Best BMS to use

buzzard

New Member
I plan on ordering the 190AH kit on DIY solar blueprints page.
I want to buy 3 kits and run it 12volt.
If I parallel 3 cells together then series the 3 sets and use the large relay to connect to my 2800 watt inverter.
Which BMS should I use? The New Daly BMS Will reviewed with the temp monitor be ok?
As the 3 cells are paralleled will the bms monitor as 1 cell.
Thanks in advance George
 

jasonhc73

Cat herder, and dog toy tosser.
How many cells will be in the series?

When you parallel batteries, they passively equalize to each other by being connected to each other. This is not the case for the series batteries though.

I use a blue-tooth controlled BMS, it has all these functions:
  • Cell High Alarm
  • Cell Low Alarm
  • Cell Hight Protect
  • Cell Low Protect
  • Total Volt High Protect (this protects the entire battery, not just the cell)
  • Total Volt Low Protect
  • Charge Over Current Protect
  • Discharge Over Current Protect (This means it will turn off the battery before you even come close to tripping a circuit breaker)
  • Cell Difference to start Balancing
  • Charge High-Temperature Protection
  • Discharge High-Temperature Protection
  • Mosfet high-temperature protection (The BMS has built-in protection for itself!)
  • Charge Low-Temperature Protection
  • Discharge Low-Temperature Protection
  • System Shut down cell voltage - This is probably the most important protection you can have, never empty a LiFePO4 battery to its absolute minimum.
This is what I bought:

I have a 16S setup. I have the little LCD screen with it, but you do not have to have the screen, everything is on your Bluetooth connected app. This BMS shows how to set up any number of series batteries, 2-20. The LCD shows capability to work with upto a 32S BMS.

I have already had the protect mode come on from Cell High Volt, Cell Low Volt, Discharge Over Current (I had it set way too low). My charger is controlled through its front panel, and a software program on a computer.

Controlling the voltage and current during a low-temperature setting is all on me to set it right.
 
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ghostwriter66

"Here - Hold my Beer"
Im pretty sure that DALY BMS you are looking which states TEMPERATURE PROTECT is ONLY for 65 (145F) and 75C and not for freezing ... all depends on where you live if you are concerned about charging in 32F temp ... I have several DALY's hooked to some of my batteries with little concern becuase here in South Texas it rarely freezes .. i just have to pay attention
 

buzzard

New Member
I will have 12 cells total
3 cells parallel then connect the 4 groups of 3 in series
I will need cold weather protect
Has anyone used these kits? I was going by Wills video and they look like good batteries but he used the 105 ah cells
Should I just make 3 batteries with its own bms then paralell them? and not need the relay
 

jasonhc73

Cat herder, and dog toy tosser.
Your setup as described, is 3P4S.

If you do 3P4S, meaning 3 cells in parallel to make one cell-pack, then 4 cell-packs in series to make one "battery", you can only have 1 BMS on this setup group of 12 cells. This is capacity first voltage second.

If you want to really monitor every single cell, you must make the series first, put a BMS on that series.
Then copy that series again to make more capacity.

This is a 4S3P setup.

Think about voltage first, this is the S part. Then think about how long you need to use that voltage, that is the P part.
 

buzzard

New Member
I have decided to build 3 banks and use a BMS on each then Parallel those 3 together.
I am currently looking through the forums for charge settings to use on my Magnum inverter charger.
I have a MS2812 2800 watt inverter.


Thanks for all the replies.
 

civilsub

New Member
I think that i may be a little slow. I am building two 4 cell 12v 100aH batteries which i plan to then put in parallel for a total of 12v 200aH. do i need two BMS's (one for each battery) or can i use one BMS to monitor the entire battery bank?
 

Fred

Solar Enthusiast
W
I think that i may be a little slow. I am building two 4 cell 12v 100aH batteries which i plan to then put in parallel for a total of 12v 200aH. do i need two BMS's (one for each battery) or can i use one BMS to monitor the entire battery bank?
why not parallel groups of two cells to make four 200 ah 3.2v cells. Then put those 4 units in series to make 12v 200 ah. One bms to monitor.
 

Solar_Mann

Solar Enthusiast
Anyone looking to parallel multiple BMS units, make sure you use common port not separate port. just throwing that out there. no problem paralleling multiple cells with 1 BMS if it can supply the current you are looking for.
 

Sgt Raven

Photon Sorcerer
Anyone looking to parallel multiple BMS units, make sure you use common port not separate port. just throwing that out there. no problem paralleling multiple cells with 1 BMS if it can supply the current you are looking for.
Let me see if I understand this. 2 100AH 3.2v cells in parallel, then those packs in series, is a 2P4S battery.
I only need 1 BMS for that configuration.
Will a 100 amp BMS work, or do I need a 200 amp BMS?

The other question, what is the difference between a common port and separate port BMS?
 

Solar_Mann

Solar Enthusiast
Let me see if I understand this. 2 100AH 3.2v cells in parallel, then those packs in series, is a 2P4S battery.
I only need 1 BMS for that configuration.
Will a 100 amp BMS work, or do I need a 200 amp BMS?

The other question, what is the difference between a common port and separate port BMS?
100amp vs 200amp just depends on what your load will be.
common port shuts off the load/charge at both high voltage and low voltage. Separate port shuts off the load port at low voltage, but keeps the charge port active
 

LukeVader

Sun Farmer
W

why not parallel groups of two cells to make four 200 ah 3.2v cells. Then put those 4 units in series to make 12v 200 ah. One bms to monitor.

I'm trying to figure this out in my head and it sounds like an interesting idea. I'm putting my 8 280ah cells in a motorhome battery bay that holds 4 golf cart batteries in size in an ammo box that's something like this https://www.amazon.com/gp/product/B...&pf_rd_p=2d1ab404-3b11-4c97-b3db-48081e145e35 and I was figuring hooking it all up with 2 of these 120 BMS https://www.aliexpress.com/item/4000425316662.html ..........but then so many people are loving on the chargery http://chargery.com/balancer.asp I was trying to figure out if I could just run one chargery BMS but how could I? This idea makes sense in my head but I just cant clearly see it cause I don't even have my cells yet.

So question 1. Is there a diagram of the setup I would need to follow (so I don't blow myself up) somewhere?
2. Which Chargery unit would I need to buy?
3. How many bus bars would I need to order now so I'm not waiting on bus bars?
4. Are some cells going to have more than one bus bar on them? I'm sure I can figure out 3 and 4 with the diagram.
5. Any other question you think I need to ask but I'm not thinking of it.

Thanks in advance for any help.
 

Sgt Raven

Photon Sorcerer
I'm trying to figure this out in my head and it sounds like an interesting idea. I'm putting my 8 280ah cells in a motorhome battery bay that holds 4 golf cart batteries in size in an ammo box that's something like this https://www.amazon.com/gp/product/B...&pf_rd_p=2d1ab404-3b11-4c97-b3db-48081e145e35 and I was figuring hooking it all up with 2 of these 120 BMS https://www.aliexpress.com/item/4000425316662.html ..........but then so many people are loving on the chargery http://chargery.com/balancer.asp I was trying to figure out if I could just run one chargery BMS but how could I? This idea makes sense in my head but I just cant clearly see it cause I don't even have my cells yet.

So question 1. Is there a diagram of the setup I would need to follow (so I don't blow myself up) somewhere?
2. Which Chargery unit would I need to buy?
3. How many bus bars would I need to order now so I'm not waiting on bus bars?
4. Are some cells going to have more than one bus bar on them? I'm sure I can figure out 3 and 4 with the diagram.
5. Any other question you think I need to ask but I'm not thinking of it.

Thanks in advance for any help.
Here's Will's video building a 2P4S battery in a small form factor.



Here is a diagram of the layout..


2P4S Diagram.jpg
 

Sgt Raven

Photon Sorcerer
I'm trying to figure this out in my head and it sounds like an interesting idea. I'm putting my 8 280ah cells in a motorhome battery bay that holds 4 golf cart batteries in size in an ammo box that's something like this https://www.amazon.com/gp/product/B...&pf_rd_p=2d1ab404-3b11-4c97-b3db-48081e145e35 and I was figuring hooking it all up with 2 of these 120 BMS https://www.aliexpress.com/item/4000425316662.html ..........but then so many people are loving on the chargery http://chargery.com/balancer.asp I was trying to figure out if I could just run one chargery BMS but how could I? This idea makes sense in my head but I just cant clearly see it cause I don't even have my cells yet.

So question 1. Is there a diagram of the setup I would need to follow (so I don't blow myself up) somewhere?
2. Which Chargery unit would I need to buy?
3. How many bus bars would I need to order now so I'm not waiting on bus bars?
4. Are some cells going to have more than one bus bar on them? I'm sure I can figure out 3 and 4 with the diagram.
5. Any other question you think I need to ask but I'm not thinking of it.

Thanks in advance for any help.
Go to this thread and look at the pic in post #17. He took the above idea and scaled it up to a 4P4S version. That sucker is a beast..

https://diysolarforum.com/threads/lifepo4-top-balancing-equipment-recommendations.4118/#post-49075
 

LukeVader

Sun Farmer
Here's Will's video building a 2P4S battery in a small form factor.

Thanks Sgt, that's exactly what I needed,a vid and pic. I should have known Will did a vid on that when he was still in the rv. Sooooooo its good news that I know how to do it but bad news of what I was thinking of what would probably happen........... more than one bus bar to a post on some of them. These 280ah batteries are notorious for having no room in the threads for 2 bus bars. :( now I need eight longer M6 screws for the 3 extra bus bars and the bms neg and cable to the positive.
 

Sgt Raven

Photon Sorcerer
Thanks Sgt, that's exactly what I needed,a vid and pic. I should have known Will did a vid on that when he was still in the rv. Sooooooo its good news that I know how to do it but bad news of what I was thinking of what would probably happen........... more than one bus bar to a post on some of them. These 280ah batteries are notorious for having no room in the threads for 2 bus bars. :( now I need eight longer M6 screws for the 3 extra bus bars and the bms neg and cable to the positive.
Go look at post #296 page #15 of this thread.
It looks like he used longer bolts with nuts. I would say, screw the bolts all the way in screw the bolts all the way in and back off 1.5 turns, starting with the nuts at the top of the bolts. Don't over tighten the bolts when they bottom out in the terminal. Then screw the nuts down to hold everything in place. Hold the bolt with one wrench and tighten the nuts with another wrench. The other option is replace the bolts with full threaded studs and nuts.

https://diysolarforum.com/threads/j...-usd-delivered-grade-a-to-canada.3387/page-15
 
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Sgt Raven

Photon Sorcerer
Thanks Sgt, that's exactly what I needed,a vid and pic. I should have known Will did a vid on that when he was still in the rv. Sooooooo its good news that I know how to do it but bad news of what I was thinking of what would probably happen........... more than one bus bar to a post on some of them. These 280ah batteries are notorious for having no room in the threads for 2 bus bars. :( now I need eight longer M6 screws for the 3 extra bus bars and the bms neg and cable to the positive.
After watching the video, it took me a few trys drawing out the pattern, to get it right. I took my messy drawing and made that diagram I posted. I don't have the mad computer skills of some here to make it up on my PC.
 

Capt Bill

Sailing Options
How many cells will be in the series?

When you parallel batteries, they passively equalize to each other by being connected to each other. This is not the case for the series batteries though.

I use a blue-tooth controlled BMS, it has all these functions:
  • Cell High Alarm
  • Cell Low Alarm
  • Cell Hight Protect
  • Cell Low Protect
  • Total Volt High Protect (this protects the entire battery, not just the cell)
  • Total Volt Low Protect
  • Charge Over Current Protect
  • Discharge Over Current Protect (This means it will turn off the battery before you even come close to tripping a circuit breaker)
  • Cell Difference to start Balancing
  • Charge High-Temperature Protection
  • Discharge High-Temperature Protection
  • Mosfet high-temperature protection (The BMS has built-in protection for itself!)
  • Charge Low-Temperature Protection
  • Discharge Low-Temperature Protection
  • System Shut down cell voltage - This is probably the most important protection you can have, never empty a LiFePO4 battery to its absolute minimum.
This is what I bought:

I have a 16S setup. I have the little LCD screen with it, but you do not have to have the screen, everything is on your Bluetooth connected app. This BMS shows how to set up any number of series batteries, 2-20. The LCD shows capability to work with upto a 32S BMS.

I have already had the protect mode come on from Cell High Volt, Cell Low Volt, Discharge Over Current (I had it set way too low). My charger is controlled through its front panel, and a software program on a computer.

Controlling the voltage and current during a low-temperature setting is all on me to set it right.
I wonder how hard the learning curve was to get it all set up and dialed in? Any comments you care to share about that piece? Look like allot of good details to monitor and adjust that are making more sense to me as consider my investment in a 8 or 16 piece 24v 280 Ah or 560 Ah LifePO4 set . Looking to learn more about my BMS options here. Thanks for sharing ;+) Bill
 

civilsub

New Member
I am still trying to figure out the proper way to size a bms. i have a 12 volt 200 watt hour battery, a 40 amp charge controller and 2000 watt inverter. should the bms be sized to the charge controller, since that is what current it is seeing or to the battery. do i need a 200a bms or can i get away with a 100a bms?
 
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