Off-grid system review

[Cult of Dionysus]

The advice of experienced people here is to strive for a single series string, or two if absolutely necessary. I believe there are sources on the net that say 3 string maximum. I am only a newbie, but I know which direction I would go.

One example of a battery that would give you a single string is the Rolls S-1660, which is 1284 Ah - exactly what you stated. 2v each, you would need 24 of them.

How do these compare to the 12 4KS25PS noted by Sunking? Seem to have comparable storage, but the 4KS25PS cost a lot more... $10k vs $14k mainland prices.

[Sunking]

Your so full of it, you'd need a 10ft ladder to smell clean air.

Well thank you partner, I appreciate it. Back at you.

[Cult of Dionysus]

Living Large, Donald, appreciate your input. I know Im off the mark on a lot of things, hence why I'm here.

Just trying to get a solid baseline, as most of the solar guys on the Big Island do gridtie panels only...

[Sunking]

Your so full of it, you'd need a 10ft ladder to smell clean air. The site is in one of the driest, sunniest parts of Hawaii. I'm gonna get plenty of sunshine in winter, PLENTY. Will send you an update next

Does not matter where the location is, you are going to produce 80% of all your power between 10:00 am and 2:00 pm. That is how solar works regardless of where it is located. Read these Stickies and should answer most of your questions.

Off-Grid
Batteries
Inverters
Are You Sure?

[Cult of Dionysus]

Makes no difference what time of day the power is used. 80% of the power is generated in a 2 to 4 hour real time window. In winter months a 1 to 2 hour window.

Does your dryer have a motor?

Your so full of it, you'd need a 10ft ladder to smell clean air. The site is in one of the driest, sunniest parts of Hawaii. I'm gonna get plenty of sunshine in winter, PLENTY. Will send you an update next Janauary, month average.

As for the wattage, I clearly said it was a 5kW system, and I get there's an element of inefficiency. Used the manufacturers figure of 9.1 amps per panel to get the 141 figure, merely for the purpose of calculating the C rate. Must of botched that... Don't know why, but I'm hoping someone other than you explains it. I'll thank them nicely, cuz that's what polite people do.

As for the 65kWh battery bank, WHY? Because I'm supposed to have 2-3 days of redundancy? If that was what I wanted, why bother with the 6kW gensets? I'd rather invest in Honda equipment which will last longer...

My GC approached an "expert" early on and the guy would have hosed me. Happy to post the details, but even an ignoramus like me saw through it.

I'm simply trying to get a sense of what may be a decent system for me, so that I can size up what the next solar contractor will propose.

[donald]

Folks,


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

I may have missed it, but hot water? In sunny Hawaii storing energy in two electric hot water heaters may make sense, even with LP available. Especially if you use a lot of hot water. Be sure to know if you may need a 240v well pump.

Most periodic appliances have timers now. Even an electric dryer can work, although LP is probably a better choice. Panel to battery ratio isn't an absolute rule, especially with electric hot water and appliance power management. Of course you need to current limit the battery charger. And a realistic interest in actively and consistently managing energy use.

I also suggest buying less expensive batteries, because you will want to resize in a couple years. Also, paying for a professional offgrid design won't cost you anything. It will save you frustration, and help your solar subcontractor do a good job. Alternatively, see if you GC will work with an experienced offgrid subcontractor. This choice may not cost less than hiring your own consultant.

The more you research yourself, the better. Even if you hire an expert.

[donald]

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.

I believe conversion on honda to propane voids the warranty. Conversion on Yamaha apparently does not void the warranty. In the only testing available, Yamaha has the longest lasting engine. BUT, I wouldn't buy Yamaha without a good repair shop. My local Yamaha shop is much better than the Honda dealer. So for me the decision was easy.

For most people in most places Honda is the better choice because of market share. But not the only good choice.

I think that designing an off grid home that may never use the generator is usually an expensive choice. The redundancy of two small quality Japanese gensets on LP is usually a better value than a single diesel for the same total price. In Hawaii I probably wouldn't buy a backup genset. The "backup" genset can sit on the shelf at the store.

[Living Large]

5 LG 300 Black Mono X panels (total of 141 Ah) Complete jibberwalkie milky wilky baby talk nonsense. No such thing exist. Panels are specified in WATTS. I assume those are 300 watt panels x 15 = 4500 Watts
This is a teensy weensy strong, but it is true it is 4500W.

24 Rolls S550 6V, 428 Ah batteries (total of 1284 Ah) I will; be frank STUPID. You need 65 Kwh battery capacity. At 48 volts = roughly 1350 AH battery. That would be 12 units of Rolls 4KS25P batteries all wired in series.
Being frank is not always best. This is why I am not married.

2 Magnum MS4448PAE inverters WHY do you need 2 4 Kw Inverters? You have no demand for 8 Kwh or power? I see no more than 2 Kw of demand and a single 4 Kw is overkill.
I was advised by a few people to have a second inverter for my system, when I thought I didn't need it. Perhaps for redundancy?

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

Comments in Bold.

[Living Large]

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.

The advice of experienced people here is to strive for a single series string, or two if absolutely necessary. I believe there are sources on the net that say 3 string maximum. I am only a newbie, but I know which direction I would go.

One example of a battery that would give you a single string is the Rolls S-1660, which is 1284 Ah - exactly what you stated. 2v each, you would need 24 of them.

[Sunking]

15 LG 300 Black Mono X panels (total of 141 Ah) Complete jibberwalkie milky wilky baby talk nonsense. No such thing exist. Panels are specified in WATTS. I assume those are 300 watt panels x 15 = 4500 Watts
24 Rolls S550 6V, 428 Ah batteries (total of 1284 Ah) I will; be frank STUPID. You need 65 Kwh battery capacity. At 48 volts = roughly 1350 AH battery. That would be 12 units of Rolls 4KS25P batteries all wired in series.
2 Magnum MS4448PAE inverters WHY do you need 2 4 Kw Inverters? You have no demand for 8 Kwh or power? I see no more than 2 Kw of demand and a single 4 Kw is overkill.
2 Midnite Classic 150 charge controllers You only need 1 controller running 48 volt battery at 4500 watts
1 Magnum AGS-S
2 Honda EU3000iS Why? You only need 1 6 Kw genny with a 48 volt 100 AMP Charger

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

Comment in RED

[Living Large]

WHen I read about Chris Olsen's system, I think about how in the future a proven LiFePo4 system could be used to improve his design. His batteries are expensive because off grid because it's not practical to manage the FLA industrial batteries so that they last 10-15 years.
I wonder why if he can get fuel for the genset he can't get heating oil or LP for heat? Diesel could even be used for boiler and genset.

You can PM him and ask directly. I am SURE he would engage in that discussion with you, and explain his thinking.

[Sunking]

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.

Makes no difference what time of day the power is used. 80% of the power is generated in a 2 to 4 hour real time window. In winter months a 1 to 2 hour window.

Does your dryer have a motor?

[SunEagle]

WHen I read about Chris Olsen's system, I think about how in the future a proven LiFePo4 system could be used to improve his design. His batteries are expensive because off grid because it's not practical to manage the FLA industrial batteries so that they last 10-15 years.
I wonder why if he can get fuel for the genset he can't get heating oil or LP for heat? Diesel could even be used for boiler and genset.

Since Chris has been doing the Off Grid life style for quite a few years I feel he has determined which is the best route to provide electricity for his home.

I am sure getting fuel to run his generators will be easier than babysitting a battery bank of any type chemistry.

Sometime in the future a cheaper and more friendly energy storage device will be available but until then (at least for most off grid people) batteries are expensive and not the most economical path to follow.

[donald]

WHen I read about Chris Olsen's system, I think about how in the future a proven LiFePo4 system could be used to improve his design. His batteries are expensive because off grid because it's not practical to manage the FLA industrial batteries so that they last 10-15 years.
I wonder why if he can get fuel for the genset he can't get heating oil or LP for heat? Diesel could even be used for boiler and genset.

[SunEagle]

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)How did you calculate 141Ah?
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.

See above question in BOLD. I'm not sure how you got 141Ah for your panels. You have 15 x 300W = 4500watts charging a 48v battery system. That would get you about 94Amps of charging capacity or a C/14 charge rate.

Next possible issue is having 3 48volt banks of batteries wired in parallel. You may have a hard time getting them to charge and discharge evenly.