Re-purposed UPS as Inverter

[Supervstech]

I have a UPS fetish with four different systems, three are APC. Show & Tell. This is what I’ve learned so far:

1. Only the APC “XL” models are rated for continuous operation. You can easily identify by the rear external battery connector.
2. Most other consumer UPS’s are designed to overheat shortly after the internal batteries are depleted. Running the non-XL UPS at minimal power, or adding fans to get around the heat issue won’t work. As stated above, the UPS will still shutdown based on a timer.
3. The XL will automatically recalculate expanded battery capacity when using AGM. I have no experience (yet) powering with LiPo.
4. The APC battery display is expecting a normal AGM voltage range. If you connect to solar, the higher battery voltage will manifest as one blinking bar. It's not indicating low battery. Show & Tell.
5. Higher battery voltage can affect the APC capacitors (the little ones, not the big H-bridge ones). This affected my 2700W unit that will no longer boot. My to-do list is to replace them and see if it works.
6. If you want a reliable pure-sine, low-frequency inverter a used UPS is your cheapest method.

My BIG apc 2500XL Is my favorite. It was a monster huge unit about 30” tall, and weighed a ton.
I ripped the thing apart, put the board in a little suitcase, and am working on setting it up for more portable use.

 

[Delmar]

My BIG apc 2500XL Is my favorite. It was a monster huge unit about 30” tall, and weighed a ton.
I ripped the thing apart, put the board in a little suitcase, and am working on setting it up for more portable use.

Great minds think alike. Once I repair my beloved 3000XL beast the plan is to remount the heavy transformers in my golf cart chassis, and make a portable box for the circuit board. The LF design can easily start any power tool where my HF Reliable 2500W struggles.

 

[Supervstech]

Great minds think alike. Once I repair my beloved 3000XL beast the plan is to remount the heavy transformers in my golf cart chassis, and make a small box for the circuit board. The LF design can easily start any power tool where my LF Reliable 2500W struggles.

Heh, built in onboard battery charging!

 

[Happy Joe]

Has anyone here ever re-purposed any UPS's for use as an Inverter ?
I acquired long time ago a new, never used APC 1400 rack mount 24v. it's good for 950W
I like that it can be cold started with out any AC input. I'm using it in one of my small solar projects.
I'm using 3 of the 295 watt panels i got earlier ( Canadian Solar ) and 4 100Ah batteries in a 2s2p configuration ( 24v 200Ah )
I got a good deal on a MPPT charge controller , it's good for 50A.
I got lucky and scored 2 free cabinets. one is a small truck box, the other is a NEMA3 DOT cabinet.
I'll share pictures later on.
I had to disable the beeper in the inverter, and the battery gauge it way out of calibration.
It started off full, but after about an hour the battery gauge showed the pack was flat, but the voltage on the controller showed 28.5v
So the inverter battery level meter is not used to a 200Ah battery....lol ( it is supposed to have 4 7AH batteries..) 24v 14Ah.

I wonder if there is a way to re-prorgram the meter on UPS and silence the beeper.
So far things are working ok,, I only have a light load on it right now.. will add more things later on.
Actually have Another UPS plugged into it, and my TV and DVR. 8 Cameras, the UPS seems very happy, it hasn't acted up a bit.
I thought they might not like each other, but it's doing good.

Yep! back in the stone ages... my first "Power station" was a repurposed UPS... (as you found; disable the power outage beeper or it will drive you crazy).
I put a larger (32AH) SLA battery bank, in an ammo can... this was well before lithium batteries were available...
Then purchased a stand alone inverter to power the compact fluorescent bulb (LED bulbs were very expensive back then.
Lost a couple of inverters to near miss lightning strikes (near hit is a better term, IMO: never camp under lightning struck trees...

...Good luck and have fun!

...life is a trip!

 

[Dacflyer]

I have a UPS fetish with four different systems, three are APC. Show & Tell. This is what I’ve learned so far:

1. Only the APC “XL” models are rated for continuous operation. You can easily identify by the rear external battery connector.
2. Most other consumer UPS’s are designed to overheat shortly after the internal batteries are depleted. Running the non-XL UPS at minimal power, or adding fans to get around the heat issue won’t work. As stated above, the UPS will still shutdown based on a timer.
3. The XL will automatically recalculate expanded battery capacity when using AGM. I have no experience (yet) powering with LiPo.
4. The APC battery display is expecting a normal AGM voltage range. If you connect to solar, the higher battery voltage will manifest as one blinking bar. It's not indicating low battery. Show & Tell.
5. Higher battery voltage can affect the APC capacitors (the little ones, not the big H-bridge ones). This affected my 2700W unit that will no longer boot. My to-do list is to replace them and see if it works.
6. If you want a reliable pure-sine, low-frequency inverter a used UPS is your cheapest method.

My APC1400 runs 24/7 i have an additional fan it keeps the transformer much cooler, I can draw 600W and it gets a lil warm, but not hot.

 

[Dacflyer]

Yep! back in the stone ages... my first "Power station" was a repurposed UPS... (as you found; disable the power outage beeper or it will drive you crazy).
I put a larger (32AH) SLA battery bank, in an ammo can... this was well before lithium batteries were available...
Then purchased a stand alone inverter to power the compact fluorescent bulb (LED bulbs were very expensive back then.
Lost a couple of inverters to near miss lightning strikes (near hit is a better term, IMO: never camp under lightning struck trees...

...Good luck and have fun!

...life is a trip!

"IMO: never camp under lightning struck trees"...... They are already carbonized...great conductor for lighting..lol..
My UPS has 266Ah worth of batteries..