Home System - Getting It Started

[HARG Hunter]

Now that I've tuned in my off-grid cabin system, I'm finally getting around to starting up a system for my house.

This will be off grid and I'm starting it primarily as a back-up for power outages and a supplemental system.

If it matters, I'm looking at starting with 800w of panels, 2000w Pure Sine Inverter, Rover Elite MPP Charge Controller.
Going to install a completely different set of outlets that run completely off of solar. May slowly start running some things off of solar to save a few bucks on energy as well as test the limits of the system to see what I can expect to run if/when the power goes out. Eventually I want to grow the system to keep my sump pumps running in the case of a power outage too, as I have a history of getting flooding every few years in spring.

I've got most of my components figured out. Just thought I would get everyone's updated opinions on Batteries if they have changed much recently.
I'm using AGMs at my cabin because it stays there year-round in freezing temps. They've been great!

For the home system the batteries will be stored in my basement, so temps aren't an issue.
Thus - I'm going with lithium. Looking to start with maybe 400 ah worth of storage. Any opinions on the best way to go?

 

[Nobodybusiness]

Now that I've tuned in my off-grid cabin system, I'm finally getting around to starting up a system for my house.

This will be off grid and I'm starting it primarily as a back-up for power outages and a supplemental system.

If it matters, I'm looking at starting with 800w of panels, 2000w Pure Sine Inverter, Rover Elite MPP Charge Controller.
Going to install a completely different set of outlets that run completely off of solar. May slowly start running some things off of solar to save a few bucks on energy as well as test the limits of the system to see what I can expect to run if/when the power goes out. Eventually I want to grow the system to keep my sump pumps running in the case of a power outage too, as I have a history of getting flooding every few years in spring.

I've got most of my components figured out. Just thought I would get everyone's updated opinions on Batteries if they have changed much recently.
I'm using AGMs at my cabin because it stays there year-round in freezing temps. They've been great!

For the home system the batteries will be stored in my basement, so temps aren't an issue.
Thus - I'm going with lithium. Looking to start with maybe 400 ah worth of storage. Any opinions on the best way to go?

Very personal Recommendation. Everyone is going to be different according to what they want and what the can afford. I personally bought 112 Eve 3.2v 280 AH cells and made 7 x 48v 280ah packs. Gives me a little over 100KW in storage.
I use 2 Sol-Ark 12Ks in parallel. I have 32 x 400 Watt Q panels. About 12.8 KW total.
I have spent about $30,000 total but it runs my entire house and my shop. It’s ALWAYS cheaper to buy individual cells and make your own batteries. You just need to see what your requirements are and match your system to that.
Determine what you want to do with your installation then tailor it accordingly.
Good Luck.

 

[HARG Hunter]

Definitely willing to consider building my own.
I've been watching Will's videos on this, and I think I can do it.
I know for sure I can save a lot of money on batteries that way and stick it into panels.

I specifically looked at the Eve 3.2v 280 ah cells you mention. Looks like an easy way to build a decent sized bank for less.
Thanks for the input.

 

[Bluedog225]

Very personal Recommendation. Everyone is going to be different according to what they want and what the can afford. I personally bought 112 Eve 3.2v 280 AH cells and made 7 x 48v 280ah packs. Gives me a little over 100KW in storage.
I use 2 Sol-Ark 12Ks in parallel. I have 32 x 400 Watt Q panels. About 12.8 KW total.
I have spent about $30,000 total but it runs my entire house and my shop. It’s ALWAYS cheaper to buy individual cells and make your own batteries. You just need to see what your requirements are and match your system to that.
Determine what you want to do with your installation then tailor it accordingly.
Good Luck.

Now that is a system! I like your style. That’s about the price to run electricity to my place.

I’d like to go there once I figure out the details on building 48v packs. What BMS are you using?

 

[Hedges]

Terminals have caused various problems for some people. Consider packs with welded terminals (the way the cells were designed to be used)

Why DIY ?? Stop with Eve or Lishen or aluminium terminal cells without factory build stud/thread.

Hi guys. Serious question. Why. I've been struggling for almost 1.5 years now with Eve and Lishen, and yes, learning a lot. I now know a lot more then when I started and shared most of my learning curve. Due my latest accident, I had no usable cells left FIY, that's almost $6.000 worth, +50...

diysolarforum.com

 

[GLC]

I started off with 4 - 305 watt panels, 1-40 amp solar controller, 4 - 100 ah hour batteries and a 4000 watt pure sine wave inverter. Without battery cost, I had appx $1400 in the setup. It powered my lighting, tv's, ceiling fans and fridge. Since then I have almost tripled my system including heating my water. Good luck-it may become an addiction.

 

[Steve_S]

Something to consider before getting too deep into it. If you decide to build a 400AH Battery Bank you will require more than 800W of panel and 30A charge rate!

I just ran a charge on a 24V/768AH Bank that was sitting at 26.1V / 56% / 3.2625Vpc average.
Charge Rate of 75A CC then CV ran for 5 hours to reach 100% / 27.5v / 3.4375Vpc avg, and that was cut off @ 14A (endamps).
Within 1 Hour after the charge stopped bank settled to 26.5V/3.3125Vpc avg. While delivering an average load of 6A out from the end of charge.
* This particular bank is 2x 280AH Eve Bulk & one 175AH pack. (just some tests & thrashing I am doing ATM)

Without a doubt, DIY builds are less costly but time-consuming (more the waiting to get the stuff that makes everyone a tad batty).
You can fortunately get properly Matched & Batched 280AH & 304AH cells and of course heaps of Grade B & Brokered cells out there for less.

Something else to ponder upon.
Matched A Grade will provide their Specified AH from the Working Voltage Range, so when they are "Fully Capacity Tested" they usually come out higher than the label rating. IE a 280AH A will show 288-292AH Gross Capacity from 2.500-3.650. Working Voltage being 3.000-3.400 is where the 280AH should be coming from +/-0.050V pending on setup.

If you buy Bulk or B cells which only test out at 277AH Gross or so, (even if the label says 280) you will not likely get more than 260AH from the working voltage range. Consider that you are paying for Amp Hours delivered and when you do the numbers, Matched & Batched (even if they cost a little more) actually saves you on the other end of it. Another point on the Matched & Batched cells, is the likelihood of Runner Cells is greatly diminished which can clobber a pack capacity because they either trigger a Lo or Hi Cutoff at the BMS before the other cells at that point. Only takes one cell to Handicap a Battery Pack capacity. Imagine getting 7 Good Cells and one dud that caps the others to 75% usable capacity, you'd be TICKED to be polite...

Good Luck

 

[HARG Hunter]

Now looking at going with the Rover 60A MPPT charge controller.
Also watched a few videos from Will, and now I'm considering buying the CHINS 100ah LifeP04 batteries. Only $329 each.
Will gave those batteries a rave review for the price. The quality was good as well.

 

[HARG Hunter]

OK...I'm just going to keep posting my updated ideas and design.
Going to make it a 24v system.

(4) 200 watt 12v Panels (Sticking with 12v panels so I could use at my cabin in the future if needed) $219 per panel
(2) CHINS 12v / 100ah LifeP04 batteries (In series to get 24v) $329 per battery
(1) Rover 60a Charge Controller - $350
(1) GIANDEL 24v 2000w Pure Sine Wave Inverter - $370

Looks like about $2500 when I add in wires and cables.

With the system being this size, would an inline fuse between the inverter and batteries be enough, or do I need to add fuses or breakers anywhere else in the system? I will basically be wiring up 2 circuits for the house/garage that will run essentials. Fridge, Freezer, Outlets and Lights spread around the home etc... My wife works from home, so I would also power our internet modem and WIFI router as well. I haven't used my watt meter on everything yet, but hoping to run many of these things continually on this system even when power isn't out.

Please challenge me and pick this apart!

 

[MrM1]

I also think a main consideration for future expansion and future proofing your system to your personal needs and tastes is considering the system voltage you will design. Pretty much, once system voltage is established, it is probably the most difficult aspect of the system to change or upgrade and can be limiting to future plans. So I would weight carefully the system voltage: 12 / 14 / 48 volts.

 

[Bluedog225]

There was a recent thread on the benefit of 48 over 24. Might be worth checking out.

 

[Hedges]

OK...I'm just going to keep posting my updated ideas and design.
Going to make it a 24v system.

(4) 200 watt 12v Panels (Sticking with 12v panels so I could use at my cabin in the future if needed) $219 per panel

Please challenge me and pick this apart!

Cabin (12V battery?) isn't a reason to use "12V" panels. With an mppt charger, 24V or 36V panels are fine.

$219 for 200W PV panel? Check local Craigslist and eBay sorted by distance. You can find used panels $0.20 to $0.35/W, new excess $0.35 to $1.00/W (leftovers from large installs, extra bought in case some get damaged.)

You were going to spend $880 out of $2500 on PV. It becomes even less for bargain panels. Are you area limited? Look for panels 20% or higher in efficiency, to deliver more power in same space (unless the ones considered already were.)

800W PV, 2400Wh battery, 0.33C which is reasonable. Set BMS for low-temperature charge disconnect according to temperature where 0.33C is OK. If you can orient PV panels multiple angles, you get more hours and lower peak, maybe 560W peak allowing lower disconnect temperature.

I like over-paneling (power clipped at scc capability on good days) so full power on bad days.
I like battery charge current regulated at desired level, while additional PV power available for inverter - this requires communication between scc and battery current sensor. Probably built in to an AIO that has programmable charge current. Some component systems (Victron scc can be controlled). AC coupled systems with separate battery inverter. But I doubt Rover + Giandel can do that.

60A scc x 24V = 1440W
1440W / 2400 Wh = 0.6C
The Rover could deliver up to 0.6C to those batteries. OK for now with small PV array. What is battery max charge current? Can Rover be programmed lower? That would let you set max charge current if you added panels. Set BMS disconnect temperature accordingly.

 

[HARG Hunter]

Cabin (12V battery?) isn't a reason to use "12V" panels. With an mppt charger, 24V or 36V panels are fine.

$219 for 200W PV panel? Check local Craigslist and eBay sorted by distance. You can find used panels $0.20 to $0.35/W, new excess $0.35 to $1.00/W (leftovers from large installs, extra bought in case some get damaged.)

You were going to spend $880 out of $2500 on PV. It becomes even less for bargain panels. Are you area limited? Look for panels 20% or higher in efficiency, to deliver more power in same space (unless the ones considered already were.)

800W PV, 2400Wh battery, 0.33C which is reasonable. Set BMS for low-temperature charge disconnect according to temperature where 0.33C is OK. If you can orient PV panels multiple angles, you get more hours and lower peak, maybe 560W peak allowing lower disconnect temperature.

I like over-paneling (power clipped at scc capability on good days) so full power on bad days.
I like battery charge current regulated at desired level, while additional PV power available for inverter - this requires communication between scc and battery current sensor. Probably built in to an AIO that has programmable charge current. Some component systems (Victron scc can be controlled). AC coupled systems with separate battery inverter. But I doubt Rover + Giandel can do that.

60A scc x 24V = 1440W
1440W / 2400 Wh = 0.6C
The Rover could deliver up to 0.6C to those batteries. OK for now with small PV array. What is battery max charge current? Can Rover be programmed lower? That would let you set max charge current if you added panels. Set BMS disconnect temperature accordingly.

Thanks again for input. Still somewhat of a rookie here and I forget that panels and system voltage don't have to match.

I also always forget to check for local used panels. Just found someone on Facebook marketplace selling a 400w and 380w panel for $350 combined. Can save almost $500 right off the bat. Thanks for reminding me of that.

I won't have to worry about low temp disconnect, as these will all be stored in my basement.

I have indeed considered getting an All-in-One unit for sure. Seems like the cost would be similar to what the components would cost separately, plus I would save a little in cabling between components. Battery max current charge is 70 amps, Rover charges at 60 amps.

 

[Hedges]

I also always forget to check for local used panels. Just found someone on Facebook marketplace selling a 400w and 380w panel for $350 combined. Can save almost $500 right off the bat. Thanks for reminding me of that.

Look for similar Vmp if you plan to connect in parallel. If used in series, you'll get the lower Imp.

"Used" ought to be less than $0.50/W, more like $0.25/W
For $0.50/W you might get new panels, and all same model.
Check Santan for an idea of prices, even if you then shop locally for shipping reasons.
If you buy $800 worth (twice as many watts at half the price?) shipping a pallet from Santan could be OK. Pick up at freight terminal.

Design entire system before buying anything. Consider Voc (adjusted for cold), Vmp (adjusted for hot), Isc. Make sure they fit scc range.

I have indeed considered getting an All-in-One unit for sure. Seems like the cost would be similar to what the components would cost separately, plus I would save a little in cabling between components. Battery max current charge is 70 amps, Rover charges at 60 amps.

Consider 48V as someone suggested (you'll need higher voltage PV string to charge it).
Mpp has 24V AIO around $800, 48V around $1500. Midnight DIY another to consider.

 

[Hedges]

Not all used panels are good.
I tested a dozen 18 year old Sharp 165W panels from an underperforming string.
Three produced lower Isc.
Two had good Isc, but loaded with a space heater having resistance suitable for about Imp at Vmp, voltage & current were low.

 

[Nobodybusiness]

Now that is a system! I like your style. That’s about the price to run electricity to my place.

I’d like to go there once I figure out the details on building 48v packs. What BMS are you using?

Sorry for the late reply. Just saw this. I have a couple actually. Daly, JBD, Overkill. I have been using them all in differing amounts.

I use voltage reference in my inverters so doesn’t matter which BMS I use.

 

[Nobodybusiness]

Something to consider before getting too deep into it. If you decide to build a 400AH Battery Bank you will require more than 800W of panel and 30A charge rate!

I just ran a charge on a 24V/768AH Bank that was sitting at 26.1V / 56% / 3.2625Vpc average.
Charge Rate of 75A CC then CV ran for 5 hours to reach 100% / 27.5v / 3.4375Vpc avg, and that was cut off @ 14A (endamps).
Within 1 Hour after the charge stopped bank settled to 26.5V/3.3125Vpc avg. While delivering an average load of 6A out from the end of charge.
* This particular bank is 2x 280AH Eve Bulk & one 175AH pack. (just some tests & thrashing I am doing ATM)

Without a doubt, DIY builds are less costly but time-consuming (more the waiting to get the stuff that makes everyone a tad batty).
You can fortunately get properly Matched & Batched 280AH & 304AH cells and of course heaps of Grade B & Brokered cells out there for less.

Something else to ponder upon.
Matched A Grade will provide their Specified AH from the Working Voltage Range, so when they are "Fully Capacity Tested" they usually come out higher than the label rating. IE a 280AH A will show 288-292AH Gross Capacity from 2.500-3.650. Working Voltage being 3.000-3.400 is where the 280AH should be coming from +/-0.050V pending on setup.

If you buy Bulk or B cells which only test out at 277AH Gross or so, (even if the label says 280) you will not likely get more than 260AH from the working voltage range. Consider that you are paying for Amp Hours delivered and when you do the numbers, Matched & Batched (even if they cost a little more) actually saves you on the other end of it. Another point on the Matched & Batched cells, is the likelihood of Runner Cells is greatly diminished which can clobber a pack capacity because they either trigger a Lo or Hi Cutoff at the BMS before the other cells at that point. Only takes one cell to Handicap a Battery Pack capacity. Imagine getting 7 Good Cells and one dud that caps the others to 75% usable capacity, you'd be TICKED to be polite...

Good Luck

An active balancer solves any but the most goofy runners. I use Hel-Tek active balancer.
All the batteries I received were over Stated AH.

 

[Nobodybusiness]

OK...I'm just going to keep posting my updated ideas and design.
Going to make it a 24v system.

(4) 200 watt 12v Panels (Sticking with 12v panels so I could use at my cabin in the future if needed) $219 per panel
(2) CHINS 12v / 100ah LifeP04 batteries (In series to get 24v) $329 per battery
(1) Rover 60a Charge Controller - $350
(1) GIANDEL 24v 2000w Pure Sine Wave Inverter - $370

Looks like about $2500 when I add in wires and cables.

With the system being this size, would an inline fuse between the inverter and batteries be enough, or do I need to add fuses or breakers anywhere else in the system? I will basically be wiring up 2 circuits for the house/garage that will run essentials. Fridge, Freezer, Outlets and Lights spread around the home etc... My wife works from home, so I would also power our internet modem and WIFI router as well. I haven't used my watt meter on everything yet, but hoping to run many of these things continually on this system even when power isn't out.

Please challenge me and pick this apart!

If this is a stationary system I would seriously consider going with 48v.

 

[Nobodybusiness]

Now that is a system! I like your style. That’s about the price to run electricity to my place.

I’d like to go there once I figure out the details on building 48v packs. What BMS are you using?

You can do it even cheaper if you use the Chinese Inverters. With all the crap going on with the supply lines and the fact it’s almost impossible to get manufacturing support for some of them I went with Sol-ark. I know they are Deye inverter rebranded but the engineers are top notch and are always willing to help.
Plus I was going to use AC coupling initially also.

Building your own batteries is really fairly simple.
Considering you can buy a 280ah cell for $125 delivered to your door.
16 cells x125 is $2000 plus $200 for a BMS.

$2200 for 15KWH. No brainer.

No maintenance and when they die after 3000+ cycles I’ll replace them with whatever’s new and inexpensive then.

I have been a follower of RE for years. Was one of the first subscribers to Richard and Karen Perez Homepower magazine years ago.

It’s just now become economically feasible to do with a decent ROI.

 

[HARG Hunter]

If this is a stationary system I would seriously consider going with 48v.

I've been looking at that.
Wouldn't it be a helluva lot more expensive for my battery bank then?
(4) 12v - 100ah batteries only get me 100ah if I wire them in parallel to get to 48v.

(4) 12v - 100ah batteries would get me 400ah if I leave them at 12v.

Just wondering if the gain in 48v would make up for the cost. I'd be looking at an additional $3000 to achieve the same storage, or am I missing something?