Portable
Power Source
Projects ----------------- Power Source Module |
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COMMENT??? Got A Question??? A Click on the Wizard opens Technical questions or just want make |
| One of the problems many face out in the field is a reliable source of power to run lights and equipment. Sure, most portable equipment has its own internal battery and is easy to carry around. But there are times when it is advantageous to set up a control center and operate larger professional type equipment. You may want to put a camera some distance away and remote view it on a monitor. Some EVP work requires the mikes be placed in a room away from a stereo or multi track recorder. Most of this kind of equipment is not the type you would carry around because it is large, bulky, and requires considerably more power than some of the portable gear. Some may even not use batteries relying instead on 120 VAC power. |
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Another concern some have is battery life. It Seems like the batteries are always running down just when you need them. Is it because you used them more than you thought or has some force drained them? That is another discussion for another time. In any event, more reserve power is what you need to insure against this. and it would be a big help if you could monitor the state of the battery and be able, with the flip of a switch, bring in another fresh battery to keep things running smoothly.
The Power Source Module is the solution to those problems. It is a portable power supply built into a hand cart which can be taken wherever a need for power arises. Dual batteries provide both adequate power and redundancy to keep your other equipment running through a long investigation. It includes a 120 VAC inverter to supply 150 watts of AC for those devices intended to be used on normal house power. A built in charger will replenish the batteries after the investigation, and a utility light is mounted on the handle to aid in setting things up for those investigations that take place at night.
Construction of the device is quite easy. Exact dimensions and layout is not critical. The picture above shows the physical unit, its wheels and handle comprise the most complex part of the project. At the top of the handle a bulb mounted inside of a semi-clear film canister is used as the utility light. The two batteries are placed inside the box at the bottom and the wheels and axle mounted at the rear as shown.
The schematic is shown above. As built it utilizes two 12 Volt deep cycle batteries. If you want you can forgo the redundancy and use just one, however the total operating time will also be cut in half. Simply connect the two Positive battery lugs together and the two negative lugs likewise when installing them on the battery posts.
Three output receptacles are provided for 12VDC. These provide for external devices intended for 12 Volt operation to be plugged in. A large value capacitor is provided to allow for filtering to prevent interaction between various loads. The two switches, load and charge, select which battery is being used for each function. The use of a two position power switch for these functions permit a depleted battery to be removed while the system is in operation. This battery can be taken off-site and charged before being returned to the module. This allows for continuous uninterrupted operation. It is also possible to charge one battery while the other is being used.
Finally, the 120 VAC inverter is mounted on the box. This is a separate unit purchased and placed as desired. It can either be plugged in as one of the loads or may be hard wired across the output connectors if desired. The recommended size is 150 watts; however a 250 watt unit could be utilized with some reduction in battery life.
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The photo shows the control panel on the top of the box. The inverter is on the right and is shown plugged in to one of the output connectors.
The meter and selector are to the left center of the panel. |