$6256 for (64) (280Ah)(New) LiFePO4

mzoid

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No. It’s my understanding that if you get the correct BMS for your application, one BMS can control a 1, 2p, 3p or 4p16s battery bank.
That’s why I’m looking at Batrium or Orion.
However, also keep in mind depending on the inverter you have, a BMS is not required, but is highly recommended.
Can it be done the way you described above? Yes it could, but that’s added expense, and the more items you have that are electronic, the more opportunity for you to have issues. Over complication.
Thanks Shawn. Yes, good to keep things as simple as possible. The complexity argument cuts both ways though, in this instance, because a failure of the BMS when you are using only one, can leave you dead in the water, whereas a single BMS out of 4 failing, and everything might be able to carry on happily while the defective one is replaced? Same consideration for protecting the batteries from damage: if a low or high temperature cutoff or voltage cutoff fails, you can have all of your cells damaged, or just one quarter of them. Over a period of 10-15 years, the odds of this becoming more than a hypothetical are something worth some pause?
 

Shawn Hayes

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Thanks Shawn. Yes, good to keep things as simple as possible. The complexity argument cuts both ways though, in this instance, because a failure of the BMS when you are using only one, can leave you dead in the water, whereas a single BMS out of 4 failing, and everything might be able to carry on happily while the defective one is replaced? Same consideration for protecting the batteries from damage: if a low or high temperature cutoff or voltage cutoff fails, you can have all of your cells damaged, or just one quarter of them. Over a period of 10-15 years, the odds of this becoming more than a hypothetical are something worth some pause?
You definitely have a way of doing it. Most here may disagree? Not sure what inverter you’re using, but you can operate with conservative settings without a BMS. Again not recommended for long term use without a BMS however, it’s possible. However I will use only one (Batrium or Orion) BMS with my 4p16s bank. I know if the BMS fails I can still operate, operate safely within certain inverter preset limits. So I would not be dead in the water. And could get a replacement BMS within a reasonable amount of time without concern.
I’m using a Sol-Ark 12k btw.
 

mzoid

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You definitely have a way of doing it. Most here may disagree? Not sure what inverter you’re using, but you can operate with conservative settings without a BMS. Again not recommended for long term use without a BMS however, it’s possible. However I will use only one (Batrium or Orion) BMS with my 4p16s bank. I know if the BMS fails I can still operate, operate safely within certain inverter preset limits. So I would not be dead in the water. And could get a replacement BMS within a reasonable amount of time without concern.
I’m using a Sol-Ark 12k btw.
I sometimes forget I am thinking about this differently than most folks as I'm setting it up for a remote island location where acquiring replacement units will be a challenge. The $30 cost of a BMS in my application is not really a consideration. I'll probably order 4 or 5 of them so I have 2 or 3 backup ones beyond the first two that go into service. I'm even oversizing the battery bank so that my average consumption will draw only 27% of the bank: the bank stands a good chance of lasting longer than I do! Everything looks a bit different when thinking about remote location, and lots of redundancy.

Haven't picked the inverter yet.
 

Shawn Hayes

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Yes, details and context of your situation definitely helps put things in perspective.
I agree with you about having redundancies, there are multiple ways of doing that as well.
 

itsmattmp

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So if you have a 280 ah LiFePo4 w/ a discharge rate of 1C, build a 4p16s pack, 1C rating should get multiplied X 4, correct?
280 ah X 4p = 1120 ah, would the peak amp draw be 1120 amps for one hour?
One consideration I've been made aware of here, if planning to draw that many amps, is the weak spot will be your bus bars. Granted, the bus bars will be short, so should be able to handle a large load, but I have a Blue Sea 250 Amp bus bar and it's a quarter inch thick. That bus bar is 4 times as long as these will be, but still something to consider. Might want to double or triple your bus bars if you're planning on that level of amps.

My bank will be half your size, but I'm interested in how you're planning to arrange your pack with a single BMS. I too am using a single BMS for my 2p16s bank. It's the Chargery with their 600 amp solid state relay. Third parties also make larger relays that could be used, but 600 works great for my use.
 

Shawn Hayes

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I bought 4/0 welding cable to make bus bars where packs are connected serially.
I’ll be using either Batrium BMS or Orion BMS. I will be connecting and monitoring my pack as if it’s only 16 cells. There’s 4 cells are in a “pack”, hence one cell. Voltage should transfer between those in parallel and Batrium BMS can active balance those in series. One lead per “pack” of 4 batteries to monitor that pack as one cell.
Good matched cells & top balanced cells really help when starting.
Orion only offers passive balancing.
 

itsmattmp

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I bought 4/0 welding cable to make bus bars where packs are connected serially.
I’ll be using either Batrium BMS or Orion BMS. I will be connecting and monitoring my pack as if it’s only 16 cells. There’s 4 cells are in a “pack”, hence one cell. Voltage should transfer between those in parallel and Batrium BMS can active balance those in series. One lead per “pack” of 4 batteries to monitor that pack as one cell.
Good matched cells & top balanced cells really help when starting.
Orion only offers passive balancing.
Nice. That makes sense that most of the current would be taking place across the series connections. Nice solution.
 

Shawn Hayes

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I’m still learning every day here. I’ve learned a lot from folks here and researching online. I’m very grateful for those who help and share!! I hope what I do and learn can help in return.
 

Shawn Hayes

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If anyone has experience with the Orion BMS or Batrium BMS would share info, that’d be awesome?!? I haven’t made that decision/ purchase yet......
 
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