a cyclic one. Long periods of battery discharge do not occur in normal automobile use except perhaps for repeated short operating times when the battery cannot fully recharge, if a load is left on the battery (such leaving the lights on with the engine off), or if the battery is not charged yet parasitic loads (computers, clocks, alarms, etc.) are draining charge. Genesis/Odyssey batteries are rated with a cycle life expectancy of about 400 cycles of 100% depth of discharge (DOD), that is, the OCV voltage is 11.58 v or less, if the discharge occurs over a 5-hour period. When DOD is less than 100%, cycle life increases. Cycle life expectancy also increases as the time allowed for recharge between discharges, the cycle time, increases. Reduced cycle time means higher overcharge levels which lead to increased grid corrosion and reduced battery life. Perpetual undercharging of the battery also reduces cycle life.

The Genesis and Odyssey line of batteries feature rugged construction with strong external packaging and pure lead-tin internal composition. 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 having an additional metal case outside the plastic case. 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 absorbed electrolyte 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. No maintenance of the electrolyte is ever required. External deposits on and near the battery due to outgassing are virtually nonexistant.

So, after reading all the above material, is the Dyna-Batt/G16EP/PC680 the right battery to put in the Mitsubishi 3000GT or Dodge Stealth (or any other vehicle for that matter)? The answer depends on what your requirements are. If space and weight savings are important to you, then a small SLA battery is a good choice if you do not run accessories with the engine off or use the car in cold climates. If space and weight are not so important, a larger SLA battery would be a better choice, especially if parasitic losses are a problem or the engine is started often in cold weather. If price is the dominant issue, a standard, generic flooded battery might be cheaper, especially if a large cranking amp rating or reserve capacity are required.

Proper charging of SLA batteries is important to maximize life expectancy and to be sure that the battery is properly charged before the engine is shut off. The 3000GT/Stealth alternator does provide temperature compensation of charging voltage. The charging voltage is not exactly constant but is regulated to stay within a limited range. The table below summarizes the standard values for the stock alternator plus the optimal constant-voltage charge voltage for both cyclic and float charges. The temperatures shown are the operating temperatures of the alternator itself. Overall, the stock alternator does a reasonable job of supplying the correct voltage to recharge the battery after the initial drain of starting the engine (cyclic application).

3000GT/Stealth Alternator Hawker Genesis
Temperature Regulated
CV Cyclic Optimal
Charging Voltage
CV Float Optimal
Charging Voltage
-20C (-4F) 14.2-15.4 ~16.3 ~15.2
20C (68F) 13.9-14.9 ~14.8 ~13.8
60C (140F) 13.4-14.6 ~14.2 ~13.1
80C (176F) 13.1-14.5 ~14.1 ~13.0

As noted above, all SLA batteries have one very serious drawback, they do not like heat. Even moderate temperatures by engine-bay standards, such as 100F to 120F (38C to 49C), can drastically reduce the life expectancy of the SLA battery if it is subjected to these temperatures for any length of time. It will take a while for the internal temperature of the battery to raise to engine bay temperatures. This temperature transfer delay may work favorably concerning the charging voltage: the hotter alternator (presuming it heats up easier than the battery does) puts out lower voltage. The metal case used on some models helps to protect the battery a little from heat transfer. The SLA battery's heat sensitivity may not be a problem unless the car is used for long trips (maybe an hour or more?) or extended race track use. However, intake air temperatures (the battery is located just behind the air filter) usually stay within 10F to 20F of the outside air temperature except when the car slows down or is stopped (measured with a TMO datalogger when I was still using the stock MAS and air filter). It might be more likely for the battery to heat up after the car is parked and the engine heat has a chance to radiate to other other parts in the engine bay.

The high, underhood (engine bay) temperatures of the turbocharged models make it desirable to move the battery away from the engine and into the rear storage compartment. The fact that SLA batteries cannot leak and have very low outgassing makes them ideal for this. Moving the battery out of the engine bay provides much needed space for aftermarket devices like water injection or boost control, plus it marginally decreases the front-heavy weight bias of our cars. Shown below is a stock-sized, 42-pound, flooded battery next the comparatively diminuative, 13.5-pound, Dyna-Batt.

Battery size comparison

The picture above illustrates one problem when changing battery types, the physical dimensions may be different than than the stock battery bracket is designed for. The 10"L x 7"W x 8"H (top of terminals) DieHard battery pictured above fit just fine with the stock clamps and support plate. Adaptations are required for substantially smaller batteries. The stock battery belongs in Battery Council International (BCI) Group 24, which has a 10.25" length, 6.81" width, and 8.88" height (top of terminals) size with a CCA rating of 350 to 625 amps and a reserve capacity of 70 to 95 minutes. Alternate BCI group sizes include 34, 75, 25, 26, 21, and similarly-sized groups. Please note that the CCA and reserve capacity rating of these alternate groups might not meet, or they may exceed, the 3000GT/Stealth stock battery specifications. For some BCI group numbers and specifications look at http://www.exidebatteries.com/bci.cfm and misc/odysseygroupsizes.pdf.

The factory service manuals have the following specifications for the stock battery.

Mitsubishi 3000GT / Dodge Stealth Stock Battery
  Up to 1993 models From 1994 models
Battery type 75D26R-MF 75D23R-MF
Ah (5 hr) 52 52
CCA 490 520
Reserv. cap (min) 123 118
Load test (amps) 240 240

Other SLA Batteries

Sealed lead acid batteries from other manufacturers can offer features and performance similar to the Hawker Energy batteries. Along with the Genesis and Odyssey batteries, SLA batteries from Optima and Exide are suitable for use in automobiles. However, typical SLA batteries like those from Panasonic, Power Sonic, and Yuasa are more suitable for non-automotive applications. The Genesis, Odyssey, Optima, and Exide batteries are designed to produce the high current output required for starting engines, to operate in the temperature extremes found in an automobile, and to better withstand shock, impact, and mechanical vibration. The Excel spreadsheet below summarizes the features of selected batteries from the manufacturers listed above. To print the two tables, you may need to adjust margins and column widths so that the each table fits on a single page (landscape mode).

misc/sla-batts.xls (30 KB)

Selected examples and features of recommended SLA batteries, are listed below. Dimensions and weights are approximate. For a stock-sized replacement, look for BCI Group 24, 34, or 75 batteries. The Genesis and Odyssey batteries have superior float and cycle life compared to the Optima and Exide. However, they pay for this in slightly reduced cranking capacity. For lightweight batteries (less than 30 pounds), Genesis, Odyssey, SVR, and Optima are the only choices. In standard weights (37 to 42 pounds), any of the brands would be a good choice. The Odyssey PC 1200 costs the most but has the smallest size. The Optima 75/35 and Odyssey PC 1200 both weigh in at less than 36 pounds. The Exide batteries offer outstanding cranking capacity, reserve capacity, and a long warranty at a very reasonable price. The AC Delco batteries would also be a good choice for a stock-sized replacement. I have highlighted what I feel are the best values in the three general "classes" of these batteries. In case you didn't notice, there is a fairly direct correlation between the weight of the battery and its CCA rating (17-18 CCA/lb) and Reserve Capacity (~2.1 min/lb for batteries less than 30 lb; ~2.7 min/lb for batteries over 30 lb). If you want, or need, lots of amps, the battery will be (relatively) heavy and large.

Brand Model Size
LxWxH inches
CCA Reserve
Ah (20 hr)
Braille B14115 5.80 x 3.32 x 5.88 11.5 360 - 15 $175
Universal UB12180 7.13 x 2.99 x 6.57 13.5 ~280 - 18 $20
Genesis G16EP 7.15 x 3.01 x 6.65 13.5 280 28 16 $70
Odyssey PC 680 7.27 x 3.12 x 6.67 15.0 280 28 16 $77
SVR SVR28-12 6.88 x 6.50 x 4.88 23.0 600* 40 28 $74
Genesis G26EP 6.57 x 6.92 x 4.96 23.0 470 53 28 $123
Odyssey PC 925 6.69 x 7.05 x 5.04 26.0 470 53 28 $106
Universal UB12350 7.71 x 5.16 x 7.25 24.0 - - 34 $37
SVR SVR33-12 7.75 x 5.00 x 7.25 26.0 500 45 33 $66
Optima Yellow Top 51 9.25 x 5.00 x 9.00 26.0 500 70 41 $115
AC Delco 75P-7YR 9.50 x 7.10 x 7.30 32.8 550 80 ~40 $100
Genesis G42EP 7.78 x 6.53 x 6.72 32.9 630 91 46 $???
Odyssey PC 1200 7.87 x 6.66 x 7.55 35.4 630 91 46 $149
Optima Red Top 75/35 9.31 x 6.81 x 7.63 33.1 650 90 44 $100
AC Delco 34P-7YR 10.3 x 6.80 x 7.80 37.7 650 95 ~48 $100
Exide Select Orbital 75 9.00 x 7.00 x 7.44 36.0 690 80 45 ~$130
Optima Red Top 34/78 10.0 x 6.88 x 7.81 38.8 750 104 55 $125
Exide Select Orbital 78 10.1 x 7.00 x 8.1 38.0 770 95 50 ~$140
AC Delco 65P-7YR 11.9 x 7.50 x 7.60 45.6 800 130 ~65 $100
SVR SVR80-12 10.6 x 6.50 x 6.25 57.0 800 150 80 $111
Odyssey PC 1700 13.02 x 6.62 x 7.68 58.7 930 156 78 $199
* the CCA for these SVR batteries seems out of line with other capacities.

Some online sources to purchase these batteries include the following internet stores.
1st Optima Battery Sales Optima
The Alternative Energy Store Universal (Very low prices!)
Bargain Brothers Electronics Optima (Very low prices!)
Batteriesareus.com/ Optima
Battery Mart Odyssey (Great prices. Great customer service!)
BatteryStuff.com Optima
BatteryWeb.com AC Delco, Hawker, Odyssey, Optima, Panasonic, Power Sonic, Yuasa
Portable Power Systems Hawker, Panasonic, Power Sonic, plus SAE terminals for Hawker batteries (Great prices. Great customer service!)
The Battery Station Power Sonic, Yuasa
Remy Battery Optima
ThunderStruck Motors Optima, Genesis ($49 for G16EP)
West Coast Batteries Odyssey (plus hold downs!)
Wholesale Audio SVR

Interstate Batteries is not included in the above list. Their Extreme Performance line of batteries are full-size AGM batteries that look like Optima or Exide batteries (spiral-wound grids) and deliver 750 to 850 CCA in the $136 to $186 price range. Also, Interstate's Deep Cycle Series and High Rate Series fall into the same class as the Panasonic and Power Sonic batteries: probably OK for accessory, UPS, or wheelchair use, but there are better choices for automotive starter batteries. I did not include Concorde's Chairman Batteries, which are true AGM deep-cycle batteries intended for automotive use. Delphi has a series of full-size AGM batteries with CCA ratings in the 550 to 800 amp range that are not included here. The Champion Vortex AGM is, I think, an Exide battery and so not listed above. SVR Batteries has a line of motorcycle batteries that look like re-badged Yuasa batteries and might be an alternative when a very lightweight battery (less than 20 pounds) is required.

Some owners have had success using these lightweight SLA batteries designed for uninterruptable power supplies, wheel chairs, and general 12V equipment power. These include offerings form Yuasa, Power Sonic, Panasonic, and Universal. As mentioned above, these type of batteries are not designed to produce sustained high rates of current for engine starting, or to resist the longterm effects of vibration. Nevertheless, for their price and size, they may work for some owners and their needs, for example, drag racing or warm-weather daily driving. Examples from Braille and Universal are mentioned in the table above (thanks to Stephen Williams and Troy Carter for pointing these out to me). The Universal UB12180 and UB12350 are particularly interesting because of their very low price. One drawback for automotive use might be the "M5 nut and bolt" terminals this type of battery usually uses. The Braille B14115 includes automotive type terminals, and claims superior performance to the Odyssey PC 680. However, it comes with a Dyna-Batt like impressive MSRP of $175!

Don't get fooled by re-badged batteries!
The Stinger Power2 SP800, SP1000, and SP1700 batteries are just re-packaged Hawker Genesis G26EP, G42EP, and G70EP batteries, respectively. The Stinger batteries have list prices of $215 for the SP800, $260 for the SP1000, and a wopping $385 for the SP1700. OUCH! The Black Panther line of batteries are also re-badged Hawker Genesis/Odyssey batteries with a big price markup. Holley has also gone into the markup business selling the PC925 as the Race Cell Battery with part number 880-105, available at Summit Racing at the discount price of only $199.95! Summit Racing also sells the PC1200 as Holley part number 880-110 for $246.95! WOW! (Thanks, Wayne, for spotting these "Holley" products!) The Batcap Xstatic 800 model looks exactly like a the G16EP (or Odyssey PC 680) and it sells at a suggested retail price of $179 (and I thought the DynaBatt was marked up too much!). The onwer of Batcap, Ray Mackenzie, claims the case is the same but the internal components are unique and assembled at Batcap. Batcap claims an astounding 800 CCA for this 14-pound battery, a capacity that is not achieved by any other SLA battery weighing less than 40 pounds. I recommend potential buyers contact Ray to request substantiation of this claim, or have the battery independently tested (800 A discharge for 30 seconds at 0F with voltage maintaining at least 7.2 V), before purchasing this battery. The Odyssey versions of these exact same batteries sell for $77 for the PC 680, $106 for the PC 925, $146 for the PC 1200, and $199 for the PC 1700. Have I mentioned I like the Odyssey, Optima, and Exide line of batteries?

Hawker Energy Odyssey PC 925 battery

Battery Care

What kills sealed lead acid batteries? Corrosion on the positive plates and sulfation on the negative plates.

A small amount of corrosion, which is the transformation of lead into lead dioxide, occurs naturally when the battery is charging. The product of corrosion, lead dioxide, builds up on the positive plates and reduces storage capacity. Overcharging the battery, either with current too high for the voltage used or with voltage too high at any current level, will cause extra corrosion. In addition, the corrosion rate increases at higher temperatures at any charging voltage or current. Corrosion is irreversable and will shorten battery life.

Some sulfation (the production of large sulfate crystals that bond with the lead in the negative plates) occurs when the battery is discharging. Excessive sulfation is caused by deep discharging of the battery or if the battery is maintained in a continuously undercharged state. Excessive sulfation can sometimes be reversed.

In summary, to maximize the life of your sealed lead acid battery do the following.
In consideration of the last point above, which is strongly emphasized in the Odyssey Owner's Manual, I have peeled back a very small amount of the corner of the Dyna-Batt decal to find that the Hawker Energy decal was removed. This may explain why I have heard several reports of owners having Dyna-Batt batteries that have failed. The decal may be part of the vented and sealed design or the manual may be referring to the plastic itself that the decal adheres to (I am not sure). Because there is no way to replenish lost water in the battery, any venting of water vapor, oxygen, or hydrogen, will reduce battery life. In the Odyssey Owner's Manual, Hawker Energy even says "REMOVING THE LABELED COVER" ... "WILL VOID YOUR WARRANTY". The other two actions that will void the Odyssey warranty, which is full replacement if it fails within 3 years of automotive use (2 years for motorcycle use), is exposing the battery to gasoline or diesel fuel or removing or destroying the battery's date code. This date code is removed on the Dyna-Batt. I have an Odyssey Owner's Manual because I bought a PC 925 to replace the Dyna-Batt when I moved the battery to the rear compartment (2-battery-move.htm).

Performance Distributors also does not provide any information about charging the Dyna-Batt other than saying "don't overcharge it". I suspect many owners are using standard automotive-type battery chargers that may exceed 15 volts and therefore reduce battery life. Charging voltage should not exceed 15 volts unless the battery internal temperature is below 10C (50F). See the temperature-compensated charging chart above.

If the exorbitant price tag is not enough to dissuade prospective buyers from the Dyna-Batt, the warranty violations and complete lack of instructions for proper care should convince them not to purchase the Dyna-Batt from Performance Distributors.

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Page last updated April 27, 2008