You can undercharge the cells too... that's another option? I think if it has a 7805 it's quite possible a higher voltage is just fine.
Oddly enough I was looking at ICL7106 and apparently it can deal with higher than 9V just fine...
eccerr0r
Solder Sloth
Last Activity: Today, 08:48 PM
Joined: 11-08-2012
Location: CO
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You can also use an LDO, but knowing the load would be better, many can take the voltage swings from fresh to dead just fine and thus not need a regulator at all.Leave a comment:
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The reason why using a zener this way this is dumb because it actually is even worse than a linear regulator. Using a linear regulator with a transistor is actually more efficient - because a zener shunt regulator, whenever it's on it will consume full wattage whether you're actually using your device or not. At least a linear regulator, it will waste energy only when you're using your device....Leave a comment:
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Batteries still have a nominal voltage.
Yes looks like this thread seems like a "I must use this" solution to a problem despite there being more efficient solutions out there. Using a zener diode in this fashion is really dumb, alas, if all you have is a hammer...Leave a comment:
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OVP, just shunt the output with the diode... Heatsink not required.
As a regulator, take the highest amount of current your circuit can possibly draw and select R with V=IR where V=(lowest expected source voltage - zener diode voltage). If you get a negative resistance, the circuit is impossible. Then you have to make sure that the wattage of the resistor is at least (highest expected source voltage-zener diode voltage)^2/R and the zener diode wattage is higher than ((highest expected voltage - zener voltage)/R)*(zener voltage) which should be less than 10 since you have 10 watt zeners....Last edited by eccerr0r; Today, 07:51 AM.Leave a comment:
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if you're insisting on using the zener diode to regulate, resistor depends on how much current your device uses. Without knowing the device, it's impossible to tell what resistor is needed.
If using as a OVP device, you don't need a resistor, making usage easier.Leave a comment:
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normally these high wattage zeners are not for regulation, rather they are for OV protection...Leave a comment:
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hmm. 40A seems a bit optimistic then... yeah heatsinking is necessary to hit 40A but it's on the wrong side of mosfets...Leave a comment:
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Do also consider your video card as a potential issue...
Looks like this is an analog only monitor like my old 17" that I bought when they first came out...Leave a comment:
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[ATTACH=JSON]{"data-align":"none","data-size":"full","data-attachmentid":3620257}[/ATTACH] "2.3"...
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and interesting... I have a chinesium 40A 4S Li-ion Co/Mn BMS that has 10 mosfets on it. The weird part is that it actually spent the effort and designed the PCB to dissipate heat from the balancing resistors...though still probably can't dump more than a few watts or so.
Too bad it's not good for Fe cells....Leave a comment:
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Well, glanced through a couple sections and it's exactly how I envisioned it, pretty much has the same concept except done via software as an all analog version I had posted somewhere. Yeah the digital version is nice because you can easily change the constants as needed. I don't think I'll be going this route, at most I'll probably manually balance if the bms doesn't already have a 100mA balancing function ...
Speaking of which I would have thought it should do the balancing current as a ratio of the capacity of the pack, other than heat dissipation I wonder why it's otherwise.....Last edited by eccerr0r; 04-21-2025, 01:03 AM.Leave a comment:
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Going to try hard not to have to buy more stuff, but batteries I cannot make out of resistors and capacitors. I have some 75N06's that I could use, technically I could just outright replace them and get a bit better performance.Leave a comment:
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Because 30BY5 looks like a vacuum tube part number :p
60N06 above the 30BY5 is a reasonable part number based on the photograph, unless that was meant to be something else..
60N06 has reasonable specs for a prot mosfet... though might not be enough for reconfigure for lower volts and more amps.Last edited by eccerr0r; 04-20-2025, 12:39 PM.Leave a comment:
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your picture has a cut off picture of the MOSFETs? Trying to extrapolate the cut off portion of the photograph... but if it's really 60N06 something doesn't seem quite right... or maybe it is...Leave a comment:
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6 x 60N06? hmm...Leave a comment:
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Since you have it open can you read the parts used for the mosfets? I'm wondering if I do end up modding for 12V I'll need to add some more mosfets. 15A would mean I don't have to but would be nice to discharge at 1C... meaning now 12A at 12V.
Oh an *#@(#**%#@#!#. I have a 2A wall plug that was oddly enough 29.2 volts. I modded it to 25.2 volts... I wonder if I need to mod back though I'll have a need to use both voltages...
Then again this 24V PSU I just fixed I probably could somehow hack in some CC/CV support, and technically it probably would be a little more efficient...Last edited by eccerr0r; 04-20-2025, 01:12 AM.Leave a comment:
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Well at least that's 5Ah. hmm.
I wonder if it really can take 15A... though I guess it depends on the kind of mosfets that are being used, and the cell health of course...Leave a comment:
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interesting... going to be annoying to reconfigure then... but still, balancing needed to be done somewhere or were these packs never intended to be balanced -- which is hard to believe....Leave a comment:
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But wouldn't that mean you have to take the pack apart to access the interstitials? You can't connect the bms protection wires without opening it, and it must be able to balance as-is else that's a recipe for leaking magic smoke...?...Leave a comment:
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