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diy solar

Testing an APC 600W UPS by powering my fridge

Fridge nameplate is 11.6A but my kill-a-watt measures 0.9-1.0A when running.

The SUA1000XL easily started the fridge, but oddly only ran for three hours before having a low battery warning. This matches the 100W run graph with no external batteries connected. I inspected the external 35AH battery pair and discovered the inline 25A fuse I added was blown. Evidently the 35AH pair got the compressor started just as the fuse blew, and it continued running on the 18AH pair.

I inspected the APC inline fuse on the 18AH pair and it was 100A? No way the battery wires are rated for that. Also at 25V = 2500W on a 800W UPS? Now I am wondering what I should fuse the 35AH pair. Might move the 100A fuse to the 35AH pair and fuse the 18AH pair at 50A.

I inspected the inline fuse on my SUA3000XL and it was 140A? At 50V = 7000W on a 2600W UPS? APC sure isn't shy about fusing their XL UPS’s.
 
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I'm the guy thats been mucking with APC inverters for quite a while, you have to reprogram them so they don't shut down due to too short calculated run time, all you need is a APC serial cable and a computer with a serial port.
I am tempted to try this with the BR1000MS however plan to stay with the XL models that are specifically designed for external batteries.

Also when the SUA1000XL deep charges it automatically runs the cooling fan to prevent the unit from overheating. The XL models are bulletproof.
 
Thanks for the link.. By chance, and the battery meter be calibrated any for the larger battery banks ?
Mine shows empty all the time.
 
What is the model number of your APC 1400?

Alternately I am looking at a SUA1000XL that is factory setup for continuous run with external batteries. Stupid expensive new so am looking for a good used one. Not approved by Bernie Sanders.

Sorry for the delay.
Mine is a SU1400RM2U

MAAST >> What sort of run times could I expect with my set up. 200AH @ 24V Average draw is about 300W to 500W but not constantly..
 
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Thanks for the link.. By chance, and the battery meter be calibrated any for the larger battery banks ?
Mine shows empty all the time.
Here is another variable I learned on my golf cart system (see this thread). When connected to solar with a light AC load the battery indicator will flash one bar. This is not from low battery, but instead excessive battery voltage.

My fridge compressor switched off so I had minimal power draw at the time. The high battery voltage messed with the internal electronics so the SUA3000XL is now very resistant to start. When running on solar make sure you have a decent load on the UPS. Or disconnect the UPS.
 
Delmer >> that's interesting to know.. That's what mine is doing.. 1 bar flashing..
So if the voltage gets lower will the meter start to work properly ?
I'll probably just install an external SOC meter.
At least with the higher end voltage, the inverter won't shut down.....yet.
 
Delmer >> that's interesting to know.. That's what mine is doing.. 1 bar flashing..
So if the voltage gets lower will the meter start to work properly ?
I'll probably just install an external SOC meter.
At least with the higher end voltage, the inverter won't shut down.....yet.
Per my Golf Cart Show & Tell:
* Using the solar panels measured 52V at the battery while running. However the “battery charge” only has one blinking bar indicating the battery pack is near dead.
* Sun went behind the clouds and the battery dropped to 51V. The “battery charge” stopped blinking.
* Sun came out and battery climbed to 53V, UPS stated blinking again.

The UPS is setup for AGM batteries, and my golf cart has FLA batteries that operate at a lower voltage. Non-solar operation only displayed a couple of bars.

The UPS never shutdown from high battery voltage. However after I manually turned it off, it was then very resistant to restart.
 
I'm gonna try something when i get home today,, just for giggles, i'm going to plug up the inverter, just to see what it will do.
I think i vaguely remember once...i had put a set of 35Ah on this same unit,,and the battery level was down to 1 bar, but after a few hours of charging the bar went up to a full charge.. I'm gonna try that and see if it changes any..
 
MAAST >> What sort of run times could I expect with my set up. 200AH @ 24V Average draw is about 300W to 500W but not constantly..
A quick number crunch using 400W and 100AH (50% of bank capacity) gives a roughly 6 hour run time.
 
Thanks... can you explain how you come to that,, so i can learn and practice figuring things out..
math never was a strong subject for me..
My charge controller tells me that i generated 3,365W today.
Does that sound plausible from 885W @ 120VDC in and 24v out.
 
Thanks... can you explain how you come to that,, so i can learn and practice figuring things out..
My charge controller tells me that i generated 3,365W today.
Does that sound plausible from 885W @ 120VDC in and 24v out.
400W = 24V x 16.7A so I just divided 100AH by 16.7 Watts = Voltage x Amperage

I'm assuming you mean 3365 watt-hours, but it seems a little high for 885W but doable depending on where you live and your sun conditions.
 
Yes, Watt hours..
Well, I am in NC, and it claims that i should get 5 hrs peak sun..
I do get about 1 or 3 hours of non peak sun as well.
I'll check again this afternoon and see what it says.
 
I might just try to see if mine will start a fridge.. May try it sometime this week..
 
By chance, and the battery meter be calibrated any for the larger battery banks? Mine shows empty all the time.
Just realized I never answered your question. The SUA1000XL is designed for external batteries, and when it performs a routine self-test it will automatically correct the battery display. No mucking around with the serial port required.

However…the battery display is calibrated for AGM. When I connected my SUA3000XL to my golf cart FLA it will display low.
 
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