For those thinking of a Computer Power Supply

[kludge]

This seems like a better idea to me...

http://www.parts-express.com/pe/showdet ... er=320-315

[legojenn]

This seems like a better idea to me...

http://www.parts-express.com/pe/showdet ... er=320-315

Now that I am planning a new trailer, I am looking at things that are nice-to-haves for the next build. I was wondering if anything more than a switch is required to alternate between a marine battery and this to power lights, fans, etc in a trailer.

[Wimperdink]

Its a better solution for a bench top wherein some one is testing sensitive electronics, but for someone who likes repurposing stuff and only needs to run some 12v lights then the computer power supply can be a much cheaper option. That being said, I wouldn't go and purchase a cps for the expressed purpose of modifying.

[kludge]

Now that I am planning a new trailer, I am looking at things that are nice-to-haves for the next build. I was wondering if anything more than a switch is required to alternate between a marine battery and this to power lights, fans, etc in a trailer.

Yes, it can be that simple. Especially if you want to charge from the TV and avoid the expense of an RV-style DC converter/charger. Then at home you can connect the battery into a battery tender/maintainer.

Its a better solution for a bench top wherein some one is testing sensitive electronics, but for someone who likes repurposing stuff and only needs to run some 12v lights then the computer power supply can be a much cheaper option. That being said, I wouldn't go and purchase a cps for the expressed purpose of modifying.

Agreed, I wouldn't go out and buy a new CPS just to convert it, you wouldn't save THAT much, but if I were scrapping and computer and just happened to have it for free, sure why not.

[Lgboro]

If you are willing to sacrifice the ability to safely charge your battery and other convenience features of a regular RV supply a computer power supply will work, but, it is a far inferior system to a specialized RV power center. By the time you incorporate the safety features and convenience into a computer supply centered system you will exceed what you can purchase an RV power supply. Just not a place I choose to cut corners if there is such a place.

[Dale M.]

Something to keep in mind.... Computer power supplies are set to 12 volts (Period) most marine and RV accessories are designed to run on 13.8 volts (fully charged wet cell battery). While this will work, and probably will not be a problem, if you are trying to charge a wet cell battery (aux power) battery will it will not ever be fully charged... To charge a battery you must supply a charge voltage at least 1 volt above battery voltage, so a 13.8 volt battery requires at least 14.8 volts to take a full charge....

Just saying....

Quite frankly a computer power supply would be the last thing I would consider as a DC voltage supply in a travel trailer....

Dale

[Wimperdink]

Don't charge a battery from one. First there is no regulator to stop charging when the battery is full and I agree that you need 13+v to effectively charge a battery. Also, most 12v appliances only need 12v or they would be 13.8v appliances. Yes they will operate safely up to whatever rate your alternator generates but are designed to work at 12v too.

Use the cps to operate lights and phone chargers, and a small cheap battery tender to keep the battery charged. If you don't know how to use relays to separate the power sources then ask or set your wiring up to manually unplug from the battery and plug into the cps when switching from ship to shore power. Still no need to scare people away from a cheap viable solution.

[Bogo]

Another problem with most computer power supplies is they often have a minimum amount that the power supply must be outputting or it won't regulate the voltage properly.

As others have said, it likely isn't worth it to buy one for the purpose. A RV converter/battery charger would be a much better purchase. 15 to 20 amp output ones aren't that expensive. Combine it with a small marine RV battery and you can go hookupless for awhile.

As for voltage, most car cellphone chargers, etc. will work from at least 15 VDC down to 11 to 9 VDC.

To allow an lighter outlet to be powered from either of two sources, you can use an ON-ON or ON-OFF-ON SPDT switch controlling a lighter outlet. Wire the center +12VDC pole to the common lug on the switch, and other two poles to the battery, and CPS respectively. The grounds would need to be all tied together. Optionally a DPDT switch could be used. The ON-OFF-ON switch would allow the outlet to be switched off when in the center position.