Need expert help on new large battery bank for off grid..

Hey guys, I have a vacation home off grid and I am building a new battery bank. The system will be 48v. My inverter will be 48v 3000 watts. I got a good hook up on 12 volt AGM batteries they are 140ah at 20hr rate. I bought 24 of them. I will make 6 strings of 4 batteries each. I know its overkill but I could not pass up the deal. We only go a few weekends a month so most of the time the bank will be at idle.
Here are my questions:
1. I have a buss bar on each end. Cable length from each string in 18". I will need to buy 12 cables for 6 strings. What guage cable do I need for this?
2. I would like to run breakers. Should I run a breaker on each string? Thats 6 breakers.
3. What size breakers do I need for each string?
4. Coming off the bus bars combing all the batteries what guage wire should I run to the inverter? These two cables will be 32" each.
5. I have a midnight solar 200. How critical is it for the output cables to be the same length? Would 18" pos and 50" neg be a bad set up?
6 In the middle of each string I will run a 1" x 1/4" copper flat bar about 4" long. so the battery have a 1" space between them. It gets up to 100deg here. Is this copper bar sufficient?

Thanks
Bryan
Here are my questions:
1. I have a buss bar on each end. Cable length from each string in 18". I will need to buy 12 cables for 6 strings. What guage cable do I need for this?
2. I would like to run breakers. Should I run a breaker on each string? Thats 6 breakers.
3. What size breakers do I need for each string?
4. Coming off the bus bars combing all the batteries what guage wire should I run to the inverter? These two cables will be 32" each.
5. I have a midnight solar 200. How critical is it for the output cables to be the same length? Would 18" pos and 50" neg be a bad set up?
6 In the middle of each string I will run a 1" x 1/4" copper flat bar about 4" long. so the battery have a 1" space between them. It gets up to 100deg here. Is this copper bar sufficient?

Thanks
Bryan
Comments
I am available for custom hardware/firmware development
3,000w inverter @ 46V would be 65 amps. I'd put 50-70A DC breakers (from Midnight Solar) on each battery string. Mounting breakers might be an issue, because the arc chute wants to be oriented with the breaker upright, as if it were in a panel. The leads in and out of the breakers count as part of the matched lengths.
Battery cable wires, assume only one string is working , 65A at full load in the inverter would be #4 wire, I'd use #2 - good for 95A, and you need margin so your 70A breaker blows before the wire does.
I'm sure there's some spec that says 60A circuit to be wired with 120% rated wire (72A)
Bus bar to inverter, at least 1/O cable. There will be starting surges from motors, and you want the inverter to be well fed.
Battery - Battery interconnects, you want something that will flex, and not bend/crack a terminal or case, Either tinned flat braid, or MT cable.
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
Not as handy as a breaker but a lot easier to mount.
Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor
21 SW280 panels on Schletter ground mount
48v Rolls 6CS 27P
What about somthing like this?
https://www.bluesea.com/products/category/14/32/Circuit_Breakers/285-Series
OR
in 4 years when you replace batteries, you may only purchase 2 strings, and work the snot out of the battery bank, saving money on excess bank capacity.
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
Two of these enclosures can mount the six breakers, 3 in each.
https://www.solar-electric.com/mnedc-quad.html
This is the breaker used in the enclosure, I believe Mike suggested 70 amp.
https://www.solar-electric.com/pamodccibr.html
Remember, the breakers protect the cable and must be able to carry the full amperage draw of the inverter.
I can't hardly imagine needing more than 12 of those batteries. In fact, I would be inclined to believe that 8 would work fine. FWIW....I have found that good batteries store OK if kept cool and charged over 12.5 volts.
Breaker sizes - PV strings- 8 to 12 amps
PV to charge controller - 25 to 30 amps, THHN #6 AWG cable
Controller to battery bank - 60 to 70 amps, Recommend a THHN #4 AWG cable, although a #6 will do.
Could I ask why you are using such high voltage PV strings? Are the solar panels mounted very far from the controller and batteries? Otherwise, three panels in series would have been more efficient.
https://www.bluesea.com/products/2151/Dual_MRBF_Terminal_Fuse_Block_-_30_to_300A
With fuses, you loose an easy way to disconnect one string from the system.
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
As for the panels what am I losing? I have the midnight solar 200v model. The way my roof is perfect wide for 4 panels. I made adjustable frame for summer and winter. Heck my little Honda eu1000 gen is all I need. I don't need any color or batteris. But what's the fun in that. I feeling of running my account for free off the sun.. When I am full time I will need to figure how to a/c all the house... dc mini splits will be the way to go.
Few times a year I do go for a 2 week stretch.
Anybody have a good source to buy tined copper cable lugs? I think I will get about 100 of them.
Something like this? But cant find breakers that will except #2 cable.
https://www.solar-electric.com/mndico.html
http://www.ebay.com/itm/10-Ton-Hydraulic-Wire-Battery-Cable-Lug-Terminal-Crimper-Crimping-Tool-9-Dies-E1-/221862199523?hash=item33a80480e3:g:DuYAAOSwTA9X2MAV
Or is this a more simple way to do it?
http://www.ebay.com/itm/Heavy-Duty-Battery-Welding-Cable-Hammer-Crimper-8-4-0-GA-5-YEAR-WARRANTY-/282168744327?hash=item41b2915987:g:xlEAAOxycERRjV1U
https://www.solar-electric.com/36432.html
please don't use a hammer lug crusher
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
In many cases, I think this is a good way to go. AC for the entire building might take excessive power - but one very well insulated and air sealed room will be much less while providing a place to escape the heat. If you want to get fancy, consider adding lots of thermal mass and materials that absorb humidity (sort of a thermal and humidity battery).
I am available for custom hardware/firmware development
Marc the batteries are made by data safe they are 12HX540-fr. Hard to find solar related data on them. If you look up trojans they are identical. http://www.trojanbattery.com/pdf/datasheets/12AGM_Trojan_Data_Sheets.pdf
Not an issue. each cable should be as short as possible.
--vtMaps
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
I could not readily locate DOD/Cycle rating on these, but Enersys batteries of this general type tend to run around 500 cycles at 50% depth of discharge. If you limit it to 25%-30%, you are likely to get closer to 1000 or more charge/discharge cycles from a new set.
In general terms, it is important to provide these batteries an extended float time as often as possible.
and putting a Z bend/kink in it, will allow stress to be absorbed in the flex of the wire, not the battery terminal.
But if you are only experiencing a 20 or 30 degree swing, that's not much. Here I deal with 105F summer and 20F
See attached pic and link. (expansion loop)
http://engineering.stackexchange.com/questions/569/what-is-the-purpose-of-these-diversions-in-a-natural-gas-line
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,