NeilP
1 GW
Black one is the cheapo from e-bay ...they are great...you have to buy your own battery though...9v PP3
Switch mode supply mod
- Thread starter Jeremy Harris
- Start date
Yeh I have 3 of the black ones lol they sell them at princess auto and canadian tire!NeilP said:
I usaly pay ~10 bucks for them but.... Its not even worth replacing the fuse when you forget it pluged in to mesure amps and then test volts!
auraslip
10 MW
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- Mar 5, 2010
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- 3,535
gosh - they're $3 shipped on ebay. That's cheaper than the 9v in them.
auraslip
10 MW
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- Mar 5, 2010
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I let the smoke out 
I was thinking they felt hot. So I tried I tested a 12v computer fan to the negative and positive on the other unit, the fan spun up, but when I took it off the other one burnt up like a smoke bomb. It was on it's side, hence the scorch marks going sideways.
I'm hoping it's just the mosfet there.... hope It's fixable
I was thinking they felt hot. So I tried I tested a 12v computer fan to the negative and positive on the other unit, the fan spun up, but when I took it off the other one burnt up like a smoke bomb. It was on it's side, hence the scorch marks going sideways.
I'm hoping it's just the mosfet there.... hope It's fixable
auraslip
10 MW
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The part I blew is a 408g SCR-
So I guess because ONE of the meanwells was current limited the fuse didn't blow? In any case, both aren't working and both show trace damage from heat but only one of the SCRs burned up.
I'm guessing that quickly removing the extra load of the fan (it was a huge server fan rated at 1amp) caused the voltage to spike and turn on the SCR - which promptly shorted out and smoked it and a bit of pcb trace -
So I guess because ONE of the meanwells was current limited the fuse didn't blow? In any case, both aren't working and both show trace damage from heat but only one of the SCRs burned up.
I'm guessing that quickly removing the extra load of the fan (it was a huge server fan rated at 1amp) caused the voltage to spike and turn on the SCR - which promptly shorted out and smoked it and a bit of pcb trace -
NeilP
1 GW
Bad luck on that, hope it is an easy fix
wineboyrider
1 MW
WTF? Mine still works great... :?
NeilP
1 GW
Well my two S-350-48's are ok...despite the fact that two nights ago I tried to connect the pack the wrong way....big flash and vaporised the connector. Lucky no damage to the Meanwells, but did zap the tppacks cc/cv board
auraslip
10 MW
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On both units I removed the burnt up SCR(scr1), the failed zener diode(zd2), and replaced a burnt up resistor. Everything works! I guess I just won't have over voltage protection, which might be a problem if one of the meanwells in series dies and exposes the other one to the full voltage of the battery pack?
Burned up traces and a charred hole in the board
I can't believe nothing else failed!
Burned up traces and a charred hole in the board
I can't believe nothing else failed!
wineboyrider
1 MW
Glad I'm not the only one that knows how to do that.NeilP said:
auraslip
10 MW
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My new setup looks like a prop bomb from CSI miami
I got these velcro straps from wal-mart. A roll of 60 was like $3 - they are awesome! I velcroed the units back to back with two 12v fans in series running off one of them. I tried a normal 12v, but at 28v is started smoking in like 30 seconds.
The two fans in series are still running fast and loud because 28v / 2 = 14v each. I wonder if the extra cooling from the fans will allow me to take it above the 6a current rating?
Next up I'll make a carrying strap with the velcro - I'm totally sold on that stuff for wire management - so much better than zip ties.
I got these velcro straps from wal-mart. A roll of 60 was like $3 - they are awesome! I velcroed the units back to back with two 12v fans in series running off one of them. I tried a normal 12v, but at 28v is started smoking in like 30 seconds.
The two fans in series are still running fast and loud because 28v / 2 = 14v each. I wonder if the extra cooling from the fans will allow me to take it above the 6a current rating?
Next up I'll make a carrying strap with the velcro - I'm totally sold on that stuff for wire management - so much better than zip ties.
wineboyrider
1 MW
@auraslip: That thing looks like something out of a james bond movie!
8) 8) 8) 8) 8) 8) 8)
8) 8) 8) 8) 8) 8) 8)
wineboyrider
1 MW
1 million dollars? LMAO ! I love Austin Powers!auraslip said:
1 million dollars or all blow up the entire sphere!
Okay guys, I need your help.
I've been modifying Meanwell S-350-48 clone for charging LiPo, and so far it went well. I've managed to rise maximum voltage and limit current with R33 mod.
Now, I've tried Q5 mod, but when I connect the fan PSU starts buzzing and current limit goes up. Business as usual. Someone suggested removing Q5 completely, although I can't see how could that help, but still PSU buzzes with I connect the fan. So I've tried limiting the current it's pulling via resistor in series with the fan, but as soon as you connect it, it starts buzzing although current is just few mA (fan doesn't even try to spin).
So, I've grabbed MW schematics, analyzed it, and tried connecting the fan directly to the input of the 7812 (there is about 20V), but as soon as you load FL1 and FL2 outputs with anything, let alone a fan, PSU starts buzzing and current limit goes up.
I'm stuck now, I don't have access to any 48V or higher voltage fans, and can't work out why PSU buzzes as soon as you load FL1 and FL2. I'm aware I could probably go around and connect the fan some other way, but I would like to get to know SMPS better, and stop this problem at it's root.
Edit: I've added MW schematics for those who are willing to help but can't be bothered to find it.
I've been modifying Meanwell S-350-48 clone for charging LiPo, and so far it went well. I've managed to rise maximum voltage and limit current with R33 mod.
Now, I've tried Q5 mod, but when I connect the fan PSU starts buzzing and current limit goes up. Business as usual. Someone suggested removing Q5 completely, although I can't see how could that help, but still PSU buzzes with I connect the fan. So I've tried limiting the current it's pulling via resistor in series with the fan, but as soon as you connect it, it starts buzzing although current is just few mA (fan doesn't even try to spin).
So, I've grabbed MW schematics, analyzed it, and tried connecting the fan directly to the input of the 7812 (there is about 20V), but as soon as you load FL1 and FL2 outputs with anything, let alone a fan, PSU starts buzzing and current limit goes up.
I'm stuck now, I don't have access to any 48V or higher voltage fans, and can't work out why PSU buzzes as soon as you load FL1 and FL2. I'm aware I could probably go around and connect the fan some other way, but I would like to get to know SMPS better, and stop this problem at it's root.
Edit: I've added MW schematics for those who are willing to help but can't be bothered to find it
.Attachments
NeilP
1 GW
I think the buzzing when fan starts is a false lead, it is not the fan itself causing the psu to start buzzing, but rather something to do with the current limiting
Yes, current does increase when fan starts, this is one reason for doing the always on fan mod...set your current limit with the fan running. That wont solve the buzzing though
If you had fan off, and psu under load, and kept turning the current limit down, buzzing eventually starts, even without fan running
Buzzing seems to be a function of how much the limiting is working
Yes, current does increase when fan starts, this is one reason for doing the always on fan mod...set your current limit with the fan running. That wont solve the buzzing though
If you had fan off, and psu under load, and kept turning the current limit down, buzzing eventually starts, even without fan running
Buzzing seems to be a function of how much the limiting is working
Yes and no.
If I limit current down to 1-2A, it buzzes on it's own, but if I set it up to 4-5A it works nicely, as long as there is no fan connected. I've tried with and without Q5 mod, and Q5 present on the board or not. I didn't make a slightest difference. As long as there isn't anything connected to fan socket or FL1 and FL2, where thermal protection circuit get it's power from, PSU is working silently.
The instant you connect any load to the fan socket or FL1/FL2, current limit goes up and it starts buzzing.
If I limit current down to 1-2A, it buzzes on it's own, but if I set it up to 4-5A it works nicely, as long as there is no fan connected. I've tried with and without Q5 mod, and Q5 present on the board or not. I didn't make a slightest difference. As long as there isn't anything connected to fan socket or FL1 and FL2, where thermal protection circuit get it's power from, PSU is working silently.
The instant you connect any load to the fan socket or FL1/FL2, current limit goes up and it starts buzzing.
My SP-500-24's SVR2 mod does put out more current when the fan is not running. I have it set to 15.0xA when the fan is at full speed. It starts off around 15.2-15.3A and drops as the fans throttle up.
A bit odd, but its not really a big deal if you ask me. It used to have a SLIGHT buzz running at 19-20A off 110-115VAC, but its perfectly silent at 15A. It technically is de-rated to 18A at that input voltage, which might have something to do with it.
A meager 1500W works fine, and it won't trip a standard 15A breaker, so I'm happy with it.
A bit odd, but its not really a big deal if you ask me. It used to have a SLIGHT buzz running at 19-20A off 110-115VAC, but its perfectly silent at 15A. It technically is de-rated to 18A at that input voltage, which might have something to do with it.
A meager 1500W works fine, and it won't trip a standard 15A breaker, so I'm happy with it.
Alan B
100 GW
The buzzing may be the supply dropping into hiccup mode to limit overcurrent.
It's not, I'm constantly monitoring current.
My PSU actually works fine in 6A+ range, but I'm getting pretty close to maximum wattage rating (it's a clone, don't forget), and as I still ride on 1P LiPo pack, I don't want to go over 1C charage.
My PSU actually works fine in 6A+ range, but I'm getting pretty close to maximum wattage rating (it's a clone, don't forget), and as I still ride on 1P LiPo pack, I don't want to go over 1C charage.
Alan B
100 GW
It doesn't have to "be" real overcurrent, if the supply control circuit "thinks" it is overcurrent it may engage hiccup. The mods to the circuitry being made are disturbing the original design. I have not done an analysis, just mentioning the possibility.
NeilP
1 GW
Well if you do get the buzzing solved...you will be the first...I think we are all just living with it and there does not seem to cause any ill effects apart from the annoyance...I am sure long term it is not good but...mine is ok with occasional buzzing after more than 6 months
That's my only worry that it will decrease lifespan of the PSU, I'm not that annoyed by the buzzing. I hoped someone here would at least have a clue of what is going on here, unlike me, but nevertheless I'll try to fix it. I'll post my results here, if I come up with any.
I couldn't find any info about pushing Meanwells to their limits voltage wise, so does anybody know could I possibly push MW to ~65V for 16S LiPo charging? What else would need to be modified except, obviously, output caps? I know how to up the voltage, but I'm not sure what other components need to be rated for such high voltage.
