12v supply and smart charger

[HandyAtLeast]

Hello,

New here. First post.

Just wanted to share a great 12v power supply that I found for about $20. It is only 1.5 amps, but it is also a 13.8v smart charger. If the AC fails (is disconnected) it switches to battery automatically. It also has signals out for AC fail and low battery. This thing takes care of a lot of wiring and would make for a quick and simple power option.

See it here: http://www.mpja.com/prodinfo.asp?number=18116+PS
They also sell 12v@7aH sealed lead acid batteries for $21. Here: http://www.mpja.com/prodinfo.asp?number=14819+BT

[Shadow Catcher]

The problem is that this is meant for a battery back up for say an emergency exit sign. this would be sufficient for a couple of very small LED lights but not much more as you have a grand total of 20 watts available.
You need to do an assessment of what your exact needs are likely to be and then increase that estimate by some factor. I am assuming $$$ are a factor, even so buying what you will need is probably the best policy i.e. http://cgi.ebay.com/ebaymotors/45-AMP-R ... ccessories

[GuitarPhotog]

I'm pretty cheap, but when it came to a 12 VDC power supply/battery charger, I decided that the minimum acceptable one was the WFCO 8725. It supports charging a battery (up to 10 A charge current), 3 additional 10A 12 VDC circuits, and up to three 120 VAC circuit breakers.

I could not build all that for the <$100 that the WFCO cost at RVAdventure.net.

<Chas>

[bdosborn]

3 times the output for the same amount of money:

Real Battery Charger



Bruce

[HandyAtLeast]

I was thinking on a small scale for some lights, a radio, and maybe a small fan. It is intended for a UPS system, but would charge any lead-acid or lithium battery(s). I was more interested in it for the smart battery charging capabilities and its ease for wiring, mounting, and low battery signal. This manufacturer also makes higher wattage units. I found a 55w one for $16.

[bdosborn]

I'm not sure its up to the conditions in a trailer, dusty and lots of vibration. Also, at 0.5 amps charging, it would take a week to charge a group 27 battery. You should do an inventory of your electrical usage:

Battery Worksheet

I think you'll find that 7 amp-hrs is pretty small. Most people use that much in an evening. But, you might be able to get it to work, let us know how it turns out if you use that setup.


Bruce