Off-grid system review

[Cult of Dionysus]

Folks,

Still playing around with my system specs. Calculated my estimated daily power consumption, and came up with a total daily draw of 14 - 16 kWh. The main load is the 3-hp Grundfos water pump with VFD (moderates the start-up surge).

Grundfos water pump (6-7 kWh a day)
EnergyStar dishwasher (2 loads, 2 kWh)
EnergyStar front load laundry machine (2 loads, 1 kWh)
EnergyStar fridge/freezer (1 kWh)
65” TV (1.5 kWh)
LED lights with dimmers (0.5 kWh)
Sockets (1-2 kWh a day)
Range/Oven (propane)
Dryer (propane)

I want to stress that we plan to run most of this during the day and can stagger things. We won’t use more than 4 kWhs at night, if that much (one load of dishes, tv, lights, fridge/freezer). And I am fine running the generators for the handful of days when the weather isn't perfect.

Based upon the above needs and everyone’s previous input, I’ve come up with the following 5kW system. The charge rate is now at 9.1.

15 LG 300 Black Mono X panels (total of 141 Ah)
24 Rolls S550 6V, 428 Ah batteries (total of 1284 Ah)
2 Magnum MS4448PAE inverters
2 Midnite Classic 150 charge controllers
1 Magnum AGS-S
2 Honda EU3000iS

Would be interested to hear if you think I’m on the right track.

[ChrisOlson]

I found the YouTube video of his system in action, with electric appliances steaming away, impressive. I still am amazed at his ability to have an electric oven and dryer steaming away.

Well, I've been busy here. Like I said, I got new projects going that is outside the scope of "renewable energy" forums, so have little time to participate. When our present battery bank wears out we will not be buying another one. I've designed and built a dual redundant, failover co-generation CHP setup using 900 rpm diesel power that will be replacing our present system this coming summer. I can put the entire system in for less money than what it will cost to replace our present batteries in a few years. I have the first unit built and tested and sitting in my shop. It has a Cummins 4BT power unit. The units are 25 kVA prime, each. I'm building a second unit for redundancy and peaking - have it about half done right now and trying to get it done before spring. It took me 2 1/2 months to build the first one. I'm hoping to have the second one done by April so we can fire up the excavator in the spring and start construction on our new power plant.

The XW inverter is "smart" enough, has AC coupling capability, and has good enough controls and monitoring to be able to use it as the "grid" and "brains" for the system to tell the Cummins Power Command system how to control and sync the CHP units. We will have full 200A service to both our house and my shop when I get it done.

Our new system will eliminate having to burn wood for primary heat, provide us with virtually unlimited power with totally automatic control, used staged generators to cut fuel burn when only one is needed, and eliminate the expense and headache of batteries. Sure, it's not really "going green". But I could care less about "going green" except when it comes to saving green on off-grid power costs. And the type of system I have designed is in common use in remote Alaska villages and South Pole Station in Anarctica for many, many years. The US becoming the largest oil producer on earth pretty much made so-called "going green" obsolete as far as I'm concerned.

[Living Large]

Welcome back Chris.

You have provided very good explanation and some detail on the costs off grid living. Most newbies believe they can save money by disconnecting from the bad POCO but in the end will spend more.

Chris was generous with his time and advice in my first few days here via IM and email (thanks again, Chris). It became apparent quickly that what he calls "gen support" didn't really apply to me, but in the process he opened my eyes to several considerations and got me started.

I found the YouTube video of his system in action, with electric appliances steaming away, impressive. I still am amazed at his ability to have an electric oven and dryer steaming away.

[SunEagle]

Not been here in awhile - been busy with other stuff. But seen this thread and wanted to inject some info.

The reason our system works, and we can have an all-electric off-grid home is because we use a peaking generator and extensive use of wind power in the winter time (7.5 kW Bergey Excel-R which we put in two years ago). That turbine can easily produce 60 kWh/day at moderate wind speeds in the winter when it's needed most. We actually have a fairly small battery bank for a 25-30 kWh/day off-grid home at only 1156ah. But, when high-draw loads come on so the inverter is operating in overload it starts the genset and shifts the load from the inverter to the generator. We use a quite small 4.0 kVA genset, the inverter is sine wave sync'd on both phases (split-phase power) with the genset, so the genset carries the first 4.0 kVA of the load and the inverter carries the rest. This takes the load off the battery bank so Puekert Effect don't sack the bank out and we keep the discharge rate at reasonable levels at peak load. And saves on fuel because we don't need a 10 kW genset to support a 10 kW load when the generator is operating. And saves on inverters because we don't need stacked inverters to carry 10 kW intermittent loads. And saves on batteries because we don't need a big battery bank to support stacked inverters. And saves on solar panels and wind turbines because we don't need a bunch of controllers and extra expense to properly charge a big battery bank.

Sure, it means burning generator fuel to support loads over 6 kW. But for us, big deal. Off-grid living is not cheap in the first place and we're not short on money. So a $150/month generator fuel bill for 5 months of the year to support our peak loads is not a big deal for us.

And yes, our system is grossly over-sized for the summer months and we run central A/C in our house just to use it up. BUT - the generator is still used in summer too to support peak loads at times. Just our peak loads are higher in winter than in summer because in winter my wife uses the electric clothes dryer, for instance, where in summer she uses the clothes line. And we cook outside on the grille in summer instead of using the electric range in the kitchen. As a couple examples. It's 20 below zero here in the winter time, so that also means the gensets are preheated 24 hours a day for when they're needed - more power consumption. The days are short, so that means longer hours inside running lights, and more time spent in my shop using lots of power. And on and on.

So I designed our system to use the smallest battery bank that is feasible, and use generators to support it when otherwise more inverters and batteries would be needed. Batteries are most expensive thing for off-grid power. Not generators. Generators are cheap (in the off-grid world). None of it is cheap compared to the world of utility power. While we live here off-grid for the last 15 years at about what it would cost for someone to live in California on peak power rates, that is only out-of-pocket expense. We got close to $100 Grand invested in the equipment, wiring, controls, monitoring and misc to produce that power. And that's what makes off-grid power expensive because all that equipment has to be maintained, eventually replaced or upgraded. I put the pencil to it and figured out that we can buy like 6 generators and run a pipeline from the Bakken Oil Field to fuel 'em for less than what a battery bank costs.

Welcome back Chris.

You have provided very good explanation and some detail on the costs off grid living. Most newbies believe they can save money by disconnecting from the bad POCO but in the end will spend more.

For people like you that choose to live "off grid" it is not due to financial reasons, it is a choice of life style that you prefer and are willing to pay the cost to live that way.

I hope you were able to get out of the cold North for a while and enjoy the warmer weather down South while cruising around in you boat.

[ChrisOlson]

He has a very large system due to his northern location - it is designed to get a reasonable amount of generation in the winter - it is over sized most of the year so that works great for him.

Not been here in awhile - been busy with other stuff. But seen this thread and wanted to inject some info.

The reason our system works, and we can have an all-electric off-grid home is because we use a peaking generator and extensive use of wind power in the winter time (7.5 kW Bergey Excel-R which we put in two years ago). That turbine can easily produce 60 kWh/day at moderate wind speeds in the winter when it's needed most. We actually have a fairly small battery bank for a 25-30 kWh/day off-grid home at only 1156ah. But, when high-draw loads come on so the inverter is operating in overload it starts the genset and shifts the load from the inverter to the generator. We use a quite small 4.0 kVA genset, the inverter is sine wave sync'd on both phases (split-phase power) with the genset, so the genset carries the first 4.0 kVA of the load and the inverter carries the rest. This takes the load off the battery bank so Puekert Effect don't sack the bank out and we keep the discharge rate at reasonable levels at peak load. And saves on fuel because we don't need a 10 kW genset to support a 10 kW load when the generator is operating. And saves on inverters because we don't need stacked inverters to carry 10 kW intermittent loads. And saves on batteries because we don't need a big battery bank to support stacked inverters. And saves on solar panels and wind turbines because we don't need a bunch of controllers and extra expense to properly charge a big battery bank.

Sure, it means burning generator fuel to support loads over 6 kW. But for us, big deal. Off-grid living is not cheap in the first place and we're not short on money. So a $150/month generator fuel bill for 5 months of the year to support our peak loads is not a big deal for us.

And yes, our system is grossly over-sized for the summer months and we run central A/C in our house just to use it up. BUT - the generator is still used in summer too to support peak loads at times. Just our peak loads are higher in winter than in summer because in winter my wife uses the electric clothes dryer, for instance, where in summer she uses the clothes line. And we cook outside on the grille in summer instead of using the electric range in the kitchen. As a couple examples. It's 20 below zero here in the winter time, so that also means the gensets are preheated 24 hours a day for when they're needed - more power consumption. The days are short, so that means longer hours inside running lights, and more time spent in my shop using lots of power. And on and on.

So I designed our system to use the smallest battery bank that is feasible, and use generators to support it when otherwise more inverters and batteries would be needed. Batteries are most expensive thing for off-grid power. Not generators. Generators are cheap (in the off-grid world). None of it is cheap compared to the world of utility power. While we live here off-grid for the last 15 years at about what it would cost for someone to live in California on peak power rates, that is only out-of-pocket expense. We got close to $100 Grand invested in the equipment, wiring, controls, monitoring and misc to produce that power. And that's what makes off-grid power expensive because all that equipment has to be maintained, eventually replaced or upgraded. I put the pencil to it and figured out that we can buy like 6 generators and run a pipeline from the Bakken Oil Field to fuel 'em for less than what a battery bank costs.

[Living Large]

acrel-bms was a Chinese salesman - now history.

Excellent!

[russ]

acrel-bms was a Chinese salesman - now history.

[Mike90250]

16 Rolls S550 batteries

These are lead-acid batteries, and do not need a BMS, mr acrel-bms (unless there is money left over and instead of a beer, he wants a BMS).

[Living Large]

Is a BMS installed on the system?

Why? Does he need one?

[SunEagle]

Beware generator sound enclosures, if not done right, they will cook your genset.

Look at a pair of the Honda 4Kw gensets (non inverter types) they have electric start and are supposed to be pretty quiet, and are well engineered. They may even have conversion kits to propane.

Generator efficiency. It's not Volts, it's measured in watts or Kwatts. 1,000watts = 1Kw Most generators are efficient at about 80 or 90% of their continuous rating (not their peak surge rating)

Mike

I agree with you. A safe and working sound proof enclosures requires the proper amount of air flow to both feed the combustion process and cool the generator. On top of that the exhaust from the generator needs to be vented and possibly extended above 6' so people aren't affected by them.

[Mike90250]

Look at a pair of the Honda 4Kw gensets (non inverter types) they have electric start and are supposed to be pretty quiet, and are well engineered. They may even have conversion kits to propane. .

I didn't mean connected to run in parallel, I meant 2 of them, to be used alternate days, always having a backup.

Currently, my 80yr old diesel genset is running, and my new diesel genset with 50 hours on it, has been in the repair shop for 3 months with governor issues. And the injector is carbonated up. If you have batteries, you need genset$.

[Cult of Dionysus]

Look at a pair of the Honda 4Kw gensets (non inverter types) they have electric start and are supposed to be pretty quiet, and are well engineered. They may even have conversion kits to propane. .

My understanding was that only the smaller Honda generators can be paired (3Kw and below)...

You thought I was just trying to beat you up. Not my intent I was trying to give you an Attitude Adjustment Upside the Head with a 2 x 4 before you did something stupid. Now you know I was right in making you rethink things. I have been designing electrical power generation systems professionally for 37 years.

Not at all. I had some misconceptions (supported by a general level of ignorance) that were preventing me from accepting what you were saying. FYI, I had skimmed all the stickies last year and again before posting my OP, but this stuff isn't simple by any measure. It's like if you'd come to me for some legal advice (I'm a lawyer), and I give you some case law... You can read it, and you will get some points, but that doesn't mean you could effectively handle whatever the underlying issue was yourself.

The guidance from you and everyone else has been very helpful.

[Living Large]

Generator efficiency. It's not Volts, it's measured in watts or Kwatts. 1,000watts = 1Kw Most generators are efficient at about 80 or 90% of their continuous rating (not their peak surge rating)

I don't know if you were addressing me or not. I was listing parameters to consider. I mentioned voltage to warn the poster that generators come in different flavors voltage-wise, so he'd keep that in mind depending on if he plans a 115V or 230V system.

[Mike90250]

.... Then what about noise level. Lower RPM = quieter, generally speaking. Sizing the generator properly - at what load is it most efficient? 230V/115V or 115V? These are all things to think about, depending on your situation. FYI - I found researching generators pretty tedious.

Beware generator sound enclosures, if not done right, they will cook your genset.

Look at a pair of the Honda 4Kw gensets (non inverter types) they have electric start and are supposed to be pretty quiet, and are well engineered. They may even have conversion kits to propane.

Generator efficiency. It's not Volts, it's measured in watts or Kwatts. 1,000watts = 1Kw Most generators are efficient at about 80 or 90% of their continuous rating (not their peak surge rating)

[Amy@altE]

You thought I was just trying to beat you up. Not my intent I was trying to give you an Attitude Adjustment Upside the Head with a 2 x 4 before you did something stupid. Now you know I was right in making you rethink things. I have been designing electrical power generation systems professionally for 37 years.

I think he was referring to an old post in the summer where he was told he could do load shifting to minimize his battery bank, but took it too far.