Deep-cycle applications

Another feature of AGM separators is their compressibility. With compression of the plate and separator stack, this AGM property guarantees good plate-separator contact, even if the plates are not perfectly smooth. Also, battery assembly is facilitated since the stack can be easily inserted into the cell after compression to a thickness lower than the cell dimension. An undesirable result of the compressibility is that the AGM separator does not exert sufficient resistance against expansion of the positive plate during battery cycle-life. This expansion is particularly prevalent in deep-cycle applications and can cause the battery to suffer premature capacity loss (PCL) via reduced inter-particle conductivity — a phenomenon known as PCL-2 [7]. In the literature, two additional characteristics, which are related to the PCL-2 failure mode, are discussed, namely, AGM separators shrink when first wetted with electrolyte and their fibres can be crushed at high pressure levels [8-10]. These features result in a loss of separator resilience, i.e., a lessening of the ability to display a reversible spring effect. 

Fig. 9.20. Three categories of premature capacity loss (PCL) in deep-cycling applications.

Cost. Although VRLA is expected to settle at about 25% higher cost than flooded, there may be some applications where this cost increment is acceptable. High-capacity, deep-cycle applications are one case where low-cost automotive flooded batteries cannot usually match VRLA performance, but where alternative batteries that cost an order of magnitude more are not feasible. In this comparison, the lower cost of VRLA relative to Ni-MH or lithium batteries must be weighed against the higher mass and lower reliability of VRLA, but should the mass and life be within... 

Deep-cycle batteries store and deliver energy for motive power applications, such as golf carts, forklift trucks, and airport service vehicles. Use of batteries to... 

The recharge voltage on this type of cell is lower than that of other types of lead-acid battery. This is probably the most sensitive cell in terms of adverse reactions to overvoltage charging. Gel batteries are best used in very deep-cycle applications and may last a bit longer in hot weather applications. If the incorrect battery charger is used on a gel cell battery, poor performance and premature failure are certain. 

In SLI lead-acid batteries for automobile applications, SBC in negative plate is the preferable material for the anode coating, whereas the 4BS compound is preferred in deep-cycle lead-acid batteries. After curing of negative plates, they are all converted to a lead electrode. 

Many types of automobile vehicles (see examples in Figure 10.5) use lead-acid batteries either for SLI purposes or engine powering. The first type of application uses SLI batteries, and the second type uses deep-cycle batteries. Both SLI batteries and deep-cycle batteries use exactly the same chemistry for their operation. The difference between them is mainly their design. 

Batteries for traction and deep-cycle applications use cells with either pasted or tubular positive plates. In general, the performance of the two types of plates is similar, but the tubular or gauntlet plates show lower polarization losses because of the larger active surface area, better retention of the positive active material, and reduced loss on stand. The loss of capacity on stand at room temperature for the two plate stmctures, as measured hy the drop in specific gravity, is shown in Fig. 23.26. 

Nickel-zinc provides the lowest-cost option for a long-cycle-life alkaline-rechargeable system. The nickel-zinc system is suited for mobile applications such as electric bicycles, electric scooters and electric and hybrid vehicles or other deep cycle applications. Nickel-zinc may also replace other nickel based batteries with a less expensive system. 

Nickel-zinc batteries may be useful for military application requiring deep cycle capability. Nickel-zinc batteries may also be employed in torpedoes, swimmer delivery vebicles, and other submersibles. Nickel-zinc has long cycle life and low cost and meets the deep cycle requirements of torpedoes and submersibles. 

Special formulations have been developed for cementing operations in arctic regions or for deep water applications [206,208,256,720,739,1792]. In low-temperature formations, wherein the cement is subjected to freeze-thaw cycling, freezing-point depressants must be added. Salts may serve as such, but traditional organic freezing-point depressants, such as ethylene glycol, also may be added [1022-1024]. 

Flaving had over 150 years of technical development behind them, lead-acid batteries can be custom-tailored to specific applications, such as those requiring deep discharge cycles (e.g., where the batteries are used as the sole power source for electrical equipment) and for battery backup uses such as in large uninterruptible power supply systems in data centers. Moreover, lead-acid cells not only have low internal resistance but also experience no memory effect as do some more exotic cell designs, such as NiCads. This enables these cells to produce enormous currents and have a moderately long, predictable life.1... 

Other cycles can be horizontal one that does not deliver new user-visible functionality but instead carries a minimal use case through increasingly deep layers of the application and infrastructure components, exercising all communication channels. An example is a single user interaction carried from the user interface through the business object layer via an object request broker (ORB) to the applicable databases and back. 

Beard BL, Johnson CM, Skulan JL, Nealson KH, Cox L, Sun H (2003) Application of Fe isotopes to tracing the geochemical and biological cycling of Fe. Chem Geol 195 87-117 Bender ML (1990) The delta-O-18 of dissolved O2 in seawater - a unique tracer of circulation and respiration in the deep-sea. J Geophys Res 95 22243-22252... 

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