diy solar

diy solar

Finally found a LiFePO4 BMS with Low-temp Charging Protection

OverkillSolar said:
Plenty in stock. I just ordered 100 more and I'm trying to get the connector installed for the shutoff switch in this batch.
Click to expand...

Do you have an ETA for these, with the shutoff switch? I am close to ordering and would like to wait for this function as this will be a nice feature for when my camper is parked/unused for extended periods.
 
chevymike said:
Do you have an ETA for these, with the shutoff switch? I am close to ordering and would like to wait for this function as this will be a nice feature for when my camper is parked/unused for extended periods.
Click to expand...
a few weeks, but this feature is enabled on all of them so far, they just lack the connector. If you want it I could add the connection for you, just send me a message with the order.
 
overkillsolar
when these BMS shut down at low temp. will just the charging stop . or both the charging and load?
Do these have the capability of shutting down charging and loads separately ?
The switch mentioned what will it shut off?
I building 280 ah 4s system for small camper .
 
NEWYORKHILLBILLY said:
overkillsolar
when these BMS shut down at low temp. will just the charging stop . or both the charging and load?
Do these have the capability of shutting down charging and loads separately ?
The switch mentioned what will it shut off?
I building 280 ah 4s system for small camper .
Click to expand...
This is a “common port” BMS, meaning that all chargers and loads connect to the same point. When charging is cutoff, the loads can still pull power out of the battery. Similarly if discharging is cut off, the charger can still push power into the battery.

In this way it works exactly like a battleborn battery.

The switch I mentioned let’s you cut off discharging with a physical external switch. (You can also shut it off from the phone apps)
 
Has anyone successfully mapped out what the other connections are on this JBD BMS? Apart from the comm and balance lead connections?

Looking from left to right on mine, I see:
  • CANBUS?
    • CANH
    • CANL
    • GND
  • Mystery
    • B
    • A
  • Mystery
    • "SW" with 2 terminals
  • Comm port - TTL? what baud?
    • VDD
    • TX
    • RX
    • GND
  • Mystery
    • Bat+
    • NC
    • Bat-
  • Balance lead 4S
    • BC4
    • BC3
    • BC2
    • BC1
    • BC0
 
jaffadog said:
Has anyone successfully mapped out what the other connections are on this JBD BMS? Apart from the comm and balance lead connections?

Looking from left to right on mine, I see:
  • CANBUS?
    • CANH
    • CANL
    • GND
  • Mystery
    • B
    • A
  • Mystery
    • "SW" with 2 terminals
  • Comm port - TTL? what baud?
    • VDD
    • TX
    • RX
    • GND
  • Mystery
    • Bat+
    • NC
    • Bat-
  • Balance lead 4S
    • BC4
    • BC3
    • BC2
    • BC1
    • BC0
Click to expand...
On the one I sell, The only header that’s populated is SW, it can be enabled from the apps and it functions as a discharge cut off switch. Could be useful to prevent discharging in storage or prevent unauthorized use, in the case of electric vehicles. I ordered the next batch with the 2 pin connector installed.

The comm port is TTL 9600 baud. The protocol datasheet is on my github page.
 
After my first discharge test of my XUBA 280AH battery a couple of things.
1) the BMS had it at 0% for days when the battery got down to 13.1V
2) ran it down to 12.8V and the BMS changed it to a 308AH battery and said it had 3 cycles on it.
3) the 1st test ended at 12.8V with an Error code on the fridge, voltage too low to start compressor.

Doing my 2nd big long term slow draw test and it has already run 4 more days this time. I changed the fridge from half fridge, half freezer this time, to fridge/fridge and only charged my tablet from 0% to 100% once. Right now it says 34% left and that it has 5 cycles on the battery.
Not sure how the BMS counts the number of cycles, it doesn't make sense to me.
It does seem the BMS has adjusted the percentage left for this test, compared to the 1st test.
It does seem the BMS is Smart as it adjusts some of the stuff after being run thru a charge/discharge cycle.
 
It looks like this 120A Smart BMS w/Bluetooth really is smart and learns.
I had it set for 280AH on my 12V battery.
The first big slow test, it was sitting on 0% left for days at 13.1V. and it lasted 6.5 days.
Last test the fridge cut it off at 12.8V with compressor failed to start Error.
After the first test, it changed the battry capacity to 308AH.
Running the 2nd test like that and now 12 days in. BMS says 12.8V and 19% 59AH left.
BMS is set to cut off at 11.5V or 2.875V cell.
12V fridge is set to the lowest of 3 battery voltage cutoffs.
Waiting to see if the fridge or BMS cuts it off this time.

Only thing that doesn't make sense, is the cycle count. The first time around it said 3 cycles and it says 6 cycles now.
 
Sgt Raven said:
It looks like this 120A Smart BMS w/Bluetooth really is smart and learns.
I had it set for 280AH on my 12V battery.
The first big slow test, it was sitting on 0% left for days at 13.1V. and it lasted 6.5 days.
Last test the fridge cut it off at 12.8V with compressor failed to start Error.
After the first test, it changed the battry capacity to 308AH.
Running the 2nd test like that and now 12 days in. BMS says 12.8V and 19% 59AH left.
BMS is set to cut off at 11.5V or 2.875V cell.
12V fridge is set to the lowest of 3 battery voltage cutoffs.
Waiting to see if the fridge or BMS cuts it off this time.

Only thing that doesn't make sense, is the cycle count. The first time around it said 3 cycles and it says 6 cycles now.
Click to expand...
Anxiously waiting to see how this turns out Sgt Raven!
 
Tball said:
Anxiously waiting to see how this turns out Sgt Raven!
Click to expand...
At this point it works great and so does the XUBA 280AH cells.
Sure it would cycle a bit more if I was pulling food out of it. But by then I'll have the solar hooked up too.
Even if for some reason it went down to 10V, that's still 2.5V per cell and they should be OK.
 
I haven't seen this before, like this. On the Cell voltage readout page.
1) 3.176 _______ 2) 3.154
3) 3.165 _______ 4) 3.149

Cells 1 and 4 are flashing and it's like it is trying to take power from #1 and move it to #4....
Weird....

Any time before, it would balance either even numbered cells or odd numbered cells together
It normally looks like it is balancing when those even/odd # cells are flashing.
 
Sgt Raven said:
I haven't seen this before, like this. On the Cell voltage readout page.
1) 3.176 _______ 2) 3.154
3) 3.165 _______ 4) 3.149

Cells 1 and 4 are flashing and it's like it is trying to take power from #1 and move it to #4....
Weird....

Any time before, it would balance either even numbered cells or odd numbered cells together
It normally looks like it is balancing when those even/odd # cells are flashing.
Click to expand...
From what i understand the flashing is the high and low cell.
 
NEWYORKHILLBILLY said:
From what i understand the flashing is the high and low cell.
Click to expand...
Yeah, the BMS shut down around 7:30am and the battery was completely off when I woke up this afternoon.
Hooked up to my PS and it turned back on real quick and was close to 0% and zero AH left.
Now the lowest and highest cells are flashing, so I think we can confirm that.
But it didn't do that, before. Maybe it needs to be below a certain voltage or voltage spread?
I'll see what happens as it charges back up.
Strange thing, after my first long test, which ended at 12.8V my AHs jumped to 308AH.
Now it is back down to my preset 280AH.
 
NEWYORKHILLBILLY said:
From what i understand the flashing is the high and low cell.
Click to expand...
Just checked it again and my cells are all 3.28xV and the flashing stopped.
SWAG the high/low flashing is when it is around 3.1xxV.
It should start flashing either both even or odd cells, when they're above 3.4xxV, when it goes into balancing mode.
 
Sgt Raven said:
Just checked it again and my cells are all 3.28xV and the flashing stopped.
SWAG the high/low flashing is when it is around 3.1xxV.
It should start flashing either both even or odd cells, when they're above 3.4xxV, when it goes into balancing mode.
Click to expand...
honestly i new to all this stuff.I just had seen in one of the videos reviews of the meter it was flashing high and low cells .
 
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