mwkeefer
1 MW
But the hissing means the mods we already have and the svr2 both effect the lower voltage rail in the same way
Switch mode supply mod
- Thread starter Jeremy Harris
- Start date
mwkeefer
1 MW
Arlo1 said:
Lets play a game first... (the diode looks like a transistor but is alone and next to teh coil heatsinked to the case)
Split your pack into 12S2P parts (should be easy enough) then test each 48v supply to see if they are both outputting 3A or if one is controlling the current output on the other...
This will identify which unit isn't operating properly and we can debug the issue to resolution.
-Mike
baerfoot
1 mW
Here is the Ebay seller I bought from: e_lightningHyena said:
mwkeefer
1 MW
Arlo1,
In looking at your pics from my desktop (I was on my iphone) I see there is evidence in the top view photo that there indeed was a switch mounted in there... I wonder if that wasn't a modified return they just re-shipped without checking?
When you pull that PCB, grab some shots of the underside before salvaging the Blown real good units 110/220 switch...
I am clueless on your S-350 with .3a - like I said the output diodes (the clamping diode) will go bad and cause that or no output but normally it causes the fuses to pop until replaced.
baerfoot,
Can you read the values for the transistor near SVR2 and also the color codes of the resistors surrounding it... that is indeed the same PCB as many of us but those parts were not populated but left blank, another difference is you have 4 caps in the front output stage while all my S-350-48s have 3, I would say that model was built with a different level of quality or atleast features.
That said you don't "need" to pull the switch from the other unit, just rewire for 110 (fake the switch) if that's what you will use all the time.
-Mike
In looking at your pics from my desktop (I was on my iphone) I see there is evidence in the top view photo that there indeed was a switch mounted in there... I wonder if that wasn't a modified return they just re-shipped without checking?
When you pull that PCB, grab some shots of the underside before salvaging the Blown real good units 110/220 switch...
I am clueless on your S-350 with .3a - like I said the output diodes (the clamping diode) will go bad and cause that or no output but normally it causes the fuses to pop until replaced.
baerfoot,
Can you read the values for the transistor near SVR2 and also the color codes of the resistors surrounding it... that is indeed the same PCB as many of us but those parts were not populated but left blank, another difference is you have 4 caps in the front output stage while all my S-350-48s have 3, I would say that model was built with a different level of quality or atleast features.
That said you don't "need" to pull the switch from the other unit, just rewire for 110 (fake the switch) if that's what you will use all the time.
-Mike
SO as I was finaly chargin at a good rate my old charger blew up. 
I belive its just the fets the little china man sold me trying to help me out. But Im realy getting sick of waiting for these to come from hong kong! I have one more on its what that was ordered about 4 weeks ago. Wished there was something simler and closer!
I belive its just the fets the little china man sold me trying to help me out. But Im realy getting sick of waiting for these to come from hong kong! I have one more on its what that was ordered about 4 weeks ago. Wished there was something simler and closer!
Hyena
10 GW
Arlo 10 amps is too much for a 350w 48v unit! I assume you have it set at 50v to charge your 24S pack in 2 halves ? That's nearly 500w, no wonder it blew! Back your next one off to about 7 amps of charge current and you should be right
My current is not adjustable unless I lower the voltage but I run both power supplies in series to charge at 100.8 volts that is what I chage a ballanced pack to, I dont want to lower that, I have never had problems with this till just recently. The last one blew because of the infirior fets I used to fixe it!Hyena said:
Hyena
10 GW
Yeah but if you're charging at 10 amps that's 140% of what it's rated to do and it's only luck that kept it from blowing up sooner.
They're not current adjustable out of the box, but most of this thread is about how to mod them to do it - either mod the shunts or resistors.
They're not current adjustable out of the box, but most of this thread is about how to mod them to do it - either mod the shunts or resistors.
Ok so I have 2 working power supplies. And there are 48 volt 7.3 am MW they are charging at 9.5 amps even after modifing the shunt in one of them. But I think If I modify the fans to stay on they will be ok.Hyena said:
So has anyone figured out how to modify the fans to stay on?
mwkeefer
1 MW
Arlo,
The thermistor is green and just between the big coil and the transformer... I would actually remove it and replace with perhaps 470 ohm to 700 ohm, please note this should be done first before any current modifications... That's because the fan speeding up will lower the voltage on the regulation side of the thing which controls current output, this results in higher amps (ask anyone, about an Amp when the fan kicks in).
Once the thermistor is replaced and the voltage is set correctly, then you can configure your current output with either shunt removal (if you have more than one, in essence increasing the resistance or just modify R33 to compensate and get the correct current output.
Calibrating output current is fairly straight forward... Since you know the maximum watts you want to pull constant, lets assume 400 which works fine with the fan mod and some Arctic Silver paste... so assuming the 50v mark for charging 1/2 of your 24S pack you would want to calibrate the constant current output at about 8 Amps.... here's the fun part, not 8 amps at lower voltages because then when the voltage rises you will exceed the 400w mark... this 400w mark or 8A limit must be effective for your cross over / delta voltage of 50V... so at 50V (where taper will shortly begin) the output should be 8A.
Hyena is right... 10 amps will last about 22 seconds if your lucky on an S-350-48... and there are issues with turning a single supply up to 99/100v.
That said, you could run a pair in series tuned to 50v each and with just one modified for 8A it will automatically limit its brother supply... this will let you safely charge the entire pack at once at 2A shy of 10A... add more supplies in parallel first if you want to charge at 18 A (a total of 4 supplies).. I know that defeats the purpose for portable use.
In my testing I can get to 79v (range moved up not extended) and run perfectly stable with a few component (resistors) changes to compensate for the higher voltages but above 79v... I may get a day, an hour or even as much as a week (well 6 days) once... but even reduced to 320w output power, poof snap. I've ruined more supplies than I can tell you trying to exceed the 80v mark (83 was my target) with a single unit.
Hope it helps!
-Mike
The thermistor is green and just between the big coil and the transformer... I would actually remove it and replace with perhaps 470 ohm to 700 ohm, please note this should be done first before any current modifications... That's because the fan speeding up will lower the voltage on the regulation side of the thing which controls current output, this results in higher amps (ask anyone, about an Amp when the fan kicks in).
Once the thermistor is replaced and the voltage is set correctly, then you can configure your current output with either shunt removal (if you have more than one, in essence increasing the resistance or just modify R33 to compensate and get the correct current output.
Calibrating output current is fairly straight forward... Since you know the maximum watts you want to pull constant, lets assume 400 which works fine with the fan mod and some Arctic Silver paste... so assuming the 50v mark for charging 1/2 of your 24S pack you would want to calibrate the constant current output at about 8 Amps.... here's the fun part, not 8 amps at lower voltages because then when the voltage rises you will exceed the 400w mark... this 400w mark or 8A limit must be effective for your cross over / delta voltage of 50V... so at 50V (where taper will shortly begin) the output should be 8A.
Hyena is right... 10 amps will last about 22 seconds if your lucky on an S-350-48... and there are issues with turning a single supply up to 99/100v.
That said, you could run a pair in series tuned to 50v each and with just one modified for 8A it will automatically limit its brother supply... this will let you safely charge the entire pack at once at 2A shy of 10A... add more supplies in parallel first if you want to charge at 18 A (a total of 4 supplies).. I know that defeats the purpose for portable use.
In my testing I can get to 79v (range moved up not extended) and run perfectly stable with a few component (resistors) changes to compensate for the higher voltages but above 79v... I may get a day, an hour or even as much as a week (well 6 days) once... but even reduced to 320w output power, poof snap. I've ruined more supplies than I can tell you trying to exceed the 80v mark (83 was my target) with a single unit.
Hope it helps!
-Mike
Thanks I did modify the shunt on one of them. So of all 4 psu's I have they all only have one shunt in J1 through J5 is that then one to modify? And I will take one of my fried bords to work and mesure resistance with and with out heat to find the thermistor. I have been charging with 2 psu's in series for 8 months now but just recently blew up 2 of them. I want this to be reliable. So anyways thanks again, time for work lol.
Thanks mikemwkeefer said:
But I still cant find the thermistor in mine is it possible I dont have one all the green parts in mine start with a C so that meen they are caps doesnt it? I was wondering wouldnt it be eiser to jumper the transistor that controls the fan?
Hyena
10 GW
It looks similar to a cap but will be right next to the big coil, most likely on longish legs sticking up quite high. Post a pic of the section of your board around the coil and I'll circle it for you.
edit: "here's one I prepared earlier"
Yours probably won't be exactly the same but should be quite similar
edit: "here's one I prepared earlier"
Yours probably won't be exactly the same but should be quite similar
mwkeefer
1 MW
Thanks Hyena - I've been swamped today...
As you can see in the picture, it will always be the smallest thermistor (there are usually 2 more near the AC side input caps) and will be basically in the center of a triangle between the Coil (looks like a big RF Choke), the transformer which covers ZD1 and the 8 pin dip which is either an opamp or an optocoupler I can't see well enough right now on that pic and it's not identical to my own.
I have 80% of the scenes for a full step by step how to video shot, I need to finish tommrow and then run production quickly through premier... I will post the video in a new howto thread along with my alpha rough draft of my meanwell modifications manual AKA Meanwell Unleashed = )_
-Mike
As you can see in the picture, it will always be the smallest thermistor (there are usually 2 more near the AC side input caps) and will be basically in the center of a triangle between the Coil (looks like a big RF Choke), the transformer which covers ZD1 and the 8 pin dip which is either an opamp or an optocoupler I can't see well enough right now on that pic and it's not identical to my own.
I have 80% of the scenes for a full step by step how to video shot, I need to finish tommrow and then run production quickly through premier... I will post the video in a new howto thread along with my alpha rough draft of my meanwell modifications manual AKA Meanwell Unleashed = )_
-Mike
Ok thanks guys mine isnt green its black. And I will mod it tomorow. Video will be awesome. Getting one of these to 101 volts would be nice so a guy could have on bord charging. But it might just be easier to stuff two into one case. What do we need to be able to run at Hi amps like 2 bords in series >15 amps. Im sorry I will try to spend more time reading the entire thread this weekend.
mwkeefer
1 MW
Arlo1 said:
80 ish volts I've had issues long term, 2 in series would give you about 7.6A at 101v you can always look at the 700w unit that would do 15.2A roughly with a pair in series...
Do a bit more reading and get a feel for it, when your ready post back here or feel free to PM me if you need assistance = )_
And... when you do the thermistor mod (assuming you have a Digital Volt Meter / Ohmmeter)... measure it's out of circuit resistance the hold a lighter to it for about 10 - 30 seconds and take the resistance reading again... now you know the range from all off to all on, I normally use a 1K pot hooked in series with a resistor to adjust the fan speed for optimal operation.
-Mike
Finally got mine wired up last night. (Four SP-350-24 clones.) Set them all to 23.70volts, but the overall no load voltage was 94.2V, (94.2/4=23.55). While connected up in series I rechecked the individual supplies and they all read 23.70V. So what gives? I'm out of my leauge now. 
I'm not worried about an exact voltage reading, (within a volt or so), I can always tweak as necessary, but it would be nice to understand what's going on. I'm especially curious as to what might happen when I connect it up to the batteries as a charger and put a load on it. If it drops any more under load I'll need to adjust the voltage higher.
I'm not worried about an exact voltage reading, (within a volt or so), I can always tweak as necessary, but it would be nice to understand what's going on. I'm especially curious as to what might happen when I connect it up to the batteries as a charger and put a load on it. If it drops any more under load I'll need to adjust the voltage higher.
number1cruncher
1 kW
DaveAK said:
Not sure why it doesn't add up, hopefully someone can answer that.
DaveAK said:
Do not increase the voltage AFTER hooking up the pack. The supply voltage will definately drop under load to meet the battery voltage. Remember the first stage of charging Lithium is constant current, the voltage is variable and will rise until it meets your set point. The second stage is constant voltage, the current is variable and will taper to 0A when the pack is full.
Good luck!
I wasn't very clear, but what I really meant to say was that I would do these adjustments if basically I don't get a full charge. I'll monitor it throughout the charging process, but if the pack doesn't end up at the desired voltage then I'll tweak the charger and test again.number1cruncher said:
