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Help!!! Smoke during top balancing

Yes, the output enable button on his supply is unusual in cheap supplies. Most don't have that, and it is actually a good safety feature. It does make it difficult to figure out why his supply wasn't working

bc i didnt have the output button pressed when i was testing the voltage early on.
 
so with the 12v battery you have a main battery positive and a main battery negative, to wire the power supply in parallel means attaching both leads of each supply to positive and negative accordingly , i am confused about how this 12v battery would be charged in series then?

i thought i understood the concept of parallel vs series, at least in relation to the way the battery pack is assembled. in this case 3.65volts vs 12v

but i was not aware the power supply could be wired parallel vs series as well which is throwing me off now
You wouldn't normally wire power supplies in series. Some do support that, but since both your supplies can achieve the desired voltage, wiring them in parallel will double the amps.
 
Please check the BMS settings and let us know the high cell voltage disconnect and low cell voltage disconnect settings before you start, wouldn't want you to overcharge the cells. Some BMS come with strange default settings, just FYI.
i have the overkill solar 120amp 4s
 
so with the 12v battery you have a main battery positive and a main battery negative, to wire the power supply in parallel means attaching both leads of each supply to positive and negative accordingly , i am confused about how this 12v battery would be charged in series then?

i thought i understood the concept of parallel vs series, at least in relation to the way the battery pack is assembled. in this case 3.65volts vs 12v

but i was not aware the power supply could be wired parallel vs series as well which is throwing me off now
Short explanation:
Wire in series to increase voltage.
Wire in parallel to increase amps.
 
Short explanation:
Wire in series to increase voltage.
Wire in parallel to increase amps.
ok so lets say you wanted to wire a power supply in SERIES , to a battery that is wired in parallel , for example, i had my battery wired in parallel to top balance , how would you wire the power supply in series then?
 
ok so lets say you wanted to wire a power supply in SERIES , to a battery that is wired in parallel , for example, i had my battery wired in parallel to top balance , how would you wire the power supply in series then?
Most power supplies don't actually support being wired in series. Wiring your cells in parallel to top balance is to be able to get them all to identical states of charge (3.65 volts being 100%). Wiring the power supplies in series would enable you to reach 60 volts at 5 amps, but it is very unlikely the supplies support this.
I don't recommend trying it, but to series connect them you would take the positive of one supply and connect it to the negative of the second. Just like the cells, but likely the supplies don't support this and would release magic smoke.
 
Most power supplies don't actually support being wired in series. Wiring your cells in parallel to top balance is to be able to get them all to identical states of charge (3.65 volts being 100%). Wiring the power supplies in series would enable you to reach 60 volts at 5 amps, but it is very unlikely the supplies support this.
I don't recommend trying it, but to series connect them you would take the positive of one supply and connect it to the negative of the second. Just like the cells, but likely the supplies don't support this and would release magic smoke.
ok im going to send photos when i get everything set up before i turn anything else on , and photos of the BMS parameters off the bluetooth app



PS , i am overwhelmed with the support ive gotten on this thread, this is by far the most helpful forum ive ever been apart of, sincerely thank you to all
 
ok so lets say you wanted to wire a power supply in SERIES , to a battery that is wired in parallel , for example, i had my battery wired in parallel to top balance , how would you wire the power supply in series then?
configure the battery exactly how it's shown in the overkill manual for a 4 cell 12v battery (pic below). Where the diagram shows red and black terminals at the top center, that's basically the red and black connection to the power supply. If you got the longer black cables on the bms, you might be able to connect the BMS directly to the power supply terminal post. Set the power supply to 14.6v and 4a and wait for BMS cutoff on a single cell.

Then reconfigure in parallel to do the top balance at 3.65v.

1614567010510.png
 
That's an interesting thought. I don't have his power supply, but I do have a cheap 10 amp supply. I might hook it up and see what happens or if anything heats up at max output at varying voltages.

The Longwei I have is identical to the Dr. Meter that Will recommends. Just different names on the plastic. The official Longwei store even sells the Dr. Meter branded supply.
The cold side of the power supply has rectifier diodes that convert AC to DC, the Diode has Voltage and current rating, so if they use 5A curent rating diode, no matter what the output Voltage is set to if you draw 5A of current through the diode, it has dissipate that heat, if they use 10A diode and the circuit can support that current then you can have 10A flow through diode, but diode will dissipate more heat so proper heatsink should always be used to keep the Diode junction tempearture at safe level, 150 C is typical. Vf of typical Schottky diode used in switching power supply has Vf around 0.20 ~ 0.50V, so @ 10A the diode will have to dissipate 5W power, that is why I say limit the current to about 80% for head room.
Basically if power supply set to output 1 V at 10A or 10V at 10A, the didoe will have to dissipate the same power, and that is just the diode the the current will have to flow through to the loc, but in circuits details you will also have other component in series to the output of the power supply as well so all of them has to be aboe to handle the current flowing thoiugh them.
 
OP, what ever you do, you have to connect the BMS sensing plug into the the BMS LAST otherwise you can damage the BMS, and unplug it first before start removig the cables from batteries. Read the manual that comes with the BMS.
 
but i was not aware the power supply could be wired parallel vs series as well which is throwing me off now
Don't even think about power supplies in series. Just connect each supplies positive to the battery positive, and negative to the battery negative.
 
. Read the manual that comes with the BMS.
+1 on this. That overkill solar manual is excellent. Read every word and ask questions on anything you don't understand.

I was on the fence about building my own batteries until I read that manual. It's a good balance of explanation and instruction. And it's very beginner friendly. Was happy to give them my $ when it was time to buy my BMS's.
 
hello , the problem was i had to push the "output" button , for it to actually work. Which BTW is does not say anywhere in the manual.


"(6) Output On/Off push button"

"turn off the output terminal with push botton(6)"

"2.2.3.5.Set your desired output voltage and then turn off the output terminal by push button(6).
2.2.3.6.Connect to your load positive to positive and negative to negative.
2.2.3.7.Turn on the output terminal again and check if display shows(CV)."

RTFM :)
 
So the switch is for the Output.
How about the Current reading on the meter with no load connected as shown on OP picture? Is there a procedure for setting the CC?
 
So the switch is for the Output.
How about the Current reading on the meter with no load connected as shown on OP picture? Is there a procedure for setting the CC?

All the manual says is the method we already knew:

"Short the black and red output terminals and turn on the output terminal by (6),icon becomes ,adjust the current limiting value to your desired value( x Amp) by turning knob(5).Turn off the output terminal and take out the shorting connection."

I was looking through manual to see if with output off the display shows settings rather than measurement. I don't think it says so, but that's probably what it does.
 
So if youhave to short the outout together to allow the curent to flow to set the CC, that means if there is no connection to the output terminals, I.E. no load connected or shorted leads then it shoud not show any current reading at all. I think OP need to veriy how the one that smoked and compare it to the second unit that he has instead of keep on using the smoked one if has fault.
 
Setting up the battery to charge in series

I haven’t even adjusted any setting yet and cell 3 is reading 4.263 volts, when I tested each cell with the multimeter they were all at 3.32 , why the increase ?

I unplugged the BMS for now until I figure it out
 

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If DMM says every cell is 3.32V things are OK.
I could understand BMS reading somewhat high cell voltage during charging if there was a high resistance contact. It would read low during discharge.
Your BMS readings are all over the map. And you appear to have only BMS connected to positive of pack, no charging source. So I don't know what is going on.
Some people found poor crimp or poor contact in BMS harness connector.
 
If DMM says every cell is 3.32V things are OK.
I could understand BMS reading somewhat high cell voltage during charging if there was a high resistance contact. It would read low during discharge.
Your BMS readings are all over the map. And you appear to have only BMS connected to positive of pack, no charging source. So I don't know what is going on.
Some people found poor crimp or poor contact in BMS harness connector.


I haven’t connected a power source I just set it up and then saw the reading and stopped,
 
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