Frequently asked questions

What is the true output current of the Chargetek products? How much charging current will be available for each of my batteries?

This question is asked repeatedly by many people in the market to purchase a charger. There is a lot of confusion and justifiably so based on how chargers are specified and marketed.

As an example, let’s discuss the TPRO-320. It is a three-output charger with all outputs completely isolated. It is specified as a 20Amp charger. All outputs are sensed using microcomputer control to determine the state of charge of each battery. If, for example, one battery is deeply discharged and the other two are nearly charged to full capacity, then the TPRO-320 will provide the full 20A of charging current to the deeply discharged battery. This on board intelligence and ability to provide full charging current to any output differentiates the TPRO-320 from other competitive unit.

What is a battery charge cycle?

A battery charge cycle describes how a battery charger returns the capacity to the battery. Different battery chemistries, such as lead acid, Ni-Cad, etc. require different methods of charging. The CT 500 and CT2000 has a three state charge cycle which most lead acid battery manufacturers recommend as the best and most efficient way to return full capacity. Please refer to the figure below.


Stage 1: Constant current charging or bulk charge mode

Assuming the battery is starting in a discharged state, the charger is operating in constant current mode, where the charger current is maintained at a constant value and the battery voltage is allowed to rise as it is being recharged. Approximately 80% of battery capacity is returned in the constant current region.

Stage 2: Absorption mode

When the battery voltage reaches approximately 2.4 volts per cell, or 14.6 volts for a 12V battery, the charger voltage is held constant at this level and the battery current is allowed to reduce. It is this region where the last 20% of battery capacity is returned. This voltage level is maintained until the battery current reduces to approximately C/50 to C/100, where C is the amp-hour rating of the battery. For instance, if it is a 100 amp-hour battery, the voltage should be maintained at 2.5V per cell until the current decreases to 1-2 amps. The exact amount is not usually critical.

Stage 3: Float mode

At the point where the current is reduced to C/50 to C/100, the battery charger enters float mode. Float mode is where the voltage on the battery is maintained at approximately 2.25 volts per cell, or 13.5 volts for a 12V battery. This voltage will maintain the full charge condition in the battery without boiling our electrolyte or overcharging the battery.

Will the charger operation or personal safety be affected by water? Just how waterproof is it?

The Chargetek Charger line is completely sealed and waterproof. Our chargers are fully encapsulated to provide a hermetic seal and environmentally rugged package, which protects it from water, dust and other contaminants. There are no loose parts to shake loose or vibrate in high G or high vibration environments. Chargetek chargers will operate while submerged but we do not recommend it because AC cords or battery wires can be cut or damaged over time, accidental splicing can occur, or other damage during the product life which would expose the user to electrical shock.

In addition, chargers that are designed to operate submerged should be tested at extreme depths. Every 33 feet is of water is equal to the same pressure as atmospheric pressure at sea level. This increase in pressure can force water in microscopic cracks where water would not be able to penetrate at sea level.

How are the Chargetek chargers protected from shock and vibration damage?

Extremely high levels of shock and vibration can be produced in marine or industrial applications. Mechanical shock is generated by the sudden decrease in velocity, such as when something is dropped or suddenly impacted. Vibration is repetitive mechanical movement caused by a periodic or aperiodic stimulus. Electronic product failure can result from either one of these occurrences. Our full encapsulation prevents parts of the charger from any movement, which neutralizes the destructive forces of shock and vibration from damaging our products. The charger is essentially one solid piece with no chance for components to move, shake, rattle or loosen.

Aren’t all encapsulation or potting materials the same?

Absolutely not! You should ask the manufacturer of any product you are considering buying what type of material is used in their product. Our Chargetek line uses only UL approved flame retardant encapsulation material. UL classifies material according to their flammability. Just because a material has a UL approval does not mean it is flame proof, it simply means that it has been tested to one of UL’s flammability classifications. Our material has a 94V-O rating signifying that it is flame retardant. Many materials found in chargers, lighting ballasts and other electronic products have UL approved material with an HB rating signifying they are not flame retardant, but will sustain a flame once ignited.

Why does overcharging damage batteries?

Overcharging a battery occurs when the total capacity removed has been replaced by recharging and the battery remains on charge. This overcharging creates excessive heat which can cause the battery plates within the cells to buckle and shed their active material. The battery will react to the overcharge by producing an excessive amount of hydrogen and oxygen. These gases are the result of the breakdown of the water molecules within the electrolyte. The water that has been displaced by overcharging can be replaced in a serviceable (non-sealed) battery, but, in the maintenance-free sealed batteries, permanent capacity loss will result.

Excessive discharging a battery can also damage a battery. The amount of discharge a battery can have without damage depends upon the chemistry of the battery, but in general a lead acid battery will not tolerate as deep a discharge as a Ni-cad battery or Ni-mh battery. Sealed lead acid batteries function best if they are discharged to only about 85% of nominal voltage (10.2V on 12V battery).

What is sulfation of batteries?

Sulfation is the formation or deposit of lead sulfate on the surface and in the pores of the active material of the batteries’ lead plates. If the sulfation becomes excessive and forms large crystals on the plates, the battery will not operate efficiently and may not work at all. Common causes of battery sulfation are standing a long time in a discharged condition, operating at excessive temperatures, and prolonged under or over charging.

Do I ever have to disconnect the Chargetek chargers from the batteries?

Absolutely not! On the contrary, with our chargers connected, your batteries will be fully charged and ready to go during short term or long term usage and storage. Our chargers were designed to work for you, not you working for them. Chargetek chargers are fully automatic and self-protecting which sense the state of charge of the batteries and provide the required current and voltage. Just plug in your charger; watch it play and walk away! Let the charger do all the work after that.

What safety features does the Chargetek product line have?

Our Chargers were designed with safety first in mind. The TPRO, CT/CK150 and CT500 product lines are certified to UL/CSA 1236, a very demanding marine specification. Our RTIC line is in process and will be certified by 12/1/03. All additional models will also be certified to this specification. In addition, Chargetek products are fully protected against reverse polarity, output short circuits, no spark hookup and over temperature protection. The chargers are also ignition protected, which is a must for any marine charger. Chargetek chargers will not generate sparks when connected to the batteries.

Why are the high amperage Chargetek chargers so small and light weight compared to other heavier and larger competitor products?

The Chargetek Charger line was designed using the some of the latest technology in high frequency power conversion. Traditional battery chargers use large and bulky 60Hz line frequency transformers, which then power very inefficient linear regulators to provide battery power. Our chargers use very efficient, high frequency switching technology to minimize size, weight and cost and increased performance. You can easily see this by comparing our charger size, weight and features for the same power level to some of our competitors.

How can I extend the life of my battery?

By following some simple tips your battery can provide years of reliable service. One simple practice is to maintain the full charge on the battery at all times. A fully charged battery will gradually lose its capacity, the rate at which this occurs depends upon the exact battery and type. Sulfation will occur if the battery is not charged for a long period of time and the battery may reach a point where the battery will no longer accept a charge.

As mentioned in a previously, overcharging your batteries for an extended time will damage the batteries plates and boil electrolyte. Unfortunately, many battery charging and maintenance devices are not designed to be left safely attached to your batteries for more than a day or two at a time. All Chargetek products are designed to be connected to the batteries indefinitely.

What is the Chargetek warranty and repair policy?

As a consumer, the manufacturer warranty covering your purchase should be scrutinized and fully understood. We record and track each charger sold by a unique serial number or day code, depending upon the product. Our warranty policy provides you with a new charger if any failure occurs during the two-year coverage period. If you have any problem the two year warranty period, we will exchange your unit for a brand new one.

CT 2000 product information

The recall for the CT2000 has officially been completed by the CPSC. Fortunately, there has been no property damage or injuries as a result of the defect and the problem has been corrected. However, if you still have a CT2000 that corresponds to the serial numbers in the press release below or manufactured in the years of 2001 or 2002, do not hesitate to return your unit to us. To arrange for a free replacement or if you have any questions, please contact Chargetek at (866) 482-7930. For more information, please click here:



   Chargetek, Inc.

1860 Eastman Avenue Unit 109
   Ventura, CA 93003
   Phone:  (805) 482-7930
   Fax:  (805) 482-7936
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