Battery backup for modem/router/phone question

[Kyle1886]

Battery / phone backup with a simulated sine wave UPS.

I have a simulated sine wave UPS that I want to plug my Uverse ATT modem/router into for battery back up. This modem does not have a battery backup like my old modem/router. (battery back up lasted 4 + hours). When I lose power now; I lose telephone.

Since the incoming power is going through an AC adapter block before getting to the modem, I see no reason that I cannot use a modified sine battery back up.

Modem Adapter
Input 120v - 1A
Output 12v - 3A 36 w

I'm assuming the input of 120v is being converted to 12v DC, if that's true then modified sine wave will be okay.

Even if it's not converted, it's only for battery to power the phone/modem should it be needed.

Obviously this is Not one of my areas of expertise. Since I already have the UPS (1350va -810w), why not use it for a small light and the modem/router/phone for battery backup.

Thank you.

Respectfully,
Kyle

[ldsnet]

Since the electronics are not using the input frequency or wave for timing, yes, your modified sine wave UPS will work just fine at keeping the modem and routers alive.

[Kyle1886]

Thank you Idsnet.

As a follow up if I plug the UPS into one of my Honda inverter generators, will that "clean" up the UPS output?

Respectfully
Kyle

[Dirtlaw]

I have an APC backup attached to my Uverse ATT modem/router -- it seems to work OK. I have a bigger one attached to my general purpose computer which indicates that a power out has occurred. Based on that my read is that both do their job.

[Fizz]

Most computer networking equipment is fine with non-pure sine UPS.

There are circumstance I've come across where power supplies/adapters will buzz, hum, or get hot(er) when given modified sine. Just try it and find out. For these devices you probably don't want to use them on a modified sine UPS. But, I haven't damaged a device temporarily testing them in a power failure scenario.

If you hook up a generator to the UPS, you'll be providing sine. In that circumstance the UPS is doing nothing anyway.

The way entry level UPS backups work is they detect a voltage drop, they then disconnect the load from line power, and toggle/switch to providing power from the battery. Thus, when you have AC input from the wall (or generator), the battery isn't really doing anything whatsoever for the electrical load. If the input power drops/spikes, the electronics quickly toggle in a few ms. Essentially, until a power fault occurs a device plugged into a UPS is effectively plugged directly into the wall, and the UPS does no conditioning or anything else.

There are double-conversion UPS that run full time from the battery pack, and the line is there to keep the batteries charged. There is no 'switching' or detection for electrical load purposes.

If you were The Flash, and unplugged and replugged a device fast enough into a working outlet, it would stay on. Basic UPS devices work the same way.

[Kyle1886]

Thanks for the prompt feedback gentlemen, it's appreciated.

I figured all the genny would do is keep the battery charged but wasn't sure.

Thanks again.

Kyle

[rttully]

I have a Back UPS non sine-wave on my modem and it works fine except that my ISP's equipment close to me always fails anyway and half the time it tales them quite a while to reset it after anything other that a very short blackout anyway.

I like the UPS for the computer though because it helps to avoid file corruption .... most of the time.

[Misterclick]

[Fizz]

Ok understanding the intent of a UPS as a specialty device. My question goes a little further. What are everyone’s thoughts on using a Jackery or Yeti power source as a “UPS”? Not sure what the effects of having equipment draw on the device while plugged in and charging for long periods would be?

I don't have any firsthand experiences with the samples you mention, but if the unit will allow you to charge and draw at the same time, no real consequence and it would basically be a double-conversion UPS.

It may shorten the life of the lithium ion packs. Lithiums get greatest longevity sitting about 80% state of charge. Theoretically, there's a charging circuit for the batteries, and a circuit for the inverter. If the load is less than the charging amps, then the load should draw from the charging circuit and leave the batteries alone and wouldn't be cycling them.

It really depends on the BMS/inverter setup how much it impacts longevity.

[Robotron2k84]

Thank you Idsnet.

As a follow up if I plug the UPS into one of my Honda inverter generators, will that "clean" up the UPS output?

Respectfully
Kyle

Do NOT connect a UPS to a generator that uses a thyristor AVC circuit. You will end up frying the thyristor as it chases voltage regulation and heats due to harmonic distortion.

Such a setup causes fires. I have to post this at least once every few months.

[Kyle1886]

Do NOT connect a UPS to a generator that uses a thyristor AVC circuit. You will end up frying the thyristor as it chases voltage regulation and heats due to harmonic distortion.

Such a setup causes fires. I have to post this at least once every few months.

Thank you for the info. Are there any other appliances, etc., that shouldn't be run by a generator, inverter type or standard?

Respectfully
Kyle

[the86d]

I had a cheap simulated sine wave UPS and it may have fried my old Alarm AC adapter for my old alarm system. High pitched whine from an AC adapter...

Make sure to get something good, but this might not fix modem issues, some they are known for what seems to be memory leaks.

[Robotron2k84]

Thank you for the info. Are there any other appliances, etc., that shouldn't be run by a generator, inverter type or standard?

Respectfully
Kyle

Not so much.

A standby (line interactive), battery backed UPS, is specifically a problem because it’s an AC/DC/AC inverter, that interferes with the genny’s ability to detect and stabilize voltage. An online UPS, a la a flywheel generator or capacitor bank does not have this issue.

Generator / UPS interference is such a problem that the newest generation of smart UPSs have a “generator mode” specifically to combat this problem.

What happens is that the UPS has logic to switch from battery to mains based on not just the voltage, but also cycles per second. The thyristor in the generator doesn’t provide a pure sine wave, and has 6 or 12 pulses per cycle. The UPS sees this and quickly cycles back and forth from mains to battery, sometimes undetectably, depending on how the UPS’ switching circuitry is designed.

This switching causes large feedback spikes that trip the thyristor and cause it to switch on and off more than it’s intended, as it tries to compensate and seek an average voltage output. This switching further causes distortion in the line and can cause more interference from the UPS.

To alleviate the issue, special conditioning circuitry needs to be present between the UPS and the generator. This is a capacitor-backed online AC/DC/AC inverter that utilizes an isolation transformer for ground spikes. Some generators bill themselves as “inverter generators,” and have a true sine output, but lack any ability to isolate intermittent ground conditions that can fry electronics. As well, to minimize the voltage swings, the generator should be 2x the maximum amperage (KVA) for the UPS, and not 2x the average load.

What UPS manufacturers have started doing, is putting in circuitry to dampen the cutover behavior of a UPS on a generator, but this is a hack and just allows a dirtier feed to bypass the inverter on the UPS, potentially putting at risk the devices downstream if the generator has large spikes. Some other UPSs call themselves dual-conversion, online backup, which includes the correct inverter configuration in the input to the regular UPS circuitry. But, again, as with the inverter-generators, lack an isolation transformer, unless you’ve talking in the $100K / data center range.

Talk to a knowledgeable electrician about generator line conditioning if seeking to install a UPS downstream of a generator, and to size the generator appropriately. I don’t know firsthand, but I’m also suspecting that a UPS line would have to be a dedicated circuit off the generator to be up to code.

[sigstroker]

Most UPS's for computer use are way way smaller than half the generator output.

[Dnele928]

I’m considering a solar generator with a solar panel to charge it. Can also charge it with regular power outlet. Then, during a power outage, my modem will draw from the generator and the solar panel can recharge during the day. Kind of like a miniature Tesla power wall with Tesla panels.

Checking out various combinations on Amazon, search for “solar generator.”