Looking for advice: is this a fair price?

Hi (Joel, I think),  welcome to the Fourm.

IMO,  you should get several quotes on a system that meets your needs.

I assume that you are an Amateur Radio person,  so,  even with modern Digital modes,  RFI from solar systems can limit your ability to copy weak signals.  And, solar power systems can create horrible RFI,  particularly in the HF frequency spectrum.

Again, IMO, for Grid tied, PV arrays on the roof of residential structures (these are the most common designs) you should probably AVOID any solar system that uses Optimizers on the PV modules.  These are often used to comply with Rapid Shutdown,  to help protect Firefighters who may need to access rooftops, when fighting fires.  BUT,  these optimizers are DC to DC converters which usually have minimal RFI suppression for the HF frequency ranges (below 30 mHz) and usually create intolerable RFI throughout the HF spectrum.   AND,  since these optimizers are not connected to the AC Grid, their emissions, below 30 mHz are not required to be tested.

So please get three-ish, or more qoutes on a system that will meet your needs,  speak with neighbors, and friends when considering which company you should approach to do the work,  and so on.

Many Hammie friends have had very good results with PV systems that use Microinverters (usually one per PV module),  creating no measurable RFI (probably because these inverters connect to 240 VAC grid power, and can perform rapidshutdown without using optimizers).  Since microinverters DO connect to the Grid power they ARE tested for emission compliance for frequencies between approximatrely 150 kHz and 30 mHz.  Some Ham friends with systems using optimizers (or even with neighboring systems) have reported horrible RFI,  when the sun shines from systems using these "Optimizers".

[Edited to remove an editing widow,  typos and a redundancy, etc]

YMMV,  IMO,  and so on 73, GL,  Vic

OutsourcedGuru said:

I personally don't see the value in lithium batteries, to be honest. 

I built my 11.5 kwh LFP battery for under $2,000 . Of that 11.5 kwh, about 10kwh is useable. You would need 20kwh of lead acid batteries to get that much useable power. Thats about 16 golf cart batteries. Have you priced golf cart batteries lately?   I, personally DO see the value in lithium batteries. Oh and by the way, with the kind of usage I put mine under, (about 30% dod) , I expect somewhere north of 5,000 cycles. How many cycles are you getting from your lead acids?

OutsourcedGuru said:

littleharbor2 said:

I built my 11.5 kwh LFP battery for under $2,000 . Of that 11.5 kwh, about 10kwh is useable. You would need 20kwh of lead acid batteries to get that much useable power. Thats about 16 golf cart batteries. Have you priced golf cart batteries lately?   I, personally DO see the value in lithium batteries. Oh and by the way, with the kind of usage I put mine under, (about 30% dod) , I expect somewhere north of 5,000 cycles. How many cycles are you getting from your lead acids?

Basically, the battery assemblies inside a Tesla are essentially like what you built, a bunch of small Lithium batteries welded together. The subassemblies at Tesla are replaced as a unit when individual cells go out because they're a pain to quickly repair one.

In fact, feel free to watch all the YT videos of the people demonstrating how to replace individual dead cells in the 20VDC batteries typical within the power tool market. In my experience, these stacked Lithium cell battery arrangements are a recipe for problems within five years, as combined with a fair amount of down time while you're troubleshooting which cells are dead. And yes, I've watched the videos where people are building what you built. If I did go that route, I think I would build modular subassemblies rather than putting all my eggs in one basket.

A lead-acid battery can be desulfated with a welder at the five-year mark, not so with your Lithium cells.

I price deep-cycle batteries all the time since I install solar systems for customers. I prefer to buy from Continental Batteries in Albuquerque because they have full pallets of the ones I like. The price I pay is less than $200 each since I'm a veteran and frequent customer.

I don't build my batteries out of 18650 cells like a Tesla battery. Mine are built with prismatic cells. A 48 volt battery has 16 cells, a 24  volt has 8 and a 12 volt battery has 4 cells. I'm pretty sure most of the DIY lithium batteries you read about on this site are similar builds.

I am getting ready to build a couple 48 volt banks for friends. One friend just ordered her 16, 305 amp hour cells and BMS today and her bill including delivery was just over 1,750 dollars.It would take you 8 golf cart batteries to build a 210 amp hour 48 volt bank. That's going to cost the average joe about 1,600 just for the batteries and it would yield 1/3 the usable power. 

OutsourcedGuru said:

littleharbor2 said:

I don't build my batteries out of 18650 cells like a Tesla battery. Mine are built with prismatic cells. A 48 volt battery has 16 cells, a 24  volt has 8 and a 12 volt battery has 4 cells. I'm pretty sure most of the DIY lithium batteries you read about on this site are similar builds.

I am getting ready to build a couple 48 volt banks for friends. One friend just ordered her 16, 305 amp hour cells and BMS today and her bill including delivery was just over 1,750 dollars.It would take you 8 golf cart batteries to build a 210 amp hour 48 volt bank. That's going to cost the average joe about 1,600 just for the batteries and it would yield 1/3 the usable power. 

I hope that works out for you and your customers. It sounds like this for 48VDC. So, $1100 for 48V @ 100Ah versus $800 for  four  6V deep-cycle marine batteries 24VDC @ 225Ah. At least there is some modularity in the prismatic cells. A set of sixteen of the lead-acid would then be $1600 for 48VDC and it sounds like it's still less than $2200 for the prismatic at just 200Ah, right?

Here on the Continental Divide it gets cold in the winter. I found that my MacBook refused to charge. I took it into Albuquerque and paid for a battery replacement. Got home and it still wouldn't charge. Jumped onto the Apple forum where hundreds of people were making the same complaint. Lithium batteries and their charging circuits don't seem to want to charge below a certain temperature. I ended up writing a program—I'm not kidding—which does floating-point arithmetic to warm up the processor just to get the MacBook's charging circuit to get above 60.8°F so that it will then charge the Lithium battery. Hopefully you and your customers are in a warmer climate than myself.

I will just say: Interesting post......