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Finally found a LiFePO4 BMS with Low-temp Charging Protection

BMS settings to use 80% of battery capacity​

I have this BMS [JBD-SP045020 - 4S-120A] which is working really well, but I have a question.
If I only want the BMS to allow charging up to 90% full capacity, and down to 10%, what settings should I configure?

So to charge up to 540Ah and only down to 60Ah, so extent the life of my cells (purchased new). Or has anyone else got a recommended setup?
Is this possible using the XiaoxiangBMS app?

600Ah LiFePO4 (12x200Ah cells - 3 cells in parallel then connected in series) + Renogy DCC50S [550W PV]
 
clotted said:

BMS settings to use 80% of battery capacity​

I have this BMS [JBD-SP045020 - 4S-120A] which is working really well, but I have a question.
If I only want the BMS to allow charging up to 90% full capacity, and down to 10%, what settings should I configure?

So to charge up to 540Ah and only down to 60Ah, so extent the life of my cells (purchased new). Or has anyone else got a recommended setup?
Is this possible using the XiaoxiangBMS app?

600Ah LiFePO4 (12x200Ah cells - 3 cells in parallel then connected in series) + Renogy DCC50S [550W PV]
Click to expand...

While you can set those limits in the BMS, it is better to configure the upper limit in your charging device(s).
 
HRTKD said:
While you can set those limits in the BMS, it is better to configure the upper limit in your charging device(s).
Click to expand...
Are you able to advise which settings would be configured on the BMS?
I see 'Total Battery Capacity', and 'Total Cycle Capacity', but if I input 600Ah and 480Ah respectively, would this use from 0-80% or 20-100%?
 
Have you looked in your manual? My manual says to use "Battery over voltage". However, like I said earlier, the top end setting should be made in your charge controller. The BMS is the last resort.
 
Edit: clicked the wrong reply button.

@clotted Remember that the bms is supposed to be a protection device for the battery, not a controller.

You should not rely on the bms to control charge level because it will shut off the connection to the battery and equipment entirely when it's triggered.

If you're charging while using the system it will result in all your stuff abruptly shutting down. Not good practice.
 
Short_Shot said:
Edit: clicked the wrong reply button.

@clotted Remember that the bms is supposed to be a protection device for the battery, not a controller.

You should not rely on the bms to control charge level because it will shut off the connection to the battery and equipment entirely when it's triggered.

If you're charging while using the system it will result in all your stuff abruptly shutting down. Not good practice.
Click to expand...

With this BMS that's not the case. Discharge is still active even though charge is disabled.
 
Short_Shot said:
Fair enough, but that's not really the point?
Click to expand...

I'm letting you know that your statement that the BMS would shut down all your stuff is incorrect. The advice that the BMS is your last resort is correct.

ridethelightning said:
interested in this. just want a bms that will do 16 s or 8sx2 100 or 150a with confiugurable cell voltage limits
Click to expand...

Most BMS are oriented towards a single battery. It's either 8s or 16s, not 8s2p. There are higher end BMS that can handle multiple batteries.
 
Well. He did say he's not using the one Will posted originally so I can't be too sure about the features of the specific one he has and honestly that's my bad for being lazy.
 
curiouscarbon said:
3.500 Volt / cell * 4 cell = 14.0 Volt
2.875 Volt / cell * 4 cell = 11.5 Volt
Click to expand...
Yeah, I think that is what I have set, by cell voltage.
I haven't looked at my settings in a while, but I think it's in the cell voltage settings, vs total voltage.
IMO, protecting the cells from over/under voltage is important.
 
thank you for sharing your voltage settings ?

formatted it that way so people with other voltage packs can easily adopt your settings if they want ??

cheers!
 
^^^^^ Setting the pack by cell voltage protects the cells in case the pack gets out of balance.
In the AH setting, I have it set at 280AH. The first full cycle, the BMS read 0% left for days. The 2nd time I ran a full cycle, IMO it corrected itself and showed the correct percentage. I had my battery hooked up to a 12V fridge and let it run till it shut off.

Your cell voltage post reminded me the way I have it configured. Generally I think of the battery by the combined voltage.
 
I think it is important to keep the BMS power wires the same length for load sharing. Crimp and solder. But otherwise as other folks have said. I kept the BMS lead separate for service reasons.

As an added note, I like this crimper; it is available other places cheaper.
 

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HRTKD said:
I'm letting you know that your statement that the BMS would shut down all your stuff is incorrect. The advice that the BMS is your last resort is correct.



Most BMS are oriented towards a single battery. It's either 8s or 16s, not 8s2p. There are higher end BMS that can handle multiple batteries.
Click to expand...
was thinking of 2x 8s bms in series
 
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