Since so many UPS units (~30) found new homes at the recent UCARES picnic, and because I didn't get a chance to modify this batch to add Anderson Connectors or put labels on them, I thought it would be good to compile a short list of notes that may help anyone who ended up with one make good use of it.
- All of them are used. They all used to work. I don't know if they work now or not. If you ended up with one that doesn't work, let me know - I think I can get a few more and can trade you.
- I have used them to charge and maintain 12 volt SLA batteries that were rated from 7 to 100 amps.
- Multiple batteries can be floated from a single UPS.
- They will NOT power a radio bigger than an HT for an extended period.
- You can use batteries (while connected) with higher drain radios without problems as long as the batteries themselves can handle the load.
- They provide about 0.75 A of charging current. A large battery will take a LONG time to charge at this rate.
- They float at about 14.0 Volts. A little on the high side (at the expense of battery longevity), but keeps the batteries fully charged and ready for use should there be a call-out, etc.
- SLA batteries can be left connected to the UPS indefinitely. I would expect about 3-5 years of life (a guess, not a formula) from a brand new battery if left connected and never used.
- They will work as normal UPS units and can provide backup power to a computer, etc. Just be sure to use large enough leads to the battery(ies) (at least 12 ga for full rated capacity).
- To turn the units on when 120 Volt power is not available, press and hold the power button until the unit beeps, then release the button while it's beeping.
Last, here's a close up picture of the way I have modified these UPS units to put connectors on them for convenient use with my batteries:
I drilled a 1/2" exit hole for the wires (which are just barely long enough if you cut the original connectors off right at the end). I used hot glue on this one, but that wasn't the best idea I've ever had. You can see that it is loose now (3 years later) and doesn't keep the wires from moving in the hole. A grommet would have been better, but they are a bit of a pain to install and thread the wires through. I have had better success with using kneadable epoxy putty and just pressing it into place into the hole and around the wires. You may also choose to leave the original internal wiring intact and simply tap into the lines to bring a longer connection out the back. This would allow you to use an internal battery if you want as well as an external one if needed. Keep the wires as short as possible. At its full rated load, this UPS can draw over 30 Amps.
Posts
