DC-DC Battery Charging for a Mobile Ham Radio
Question:
I have a question inspired by an earlier question on your site about the Isolation Solenoid # PK5231201. My first reaction at reading the post is Is it really that simple? There are many battery chargers on the market that are just full of computer chips, capacitors, and other bits so that I may charge and maintain my batteries and keep them happy. Yet, your answer from the post referred to above seems to say, just attached the trailer battery to power from the tow vehicle. I am not criticizing. Heaven knows I am far from being an expert on the care and feeding of batteries. I was just surprised it could be that easy. My specific application is different from towing a trailer, but charging a trailer battery seems to be about the only application addressing DC-DC charging. Your input would be most appreciated. As part of my volunteer activities, I operate a mobile ham radio. I am often required to operate from a rental van or someone elses private car. The mobile radios can draw up to 10 amps, something I am not comfortable drawing from the vehicles cigarette lighter. I would like to use a small sealed lead acid battery in the car to power the radio, and use a connection to the cigarette lighter to provide low current charging to keep the battery charged. The duty cycle for the radio is about 5 so there is plenty of time for the charger to keep up. My first thought was to simply connect the cigarette lighter to the battery. A diode and 5 ohm resistor would keep the charging current down to about half an amp. So, my question: Is it this simple, or is there a more specialized, electronic solution you could recommend. Thank you for your time
asked by: Jeff E
Expert Reply:
Since it sounds like you will be jumping around with vehicles and you don't have one steady vehicle that you will be using the Isolation Solenoid # PK5231201 is not really a solution for you as it is meant more for a permanent solution that is grounded through the vehicle.
You are correct that you should not use the cigarette lighter in any vehicle for your purpose for safety reasons.
I recommend using some alligator clips and running 10 Gauge Wire # 10-2-1 from the positive and negative sides of your vehicle's battery to the corresponding sides of the battery you are using for your radio. To ensure that you do not pull more than 12 amps you can use the Bulldog Winch Circuit Breaker # BDW20318 on the positive wire run between the batteries. This will flip the breaker if 10 amps is ever achieved. You will simply need to press the button to reset the breaker.
When the vehicle is on this setup will provide a maintenance charge to the battery you are using for your radio. A maintenance charge will basically keep the charge level of the battery from depleting.
Products Referenced in This Question
Deka Jacketed 2 Wire, 10 Gauge, Brake Wire - per Foot
- Wiring
- Wire
- Jacketed Wire
- 2 Wire
- 10 Gauge
- Deka
more information >
Bulldog Winch Circuit Breaker - 10 Amp
- Accessories and Parts
- Electric Winch
- Circuit Breaker
- Bulldog Winch
more information >
Product Page this Question was Asked From
Starter Solenoid - SPST - 12 Volt - 100 Amp - Continuous Duty - Grounded
- Accessories and Parts
- Battery Boxes
- Switches and Solenoids
- 100 Amp
- Pollak
more information >
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