NeilP
1 GW
Bugger...just realised I flipped the wrong image. I should have flipped the top image...not the rear image...all the writing is backwards..Gotta go to work now.If you cant make anything out from that lot ..I'll try again tongiht
converting meanwell power suply into Lipo charger
- Thread starter wojtek
- Start date
Spicerack
10 kW
Whoa. Those overlay images were doing my head in!
I can confirm that as fechter said, there is 2.5v at the ovp position next to the green power led.
I'll try and get a few detail shots up as well of the circled areas.
I can confirm that as fechter said, there is 2.5v at the ovp position next to the green power led.
I'll try and get a few detail shots up as well of the circled areas.
Great pictures. Much better.
Yes, I think you want to mess with R127/128/129 which appear to be 3 in parallel (with one empty spot).
I cant make out the markings on the resistors themselves, so it would be helpful if you could use an ohmmeter and measure across them. Once I know what the resistance is, I'd have a better idea what value of pot/fixed resistor to use.
I'm pretty sure you can attach a pair of wires to the ends of those resistors and run them to a pot to turn down the limit.
There could be a problem if the pot goes all the way to zero, so best to insert a fixed (100 ohm?) in series with the pot to prevent overloading U100.
Removing one or both resistors first would allow turning the current limit higher as well as lower.
I think it should work like this:
Yes, I think you want to mess with R127/128/129 which appear to be 3 in parallel (with one empty spot).
I cant make out the markings on the resistors themselves, so it would be helpful if you could use an ohmmeter and measure across them. Once I know what the resistance is, I'd have a better idea what value of pot/fixed resistor to use.
I'm pretty sure you can attach a pair of wires to the ends of those resistors and run them to a pot to turn down the limit.
There could be a problem if the pot goes all the way to zero, so best to insert a fixed (100 ohm?) in series with the pot to prevent overloading U100.
Removing one or both resistors first would allow turning the current limit higher as well as lower.
I think it should work like this:
NeilP
1 GW
I am at work now, but did already measure the resistors. and compared with the markings
Overall resistance is 77 Ohm
one resistor being 1.5kOhm (1501) and the other being 82 Ohm (820)
So I am thinking a 100 ohm by itself would take overall resistanve down to 43 Ohm, with maybe a 5kOhm multi turn pot in series with that or maybe higher, maybe knock out the 1.5kOhm and use the 100 ohm resistor and a 10K pot to give adjustment higer as well for those that want to push it above rated current
Overall resistance is 77 Ohm
one resistor being 1.5kOhm (1501) and the other being 82 Ohm (820)
So I am thinking a 100 ohm by itself would take overall resistanve down to 43 Ohm, with maybe a 5kOhm multi turn pot in series with that or maybe higher, maybe knock out the 1.5kOhm and use the 100 ohm resistor and a 10K pot to give adjustment higer as well for those that want to push it above rated current
Spicerack
10 kW
Thanks fechter, you really are a maestro of stuff electronic!
I will crack the multimeter out tomorrow unless someone beats me to it to measure those little resistors. Aaarrggh! Neil, you beat me to it while I was posting this! Well done. I'll have a look at doing those mods and see what happens. Hope the magic smoke doesn't escape...
For info, the u100 chip has HA17358 marked on it.
I will crack the multimeter out tomorrow unless someone beats me to it to measure those little resistors. Aaarrggh! Neil, you beat me to it while I was posting this! Well done. I'll have a look at doing those mods and see what happens. Hope the magic smoke doesn't escape...
For info, the u100 chip has HA17358 marked on it.
NeilP
1 GW
andynogo said:
I beat you to th chip info too...check back on the previous page about half way down
Spicerack
10 kW
NeilP said:andynogo said:
I beat you to th chip info too...check back on the previous page about half way down
Read before posting Andy, read before posting!
I'll just be quiet now. Thanks for all the pics and info Neil.
NeilP
1 GW
There is so much posted, it is easy to miss little bits like that
There's probably a way to do some math to figure out exactly what current you'd get for a given resistance.
In most cases, I don't think you'd want to increase the limit. Maybe if you were running it at well below the rated voltage.
2k or 5k for the pot should be in the ballpark. A series 100 ohm would be optional to prevent problems if you ran the limit all the way down. As long as you never turn the pot all the way to zero, it would not be needed.
If you removed the 1.5k resistor and replaced it with a 1k pot in series with a 1k fixed resistor, you would have a small range in both directions.
In most cases, I don't think you'd want to increase the limit. Maybe if you were running it at well below the rated voltage.
2k or 5k for the pot should be in the ballpark. A series 100 ohm would be optional to prevent problems if you ran the limit all the way down. As long as you never turn the pot all the way to zero, it would not be needed.
If you removed the 1.5k resistor and replaced it with a 1k pot in series with a 1k fixed resistor, you would have a small range in both directions.
NeilP
1 GW
well I wont be testing mine again..I toasted it about 2 hrs ago
The component that let out flames was a PA905C4 which is a 3 pin High speed low loss rectifier
i cant be sure if it was because of the mod, or because this was the first time with a fully discharged pack ( 42 volt for 12 series )
I used a 4.7kohm pot and a selection of resistors in parallel to give about 200 ohms in series with the pot, this was in parallel with the two resistors as discussed earlier. Total overall resistance of the parallel resistors and my pot was 58 ohm at one end, up to 76 at the other
Supply set to 49.8 volts
When I previously charged a pack that was down to about 45 volt the supply sat at about 9 amps for about 45 mins or so with the fan kicking in and out , current slowly tapering off
When I connected up this 42 volt pack, voltage dropped to about 47 volts and current went up to around 13 or more amps, turning the pot to the lower resistance so dropping the overall value..brought the current down to around 6 amps, although not as smoothly or as controllably as I get when using my other meanwells and the 5 k multi turn pot
Then it all would start to get a bit random, current jumping up to 18-20 amps, then down again, and turning the pot in either direction did not seem to have any effects.
Breaking the connection between the jumper wires and the new pot also had no effect
I powered down and disconnected all and re connected and re powered the PSU this time with no pot connected...Current shot up to 12 or more amps...connected the pot and it could be brought back under control and back down to about 8 amps.
The it started getting weird again...current went up to about 10 amps...and voltage started dropping...down and down to about 18 volts...yet current was still showing at 10 amps into the pack
The the component let out the smoke and flames before I could get to it to pull the plug.
I did find another similar style 3 pin rectifier on a dead PC PSU, and the diodes checked out ok, so I tried fitting that, but it will not even power up now, so it must have taken something else with it
The component that let out flames was a PA905C4 which is a 3 pin High speed low loss rectifier
i cant be sure if it was because of the mod, or because this was the first time with a fully discharged pack ( 42 volt for 12 series )
I used a 4.7kohm pot and a selection of resistors in parallel to give about 200 ohms in series with the pot, this was in parallel with the two resistors as discussed earlier. Total overall resistance of the parallel resistors and my pot was 58 ohm at one end, up to 76 at the other
Supply set to 49.8 volts
When I previously charged a pack that was down to about 45 volt the supply sat at about 9 amps for about 45 mins or so with the fan kicking in and out , current slowly tapering off
When I connected up this 42 volt pack, voltage dropped to about 47 volts and current went up to around 13 or more amps, turning the pot to the lower resistance so dropping the overall value..brought the current down to around 6 amps, although not as smoothly or as controllably as I get when using my other meanwells and the 5 k multi turn pot
Then it all would start to get a bit random, current jumping up to 18-20 amps, then down again, and turning the pot in either direction did not seem to have any effects.
Breaking the connection between the jumper wires and the new pot also had no effect
I powered down and disconnected all and re connected and re powered the PSU this time with no pot connected...Current shot up to 12 or more amps...connected the pot and it could be brought back under control and back down to about 8 amps.
The it started getting weird again...current went up to about 10 amps...and voltage started dropping...down and down to about 18 volts...yet current was still showing at 10 amps into the pack
The the component let out the smoke and flames before I could get to it to pull the plug.
I did find another similar style 3 pin rectifier on a dead PC PSU, and the diodes checked out ok, so I tried fitting that, but it will not even power up now, so it must have taken something else with it
Bummer :?
Back to the drawing board I guess.
Back to the drawing board I guess.
NeilP
1 GW
fechter, do you want it? can I send it to you ? you are more likely to be able to do something with it than me
NeilP said:
I think the shipping cost would be more than a new one. I'm willing to look at it if you want to send it.
NeilP
1 GW
PM me with an address and I'll get a price
Spicerack
10 kW
That's a shame Neil! For now I've ordered another suply- this one's meant to be the s350 /48V. We will see if it has the SCR circuit in it for the r33 mod...
NeilP
1 GW
I have ordered another one, a clone this time,
That one you've ordered, is it similar to this one http://www.dhgate.com/regulated-switching-power-supply-48v-7-3a/p-ff8080812dcc530b012e2c86d2af0d37.html? I can't order anything from eBay because we can't use Paypal here, so could this power supply do the job?
NeilP
1 GW
Am sure ti would do the job to some degree...but wihtout seeing the inside and the exact circuit board inside it, it is impossible to tell.
From what i have seen , all of these Meanwells, look the same externally, the S- the SE, the SP, and now the NSE, so the ony way you will tell for sure is to order one and find out...or get the seller to open the top of one for you, take a picture, send it to you and then you post it up here
From what i have seen , all of these Meanwells, look the same externally, the S- the SE, the SP, and now the NSE, so the ony way you will tell for sure is to order one and find out...or get the seller to open the top of one for you, take a picture, send it to you and then you post it up here
I somehow managed to not take any pictures of the supplies beforehand, but this is what I started off with...
Mean Well SP-500-24. I intended to make 4 series of these units into a 2KW 24S LiPo charger.
R50 is in series with SVR2. I removed the stock 5.6K ohm resistor and put a 470 Ohm one, and replaced the jumper on SVR2 with a 5K multi turn potentiometer. The current decreases as you near 0 ohms, and increases as it nears open. Two of the units had R50 clipped, and it appeared to be factory. The only reason why the 470 Ohm resistor is there is to make sure SVR2 never goes to 0 ohms, which is a bad idea. With this setup, the current will go down to 5-6A.
I also replaced the stock 1K 3/4 turn POT with a multi turn, to get better control over the final charge voltage. I will avoid using this to top off the pack anyways.
Here they are thrown in series and wired up. This is just some junk extension cord wire, it got warm during testing and will clearly need to be replaced. I am waiting on some 10 AWG Turnigy wire for the DC side. The AC side will also be replaced with appropriate wire, and the input terminals covered with hot melt.
A screen cap from the video, its pulling 20A @115V and putting out 20A @ 93V. It was just loaded with a heat gun and a hair dryer.
http://www.youtube.com/watch?v=mdUHDFXxG3o
I tested it out on my battery as well, and it worked just dandy. The PS buzzes a little, and the 15A breaker trips after 20 seconds. I'm working on the breaker part.
Is it a good idea to throw a diode on the output? Do I want one on both the + and -, just one, or none at all? I'm undecided. It appears to be OK without a diode, for now at least.
Mean Well SP-500-24. I intended to make 4 series of these units into a 2KW 24S LiPo charger.
R50 is in series with SVR2. I removed the stock 5.6K ohm resistor and put a 470 Ohm one, and replaced the jumper on SVR2 with a 5K multi turn potentiometer. The current decreases as you near 0 ohms, and increases as it nears open. Two of the units had R50 clipped, and it appeared to be factory. The only reason why the 470 Ohm resistor is there is to make sure SVR2 never goes to 0 ohms, which is a bad idea. With this setup, the current will go down to 5-6A.
I also replaced the stock 1K 3/4 turn POT with a multi turn, to get better control over the final charge voltage. I will avoid using this to top off the pack anyways.
Here they are thrown in series and wired up. This is just some junk extension cord wire, it got warm during testing and will clearly need to be replaced. I am waiting on some 10 AWG Turnigy wire for the DC side. The AC side will also be replaced with appropriate wire, and the input terminals covered with hot melt.
A screen cap from the video, its pulling 20A @115V and putting out 20A @ 93V. It was just loaded with a heat gun and a hair dryer.
http://www.youtube.com/watch?v=mdUHDFXxG3o
I tested it out on my battery as well, and it worked just dandy. The PS buzzes a little, and the 15A breaker trips after 20 seconds.
I'm working on the breaker part.Is it a good idea to throw a diode on the output? Do I want one on both the + and -, just one, or none at all? I'm undecided. It appears to be OK without a diode, for now at least.
auraslip
10 MW
- Joined
- Mar 5, 2010
- Messages
- 3,535
That's super nice zomgvtek!
Similar to what I'm working on using 12v server power supplies (but probably a lot easier!)
Mine should be capable of doing 6kw - 100v @ 60a! - if I ever need it - lol - did I mention everything together will only run me $150?
Of course that's the long term prospects. Once I finish I'll be limited to 1.5kw because of my residential breaker. I'm having trouble considering that too little power
Meanwells are weird pricing wise. I see some of those sp-24-500 on ebay for like $40, and then some for like $200.
Take this as a lesson guys; if you wait long enough, eventually a genuine model meanwell will show up for a really good price on ebay - and usually a lot of 10 or more too.
Similar to what I'm working on using 12v server power supplies (but probably a lot easier!)
Mine should be capable of doing 6kw - 100v @ 60a! - if I ever need it - lol - did I mention everything together will only run me $150?
Of course that's the long term prospects. Once I finish I'll be limited to 1.5kw because of my residential breaker. I'm having trouble considering that too little power
Meanwells are weird pricing wise. I see some of those sp-24-500 on ebay for like $40, and then some for like $200.
Take this as a lesson guys; if you wait long enough, eventually a genuine model meanwell will show up for a really good price on ebay - and usually a lot of 10 or more too.
flanders
100 mW
Hi, does anyone have any idea what is needed to do a fan mod on the nes-350? i have used mine a few times to charge my 50v pack but it gets quite hot at 9.4 amps! and the fan never stays on.
I got 3 of those supplies for $41.67, shipped, and one for $50 shipped. A total of $150 for the 4 units, and then $10-15 for a few pot's, and probably $20-40 for a bunch of silicone wire.
All in all, its going to be about $200 when its done, for a 2KW PFC 24S charger.
And someone said the SP units couldn't be modified...
All in all, its going to be about $200 when its done, for a 2KW PFC 24S charger.
And someone said the SP units couldn't be modified...
NeilP
1 GW
Yea, but no one yet knows how to do the current mod on the NES models.
We had this discussion on an earlier thread, and had some advice on what to try, and where the equivalent of the R33 resistor may have been.
I tried and it ended in my NES getting smoked.
The only possible mod on these at the moment is shaving a bit of thickness off the single shunt.
As for the fan mod, well I looked at mine and it seems to be driven on/off by a transistor in the same way that the S-350 fan is powered on.
So I would suspect that simply shorting the collector - emitter with a switch or just a link if you want to leave it permanently on would do. This would be the same mod as for the S-350.
But bearing in mind my success so far with my NES supply, I guess you should get some other advice too...or just fit a 240 volt fan and wire it directly to the mains input and junk the original fan
We had this discussion on an earlier thread, and had some advice on what to try, and where the equivalent of the R33 resistor may have been.
I tried and it ended in my NES getting smoked.
The only possible mod on these at the moment is shaving a bit of thickness off the single shunt.
As for the fan mod, well I looked at mine and it seems to be driven on/off by a transistor in the same way that the S-350 fan is powered on.
So I would suspect that simply shorting the collector - emitter with a switch or just a link if you want to leave it permanently on would do. This would be the same mod as for the S-350.
But bearing in mind my success so far with my NES supply, I guess you should get some other advice too...or just fit a 240 volt fan and wire it directly to the mains input and junk the original fan
flanders
100 mW
ZOMGVTEK said:
Hi, as Neil says above no one has found a way to successfully mod the nes version yet, I have a clone on the way if it ever turns up, I was hoping to fan mod my nes-350 for now as it does run a bit hot.
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