Backup power

[jteneyck]

I've had a 17KW Generac for 4 or 5 years now.  As someone mentioned, the engine is Generac built, not from Briggs.  I have the whole house transfer switch, too, and highly recommend that option with whatever brand you go with because it's completely automatic and seamless.  I do my own maintenance after watching how little the service tech did the first two years I paid to have it done.  There really isn't much to it.  I change the oil yearly, the air filter and spark plugs every two years.  I have yet to check the valve clearance as the unit has far less than 400 hours on it - and the service tech. didn't do it the first two years either.  

Most important is to figure out how many amps you are going to need.  22 KW doesn't sound large enough if you have a 400 amp panel, unless maybe you plan to subdivide it.  

One other comment.  My security system depends on being able to dial out if a problem is detected.  This was never a problem when my phone service was from Verizon, etc. which is self powered.  But since I transitioned to cable for the phone, and the cable modem is AC powered, the security system would think the phone line had been cut every time we lost power, before the generator kicked in.  After I had the security company out and we understood why it was happening, the solution was to install a small uninterrupted power supply for the cable modem to keep it powered until the generator kicks in.  All is OK now.  The security system is so old that it can't be reprogrammed not to react this way, so this was the only solution unless I wanted to buy a new security system brain. 


John

[ridgeline]

I have a Cummins 20kw which is very similar to the Kohler. When I purchased mine I did a lot of research. It includes all of the features you are looking for. Just be on the safe side I purchased the load balance kit and have the AC/Heat pump on one load and the rest of the house on the other. I also had the optional cold weather kit installed which includes a battery and oil heater. At the time, the fuel consumption figures at 1/2 and 3/4 load were much lower for the Cummins than for the Generac. The Cummins was also much quieter. IMHO the casing for the Cummins was much better than the Genera which contributes to the noise reduction.

I typically loose power for more than 4 hours at least a couple times per year. I've had a couple of outages that went more than 24hrs. My unit is 6 years old. I had the replace the battery at 5yrs. Other than that I just had to do the regular maintenance (oil and filter changes, air filter change, valve lash adjustment).

[R Clark]

...
Most important is to figure out how many amps you are going to need.  22 KW doesn't sound large enough if you have a 400 amp panel, unless maybe you plan to subdivide it.  

One other comment.  My security system depends on being able to dial out if a problem is detected.  This was never a problem when my phone service was from Verizon, etc. which is self powered.  But since I transitioned to cable for the phone, and the cable modem is AC powered, the security system would think the phone line had been cut every time we lost power, before the generator kicked in.  After I had the security company out and we understood why it was happening, the solution was to install a small uninterrupted power supply for the cable modem to keep it powered until the generator kicks in.  All is OK now.  The security system is so old that it can't be reprogrammed not to react this way, so this was the only solution unless I wanted to buy a new security system brain. 


John

While the house was constructed with 400 amp service, LOML and I don't use near that much.  In fact, I've taken nearly 100 amps worth of circuits out of the mix since we move in: 

- 60 amp electric furnace replaced with gas; the 120V replacement circuit needed for the new LP furnace fan was reallocated from another unused circuit.
- Upgraded old electric cooktop to new gas cooktop; the changes between it and the oven resulted in a net reduction of 30 amps of circuitry
- The two 20A 220V circuits in LOML's craft room are essentially unused

But you're right...I need to go through and do an "audit" to determine maximum instantaneous use to see if I'm targeting the right sized unit.

Your point about security systems is well-taken.  We don't have one now, but 'd like to add one.  It will ride on our 4G cell plan.  Our wideband modem has a battery backup, but it only powers the phone line, and not the wifi.  A UPS would fill that gap.

[TDKPE]

But you're right...I need to go through and do an "audit" to determine maximum instantaneous use to see if I'm targeting the right sized unit.

That was a concern of mine, too.  Two panels may be a problem.  One that money can solve, but a problem.  It may be most cost-effective to have critical circuits on one panel, even if you have to move some, so a single automatic transfer switch can be used.  But that will take some investigation. 

400A at 240V is 129 hp (electrical), or 96 kW; that's a LOT of potential power for a residence, unless it's a big house with electric resistance heating, resulting in a BIG electric bill to match.

[R Clark]

That was a concern of mine, too.  Two panels may be a problem.  One that money can solve, but a problem.  It may be most cost-effective to have critical circuits on one panel, even if you have to move some, so a single automatic transfer switch can be used.  But that will take some investigation. 

400A at 240V is 129 hp (electrical), or 96 kW; that's a LOT of potential power for a residence, unless it's a big house with electric resistance heating, resulting in a BIG electric bill to match.

I have no idea why the original owner opted to configure the power panels as he did.

The electrical panels and associated low voltage wiring wall are a bewildering mess, as far as I'm concerned.  I would just rip out the low voltage stuff as most of it's antiquated and not used.  However, there are just enough things that I find very useful that it keeps me from going crazy on that low voltage wiring downstairs.

The original owner had this custom house built.  He had some good ideas, but an electrical engineering degree does not an electrician make.  Some of the things he did make me stand back and stare in wide-eyed wonder.  And not in a good way.  It's safe, but why in the world did he do some of those things?  My electrician is a master electrician; when I first contacted him four years ago, I told him that I have a very strange setup that really kind of defies description.  He was skeptical that I had anything different.  Until he saw it and stood looking at it in wild-eyed wonder, just like me. 

I'll probably start a new thread with pics, perhaps later today.  I really do want to clean up that wall.  A new generator and switching unit will obviate the need for major pieces of the stuff that's on that wall.

[fredhargis]

John, have you replaced your battery on the genny yet? I keep wondering about the lifespan of a car battery in that service. Mine sits out in the open, so it gets blistering hot in the summer (hotter than service in a car would be, I think).

[jteneyck]

John, have you replaced your battery on the genny yet? I keep wondering about the lifespan of a car battery in that service. Mine sits out in the open, so it gets blistering hot in the summer (hotter than service in a car would be, I think).

Surprisingly, no, not yet.  I had a yellow light sometime last Fall and the panel said battery something or other.  So I took out the battery and took it to the local battery shop, fully expecting I needed a new one.  The guy tested it and said it had something like 85% or it's rated amp capacity.  Hmmm.  Went home and read the manual, only to find out that the unit triggers a yellow light to check the battery every so many months, hours, sorry, can't remember.  Anyway, I put the battery back in and it's still working fine.  

When I bought the generator the guy who installed it said the batteries would last about 2 years w/o the cold weather heater package and 3 years with it.  I have that feature; there is a heater under the battery and another around the oil filter that come on at around 32F.  The generator is 4 years old now and the battery is still fine, but I will likely change it before the beginning of Winter, or at least get it tested again.  The most important time for me as far as having the generator absolutely, gotta work, is in the Winter when I'm away for a week skiing.  

Battery life is greatly effected by the charger it's tethered to.  My home security system eats batteries every two years.  The battery charger perpetually over charges it.  I've tried bypassing the on board battery charger and using a separate one, but the brain then thinks the battery is not being charged and starts chirping.  I'm not smart enough to figure out how to fool the brain of the thing.  Anyway, when I've checked the voltage of the battery in the generator it looks good, maybe around 12.5 V IIRC, where the home security system is more like 13.4 V.  If your generator battery is getting cooked by the sun can you shield it?  At the least, check the fluid levels frequently.  

John