Smart-UPS and charging with a gas generator?

[Anonymous user]

I have owned an APC Smart-700 for many years. I am in the market for a new model.

The problem I have had is the Smart-UPS cannot be charged when power to my house is out and I try to charge the UPS with power from my gas generator - a Honda EM5000SX. The Smart-UPS does not like the input voltage. I have to bypass using my Smart-UPS.

All my radio equipment and house items are happy to run on generator power.

Are there any newer UPS models that will run on most emergency power generators??

PaulF1 

[BillP]

Hello Paul,

Good day to you. May I know how did you confirm that the power from the generator is not accepted by the UPS?

You may want to look at this article discussing the reason why UPS won't operate online:

http://www.apc.com/us/en/faqs/FA158891/

[Anonymous user]

When connected to my generator and powering on my UPS, the UPS would always switch immediately to running on batteries mode. I have forgotten which red light was on the UPS front panel. In reading the UPS manual, I see there is a voltage sensitivity adjustment that might be helpful when trying to run on generator power.

I replaced the batteries on the Smart-UPS 700, but I had a new problem. Even with no load, it always lights up "Overload." This UPS is more than 15 years old, so I have decided to scrap it.

I ordered a new APC SMC1000 Smart-UPS. I'll see how it likes my generator.

PaulF1

[BillP]

I didn't have that bad a problem (Back-UPS XS 1300), just an occasional cut-out (usually when there was a sudden change in the load on the generator).

I put an APC Line-R 1200 AVR unit between my Back-UPS and the generator - that seems to have done the trick.

[Anonymous user]

I was going to suggest lowering the sensitivity on your existing UPS. Even though you've decided to replace it, it's very likely that you'll need to do the same thing on the replacement. And to be honest, even that may not be quite enough if the generator's output waveform is noisy or distorted (as many are at particularly light loads, or when a heavy load first starts up).

The caveat here is that greater distortions and voltage fluctuations may reach your equipment as a result.

You can also adjust the UPS's transfer voltages, in case your generator's output varies more than the default settings will tolerate.

You may also be better served by a true dual-conversion (or "online") style UPS, where the inverter runs at all times and the incoming power is only used to keep the batteries charged. Unfortunately, I don't think APC has any "small" UPSes with this capability.

[sbagdon]

>You may also be better served by a true dual-conversion (or "online") style UPS, where the inverter runs at all times and the incoming power is only used to keep the batteries charged. Unfortunately, I don't think APC has any "small" UPSes with this capability.

That was going to be my suggestion, yet as you mention, it's hard to find a double-conversion UPS below 3000kva... and they aren't cheap, usually. We tripped over a SURTD5000RMXLP3U, paying basically weight for it (untested, and they didn't have the plug to test it), and had to replace the batteries (RBC140 with 16 batteries), and the thing is a beast. it'll take just about any crap you send it, convert to DC, then get nice and clean split-phase 240. We don't abuse it, yet it doesn't seem to have any issues with just about any generator brand, including non-inverter generators.