Saturday, January 31, 2009

Neat Gadget Meets Mr. Battery

This may turn out to be almost an advertisement. It is pretty seldom that I am really amazed by a gadget but this one really performs and provides a great service.

Here's the setup. All RV's out there run almost everything using 12 volt DC. about the only things that uses 115 AC are the Air Conditioners, the Microwave and the Television. The lighting, the furnace, and the waterpump all are running from electricity supplied by one or more batteries. These batteries are much like the one in your automobile. Pretty much the same size and shape also. The only important difference is they are "deep cycle" batteries and weigh a bit more than the one in your average Toyota.

Automobile batteries are designed to supply very high amperage for a short time. That is because just about thier whole job is to start the engine. The remainder of the time, the engine is re-charging them so they will be ready for use next time. One down side is they discharge pretty rapidly and cannot last very long without being recharged. Another downside is if you discharge them too much they will never recover.

A Deep Cycle battery on the other hand is made with much thicker plates and can last quite a bit longer before requiring a recharge cycle. Thus the name "Deep Cycle". Deep cycle batteries are used when long life is at a premium and there is no constantly running engine to keep them re-charged. Electric vehicles like golf carts and some hybreds are examples. They are also in use in some instances where getting out and walking home might be a little hard. Another name for Deep Cycle is Marine Duty.

The main idea here is how do you keep these batteries maintained when they are not in use for fairly long periods of time. A case in point is the Recreational Vehicle. Whether it is trailer or Motor Home, Bassboat or Houseboat it shares the same problem. It might sit for weeks or months with no activity. Especially in the winter months. By the way, winter is especially tough on batteries. Just plugging them into a charger and walking away will not work. That would tend to boil out all the electrolyte over a period of time. Traditionally, disconnecting the batteries and storing them in a warm location has been one method. Couple that with periodic electrolyte level checks, hooking up to a dummy load for short periods, and cooresponding 2 to 3 hour periods on a charger is about the best method. However that means that you must adhere to a bi-weekly schedule.

OK, OK...lets get to the gadget. It is called the Charge Wizard. The Charge Wizard does almost all the battery babysitting chores for you without you having to be there. It is made by the same people that made the convertor on my trailer. By the convertor on my trailer is a Power Dynamics Model 9160. It converts 115 VAC to 12 VDC and includes a built-in battery charger. When you plug in the "land line" ( that's slang for very heavy duty extension cord) into the power pedestal at the State Park or whever you are camping, it supplies 12 Volts to the trailer and as a bonus charges up the battery. See the picture below:


The convertor is the large grey box on the right. The Charge Wizard is the little black box with the label at the upper left from the convertor.

Here is the secret. The Charge wizard plugs into the convertor and controls the battery charger by going into one of 4 possible states. Normal, Boost, Storage, and Equalize.
Normal is 13.6 volts to recharge a partially discharged battery That is within 90 percent of full charge.
Boost is 14.4 volts to recharge a battery that is under 90 percent.
Storage is 13.2 volts to maintain a float voltage on a fully charged battery.
Equalize increases voltage to 14.4 volts every 21 hours for 15 minutes to keep the battery acid from stratifying and prevent battery sulfication.
All this happens automatically without demanding frequent visits. You should however still check the level occasionally.
I love it when a device actually saves me work.













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