Best way to hook up eight 12 volt batteries for 48 volt system...
softdown
Solar Expert Posts: 3,844 ✭✭✭✭
I once posted what looked like the most efficient way to do it. Unable to find that post or google the data. My brain is admittedly pretty fried from dealing with a 1AM total power failure. Spent 1 1/2 hours running around....then working on the problems again this morning.
There are quite a few "opinions". Think I'll recognize the best way if someone has it handy.
Already have the 12 volt batteries. They are Fullriver 260Ah AGM Deep Cycle pure lead at 175 pounds/battery.
There are quite a few "opinions". Think I'll recognize the best way if someone has it handy.
Already have the 12 volt batteries. They are Fullriver 260Ah AGM Deep Cycle pure lead at 175 pounds/battery.
First Bank:16 180 watt Grape Solar with FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
Comments
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The best way involves a clamp on ammeter to verify the result.
I am available for custom hardware/firmware development
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2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.
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2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.
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That is it....thank you. Since I have two 48 volt banks, I need to run two sets of charger cables of the same length.littleharbor2 said:
My current system looks pretty decent....at first glance. Wish I would have kept records of which battery placements had to be replaced. It seems like I am often replacing the same batteries in the configuration. I used truck 8D's...not an absolutely disastrous choice but a pretty poor choice as it turns out. A highly experienced "friend" assured me they were the best bang for the buck. I have about 2 1/2 years on them and have had to replace about half. Pretty sure I damaged some with a big defective charger hooked up to an over revving genset.
Figured I would "run them until they go bad". Did not expect a 1AM power failure during the summer though it has been cloudy.
Been completely focused on fixing a sailboat bottom. A pretty danged challenging job.....surprisingly challenging really.
First Bank:16 180 watt Grape Solar with FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries -
Now we radically shift gears after the wiring challenge has been thoughtfully addressed by littleharbor2...thanks lh2!
I am tempted to just use 4 of the FullRiver batteries so I can have good batteries for my future liveaboard sailboat. Thinking I can get away with it for these reasons:
1) They weight 175 pounds vs the ~120 pounds currently being used. Very high quality solar batteries vs cheap truck batteries.
2) Switched to smaller TV. My major power consumers are TV, computer, fridge and freezer, and security systems. The 24 volt system can *probably* handle all of the refrigeration except for the main unit in the bedroom. (I'm a lightweight prepper with two freezers)
First Bank:16 180 watt Grape Solar with FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries -
Lh2 - in the top diagram with two strings, wouldn't it be better to have the negative connect to the bottom string?
Softdown - within reason it may be a toss-up. Deeper discharge on a smaller bank means fewer lifetime cycles, so more frequent but less costly replacements. I'd probably have a go at modest bottom repair, but I'd likely not try to diy a badly blistered or structurally damaged one. Getting gelcoat fair is a lot of work.Off-grid.
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter -
Lots of blisters and plenty of fiberglass removal where some custom work separated over the years. Plenty of other unforeseen challenges. Don't they always present?Estragon said:Lh2 - in the top diagram with two strings, wouldn't it be better to have the negative connect to the bottom string?
Softdown - within reason it may be a toss-up. Deeper discharge on a smaller bank means fewer lifetime cycles, so more frequent but less costly replacements. I'd probably have a go at modest bottom repair, but I'd likely not try to diy a badly blistered or structurally damaged one. Getting gelcoat fair is a lot of work.
First Bank:16 180 watt Grape Solar with FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries -
Unforeseen challenges? With boats? Oh yeah.
That's going to be a long, tough job.Off-grid.
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter -
Should I use my 2 1/2 year old 4/0 copper cables with hammered indents? I used an "indenter" that was made for battery cables.
Or should I make new cables with hydraulic crimps? Pretty sure that I should make new cables.
FWIW and unrelated (don't read if pressed for time) I bought hydraulic crimpers thinking that I would make custom solar cables in my spare time. Was told I had a professional installer that would buy them. He complained that I only knocked off ~$3/cable from normal pricing and never bought any. Tell you what, stripping cable and doing hydraulic crimps with a 20 ton press takes a fair amount of hard work to do it right. Imagine if just one crimp was unsatisfactory. I am not a Chinese factory slave. In fact, I own several modest homes. Which is why I thought I would make battery cables, home maintenance in S. Florida is very expensive.
First Bank:16 180 watt Grape Solar with FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries -
Personally, I'd test the resistance on the old cables and give the lugs a hard tug. If they're good, I'd reuse. I'm cheap and kind of lazy though, and don't have hydraulic crimpers.;-)
Three bucks off sounds pretty reasonable to me.Off-grid.
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter -
Boat building is fun. When I was in Washington, I spent some time building Yachts for Christensen Motor Yacht there.
http://www.christensenyachts.com/
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Estragon, You're absolutely right. I was actually going to add a comment about that but as usual, I got sidetracked and hit the post comment button before I had made that note.Estragon said:Lh2 - in the top diagram with two strings, wouldn't it be better to have the negative connect to the bottom string?
2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.
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I think if you read closely, one will find an explanation of why the top design is a pretty poor design. It is Method 1 vs. Method 2 which is a large improvement. http://www.smartgauge.co.uk/batt_con.html
First Bank:16 180 watt Grape Solar with FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries -
I remember when/where you bought the DC260-12's. As I posted back then, I have seen very good service from "new-old" Fullriver AGM's and I said so at the time. I would really like to know how this pans out for you as tine goes on!
On cables: My official position is always to go for pro-grade hydraulic pressed with the CORRECT connectors. My personal side is cheap so I would see if the existing cables perform as expected.
I always have more questions than answers. That's the nature of life. -
It is very tempting. I know my Ideal 61-766 and 61-768 voltmeters will measure resistance if I knew how to do it. Bought them used with no manual.Marc Kurth said:I remember when/where you bought the DC260-12's. As I posted back then, I have seen very good service from "new-old" Fullriver AGM's and I said so at the time. I would really like to know how this pans out for you as tine goes on!
On cables: My official position is always to go for pro-grade hydraulic pressed with the CORRECT connectors. My personal side is cheap so I would see if the existing cables perform as expected.
You even posted a link for the battery manual....thanks for that. They were charged a month ago and currently showing about 12.65 volts at 70F. Seems a bit lowish.
First Bank:16 180 watt Grape Solar with FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries -
Here you go, the manual for your Ideally clamp on's
Edit, sorry this is the technical manual, will look for the user manual ,think I have it somewhere.1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding. -
Found it, the user manual.1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding. -
Thanks for that! Measured five cables and got readings of .2 - .4 with .3 being the most common. I have no idea if that is good or bad. Or how accurate the readings are.mcgivor said:Found it, the user manual.
First Bank:16 180 watt Grape Solar with FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries -
softdown said:
It is very tempting. I know my Ideal 61-766 and 61-768 voltmeters will measure resistance if I knew how to do it. Bought them used with no manual.Marc Kurth said:I remember when/where you bought the DC260-12's. As I posted back then, I have seen very good service from "new-old" Fullriver AGM's and I said so at the time. I would really like to know how this pans out for you as tine goes on!
On cables: My official position is always to go for pro-grade hydraulic pressed with the CORRECT connectors. My personal side is cheap so I would see if the existing cables perform as expected.
You even posted a link for the battery manual....thanks for that. They were charged a month ago and currently showing about 12.65 volts at 70F. Seems a bit lowish.
That is what I would expect based on my experience with that battery. Remember their age and the fact that they haven't been cycled to reach BCI standards yet. Once you cycle them a dozen times or so, you will see 12.8v to 12.9v measured 4-6 hours after charging.
You will see about 13.0v measured 4+ hours after a long float time. It would be very good to put them on a +/- 13.8v float for a day or two. Then let them sit for 4-6 hours and measure again.
Put a bigger than normal load on your cable set and measure voltage drop. That will give you a starting point.
Marc
I always have more questions than answers. That's the nature of life. -
I figured out how to get your Ideal to give you more decimal points on the read out. Push the black button that says "ZERO" until it delivers the desired number of decimal points. The black button is in between the rotary dial and the readout screen.mcgivor said:Here you go, the manual for your Ideally clamp on's
Edit, sorry this is the technical manual, will look for the user manual ,think I have it somewhere.
First Bank:16 180 watt Grape Solar with FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries -
The Ideal 61-766 does not say ZERO on the button. It is the black button to the right of the button for light.mcgivor said:Found it, the user manual.
Putting the cables on the floor instead of lap yields lower measurements. Now bouncing between .1 and .2 for the most part. The bouncing readouts is concerning.
First Bank:16 180 watt Grape Solar with FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries -
Aren't manuals great? You just learned something helpful, that's a good thing, I like that.1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding. -
Don't bother trying to measure ohms of the wires - the batteries themselves have different internal resistance. But do measure amps through each parallel path to check for good balance.
I am available for custom hardware/firmware development
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I am on a board filled with electricians and some engineers. I do aquarium maintenance and the landlord gig.jonr said:Don't bother trying to measure ohms of the wires - the batteries themselves have different internal resistance. But do measure amps through each parallel path to check for good balance.
While I have read a lot about solar, I have also forgot a lot about solar. It all seems a bit complicated really:
Panels
Racks
Wiring
Controllers
Inverters
Batteries
Gensets
..to name the basics
First Bank:16 180 watt Grape Solar with FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries -
Nice. I have been breeding and raising Tanganyika Cichlids for 45 years. Very rewarding and profitable.
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Pretty epic thread drift? I've known several people that bred and sold African Cichlids including me. It paid for the fish food, you must be doing something right.Solray said:Nice. I have been breeding and raising Tanganyika Cichlids for 45 years. Very rewarding and profitable.
Very few people are more avid about fishkeeping than I was. Used to run 700 gallons of fishkeeping before going pro. Freshwater is less problematic....but doesn't provide as much cash flow.
There is little comparison between keeping home aquariums and doing full time maintenance....in my opinion.
First Bank:16 180 watt Grape Solar with FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries -
Yes.....makes a great 12 volt battery bank. Not sure why I thought it was 48 volt. Back to the drawing board.littleharbor2 said:
First Bank:16 180 watt Grape Solar with FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries -
Still have a handy link to the manual for those batteries? Been so long that the information seems a bit buried. Don't try hard if it isn't handy....I should be able to dig something up if pressed.Marc Kurth said:I remember when/where you bought the DC260-12 's. As I posted back then, I have seen very good service from "new-old" Fullriver AGM's and I said so at the time. I would really like to know how this pans out for you as tine goes on!
On cables: My official position is always to go for pro-grade hydraulic pressed with the CORRECT connectors. My personal side is cheap so I would see if the existing cables perform as expected.
I seem to recall being able to treat these batteries like FLA's.
First Bank:16 180 watt Grape Solar with FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries -
You are not going to get accurate milliohm measurements with standard meters/leads. In any sort of reasonable cabling, the resistance in the meter leads (and the resistance between the probe tips and cable) will dominate.softdown said:
The Ideal 61-766 does not say ZERO on the button. It is the black button to the right of the button for light.mcgivor said:Found it, the user manual.
Putting the cables on the floor instead of lap yields lower measurements. Now bouncing between .1 and .2 for the most part. The bouncing readouts is concerning.
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Still might be useful for finding a bad connection with the lugs?bill von novak said:
You are not going to get accurate milliohm measurements with standard meters/leads. In any sort of reasonable cabling, the resistance in the meter leads (and the resistance between the probe tips and cable) will dominate.softdown said:
The Ideal 61-766 does not say ZERO on the button. It is the black button to the right of the button for light.mcgivor said:Found it, the user manual.
Putting the cables on the floor instead of lap yields lower measurements. Now bouncing between .1 and .2 for the most part. The bouncing readouts is concerning.
First Bank:16 180 watt Grape Solar with FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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