Standard Kendrick Dual Channel Dew Controller - 2x Channels 4x outputs

The Kendrick standard dual channel dew heater controller is used with Kendrick dew heater strips, to warm your telescope, spotting scope or camera lens, eliminating fogging or dewing. It’s very simple, easy to use, compact, and lightweight. There are 4x  RCA jacks on the controller into which you can plug your heater strips. For example, you can keep the main objective lens of your small telescope or camera, an eyepiece, a finder scope and a guide scope – all condensation-free!

Whether you’re an astronomer or photographer, you can keep your optics free of fogging in damp cold conditions.

The Standard Dual Channel has a ton of new features but is really simple to use! As well, it can handle more power and use that power more efficiently! We are very excited about this newest addition to our Dew Remover System!

Features & Specifications:

• Rugged Plastic Case with modern styling.
• Zero to 100% heater control.
• Fused onboard. Auto Reset.
• On board protection from over current, over temperature, over voltage.
• LED overcurrent indication at both outputs.
• 10 amp capacity (5 amps per channel).*
• 6' detachable fused Power cord. Cord is fused at 7 amps.
• Reverse polarity protected.
• On/off switch (no other dew controller on the market has this).
• RFI (radio frequency interference) free. A critical feature for astro imagers!
• Pulse Width Modulation duty cycle control.
• 4 outputs, 2 for each control knob.
• LED Power on indicator for both outputs.
• Low voltage cut-off control with LED indication (a Kendrick standard!). **(See below IMPORTANT NOTE on this feature).
• Mosfet transistors built on board and on EACH output (no voltage drops!). Get the best possible performance out of your heaters!
• Velcro attachment. Parts included.
• 12 VDC operation.
• Dimensions: 4" x 3" x 1.35" (1.75" with knobs).
• 1 Year warranty

How it works: The power output can be varied from 0% to 100% with Pulse Width Modulation duty cycle switching. The power going to your heaters is regulated by turning the power on and off many times each minute. For example, when the controller is set to the 50% point, the heaters draw the same amount of current whenever they are on, but they are only on for 50% of the time.

Is it big enough for my telescope? Owners of 12” and larger SCTs may need two controllers – one for the main objective heater and a second for any other heaters you wish to operate. The heater strips for the objectives of these size scopes can nearly max out the power output capacity of the controller by themselves.

* We have fused the power cord at 7 amps even though the controller is capable of amperages of 5 amps per channel (10 amps total). We do not recommend replacing the power cord fuse with a larger fuse as the power input socket is not rated for a higher amperage.

** IMPORTANT NOTE - LOW VOLTAGE CUT-OFF

Firstly, Kendrick does not use Deep Cycle Marine Batteries (DCBs from here-on) in their products but many of customers do use them in the field.

Some of customers who use DCBs have asked to lower (or disable) the Low Voltage Cut-off (LVC) of our dew heater controllers so that they can get deeper into the cycle of these batteries. Some have complained that the LVC feature cuts in too early for their type of battery. There is the belief that there is no harm in taking down a DCB below our controllers 11.6 volt cut-off function.

The truth is that any lead acid battery, be it a Gel Cell, AGM or flooded batteries such as DCBs, should be cut-off at 11.6 volts. Not doing so increases the risk of damage to the battery and if taken down deep enough into the batteries charge, will ruin the battery. Having said that, the absolute lowest level a lead acid battery can be discharged to, UNDER LOAD, is 10.8 volts but this is not recommended (more on this below).

There is the mistaken belief among many that a DCB can be taken deeply into its charge cycle simply because it is a "deep cycle" battery. This is not true. What "deep cycle" really refers to is the availability of current in situations demanding higher amperage. The user of a deep cycle battery will have an easier time drawing higher amperages (ie: when starting a motor) from a DCB than he would from a gel cell or an AGM. At the amperages used by amateur astronomers, the discharge curves of these batteries is virtually identical and both should be cut-off at 11.6 volts to maintain long term viability of the battery in question. The only advantage to a deep cycle battery is that they tend to come in larger amp hour configurations than AGMs or gel cells.

Also, it is important to note that deep cycle batteries do require regular maintenance that AGMs and gel cells do not. A DCB should be tested weekly with a hydrometer to make sure the specific gravity of the battery is 12.85 and the cells must be inspected regularly to maintain fluid levels in the cells. In situations where access to a high amperage battery is important and safe transportation of the battery can be accomplished without spilling acidic electrolyte from the battery, a deep cycle battery makes sense. In any other case, an AGM or gel cell would be the preferred battery. Kendrick uses AGMs in our power packs, which are non-spillable.

Lastly and very importantly, when any lead acid battery, regardless of type, gets below it safe useable voltage (11.6 volts), the amperage will increase to keep up with the wattage demands of the equipment being used.

For example, let's assume you have a system that requires 50 watts of power and are using a deep cycle battery. At 12 vdc, you will require a current draw of just over 4.1 amps to produce that 50 watts. If you take that DCB down to 6 volts and still need 50 watts of power, you will now force the battery to push out 8.33 amps. More than double the amperage! A situation like this, even though you are still drawing only 50 watts, those extra amps can destroy the fine copper traces on your circuit boards as well as the transistors, diodes and ICs in many of the electronic devices used by amateur astronomers, especially the astro-imagers out there. BE CAREFUL!

If you value your electronics and your battery, do not bypass the Low Voltage cut-off function of our dew controllers with the use of DC to DC converters which step up voltage to 12 volts dc from voltages lower than 11.6 volts dc.

In Closing - Anyone with a battery that appears to be cutting off too early may be damaged through too deep discharge (even once), damaged from poor electrolyte maintenance or is old and no longer serviceable. A battery that is discharged to 10.8 volts regularly and then recharged can expect to get 354 charging cycles out of the battery. A battery that is discharged to 11.6 volts regularly and then recharged can expect to get 900 to 1000 charges out of the battery. A properly maintained battery will last many years.

If you value your electronics and your battery, do not bypass the Low Voltage cut-off function of our dew controllers with the use of DC to DC converters which step up voltage to 12 volts dc from voltages lower than 11.6 volts dc.