Standby Generator Power Curve

P

politics123

Active Member
Hi --

I'm probably going to install a standby generator. While my area doesn't lose power often, my sump pump cycles quite a lot when we get rain, and I'm susceptible to flooding if we get rain and lose power (even for a short period of time). As long as I'm getting a generator, it might as well power the computer and wifi :eek:

Does anyone know what the sine wave curve looks like coming from the cheaper Guardian generators? They are all advertised as "computer friendly" -- but how accurate is the claim? I'm debating the cost difference between a $3600 8kw guardian and a $7000 8kw Kohler.

Also, how loud are these? They advertise 65 dba at 7 meters, but this is going to be located right next to my house. Am I going to be able to sleep at night??


Thanks!
Michael
 
I just installed a 30KW Kohler generator but the startup is scheduled for next week, so I can't comment on the noise. Air-cooled generators are generally louder than liquid-cooled since they require more air circulation which means more openings to allow noise to escape. Seriously, though, when the power is out, which isn't often, you'll sleep better knowing your house won't flood. :)

I'm sorry I can't remember the reasons I rejected Guardian generators when I did the research, but there were reasons Guardian didn't fit the bill. As far as the computers, if you're worried about quality power, plug the computers into a power conditioner and/or a good UPS and let the generator power these.

Good luck with your decision. When the power goes out, you'll be the envy of your block!

Kevin
 
politics123 said:
Hi --

I'm probably going to install a standby generator. While my area doesn't lose power often, my sump pump cycles quite a lot when we get rain, and I'm susceptible to flooding if we get rain and lose power (even for a short period of time). As long as I'm getting a generator, it might as well power the computer and wifi :eek:

Does anyone know what the sine wave curve looks like coming from the cheaper Guardian generators? They are all advertised as "computer friendly" -- but how accurate is the claim? I'm debating the cost difference between a $3600 8kw guardian and a $7000 8kw Kohler.

Also, how loud are these? They advertise 65 dba at 7 meters, but this is going to be located right next to my house. Am I going to be able to sleep at night??


Thanks!
Michael
Click to expand...
I have one installed. It has been in for over a year now. Powers all my equipment with no problems. Ours is located on the oppposite side of the house from the master bedroom. We can hardly hear it when its running. It was running a few mornings ago and we were asking one another, "What is that sound?" as we woke in the morning. Even in the garage, right next to it, the unit sound like a lawn tractor a few doors away..
 
I agree with the UPS statement made above. Remember, a UPS generates its own sine wave and doesn't rely on the input's quality.
 
You would always want your computer and sensitive stuff on a UPS as the generator start-up time is too slow to protect those.

But I have heard that many generators and UPS's don't get along so that even when your generator is running, the UPS isn't happy with the waveform and switches to battery. I don't have any specifics, but I am sure it is up to your exact generator and UPS combo, so YMMV. If you have large enough batteries, then you don't care if the genny and UPS don't get along, at least until your batteries are drained.
 
Along these same lines.. . has anyone had their Elk / automation panel monitor the status of the A/C mains and the generator? I.E., is there a contact closure that could be used by the Elk to know when the gen is actually running? Perhaps in the transfer switch, etc?
 
AceCannon said:
Along these same lines.. . has anyone had their Elk / automation panel monitor the status of the A/C mains and the generator? I.E., is there a contact closure that could be used by the Elk to know when the gen is actually running? Perhaps in the transfer switch, etc?
Click to expand...
A simple relay is all you need to monitor the mains. 110VAC coil if you are comfortable with high voltage, plugged into an outlet or whatever, with the contacts wired to an Elk zone. If you prefer low voltage, get a 12VDC wall wart (or whatever) and a matching relay (ie 12VDC coil), again with the relay contacts wired to an Elk zone. If you wanted to monitor the generator, you could monitor the voltage before the transfer switch or maybe the gen has a 12VDC control output. Or you could use a temp probe up the exhaust pipe :eek:
 
WayneW said:
A simple relay is all you need to monitor the mains. 110VAC coil if you are comfortable with high voltage, plugged into an outlet or whatever, with the contacts wired to an Elk zone. If you prefer low voltage, get a 12VDC wall wart (or whatever) and a matching relay (ie 12VDC coil), again with the relay contacts wired to an Elk zone. If you wanted to monitor the generator, you could monitor the voltage before the transfer switch or maybe the gen has a 12VDC control output. Or you could use a temp probe up the exhaust pipe :eek:
Click to expand...

If there is a service disconnect, as opposed to a transfer switch, it will be hard to find a 110VAC source to monitor that isn't powered by the generator. Ah, it will be good enough to know when power fails, then when the generator is started / stopped.
 
AceCannon said:
Along these same lines.. . has anyone had their Elk / automation panel monitor the status of the A/C mains and the generator? I.E., is there a contact closure that could be used by the Elk to know when the gen is actually running? Perhaps in the transfer switch, etc?
Click to expand...

My transfer switch has a mechanical switch that has NO/NC leads coming off of it that activates when the switch closes. This is wired as an input zone on my ELK M1 and a rule calls me when we have a power failure.

I also have an ELK output relay which allows me to turn off / disable the generator. I have rules for this such that at 11:30PM, if the generator is not running, disable it, so a power failure at 3am won't cause me to have to go shut off the generator. Also, if the system is armed away, the generator will not start. But, the really neat thing is I can start / stop it via the telephone interface.
 
politics123 said:
Hi --

I'm probably going to install a standby generator. While my area doesn't lose power often, my sump pump cycles quite a lot when we get rain, and I'm susceptible to flooding.


Thanks!
Michael
Click to expand...

I had a similar issue and took a different route, I purchased 12volt DC pumps. And a 12V DC deep cycle batteries.
It's a bit of a DIY setup, but I am extremely happy with it. The longest time the pumps so far for about 10 hours with no issues.
With the batteries total of 500AH, I even purchased an inverter in case during the power outage I decide I need to run other things.

For extended running time, A pair of Jumper cables to my car ( running ) works very well though not economical.
During the Blackout of almost the entire east coast a few years ago, I ran my fridge, some fans and a couple of lights from the Inverter for about 7 hours.

StevenE
 
deranged said:
politics123 said:
Hi --

I'm probably going to install a standby generator. While my area doesn't lose power often, my sump pump cycles quite a lot when we get rain, and I'm susceptible to flooding.


Thanks!
Michael
Click to expand...

I had a similar issue and took a different route, I purchased 12volt DC pumps. And a 12V DC deep cycle batteries.
It's a bit of a DIY setup, but I am extremely happy with it. The longest time the pumps so far for about 10 hours with no issues.
With the batteries total of 500AH, I even purchased an inverter in case during the power outage I decide I need to run other things.

For extended running time, A pair of Jumper cables to my car ( running ) works very well though not economical.
During the Blackout of almost the entire east coast a few years ago, I ran my fridge, some fans and a couple of lights from the Inverter for about 7 hours.

StevenE
Click to expand...

Steven -- I thought about that, but last week, our Wash, DC house received 4inches of rain. I have an ELK rule that counts cycles and duration --> in 8 hrs, we cycled 780 times (taking about 7 seconds on average to empty the sump crock). At the peak, we cycled every 65 cycles.

I was thinking about a couple batteries, but I'm thinking they'd discharge completely. I also considered a "backup" inverter from the car --> but wouldn't the inverter have to be huge? (eg: sump pump starting has got to draw something around 800+ watts). I know they sell 1000 watt car inverters, but those have to be hard-wired in (and probably require leaving the car in "fast-idle" mode)

I'm curious about your jumper cables... do you connect the jumper cables to the inverter, or do you connect them to your battery to recharge it (and do you leave the battery connected to the inverter, or do you just swap batteries... run off one while you recharge another) Which inverted did you get?
 
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