1. Home
  2. Electronics Repair
  3. Uninteruptable Power Source Fuse trouble shoot,fuse location etc.

Uninteruptable Power Source Fuse trouble shoot,fuse location etc.

Hi. I have a UPS that is not functioning correctly. It's an APC "Professional Powercell" 250 watt unit that is at least 5 years old. When there is a power outage, it beeps loudly but there is no current to the outlets (computer is plugged to this). I took out the 12 v lead battery and it tests 13 volts. I pushed the "re-set" button. I dismantled the case ("no user serviceable parts) and there is a note to use only the same size fuse. Well there is no indication where the fuse is,and I believe this may be the problem since at one time I had too much stuff plugged in (not being aware of it's 250 W limit). There is an orangish part that looks like a plastic plug-in automobile fuse that says"40" on top and on the solder side says "40A

32V". I checked from this side and it has continuity,plus the element in it appears solid. Would there be a fuse somewhere else? I don't see one. Also I see a "APCC (C) 1993" on the board so maybe this thing is that old. What else would cause this failure? I consider this a learning opportunity,and I am a cheap so-and-so and will not be paying the big bucks for a new one any time soon! Your advice greatly appreciated.-Brian
Reply to
BrianAlex
Loading thread data ...

That is the fuse but there is probably also a circuit breaker on the back panel. If tripped a small blade will pop out. What model is it?

Reply to
Ronbo

t
t
d

e quoted text -

The model is; "Professional Powercell" s/n; C94093679593 and yes, it has the little blade that says "push,reset" around it (which I did). Maybe this thing is toast,but I don't quit on stuff very easily. Thx. BrianA

Reply to
BrianAlex

Re-test the battery under load to see if you still are able to get the nominal 13V.

Bob

The model is; "Professional Powercell" s/n; C94093679593 and yes, it has the little blade that says "push,reset" around it (which I did). Maybe this thing is toast,but I don't quit on stuff very easily. Thx. BrianA

Reply to
Bob Shuman

In my experience, the batteries last no more than 5 years. If this is the original battery, its time is likely up. Test under load or with a substitute and replace for $25 or so.

--
Remove -NOSPAM- to contact me.
Reply to
John Keiser

Most common failure mode of this class of UPS is u/s battery. They dry out due to overcharging. (The charge regimes employed are brutal on batteries, in the interest of fast recovery). They present as fully charged in terms of terminal voltage because they have a very small residual capacity, but can't cut the mustard when it comes to driving the inverter even at idle.

Try connecting an automobile battery instead and see if the UPS functions. That way you can quickly determine whether it is the battery or the electronics causing the problem.

Reply to
who where

the

Unless you test the battery under load, you don't really know much of anything. If it is too hard to connect the battery to the UPS when the battery is out of the UPS unit, use an automobile back-up light or something similar, but smaller than a headlight, and see if the voltage really holds up under load.

Reply to
hrhofmann

s the

OK, glad I talked to you guys. I pulled the battery and found an automobile tail-light bulb and it wouldn't even light that up! So I then checked to see if the leads that normally connect to the battery were supplying current and they are so I guess I'll just find a new Bat. I'm used to testing my AAA batteries and if they read good they are good, I see it's different with these lead ones. Thanks a lot guys!

Reply to
BrianAlex

I got tired of dealing with guesswork on batteries. So, I bought myself a Hanukkah present: West Mountain Radio CBA-II. About $150 including the optional thermal sensor. I've been running discharge curves on various batteries in my collection. I'm mostly interested in how various Lithium technologies operate, but have had time to mess with some 12v 7A gel UPS batteries. There's a rather obvious difference between a new battery and one that's been continuously (over)charging inside the UPS. I plan to post graphs, but I'm not sure of my current settings and methodology, so that will need to wait. For example, I was having problems with Powerpole connector losses when I read comments at:

by Bob WX2NJ (at bottom of page). At the rated 1c (7A) load, the connector resistance resulted in a premature cutoff point.

Anyway, the CBA II is far more accurate and entertaining battery tester than timing a fading auto tail light.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558
Reply to
Jeff Liebermann

OK, glad I talked to you guys. I pulled the battery and found an automobile tail-light bulb and it wouldn't even light that up! So I then checked to see if the leads that normally connect to the battery were supplying current and they are so I guess I'll just find a new Bat. I'm used to testing my AAA batteries and if they read good they are good, I see it's different with these lead ones. Thanks a lot guys!

When you source a replacement battery, make sure that you get one with the correct size terminal blades, not one of the 'alarm-style' types where the terminals are only about half the width. These UPSs pull HUGE amounts of current from the batts - witness the 40A automobile fuse that you found in there - even when the load is light, and it is essential that there is a really good connection to the battery, otherwise, even the small volt-drop that you get from a less-than-ideal connection, is enough to fool the control electronics into thinking that the battery is on its last legs, which then makes the UPS shut back down, bleeping forlornly at you ... Trust me, been there ... :-)

Arfa

Reply to
Arfa Daily

is the

Jeff:

My idea worked, and it wasn't any $150.00 either. I'd rather spend $150 on something more fun, like a new kitchen tv.

Bob

Reply to
hrhofmann

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.