How large is the battery?
This is the capacity in amp hours. Some batteries will not have this number displayed on their label. Typical labels will show either CCA (Cold Cranking Amps) or Reserve Capacity in Minutes. Reserve capacity is the number of minutes that the battery can deliver a constant 25 amps to a load.
How is the battery being used? What is the application?
SLI, Deep Cycle, or Standby Power.
How deeply will the battery be discharged?
Shallow cycling (discharging 20% to 50% of the battery s capacity) does not usually require as much recharge power as deep cycling (discharging more than 50% of the battery s capacity).
How often will the battery be discharged?
In general, the more often the battery is discharged, the higher the power you want to use to recharge it. This is particularly important if the battery is deeply discharged. A good rule of thumb for deep cycle batteries is to only discharge them once every 24 hours; otherwise there may not be sufficient time for the batteries to recover between discharges. This has been a serious point of concern for many industrial applications. It has also been a great disappointment to many consumers who have expected to be able to repeatedly discharge large deep cycle batteries and then recharge them with low power chargers.
How much time is available to recharge the battery before it has to be discharged again?
This question is where many industrial systems designers get into trouble. Industrial battery use is usually the most demanding, particularly with electric vehicles that require a mixture of high and moderate rate deep discharges. Time must be allotted not only to recharge the battery, but also to let it rest in a fully charged state between deep, high rate discharges. If you need to replace 100 amp hours in 4 hours, then you need at least 25 amps. However, the truth is that you will need 30 to 40 amps or more and probably 6 to 8 hours because of the way that chargers and batteries behave after the battery is 80% recharged. It is more difficult, and it takes a lot longer to replenish the last 20% of the battery charge than it does to replenish the first 80% of the battery charge. Even if you can get the battery completely recharged in 6 to 8 hours from a deep discharge, it is still not wise to deeply discharge a lead acid battery more than once a day.
Selecting a Charger
Once you have fully considered the battery type, size, and how it is to be used, then you can make a more informed decision about the charger that you need. Deltran s full line of automatic, microprocessor controlled charger products includes both linear regulators and switch-mode power converters, in power ranges from 4.5 watts (6 volts at 0.75 amps) to 600 watts (24 volts at 20 amps, 36 volts at 15 amps, and 48 volts at 10 amps).
Something to Consider before Selecting or Purchasing a Battery Charger
A wide variety of choices are available. Just remember that when you evaluate the cost of a Deltran charger, it s not just the charger that you are paying for. It s the reputation of the company, the service before and after the sale, and the guarantee that if you are not satisfied for any reason, we will make it right. Most important of all is the fact that you are making an investment in your future leisure time by purchasing the convenience of not having to replace your batteries as often as before, no matter what the application. Neither chargers nor batteries are inexpensive. Our experience over the last decade with both individual consumers and large corporate customers has shown us that batteries can last much longer with a good charger. It is not uncommon for individual consumers to double or in some cases even triple their batteries useful life with Deltran chargers. Industrial users occasionally double their battery life, and typically get at least an additional 50% service from their batteries.