About To Bite The Bullet Please Review And Share Your Thoughts

[Birdog]

After a year of procrastinating I'm about to bite the bullet and place an order. Fuel prices have made it an extremely short payout and a no brainer. I'd appreciate constructive comments concerning my product selection and design thoughts.

REQUIREMENTS:
1. I live off the grid in the East Texas woods about an hour north of Houston as the crow flies.
2. My house uses 120v power except my well pump uses 230v single phase.
3. If I turn on everything in the house and put a clamp meter on the generator out wire I use 15.9 amps on 120 power. Call it 2000 watts for simplicity.
4. If I take my clamp meter around the house and build a list, using the actual clamp on read outs, appliance stickers and liberal "what if's", I estimate my daily usage to be around 50-52kWh.
5. The interweb says average hours of sunlight in Houston range from 5:05 in Feb to 10:56 in June, with a yearly average of 7:49 hours of sunlight per day.
6. I've been living on a generator for 2 1/2 years. I expect to need generator support under my planned design. I'm hoping that, if needed, I can run the generator in the wee hours of the morning. Truth be told, I kinda sleep better with a little background noise.

DESIGN:
1. Controller: I wanted a dual Magnum 40V system but the Magnum folks tell me it's 36 weeks back-order, if I'm lucky. They say the parts are dribbling in with no rhyme or reason. So now I'm thinking Sol-Ark 12k. The difference between the 12k and the 8k isn't significant, and the power drain to run it looks to be exactly the same. I'm currently running on a 7.5kw generator that surges to 9kw.

2. Batteries: (2) eVault 18.5kWh batteries. The price and packaging is attractive but my concern here is, what if I need just a little more battery? Can I add more battery power that isn't an 18.5kWh $12k battery? I need to call them and spitball.

3. Solar Array: (16) REC-N-PEAK 2 Black Series 370's. Panels will be mounted on (2) top of pole mounts with (8) panels on each mount. The SA will be 155' from the Sol-Ark. My thinking is, assuming I'm getting 350 watts per panel at the Sol Ark (5,600 watts), during sunny daylight hours I'm using 2,000 watts per hour, leaving 3,600 watts per hour for the battery charging. Sol-Ark tech support says this design should charge the batteries in a little over 6 hours assuming an 80% draw down.

So that's about it. The top of pole mounts appear to have problems and get more expensive when you go from (6) panels per mount to (8), but I think I need (16) panels. I'd appreciate any constructive thoughts. In closing, I'd appreciate every one who reads this to shout out GO ASTROS as loud as they can.

Regards,

Bill

 

[timselectric]

Your plan seems solid. (However expensive)
And yes, you can add more batteries, of smaller ah size in parallel. Not sure if you will be using communications between battery and inverter. But if so, just leave the smaller batteries out of the communications. They will charge and discharge, along side of the large batteries. (Maybe not perfectly synchronized, but won't change your capacities)

 

[Bvillebob]

If you're just looking for a little supplement your plan sounds fine. You're planning on half a day of storage, so you'll absolutely be running the generator every day to charge the batteries. If you're looking to start being primarily solar you'll need to increase the size of things considerably.

Look into doing the batteries yourself. Over the last year I've built 60 kWh of batteries for about $10K, seems a bit more affordable than your numbers, had a lot of fun doing it and learned a lot.

I put up 12 of those panels a few months ago, I live them. Light, easy to install, the same size as my older 250's, and I have another 12 to go up this summer.

 

[Birdog]

If you're just looking for a little supplement your plan sounds fine. You're planning on half a day of storage, so you'll absolutely be running the generator every day to charge the batteries. If you're looking to start being primarily solar you'll need to increase the size of things considerably.

Look into doing the batteries yourself. Over the last year I've built 60 kWh of batteries for about $10K, seems a bit more affordable than your numbers, had a lot of fun doing it and learned a lot.

I put up 12 of those panels a few months ago, I live them. Light, easy to install, the same size as my older 250's, and I have another 12 to go up this summer.

How so? Keep in mind that in winter time I don't use my window unit ac's. That's 1500 watts of the 2000 watts my house consumes, or 75% less power requirements. Obviously the days are shorter in winter, but if I'm correct, my daily usage in winter, when days are shorter, is only 25% of 50kWh = 12.5kWh / day. If I'm using (2) 18.5kWh batteries, and assuming 80%DoD on the batteries, that means that in winter I'll have 29.6 kWh's of battery storage to give but will only need 12.5 kWh's to get through the night. Agreed I'll be close in the summertime, but if I need my generator I don't see generator time being excessive. I'll need 29.17kWh at night vs 29.6kWh of storage available. Thoughts?