Needed more power for my networking equipment - Tilted Forum Project Discussion Community

Vigilante · 09-23-2008, 06:47 PM

And of course, I like to keep the budget tight. So I found a 22 dollar lawn/garden (tractor) battery at o'reilly. I bought it originally for starting the generator when the stock battery failed and so did the pull-start. I ended up keeping it though because I knew I could use it for this.

I took the old gel-cell out and made up a cable from an AC power cord to plug into the battery cable internally. Once that was done, I put donut terminals on the other end, then drilled the battery terminals to accept a screw, and screwed the donuts on. I tested the voltage running, then on drain to make sure it would be compatible, then cut a cat litter bucket to set it in, in case of an acid leak.

The equipment, consisting of a cable modem, a cisco 1841 router, a dell gigabit switch and a netgear wireless router all pull about 55 watts total per the kill-a-watt meter a friend has let me borrow. So far it has run those devices for about 20 minutes during a power outage, so who knows how long it will go over time. I don't know yet what voltage the UPS kicks into high alert for, but if it's around 11v, then I might have a couple of hours of run time

Pics.

All set up:

Running voltage:

I wouldn't use a larger battery for such a small UPS because of charge load, but on a larger one that uses 24v (2x12v gel-cells) I might be ok with 2 slightly larger automotive batteries. Not sure how far one can push these, but there's been alot of buzz on the web over this so I don't feel too concerned over the 55w load I put on this one (APC Back-UPS CS 500).

crazybobmarley · 09-30-2008, 02:09 PM

Here's an excellent article on the subject from good ol' Dan

The DIY (or, if you must, "Ghetto") UPS

Upgrade your UPS! (with some car batteries...)

09-23-2008, 06:47 PM	#1 (permalink)
Vigilante Broken Arrow Location: US	Needed more power for my networking equipment And of course, I like to keep the budget tight. So I found a 22 dollar lawn/garden (tractor) battery at o'reilly. I bought it originally for starting the generator when the stock battery failed and so did the pull-start. I ended up keeping it though because I knew I could use it for this. I took the old gel-cell out and made up a cable from an AC power cord to plug into the battery cable internally. Once that was done, I put donut terminals on the other end, then drilled the battery terminals to accept a screw, and screwed the donuts on. I tested the voltage running, then on drain to make sure it would be compatible, then cut a cat litter bucket to set it in, in case of an acid leak. The equipment, consisting of a cable modem, a cisco 1841 router, a dell gigabit switch and a netgear wireless router all pull about 55 watts total per the kill-a-watt meter a friend has let me borrow. So far it has run those devices for about 20 minutes during a power outage, so who knows how long it will go over time. I don't know yet what voltage the UPS kicks into high alert for, but if it's around 11v, then I might have a couple of hours of run time Pics. All set up: Running voltage: I wouldn't use a larger battery for such a small UPS because of charge load, but on a larger one that uses 24v (2x12v gel-cells) I might be ok with 2 slightly larger automotive batteries. Not sure how far one can push these, but there's been alot of buzz on the web over this so I don't feel too concerned over the 55w load I put on this one (APC Back-UPS CS 500). __________________ We contend that for a nation to try to tax itself into prosperity is like a man standing in a bucket and trying to lift himself up by the handle. -Winston Churchill

09-30-2008, 02:09 PM	#2 (permalink)
crazybobmarley Psycho Location: weeeeeeeeeee	Here's an excellent article on the subject from good ol' Dan The DIY (or, if you must, "Ghetto") UPS Upgrade your UPS! (with some car batteries...)