Help with off-grid solar circuit

[Superdoom]

My personal opinion is it is an attempt by the traditional Lead Acid manufacturers to rebrand 100 year old technology to compete with Lithium.

Lead Acid manufacturing and Lithium battery manufacturing require significantly different processes so I do NOT think those Lead Acid manufacturers will retool to make Lithium. In addition, with the exception of Tesla and Nissan most of the Lithium production capacity is in Asia. The European auto manufacturers are scrambling to build battery capacity.

There is a huge disruption on the horizon, but I can't tell you if it is next year or next decade. I am too old to waste my time on old technology but for younger people they can afford to learn about the fundamentals using Lead Acid because it is is still the least expensive. By the time they burn through their first pack there will be a lot more cost effective choices.

Wise words there, I reckon. That is how I see it too, and I don’t mind using an older technology because I know there are technologies even more sophisticated than lithium-ion in regard to battery power which, like you said, may be coming next year or maybe years from now. In any case, when it does happen, those batteries might strike my fancy, or at least they may drive lithium prices down a fair bit. Lead acid batteries may drop too, though, and I love a bargain, hah!

Back to circuiting... I see you run a 9kw solar array? Are you off grid? If so, could you run me through your setup?

[Ampster]

.........
Back to circuiting... I see you run a 9kw solar array? Are you off grid? If so, could you run me through your setup?

I am on the grid. I have a 5.7 kW grid tie system facing South on my roof using a 3.8 SolarEdge Inverter. I also have an Outback Skybox hybrid inverter powered by 2.3 kW of west facing solar panels on a patio cover. That system is supported with about 9 kWhrs of Nissan Leaf batteries configured in a 48 volt pack. AC coupled to that is another 1kW of panels on that patio cover powered by Enphase inverters.

We have several public safety power outages a year for several days plus an ocassional hour or two outage. Since most of those outages have occurred during sunny weather I can ride through those with basic power coming from the 3.3 kW on the patio cover plus the batteries at night. As further backup I have a 2kW inverter that can run some 120 volt loads powered by one or the other of my EV batteries. So far I have not had to rely on that EV powered system.

[Ampster]

......... I don’t mind using an older technology because I know there are technologies even more sophisticated than lithium-ion in regard to battery power which, like you said, may be coming next year or maybe years from now. ..........

I try to follow the developments in the Lithium space and I have not seen anything yet that will be able to scale up like Lithium in the next decade. I have watched Elon Musk make strategic moves in the market and various aspects of battery manufacturing. If there is a technology other than Lithium I think Tesla would have invested in it. Tesla has invested in super capacitors and manufacturing capacity. Super capacitors are probably only relevant to EVs since that kind of surge capacity is not needed in the stationary market like we are talking about. Tesla has tweaked and will continue to tweak the chemistry and they have purchased companies that can reduce the manufacturing cost of Lithium cells. What I do hope to see is Lithium prices coming down as the capacity grows to serve those markets. The volume of Lithium batteries has increased because of smart phones and tablets but those are small form factor and are not the mega Watt hours of capacity that will be needed for the EV and grid storage markets in the near future.

[SunEagle]

I try to follow the developments in the Lithium space and I have not seen anything yet that will be able to scale up like Lithium in the next decade. I have watched Elon Musk make strategic moves in the market and various aspects of battery manufacturing. If there is a technology other than Lithium I think Tesla would have invested in it. Tesla has invested in super capacitors and manufacturing capacity. Super capacitors are probably only relevant to EVs since that kind of surge capacity is not needed in the stationary market like we are talking about. Tesla has tweaked and will continue to tweak the chemistry and they have purchased companies that can reduce the manufacturing cost of Lithium cells. What I do hope to see is Lithium prices coming down as the capacity grows to serve those markets. The volume of Lithium batteries has increased because of smart phones and tablets but those are small form factor and are not the mega Watt hours of capacity that will be needed for the EV and grid storage markets in the near future.

I agree that Li chemistry batteries is the path for the future. They are more robust in being able to deliver their energy faster and longer then FLA type batteries.

All I have been saying is that until the cost of NEW Li chemistry batteries equal or are lower then NEW FLA type batteries I will have a hard time economically justifying their purchase for home usage.

[Superdoom]

I am on the grid. I have a 5.7 kW grid tie system facing South on my roof using a 3.8 SolarEdge Inverter. I also have an Outback Skybox hybrid inverter powered by 2.3 kW of west facing solar panels on a patio cover. That system is supported with about 9 kWhrs of Nissan Leaf batteries configured in a 48 volt pack. AC coupled to that is another 1kW of panels on that patio cover powered by Enphase inverters.

We have several public safety power outages a year for several days plus an ocassional hour or two outage. Since most of those outages have occurred during sunny weather I can ride through those with basic power coming from the 3.3 kW on the patio cover plus the batteries at night. As further backup I have a 2kW inverter that can run some 120 volt loads powered by one or the other of my EV batteries. So far I have not had to rely on that EV powered system.

That’s super interesting!! I never thought about facing panels out her directions other than North... would you recommend facing panels East and West? Also, how did you rig up all your inverters to your house? Do you switch them over or something?

[Superdoom]

I agree that Li chemistry batteries is the path for the future. They are more robust in being able to deliver their energy faster and longer then FLA type batteries.

All I have been saying is that until the cost of NEW Li chemistry batteries equal or are lower then NEW FLA type batteries I will have a hard time economically justifying their purchase for home usage.

I think they are beginning to understand how carbon and carbon fiber can be used in batteries?

[Ampster]

That’s super interesting!! I never thought about facing panels out her directions other than North... would you recommend facing panels East and West? Also, how did you rig up all your inverters to your house? Do you switch them over or something?

I have a very high TOU rate beginning at 2PM and the 1kW system was the maximum allowed under my existing NEM agreement so those were the parameters driving my decision. It is actually four used 305 Watt Sunpower panels that cost $0.33 Watt but they have never output more than 900 Watts. The racking and wire I had laying around and the patio cover I had constructed to shade the west side of the home. The Enphase Inverters plus trunk cable cost $600 so the total cost was about $1000. I expect that little system to create a credit of $400 per year so it will pay itself off in less than three years.
The optimum direction to face panels is South and that is how my primary 5.7kW system faces and that was installed by a professional on my roof. I don't spend much time on roofs any more but building a patio cover is something I could do easily from a ladder. My recomendation would be to use as much of your South facing exposure unless you have reasons to have some panels facing in another direction. The best treatise on one advantage of other orientations in additiona to South is this thread:

https://www.solarpaneltalk.com/forum/solar-panels-for-home/solar-panel-system-equipment/376062-building-reserve-and-using-kwh

and there is further discussion and debate on this thread;

https://www.solarpaneltalk.com/forum/solar-panels-for-home/solar-panels-for-your-home/401536-east-array-south-array-west-array

My main Grid Tie system was professionally installed in a new 200 Amp service panel. Since I knew I was going to add a hybrid inverter and wanted a critical loads sub panel for that I installed two subpanels on the interior garage wall directly behind my exterior mounted main panel. Every thing was surface mounted to plywood that made things easy to mount and covered up the holes in the drywall that I used to access the various circuits. I used wiring gutters above and below each of the subpanels. That made swinging the circuits to one panel or the other easy and left plenty of room in the gutters for wire splices and current transformers that I use to measure consumption and generation. Also when I added the hybrid inverter it was a simple matter swing the feed from the main panel to the critical loads panel over to the hybrid inverter and provide a feed from the hybrid inverter to power the critical load subpanel.

Most of the time the power flows directly from the main panel through the hybrid inverter and then to the critical loads subpanel. The hybrid inverter can be programmed to use the grid as little as possible so when its solar panels are generating power the hybrid inverter powers the critical loads subpanel. Also the hybrid inverter can use the batteries to power the critical loads subpanels to ride through the peak rate time so that I use very little power at peak rates.

When the grid is down the hybrid inverter takes over providing all the power to the subpanel and actually disconnects the grid connections as a safety precaution to avoid backfeeding the grid and endangering any linemen that might be working on the line somewhere in the neighborhood. The small Enphase system is also connected to this subpanel so even though it is it is a grid tied system it can sync off the hybrid inverter 60Hz signal and begin to also provide power as needed to that panel. It does this through a process known as AC coupling. A schematic or line drawing would probably make this a whole lot simpler. I will try to find one from my building permit.

[Ampster]

I think they are beginning to understand how carbon and carbon fiber can be used in batteries?

Carbon has been used in flashlight batteries for a long time but carbon fiber is an entirely different thing, I agree with @SunEagle's comment but his comment has nothing to do with the use of carbon.in batteries.

[SunEagle]

Carbon has been used in flashlight batteries for a long time but carbon fiber is an entirely different thing, I agree with @SunEagle's comment but his comment has nothing to do with the use of carbon.in batteries.

Thanks. You are correct. I did not comment on the need for carbon or fibers being part of FLA batteries.

I really want Li chemistry to start being cheaper and used more. But as of this time it makes no sense to get that type of battery for my home usage. Now I think installing POCO sized Li systems are helpful but even they are limited to a number of kWh usage that could drain them over extended periods.

[Superdoom]

Thanks. You are correct. I did not comment on the need for carbon or fibers being part of FLA batteries.

I really want Li chemistry to start being cheaper and used more. But as of this time it makes no sense to get that type of battery for my home usage. Now I think installing POCO sized Li systems are helpful but even they are limited to a number of kWh usage that could drain them over extended periods.

Doesn’t the cost have something to do with the relative scarcity of lithium and cobalt to lead and carbon?

[Ampster]

Doesn’t the cost have something to do with the relative scarcity of lithium and cobalt to lead and carbon?

No, the majority of the cost has to do with the process or producing the cells and the other materials other than the Anode and Cathode, . A quick Internet search suggests that the cost of the Anode and Cathode, is about 30% of the total cost of a cell. There is no scarcity of Lithium, Cobalt unfortunately comes mostly from one country in Africa whether you call that scarcity, monopolistic pricing or Blood Cobalt the price of that one element has increased. Not all Lithium batteries use Cobalt so one can't make generalizations. BYD, a large Chinese manufacturer, makes a significant number of LFP cells that contain no Cobalt. Within the larger Lithium chemistry there is the ability to substitute some elements, which may affect battery pack construction and reduce costs.

[SunEagle]

Doesn’t the cost have something to do with the relative scarcity of lithium and cobalt to lead and carbon?

I do not believe the cost is associated with lack of materials as Ampster indicates. The cost is in the building of the batteries and the profit margin desired by the manufacturers.

[Superdoom]

Righto, sounds like scarcity of material or difficulty in obtaining such materials plays a small part in the issue, but the real issue is manufacturer pricing. I’m trying to do this for the cheapest price possible whilst still having a reliable system.

SunEagle, you sound like you know your way around lead acid batteries. Got any general advice about the voltage/amps received by lead acid batteries during bulk/absorption/float/equalization phases? Do general rules exist for this?

[SunEagle]

Righto, sounds like scarcity of material or difficulty in obtaining such materials plays a small part in the issue, but the real issue is manufacturer pricing. I’m trying to do this for the cheapest price possible whilst still having a reliable system.

SunEagle, you sound like you know your way around lead acid batteries. Got any general advice about the voltage/amps received by lead acid batteries during bulk/absorption/float/equalization phases? Do general rules exist for this?

There are a couple of Stickie posts that Sunking had put on the forum concerning FLA type batteries. Since there are now a number of different manufacturers that sell them I always tell the person to refer to the specification sheet that is associated with that particular battery. They should list all of the charging voltages.

[Superdoom]

There are a couple of Stickie posts that Sunking had put on the forum concerning FLA type batteries. Since there are now a number of different manufacturers that sell them I always tell the person to refer to the specification sheet that is associated with that particular battery. They should list all of the charging voltages.

Looked into it, and I will just be sure to look at the product information sheet and specs when setting it all up. Think I’ve basically gathered all I need to know, I just need to find the right parts. Kind of a fun process.

Also, out of curiosity, what would persons recommend be the procedure for topping up FLA batteries? Any pro-tips or words of warning?