Low Battery Light comes on with fully charged battery.

The yellow LED illuminates when the voltage at the DewBuster™ Controller falls below 11.0 volts. Any electrical wiring will lose voltage (voltage drop) as current travels through it and the higher the current the more voltage loss occurs. Normal resistance in the DewBuster™ Controller's power cord and fuse may result in as much as 1/2 volt loss, meaning the low battery light could begin to illuminate when the battery is at 11.5 volts. If you have an elaborate power setup with switches, fuses, and other connections there will be a voltage loss as current passes through each item.

To locate a problem heater strip do the following:

Do not plug any heaters in yet. Unplug the temperature sensor and turn the control knob to maximum so the DewBuster™ Controller will send full power to the heaters. Keep the DewBuster™ Controller in this setup for all of the following troubleshooting because you will only see voltage drops when maximum current is flowing.

One at a time, plug each of your heaters into the AUX or MEDIUM POWER heater jacks while observing the yellow Low Battery  light. If the light comes on when a heater is plugged in, then that heater could possibly have a short in it, but for now just leave it unplugged and plug the remaining heaters in. If you are able to plug in all heaters except one, then that heater may have a short in it. Shorts may be intermittent so if the yellow light does not come on try wiggling and twisting each heater cable near the RCA plug to see if this makes the yellow light come on.

If one particular heater made the yellow light come on, then unplug all heaters and then plug in just the heater that is suspected of having a short. If the yellow light comes on then that heater most likely has a short. Unplug it and check it with an ohmmeter for a short. A 14" heater will measure about 2.5 Ohms, 8" to 12"  heaters 4 to 8 Ohms, 3" to 5" heaters 10 to 20 Ohms, and small heaters 20 to 100 Ohms. As you can see, the larger the heater the lower its resistance should be, but if any heater reads less than 2 Ohms then it definitely has a short in it. On Kendrick heaters the most common location for a short is inside the RCA plug but this is very easy to fix.

If the yellow LED seems to come on when many heaters are plugged in rather than being isolated to one particular heater, then it may be that the power source, wiring, or connections are causing the problem. The following procedure will locate the problem:

Turn the control knob fully clockwise and plug in all heaters so that maximum current will flow as you take the following voltage measurements:

1. Measure the battery voltage directly at the battery posts. This voltage should be above 12.5 volts on a fully charged battery under load. If the voltage at the battery posts drops below 12.0 volts then the battery needs to be recharged or it is not able to handle the current flow. If you are using a power supply, take the measurement at the output terminals of the power supply. If the power supply voltage is below 12.0 volts then it is probably not big enough to provide the current being used by the heaters. If the above test revealed that the power source was unable to provide enough current, then try plugging the controller into the cigarette socket in your car and the yellow light should not come on.

2. If the voltage was OK in the above test, then measure the voltage at the DewBuster™ Controller (see diagram above) by touching the red lead to the inside of any RCA jack and the black lead to the outside terminal of the RCA jack. If the voltage at the DewBuster™ Controller is less than battery voltage then this indicates a voltage loss in the wiring or connections. If so, then measure the positive and negative side voltage drops as shown in the diagram above. With a large dew heater strip the positive side may read up to 0.5V drop and the negative side may read up to 0.1V drop. If it reads more then there is a problem. By measuring the voltage across each connection, switch, fuse, etc. you can determine where the voltage losses occur. The fuse in particular will cause a voltage loss due to it's internal resistance, and the smaller the amperage the higher the resistance will be.

After performing the above checks, if you have not isolated the problem, contact me with the details and I will help you figure out the problem.

Solutions to common problems:

• Incorrectly positioned spring in the cigarette plug. Current controllers use the cigarette plug shown above. The spring must be inserted into the plug first, then the fuse as shown above. If the spring is inserted in the wrong order it will make a poor connections and the yellow light may come on.
• Loose fitting cigarette plug. The plug should stay fully inserted so that the spring loaded tip makes good contact in the socket. Some sockets are sensitive to the rotational position, so try re-plugging in a different position.
• Cigarette plug extension cords and splitters. Many of these are only rated for a few amps and will cause a voltage drop when used with high current devices. Try plugging the DewBuster™ Controller directly into the socket of your battery pack without the splitter.
• Undersized wiring on battery pack. If possible, measure the voltage drop from the battery post to the cigarette plug terminal while the DewBuster™ Controller is drawing power.

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