OHSCrifle
OHSCrifle PowerDork
9/29/24 10:39 a.m.

Anybody own and use one of these? If so - how do you like it?

We got lucky in the hurricane Helene aftermath but I've been thinking for a couple years about getting a generator and one of these manual transfer switches to keep the fridge and a handful of other things (like my tankless gas water heater) working in an extended power outage. 

dps214
dps214 SuperDork
9/29/24 11:38 a.m.

Unless you really need it to be extra quiet, I'd save $400 with the open frame inverter 4550w. Still inverter and still quiet (just slightly less so) but cheaper, lighter, and less prone to overheating. Only real downside is that it's manual start only. I got one for taking to the track earlier this year (trailer will eventually have some from of a/c) and it's been great so far but realistically hasn't seen much use.

alfadriver
alfadriver MegaDork
9/29/24 12:56 p.m.

Since you intend to get a manual switch, I would also think the manual start generator should be an option- it's a LOT less expensive.  

But I would also consider a solar/battery set up as well.  Quieter and no need for gas.  Will be more expensive for the set up.  On the other hand, there are a bunch of inverter set ups that will allow you to use that solar energy as a supplement to your power- meaning the investment cost could eventually be offset.  Which would be really hard to do with a gas generator.

Let alone, I would very much think about how much power you really need based on your note that you would disconnect stuff to just the minimum needed, however you decide to define that.  A fridge runs off of way less than 1800W- most are under 1000W.  

I wonder if I can find the live usage of my main power... that would be useful for emergency situations.

NermalSnert (Forum Supporter)
NermalSnert (Forum Supporter) Dork
9/29/24 1:41 p.m.

I can't speak for the HF generator but I'm looking at this one because it is an

inverter gen with 220v.

 

03Panther
03Panther PowerDork
9/29/24 3:48 p.m.

In reply to alfadriver :

  A fridge runs off of way less than 1800W- most are under 1000W.  

Except for the inrush current at start up, each time. 
I am familiar with how that affects a gasoline/propane/diesel generator. 

I have also had VERY negative results with consumer level inverters of the late '90s... they would not play well with inductive loads, even at capacity ratings of twice the inrush current. (Which, at that time, was considered to be about three times the running load current)

Im sure high end inverter technology ridges and ac's have changed the dynamic, but I'm a very long way from affording that, and almost everyone I know has inductive compressor refrigeration. 

alfadriver
alfadriver MegaDork
9/29/24 4:02 p.m.

In reply to 03Panther :

I know the inrush of my fridge is below 1kW.  As is the portable AC unit we use for our camper.  And I also know that most modern inverters can easily deal with it, as they are all rated for both steady and inrush current.

I've used a cheap 1kW HF inverter to run my fridge during a power outage.  Ran fine, but I will probably upgrade that to pure sine to be safer.

ShawnG
ShawnG MegaDork
9/29/24 4:46 p.m.

I have a 4500 watt conventional generator for backup. 

It runs appliances fine but my HE furnace has issues with the power from the generator and won't run.

Plan is to buy a UPS and use that to clean up the power from the generator 

NY Nick
NY Nick SuperDork
9/29/24 6:25 p.m.

I have a 4500 conventional too. I bought it because it was the cheapest thing I could get. It works fine but darn it's loud. If I had a redo I would pay the extra money for the quieter inverter one. It may not matter for emergency back up but I feel like it would be more useful at other times. I.e. camping or at the race track or whatever. 
 

I guess it's a one time purchase so get the best one that makes sense. 

Rodan
Rodan UberDork
9/29/24 9:05 p.m.

If you're talking about this one:  HF 5000W Inverter Generator ...

We bought one and I wasn't impressed.  It's rated for 3900W continuous, but would not run 2 RV 1500W A/Cs without shutting down.  I ended up returning it for the 8750W version.  It's not as quiet, but it actually works for what we bought it for. 

TJL (Forum Supporter)
TJL (Forum Supporter) SuperDork
9/29/24 9:12 p.m.

You have to watch the ratings on the inverter generators.  they are sold by their peak power where the non inverter generators are sold by their running wattage, not the peak. The non inverter generators are more honest in ther advertising. 

Floating Doc (Forum Supporter)
Floating Doc (Forum Supporter) UltimaDork
9/29/24 9:16 p.m.
ShawnG said:

I have a 4500 watt conventional generator for backup. 

It runs appliances fine but my HE furnace has issues with the power from the generator and won't run.

Plan is to buy a UPS and use that to clean up the power from the generator 

Could you elaborate on how to set up the UPS to serve this function?

03Panther
03Panther PowerDork
9/29/24 9:23 p.m.

In reply to alfadriver :

I know the inrush of your fridge is much higher than that.. if only for a split second. In 1999, the hammer store 1k, would NOT do that. I can provide the inverter, to prove it, although I no longer have the cube dorm fridge, but one could be acquired. 
I understand yours is working. I'm wondering what changed? 
They have either decreased the inrush time (entirely possible, although I personally don't know how) or the inverters (even the cheap ones) have gotten better at dealing with that spike. (or a bit of both)

As I've said, most of my electricity knowledge, came from the '40s up to '80s

Lots has changed, but E still equals I x R

03Panther
03Panther PowerDork
9/29/24 9:25 p.m.

In reply to TJL (Forum Supporter) :

I was not aware of that. Good to know. 

ShawnG
ShawnG MegaDork
9/29/24 9:28 p.m.

In reply to Floating Doc (Forum Supporter) :

Plug the UPS into the generator, plug (connect with homemade emergency connection) the furnace into the UPS.

The UPS takes the "dirty" power from the generator and cleans it up so the computer in the "smart" furnace doesn't have a panic attack.

codrus (Forum Supporter)
codrus (Forum Supporter) UltimaDork
9/29/24 9:51 p.m.
ShawnG said:

The UPS takes the "dirty" power from the generator and cleans it up so the computer in the "smart" furnace doesn't have a panic attack.

Most consumer-grade "UPS" devices are actually "standby power supplies".  They have a battery, a charger, and an inverter, but in normal operation they are simply passing the mains through to the output port.  When power fails they switch over to running the inverter off the battery, with a brief interruption that is small enough that most things won't notice.  This means that they don't do any power conditioning.

Also, most computers have switching power supplies and don't really care all that much about the "dirtiness" of the power.  AC motors are likely to be a lot more picky about it.

 

ShawnG
ShawnG MegaDork
9/29/24 10:09 p.m.

In reply to codrus (Forum Supporter) :

Was suggested by my electrician. 

alfadriver
alfadriver MegaDork
9/29/24 10:16 p.m.

In reply to 03Panther :

Two things have changed- fridges are considerably more efficient, so the compressors use less power.  And inverters with surge have gotten better.  

My fridge is just 600W, so if it doubled for surge, that would only be 1200w.  

The cheap non-sine wave inverter ran it just fine.  

03Panther
03Panther PowerDork
9/29/24 11:18 p.m.

In reply to alfadriver :

Cool. Glad it works well. 
BTW, if math is still the same, 600 x two - three times for "assumed" inrush, is more than 1000. 
My last math class, was as long ago as my electrical engineering classes wink

codrus (Forum Supporter)
codrus (Forum Supporter) UltimaDork
9/30/24 12:38 a.m.
ShawnG said:

In reply to codrus (Forum Supporter) :

Was suggested by my electrician. 

If you spend $5K on a rack-mount, enterprise-grade UPS then maybe you get an online system.  The $150-200 consumer ones are not.  The UPS companies do not go out of their way to make this clear, so a lot of people don't realize it.

If you look at the specs a lot of the time you'll see it say something about the wave form being "sine" during normal operation (with power) and "modified sine" (or language to that effect) when operating off the battery.  If the wave form is different when it's on battery power, then it's definitely a standby system.

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