Question for offgrid system

[gmanInPA]

As long as you understand the disadvantages of batteries (they are not the magic cure for everything) and are willing to pay the price, we're happy for you.

Thanks Mike90250 - Yes, there are plenty of disadvantages involved - and plenty I'm sure I'm not even aware of at present! I totally agree that batteries aren't a magic bullet - as is the case with any system that produces energy. They all seem to have their vulnerabilities and a sober understanding of that is pretty important in setting up these systems. Glad (partially) to see you have an XW inverter - now I know at least one other person who experiences some of the madness that I experience configuring one. Do you have the Combox, or do you use the SCP to manage yours?

[Mike90250]

I have the old Gateway, SCP and a combox. I can monitor with the combox display and tweak settings on the SCP very easily. Also, you can use 2 web browsers with the same combox, one to monitor, and one to adjust with,
And somewhere in the fine print, you can discover that AC breakers 1 & 2 internally apply a 20% derate, along with the Gen Support Amps also has a derate.

[Sunking]

Perhaps you should look into how professionals design data centers and other such facilities where outages cannot be tolerated. None use solar. They use a Dual Conversion UPS sized to run the load for 1 hour at most using hybrid UPS AGM batteries. When power goes out, there is No Interruption in power with a Dual Conversion UPS. The UPS is online at all times. The batteries immediately pick up the load without any interruption, the generator comes online and takes over in less than a minute. Generator runs until power is restored.

[gmanInPA]

Perhaps you should look into how professionals design data centers and other such facilities where outages cannot be tolerated. None use solar. They use a Dual Conversion UPS sized to run the load for 1 hour at most using hybrid UPS AGM batteries. When power goes out, there is No Interruption in power with a Dual Conversion UPS. The UPS is online at all times. The batteries immediately pick up the load without any interruption, the generator comes online and takes over in less than a minute. Generator runs until power is restored.

Sunking - serious, non-smartazz question... if someone has invested in the batteries and inverter for such a system you describe - one that uses the batteries for momentary load support until a generator kicks in - Would it really be all that expensive to add some PV to essentially trickle charge those batteries?

I know PV costs more than grid-power (for most of the population)... but in the case you describe, such a battery could be relatively small (as AH go). If so, a small amount of PV to keep such a battery charged - depending on it's installation parameters wouldn't extend the cost by all that much at the point, would it? I'm not trying to justify the PV element here - you're right - it's unneeded.

[SunEagle]

Sunking - serious, non-smartazz question... if someone has invested in the batteries and inverter for such a system you describe - one that uses the batteries for momentary load support until a generator kicks in - Would it really be all that expensive to add some PV to essentially trickle charge those batteries?

I know PV costs more than grid-power (for most of the population)... but in the case you describe, such a battery could be relatively small (as AH go). If so, a small amount of PV to keep such a battery charged - depending on it's installation parameters wouldn't extend the cost by all that much at the point, would it? I'm not trying to justify the PV element here - you're right - it's unneeded.

To be honest you would have to do the math. Is it less expensive to use solar pv panels and charge controller to keep the batteries charged or to use the grid and a low cost battery charger?

Either way you still need the generator. If cost isn't an issue then go with the solar otherwise why?

If I was in the business to sell solar products I would push someone to getting them. I am here on this forum to help people make wise choices in using solar and when not to if cost and ROI is part of the equation.

[gmanInPA]

The only reason I can see for having PV in such a system is to extend fuel. You will still ultimately need fuel regardless if you have PV or not - but it could make the fuel last longer. Still, is it worth it? That's a values question IMO.

[SunEagle]

The only reason I can see for having PV in such a system is to extend fuel. You will still ultimately need fuel regardless if you have PV or not - but it could make the fuel last longer. Still, is it worth it? That's a values question IMO.

I agree the question concerns someones "values" but should also include the knowledge of wisely spending their money.

I support using PV and other renewable energy sources, but people need to understand the financial aspect completely and not let the fuzzyness of being green cloud their judgement and actions.

Go with solar for the right reasons.

[Logan005]

PV is best when grid tied. if you do have backup batteries, PV still works best grid tied and use some of that power to maintain batteries. If you decided to dedicate panels to maintaining batteries, once battery bank reaches FULL, rest of that days power is wasted. no savings there.

[gmanInPA]

Logan005 Do you consider Hybrid or Grid-interactive to be ok, or in the same boat as backup? Though there are some very annoying nuances to such - my inverter allows me to sell any surplus back to the 'grid' - which, being a branch circuit would fist be circuits NOT on the inverter loads, and then any excess from there goes to the grid. My main beef with such is that the XW limits my grid output to 18 Amps. To double that, I would need an additional inverter, or to upgrade north from 24v. Nevertheless... if someone plunked down for a 48v system with a hybrid inverter, they could put some power into the grid, but nowhere as much as a grid-tied system.

[gmanInPA]

I agree the question concerns someones "values" but should also include the knowledge of wisely spending their money.

I support using PV and other renewable energy sources, but people need to understand the financial aspect completely and not let the fuzzyness of being green cloud their judgement and actions.

Go with solar for the right reasons.

If only I could hit the like button more than once!

[SunEagle]

If only I could hit the like button more than once!

Thank you . I appreciate your understanding of my feelings on the technology.

[ButchDeal]

Logan005 Nevertheless... if someone plunked down for a 48v system with a hybrid inverter, they could put some power into the grid, but nowhere as much as a grid-tied system.

Why? Most hybrid / bimodal systems I have seen/installed are fully capable of feeding in what they produce. Mine is smaller but with a 3kw inverter I could easily handle more solar than I have. The ones we install are able to feed in all the power. Granted bimodal have less efficiency due to the batteries needing to be topped off etc.

[gmanInPA]

Why? Most hybrid / bimodal systems I have seen/installed are fully capable of feeding in what they produce. Mine is smaller but with a 3kw inverter I could easily handle more solar than I have. The ones we install are able to feed in all the power. Granted bimodal have less efficiency due to the batteries needing to be topped off etc.

ButchDeal - I was speaking only from the experience I have with my inverter - it limits the grid sell Amps. I suppose as long as I don't produce more than 18 Amps, it could feed in 100% of the production to the grid - true. Schneider's advice to me was that if I wanted to sell more PV, upgrade my inverter. For me to upgrade to any other Schneider hybrid inverter would necessitate voltage upgrade. Also - you're going to be dedicating some of the power to the batteries - hence the deficit compared to the grid-tied system. In my situation, I cannot produce more than my loads + battery charge + 18 Amps of Grid. I would think that any hybrid inverter would be limited by the Amps of it's AC breaker and even then, would want to stick to a fraction of that.

[Sunking]

Sunking - serious, non-smartazz question... if someone has invested in the batteries and inverter for such a system you describe - one that uses the batteries for momentary load support until a generator kicks in - Would it really be all that expensive to add some PV to essentially trickle charge those batteries?

I know PV costs more than grid-power (for most of the population)... but in the case you describe, such a battery could be relatively small (as AH go). If so, a small amount of PV to keep such a battery charged - depending on it's installation parameters wouldn't extend the cost by all that much at the point, would it? I'm not trying to justify the PV element here - you're right - it's unneeded.

If the economics worked, pros would do it. Fact is generator with UPS is far less expensive and more reliable. To do it your way requires a large set of batteries that need constant replacement.The initial cost of a large battery bank, solar, maintenance, and replacement cost are much higher cost and less reliable. Been doing this professionally for over 35 years. As a professional we use the most cost effective and reliable approach.

[ButchDeal]

ButchDeal I would think that any hybrid inverter would be limited by the Amps of it's AC breaker and even then, would want to stick to a fraction of that.

All inverters are limited by the AC breaker. Hybrid actually less so as they have two feed outs, though only one goes to the grid. For example my FP1 with a 3kw inverter and 3kw pv has a 60a AC1 and 60a AC2. Allowing me to feed 60a through the FP1 to the critical load panel. The 3kw inverter can only output continuous 25amps so the AC breakers will easily allow it. My PV would not generate that much except on very cold windy days

(page 33) http://outbackpower.com/downloads/do...fp1_manual.pdf