Need help with system setup !!!!

acemaverick

My wife and I are building a house, We are totally off-grid living in a RV currently. Most of our appliance are propane and e run a generator if we want to watch tv or A/C in summer. Beings its winter we don't need the generator much. I recently was hospitalized and now I'm on oxygen 24/7. The concentrator I use operates at 600W which means I to run the generator 24/7 at $40 dollars a day in fuel. I already have my solar equipment for the house. I would like to setup a temp system to just run this piece of equipment. If someone could help me based on the equipment I have would be greatly appreciated. My equipment list is below:

Aims 3000 watt inverter
Victron MPPT 150/100 controller
I have 12 solar panels
4- 100 AH 12 volt batteries
I was planning on a 24 volt system

mike95490

If your 600w is correct, you will consume  * daily *  14,400 watt hours,   That's 2x as much as my house consumes
  or about  $7 worth of electricity, daily.
To harvest that much power in 5 solar hours, you need about 44kw of PV panels and a huge battery bank.

I hope I've done something wrong, but I doubt you can solar your way.

acemaverick

I need to take a pic of specs to verify I’m correct. 

acemaverick

This is the specs for power. 

Marc Kurth

As Mike said, that is a big load because of the 24/7 run time. I suspect that you may find that the actual number will be lower, depending upon the flow rate you need. The first thing that popped into my head is to use a smaller generator while you sort out how best to integrate solar. I don't know what gas costs where you are, but the savings could pay for a small quiet generator quickly.

 A small inverter-generator would likely use around 2.5 to 3.5  gallons of gas per day. That could be reduced using solar and some additional battery power.

acemaverick

Good idea! Gas is around 3.09 a gal. It certainly much higher elsewhere but doesn’t change the fact we spend $40 a day just to operate this machine. Even if I could use battery part of the day would be a savings. Just wasn’t sure if I could make a configuration with equipment I already had. I’m getting ready to add 4 more batteries as well. Thanks for your feedback! 

Marc Kurth

acemaverick said:

Good idea! Gas is around 3.09 a gal. It certainly much higher elsewhere but doesn’t change the fact we spend $40 a day just to operate this machine. Even if I could use battery part of the day would be a savings. Just wasn’t sure if I could make a configuration with equipment I already had. I’m getting ready to add 4 more batteries as well. Thanks for your feedback! 

The inefficiency you are dealing with is running a large generator at a very low load. With a large battery bank, you would store energy every hour your generator is running anyway. There is a point of diminishing returns.....

I would start by measuring the actual power consumption at your O2 flow rate. Get a Kill A Watt meter or something similar, then you will know exactly what you need. Without this info, you could really go down a rabbit hole of poor decisions!

acemaverick

i'll grab one today. My concentrator is a 10 litres, If I'm sitting I'll be between 3-4 once i get up i'm at 5-6. I'm sure the 600 watts would be at 10 litres. I'll find out for sure.

Marc Kurth

mike95490 said:

If your 600w is correct, you will consume  * daily *  14,400 watt hours,   That's 2x as much as my house consumes
  or about  $7 worth of electricity, daily.
To harvest that much power in 5 solar hours, you need about 44kw of PV panels and a huge battery bank.

I hope I've done something wrong, but I doubt you can solar your way.

It is Sunday morning, and maybe I have not had enough coffee but I think:  14,400 watt hours / 5 hours = 2,880 

Photowhit

Sounds difficult.

Are you in recovery from Covid Pneumonia or other potentially short-term needs for the oxygen concentrator? ...or will this be long term?

Regular precautions about adding new batteries to old, I would at least wait until you figure out your long term needs. How old are your current batteries? Understand that golf cart batteries store about 1.25 kWhs of electric of that about .75 kWhs usable long term, your needs of 14.4 ÷ .85 inverter efficency = 17 kWhs a day. Should think this through for a long term plan. 

I did a quick search to see if there was a large difference in oxygen concentrators, Not much, if your needs were for an 8 liter machines, you could get down to near 400watts;

High Flow Oxygen Concentrator Review and Comparison 2021 (vitalitymedical.com)

Might even consider the possibility of a grid electric line if possible. Off grid will be a very large system, I'd suggest starting from scratch to figure out your needs. A system to supply 17kWhs + other home needs is huge, Thinking large 6-8000 watt array, and 20 kWhs of storage minimum with every cloudy day generator use.

BB.

For today--Yes an inverter-generator is probably a good start. The classic is a Honda eu2200i which should should give you (estimate), at least, 4,000 WH per gallon of fuel if running 24 hours per day:

• 600 Watts * 24 hours per day = 14,400 WH per day
• 14,400 WH per day / 4,000 WH per gallon = 3.6 gallons per day
• 3.6 gpd * $3.09 per gallon = $14.04 per day fuel costs

Get/make an extended run fuel system:

https://www.amazon.com/Mekar-Aluminum-Extended-Compatible-Generator/dp/B08GKP4J8R (cap+magnetic oil stick+less messy oil drain)
https://www.amazon.com/s?k=eu2200i+extended+run+kit&sprefix=eu2200i+extended+run,aps (general search--you can get external 5-6 gallon tank, or make your own)

A good quality Honda eu2x000i genset should run 2,000 to as much as 6,000 Hours... Note that running 24x7 is a lot of hours:

• 24 hours * 30 days per month = 720 Hours per month
• 2,000 Hours / 720 Hours per month = 2.8 months of genset "life" at 24 hours per day
• 6,000 Hours / 720 Hours per month = 8.3 months of genset "life" @ 24 hours per day

A Honda eu2200i run around $1,050 to $2,400 each (are difficult to get right now).

Costco has a "2,000 Watt" unit similar to Honda for less than $500 (I have no idea about quality/life--But non-Honda seem to be getting better)... Might be worth trying and see how it works out--Especially if this is a short term medical condition.

Longer term--There are "battery powered" O2 concentrates--I wounder about their cost and usefulness for your needs? r

For example (I know nothing about brand/website/unit)--This one does not specify energy usage--But looking at accessories--Guessing in the 30-60 Watt max energy running:

https://www.inogen.com/products/g3-systems/

One of these may not replace your present unit--But it may help reduce your power needs (and could life a bit easier for you too--mobile).

-Bill

mike95490

mike95490 said:

.......
To harvest that much power in 5 solar hours, you need about 44kw of PV panels and a huge battery bank.

I hope I've done something wrong....

yep, late night posting, something got garbled.   So a 3kw array would harvest enough, if every day was sunny and efficiency of everything was 100%.
 I'd double the array to  6kw and a battery of 40KWH since this is a critical machine, and I assume you get clouds and rain like I do