Newbie just starting

[gatorhead]

You'll be better off with 48V. Do your 12V batteries support 4 in series for 48V?

100 Ah 48V server rack batteries are particularly economical, some a bit less than your Dakotas. By the time you've got the kWh Sunshine recommends, they will have cost less.

EG4 PowerPro 280 Ah 48V is another attractive option. But first see what inverter + battery pair are available from a single brand.

You can get an AIO to keep things simple (some are dirt cheap, some cost more but have reputation or pedigree)
Or you can use separate components.
Look for something that is expandable, e.g. parallel second unit.

Thanks for the info., I decided to downgrade more to reality for now, how about a 24v 3kw system to start? I still need to figure the exact minimum wattage/current flow needed for the bare minimum, survival mode, like no Regional Power Grid, no access to propane or gas. Thanks again for your info!

 

[Hedges]

3000W / 24V = 125A. A bit more current for inefficiency, etc. but reasonable at that voltage. I'd size the cables and fuse for 200A.

There are 24V AIO, or a bit more for 48V AIO, if you want a simple build. Or components, can upgrade individually.

There are some very economical 48V LiFePO4 batteries - we've seen about $350 for 48V 50Ah. However, that wouldn't support 62.5A (typically 1C max continuous) so may need more battery capacity depending on loads (regardless of which voltage.)

Cheapest 48v 50ah battery I've found so far. $409.99 free shipping

I second that, the Eco-Worthy and DC House batteries at our cabin have also been working great.

diysolarforum.com

Take look at the suggested systems from link at top of web page. They have affiliate links which support Will, owner of the forum.

It is good to post your contemplated purchases and let forum members critique it before buying. That will steer you to better quality fuses/breakers, proper sizing, etc.

 

[gatorhead]

5kW * 10h = 50kWh of battery

You currently have 5.12kWh of battery.

Buy 8 more batteries.

Buy 12,000W ($12K including mounting/misc) of solar panels to generate 50kWh/day in very good conditions.

Buy 500A of PV charging (Could be as much as $3K).

Buy 6000W of inverters ($2-3K)

Thanks a million! Now how about I start with a 24v 3kw system, so I can deduct 40% of my costs on next year's income tax?

 

[gatorhead]

3000W / 24V = 125A. A bit more current for inefficiency, etc. but reasonable at that voltage. I'd size the cables and fuse for 200A.

There are 24V AIO, or a bit more for 48V AIO, if you want a simple build. Or components, can upgrade individually.

There are some very economical 48V LiFePO4 batteries - we've seen about $350 for 48V 50Ah. However, that wouldn't support 62.5A (typically 1C max continuous) so may need more battery capacity depending on loads (regardless of which voltage.)

Cheapest 48v 50ah battery I've found so far. $409.99 free shipping

I second that, the Eco-Worthy and DC House batteries at our cabin have also been working great.

diysolarforum.com

Take look at the suggested systems from link at top of web page. They have affiliate links which support Will, owner of the forum.

It is good to post your contemplated purchases and let forum members critique it before buying. That will steer you to better quality fuses/breakers, proper sizing, etc.

Ok, great info! Thank You

 

[gatorhead]

Or he could find a DIY solar website someplace and maybe just maybe learn something so the 'professional' can't rip him off.

Thanks! and Thanks for your service! I'm a retired AT as well.

 

[Brett V]

I used a 24 volt system with a 1500 watt inverter just to power the fridge, a freezer, TV, and a few lights if needed overnight so I could shut off the generator and go to bed.

Then the warden got me in to prepping so I upgraded to a modest 48 volt battery and put in a Growatt 6k split phase AIO because I could run the well pump off batteries. Still relied on the generator to supply primary power as well as battery charging if the grid was down.

All was good but unused functionality bugs me and that Growatt had a built in solar charge controller. So let’s get a few solar panels…what could it hurt? I was surprised at how much power I could “make” for free when the sun was shining and that’s when the bug bit.

Now a few years later, I have upgraded to 12k Growatt, almost 50 KWh of batteries, and 3500 watts of solar panels with another 3500 watts stacked on the patio waiting for me to install them.

It’s just us two old people here and with some modest conservation, we should be able to live without the grid indefinitely if anything bad happens. I heat with a pellet stove and mini split heat pump which also provides AC in the summer. Hot water is done with an electric heat pump water heater. Every light in the house is LED and we don’t have any power hungry things like a pool or hot tub.

My point is two fold. First, conservation is cheaper than energy production. See what you can do there. Second, you WILL want more power as time goes on. If you’re going to do it, start with a 48 volt system because it’s easier and cheaper in the long run since you appear interested in whole house autonomy.

 

[sunshine_eggo]

Thanks a million! Now how about I start with a 24v 3kw system, so I can deduct 40% of my costs on next year's income tax?

Your well pump may be quite brutal on start-up and require a hefty surge.

Best thing to do is step back and take into account everything you REALLY need to run. Determine your available solar and conduct an energy audit using the resources in line #1 in my signature.

If you plan to expand the system in the future, the best thing to do is design your final system and figure out how to do it in stages.

 

[Brett V]

Thanks a million! Now how about I start with a 24v 3kw system, so I can deduct 40% of my costs on next year's income tax?

It’s 30% and it’s only a tax credit. You need to have a high enough tax liability to take advantage of it.

Homeowner’s Guide to the Federal Tax Credit for Solar Photovoltaics

This guide provides an overview of the federal investment tax credit for those interested in residential solar photovoltaics, or PV.

www.energy.gov

 

[JRH]

I used a 24 volt system with a 1500 watt inverter just to power the fridge, a freezer, TV, and a few lights if needed overnight so I could shut off the generator and go to bed.

Then the warden got me in to prepping so I upgraded to a modest 48 volt battery and put in a Growatt 6k split phase AIO because I could run the well pump off batteries. Still relied on the generator to supply primary power as well as battery charging if the grid was down.

All was good but unused functionality bugs me and that Growatt had a built in solar charge controller. So let’s get a few solar panels…what could it hurt? I was surprised at how much power I could “make” for free when the sun was shining and that’s when the bug bit.

Now a few years later, I have upgraded to 12k Growatt, almost 50 KWh of batteries, and 3500 watts of solar panels with another 3500 watts stacked on the patio waiting for me to install them.

It’s just us two old people here and with some modest conservation, we should be able to live without the grid indefinitely if anything bad happens. I heat with a pellet stove and mini split heat pump which also provides AC in the summer. Hot water is done with an electric heat pump water heater. Every light in the house is LED and we don’t have any power hungry things like a pool or hot tub.

My point is two fold. First, conservation is cheaper than energy production. See what you can do there. Second, you WILL want more power as time goes on. If you’re going to do it, start with a 48 volt system because it’s easier and cheaper in the long run since you appear interested in whole house autonomy.

Good path your on…. Congrats…

 

[JRH]

Best thing to do is step back and take into account everything you REALLY need to run

Yes……NEEDS ,being the most important word…

Once you find that , ….everything else is a WANT.

“Needs”are pretty basic, few and easy to discover if you ever have had extended ZERO power..
They become glaringly obvious…

“Wants,”……well that’s a whole different can of worms…it’s bottomless…

Need firsts ……..then add Wants as money and skill allows….

J

 

[OffGridForGood]

Thanks for the info., I decided to downgrade more to reality for now, how about a 24v 3kw system to start? I still need to figure the exact minimum wattage/current flow needed for the bare minimum, survival mode, like no Regional Power Grid, no access to propane or gas. Thanks again for your info!

I suggest you look at what your future system would be, then from that standpoint, back up to a single inverter and smallish battery pack/PV for now, but know the additional pieces you will add and know they will all work together to fufill your future goals.
I strongly suggest going 48 volt right out of the gate.
I also suggest you look for an inverter capable of parallel operation, that will be available well into the future.

 

[Cabin Rising]

Ok, this is info I need to start, Thanks. So, I think it would be good to scale down for now, how about a 24V 3k system intermittently used. I can charge my batteries as long as propane is available, solar charging would be the last resort.

How about starting at the beginning. What exactly are you trying to power? Check for the approximate amount of sunlight for your area and then figure out how much battery you need to sustain your needs for rest of the day.

If you can manage 4 to six hours of sunlight, then your battery bank has to be relied on for the other 18+ hours. Do you need 3kw during the night all the time every night? If so you are still up chits creek.

I have a very small modest solar array built from used, surplus and scrapped parts. That even includes the batteries. It can supply a reliable 400-600 watts for most of the day when sun is out. This also keeps the battery bank fully charged. But after hours, I have to cut back to almost nothing so not to drain down the batteries overnight.

That does not mean I cant run anything. Just nothing that draws a lot of watts for any length of time. But for less than $1000 it has allowed me not to have to pay the poco anything for the last 4 years. So total cost is less than $250 a year for power at my cabin.

This cost is less than just the service charge for the local poco. I have already paid the poco to finally get tied to the grid. But at the same time, I am doubling my solar array. I will not only have constant power all the time, but supplementing it to keep cost reasonable. When power is down, I will still be in good shape.

Now all of this has nothing to do with your situation. If you need a constant supply of power in the 3kw range, then it would help to include some serious details about what you are doing. The cost to create electricity by solar and battery is substantially more expensive than grid power.

The initial upfront cost and constant maintenance does not come cheap. Not if expecting to maintain that much power to have available all the time. You can not live off grid the same as you do relying on the grid. Not if it includes most of todays modern conveniences in an all electric house. Now back to you.