diy solar

diy solar

Jiabaida JBD BMS with Xiaoxiang App Issues

Interesting. I apparently have V3.1.1021.

Just for kicks, what happens if you switch your phone to English? I read here that some apps don't work correctly with some languages. Might be worth a try to get it going.
 
we tried in spanish, english, german, no change. apart from that, friends have exactly same set-up (bms, batts, invertor) they are struggling with same problem; bms doesn't connect. i heard rumours bms needs to be briefly connected to 60+ volts to start it up - any truth in that?
 
we tried in spanish, english, german, no change. apart from that, friends have exactly same set-up (bms, batts, invertor) they are struggling with same problem; bms doesn't connect. i heard rumours bms needs to be briefly connected to 60+ volts to start it up - any truth in that?
Not that I have ever heard. It should work when it is happy with the cell voltages.

The photo you showed in post #16 indicates that the BMS thought one of your cells had zero volts. Does it still think that one is missing?
 
but another issue appeared... approaching cutoff V, cell-V starts to drift apart. as if BMS isn't powerful enough to keep cells balanced. specs say bal.current is 160mA - does this make sense?

BMS V drift.jpeg
this is when charging with 4+ kW
remember, BMS is bypassed, only bal.function is working.
 
but another issue appeared... approaching cutoff V, cell-V starts to drift apart. as if BMS isn't powerful enough to keep cells balanced. specs say bal.current is 160mA - does this make sense?

View attachment 120083
this is when charging with 4+ kW
remember, BMS is bypassed, only bal.function is working.
This makes perfect sense, 160ma is like trying to keep the grand canyon flowing with a garden hose.
Did you top balance before you assembled?
 
thanx - would be surely better :) thing is i have to get going what i have here& now, surely can be done. it's not like JBDs are totally useless, is it? i understand it may not be ideal in my situation.
balancing issue is not what keeps it from switching on i assume, as at times -most of d time!- cells are well balanced - yes or no?
 
Lower your charge rate, that should help slow down the runners.
I'm not an expert, nor do I have the patience, like some here but I'm catching on quick.
 
cells are well balanced - yes or no?
It looks like no. You need to balance them. The JBD BMS is a passive balancer and can only bleed off charge. It does not try to take charge from one cell and put it into another.

From the looks of it you may have a few balance wires that are loose. Does the BMS agree with what your voltmeter says?
 
This makes perfect sense, 160ma is like trying to keep the grand canyon flowing with a garden hose.
Did you top balance before you assembled?
what BMS would you guys recommend? batt.bank is 15kWh, PV-input 8kWp. now. but in 2023 we want to increase to approx 20kWp in order to also charge EVs.
battery is more of a buffer, and to keep d lights on at night; except a stove for 1 hour, no high-W gadgets depend on it.
 
I still don't see any problem with the BMS you have. The issue is that you still need to top balance your cells. Probably the easiest way to do that is by reducing your charge voltage to 57.8v (3.4v per cell) and watching the cells charge. If any start to run above the others by more than 0.03v or so, use a light bulb to bleed charge from that one cell until it is closer to the others. After they all get to 3.4v per cell with nearly zero current, they are full and should be balanced enough to set your charger back how you want it.

It will take some babysitting that way, but you won't have to break your pack to get it done.
 
I still don't see any problem with the BMS you have. The issue is that you still need to top balance your cells. Probably the easiest way to do that is by reducing your charge voltage to 57.8v (3.4v per cell) and watching the cells charge. If any start to run above the others by more than 0.03v or so, use a light bulb to bleed charge from that one cell until it is closer to the others. After they all get to 3.4v per cell with nearly zero current, they are full and should be balanced enough to set your charger back how you want it.

It will take some babysitting that way, but you won't have to break your pack to get it done.
oh they're well balanced until approx 3.5V, then they start to drift apart. i thought if perhaps 160mA bal.current is a tad weak now, it'll only be worse if we more than double PV-power.
 
oh they're well balanced until approx 3.5V, then they start to drift apart. i thought if perhaps 160mA bal.current is a tad weak now, it'll only be worse if we more than double PV-power.
You asked if your cells are balanced, and several people said no. Now you say they are well balanced. They are not balanced. Balance won't show until above about 3.45 volts or so.
 
Hi, Does anyone have android app for connecting to the batteries using the serial port instead of using bluetooth?
 
You asked if your cells are balanced, and several people said no. Now you say they are well balanced. They are not balanced. Balance won't show until above about 3.45 volts or so.
well i just say what i see/measure: balancing happening, and perfectly within the desired 0.02V setting, until approx 3.5V.
is there a technical reason cells start to drift at this V, is it common?
 
well i just say what i see/measure: balancing happening, and perfectly within the desired 0.02V setting, until approx 3.5V.
is there a technical reason cells start to drift at this V, is it common?
The voltage curve of LFP is too flat to use it as a judge of state of charge. You don't see significant change in voltage until it gets nearly empty or nearly full.

@FilterGuy put a good explanation of top and bottom balancing in the resources section.

https://diysolarforum.com/resources/explanation-for-beginners-of-top-and-bottom-balance.127/
 
Back
Top