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Recommend me a BMS for LiFePO4
#1
I need a BMS for LiFePO4, im making a 24v battery with 8, 200ah batteries, with plans on adding 8 more in parallel .

Now ive been looking at Daly,, Chargery and Electrodacus
But there is so much info its daunting!  Daly seems just straight foward but it has no way of "showing" that its working and Chargery and Electrodacus depend on Relays for control.

Originally i had ordered a Daly but it never shipped to me so now im re thinking things,
and would like recommendations on which BMS i should get
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#2
Batrium with shunt tripping unit. Expensive but so perfect.
My Powerwall Build Thread

Maniac_Powerwall: 1x 14S100P 18650 LiIo, 6x 345W LG panels, MPP Solar PIP5048GK, Batrium Watchmon4 BMS
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#3
What functions do you need first of all??

We can tell you to use 100 different types
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Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 100kWh LiFePo4 | 20kWh 14s 18650 |  66*260W Poly | ABB S3 and S5 Trip breakers
Upcoming: 14S 18650~30kWh
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#4
If you will be charging with solar I recommend the chargery bms8 (up to 8s system). That it uses a relay(contactor) is a plus when dealing with solar, when the bms decides to stop the charging, the relay will disconnect the solar panel. With the panel disconnected (not charging battery) the rest of the system is still operating normally.

With a normal bms that uses mosfets, when it decides to stop the charging, you will get voltage surges from the solar controller as it tries to keep charging the battery.

Cost for the chargery bms8 is about 100, all the parameters are programmable, you can use it on lifepo4 and you can also use it on li-ion. Everything is programmable on the LCD screen.

The chargery is as simple as it gets, once you program it the first time it works. I havent had to do anything to it since since I been using it since last year. The only modification I've done is put an on/off toggle switch on the relay to turn it off at night. The relay is always on when the bms is operating, in its on condition it uses power. Its a failsafe design, the only time the relay turns off is if the bms activates to shutoff charging or if the bms loses power.
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#5
A proper charge controller does not surge or cause issues. No need to disconnect solar and that is not the function of a proper BMS.

Get a proper charge controller and proper BMS and there is no problem
Gato likes this post
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Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 100kWh LiFePo4 | 20kWh 14s 18650 |  66*260W Poly | ABB S3 and S5 Trip breakers
Upcoming: 14S 18650~30kWh
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#6
All controllers pwm and mppt that I have tried will produce voltage surges, I also read about other people having the same problems. I only use 12 volt system so I don't know if it happens on higher voltage systems. I also tried different types of bms (all mosfet) and they all work the same and got same results. The only way to see if a charge controller will not produce surges is by actually testing it in actual use, there are too many brands/types and if you buy the wrong one, or you buy an expensive one and it still produces surges your stuck with it. I wouldn't trust a 500 dollar controller unless I actually tested it myself on my system.

What happens is when the mosfet shutoff, they only prevent current from flowing. By thier design the mosfets(electronic relays) leak voltage, the controller will still "read" that there is a "low" battery connected and will try to charge it. The controller will cycle back and forth trying to charge it and that is where the voltage surges come in. This only happens with solar controllers, when using different chargers, I get no voltage surges.

With the chargery and mechanical relays, I have never encountered any voltage surges. You must avoid voltage surges at all cost. They won't hurt the battery but they will destroy any equipment connected to the battery that cant handle surges. It will work with any solar controller cheap/expensive pwm/mppt. It also works with any type of charger AC / DC. I use 4 dollar 30 amp automotive relays with the chargery, no need to buy expensive rellays/contactors. Just buy one that handle the current you need. No need to buy 200 amp relays if you only use 20 amps max.

If charging with AC/DC any bms will work even a 5 dollar one. I use those on my 4s 220ah battery before. But for extreme performance spending more gets you more. Baltrium BMS is too expensive (overkill) for most people and smaller systems. I would avoid any bms that you need bluetooth or computer to program or view its status, its like a tv remote, you lose it or its not around how are you going to program it.
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#7
(02-29-2020, 12:48 PM)daromer Wrote: What functions do you need first of all??

We can tell you to use 100 different types
Im plan on using This battery as Back up mostly and as a buffer since i can run on solar during the day without using battery.  I have very frequent power outages and sun to spare LOL

Currently i have a Lead acid 800ah 24v bank, and im going to install the lithium's at my parents house.

I initially bought 8 LiFePOs just to make sure the vendor was good, will be getting 16 more,
I currently have two Hybrid "green" MPP's wich i was planing on using for charging also.
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#8
Jonny i dont see your issue
They only disconnect IF There is a fault. Rest is handled by the Charger.

And most decent setup use a proper breaker with trip shunt and not ebike made bms systems with mosfets.

Gato you cannot run on solar alone. You either need grid or battery. Solar is not a permanent source so to say Smile
The Ultimate DIY Solar and build place
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 100kWh LiFePo4 | 20kWh 14s 18650 |  66*260W Poly | ABB S3 and S5 Trip breakers
Upcoming: 14S 18650~30kWh
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#9
(03-01-2020, 06:51 AM)daromer Wrote: Jonny i dont see your issue
They only disconnect IF There is a fault. Rest is handled by the Charger.

And most decent setup use a proper breaker with trip shunt and not ebike made bms systems with mosfets.

Gato you cannot run on solar alone. You either need grid or battery. Solar is not a permanent source so to say Smile
Thanks Dromer For the reply !
LOL I know i cant run on solar alone,  i tried though!!
At the moment everything is on the grid, and my lead acid bank is just for when grid goes down , which is weekly sometimes.

From 9am to 4pm i can run 2 Mini split Air cons with solar to spare! I Also have one of those  Grid tie with limiter Inverters wich runs during the day providing about 700 watts. At 4pm my batteries are still in float. When the grid goes down only 1 AC and the refrigerator are run over night.

Ive "boiled it down" To needing a BMS just to control charge for the LiFePO4 from %15  to %90 in case "something" goes wrong. From what ive read LiFePO would be  best between those ranges..
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#10
Bms does not controll charging. Its protection only. Charging and load variables is set in Charger /inverter
hbpowerwall likes this post
The Ultimate DIY Solar and build place
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 100kWh LiFePo4 | 20kWh 14s 18650 |  66*260W Poly | ABB S3 and S5 Trip breakers
Upcoming: 14S 18650~30kWh
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