cassschr1
10 kW
Do you think two meanwell sp"s and above unit could be combined for 150? The mixing of the two brands?
Switch mode supply mod
- Thread starter Jeremy Harris
- Start date
I don't think the brand will make any difference. As long as you don't exceed the power rating or the voltage rating of the output parts, it should be happy.cassschr1 said:
Hyena
10 GW
Speaking of running multiple units in series, was it established 100 pages or so back that these units are isolated ?
Being able to "turbo charge" my 18S pack left connected in series with 3 of these units hooked to each 6S parallel group would be cool.
Being able to "turbo charge" my 18S pack left connected in series with 3 of these units hooked to each 6S parallel group would be cool.
Yes, all the ones I've seen are isolated. You could double check by measuring from the ground pin on the AC input to both of the output pins with an ohmmeter.
heathyoung
100 kW
Also check that the negative is not tied to the ground/earth as well!
Finally got around to using my charger and need some troubleshooting help please! 
I'm using four S-350-24 clones. I've done the fan mod on each so that the fans run constantly. I modded one to limit the current to 15A. I adjusted them to 22V a piece to give me a total of 88V to charge my 24S1P LiFePO4 pack to 3.65V*24=87.6V. I hook it up and the PSU that I did the current mod on drops to 16ish V and my output goes down to 82.4V. This is the unit that I take the negative from, through a Turnigy watt meter. It shows I'm drawing my 15A. I get the power for the Turnigy from this first supply, but even if I disconnect the Turnigy I still only get 16V from it. Other than that I'm not sure what else to say about my set up. I've installed a 200V 40A diode in between the battery pack and the charger so that I don't get any sparks when I plug it in.
What gives oh wise ones?
Edit: I'm guessing it's because I'm in the CC phase maybe? If I wait long enough will I see the voltage rise to 88V and then the amps start to drop? Why does only one of the four PSUs drop in voltage though?
I'm using four S-350-24 clones. I've done the fan mod on each so that the fans run constantly. I modded one to limit the current to 15A. I adjusted them to 22V a piece to give me a total of 88V to charge my 24S1P LiFePO4 pack to 3.65V*24=87.6V. I hook it up and the PSU that I did the current mod on drops to 16ish V and my output goes down to 82.4V. This is the unit that I take the negative from, through a Turnigy watt meter. It shows I'm drawing my 15A. I get the power for the Turnigy from this first supply, but even if I disconnect the Turnigy I still only get 16V from it. Other than that I'm not sure what else to say about my set up. I've installed a 200V 40A diode in between the battery pack and the charger so that I don't get any sparks when I plug it in.
What gives oh wise ones?
Edit: I'm guessing it's because I'm in the CC phase maybe? If I wait long enough will I see the voltage rise to 88V and then the amps start to drop? Why does only one of the four PSUs drop in voltage though?
DaveAK said:
That's right. The limiter works by dropping the voltage on the one with the limiter hooked up to it. When the batteries get up to a higher voltage, the voltage on that supply will start to come up. The idea is if the voltage drops enough, the current will drop. With your setup, there's a chance the one with the limiter won't be able to drop enough to limit the amps, but it sounds like that's not the case (good). If you can dial the amps down to near zero, then you're OK.
Just let it continue charging and see what it does.
Thanks for the reassurance! But here's something that might be worrying from what you said. My pack was only slightly discharged when I was testing the charger. So if it's fully discharged, (say 24*2.7V=64.8V), what's that likely to do to the limiting PSU? 64.8V is less than the other 3 PSUs at 22V each. What happens then?
If the battery is too low, the current might go over the limit for a while.
sjoerdvdd
10 mW
Hi guys,
Question,
I want to charge 60V of LiFePo4. Is it more easy to do it with 2 24V power supplies, which i crank up to ~34V if possible. Or is it better to get 2 48V power supplies and tune down to ~34V each?
Kind regards,
Sjoerd
Question,
I want to charge 60V of LiFePo4. Is it more easy to do it with 2 24V power supplies, which i crank up to ~34V if possible. Or is it better to get 2 48V power supplies and tune down to ~34V each?
Kind regards,
Sjoerd
Hyena
10 GW
You're better to buy the ones closest to their normal running voltage. You'd need to modify the resistors/pots in both the 24 and 48v units if you use 2 of each. You can mix and match to get your target voltage - use a 24v and 48v unit in series and they'll work straight out of the box with the voltage set appropriately. You'll probably need to mod the shunt or resistors or use an add in board to limit the current in one of them though.
sjoerdvdd
10 mW
So i understand that using one 24V and one 48V will solve the problem, but because of the current difference, i need to make some changes to the shunts?
heathyoung
100 kW
Nope. One will be running at its capability (the 48V one) and the 24V one will be running cooler. Current is the same through the whole circuit. I'd be limiting the 48V one, not the 24V one.
sjoerdvdd
10 mW
Hmm, don't really get it anymore.
if i use a 24 and 48V power supply, i need to tune down the current from the 24V unit, or tune up the current from the 48V unit, in order to level the current.. I do that by adjusting the shunts/resistors.
Or use 2 48V supplies, and tune down the voltage.
Which of these is it? since i'm confused, allready had contact with meanwell, but they require high quantities to give some serious advise..
if i use a 24 and 48V power supply, i need to tune down the current from the 24V unit, or tune up the current from the 48V unit, in order to level the current.. I do that by adjusting the shunts/resistors.
Or use 2 48V supplies, and tune down the voltage.
Which of these is it? since i'm confused, allready had contact with meanwell, but they require high quantities to give some serious advise..
When two supplies are in series, the current in both of them will be equal no matter what. The supply with the lowest limit will dictate the current you get out of the series pair. If you have a 48v supply running 5A and a 24v supply capable of 10A, you will only get 5A out and the 24v supply will be running at half its rated power.
If you put supplies in parallel, you can get the current to add (but the voltage must be the same on both). Unless the voltages of the two are exactly equal, one supply will tend to carry all the load when they are not in limiting. This is not a big problem, but reqires both supplies to have CC limiting.
Another option would be a pair of 27V supplies in series. I think you can get these up to 30v without changing any parts (not tested).
I have a 48v supply that I cranked up to 60v, but it required changing the zener. It could do about 54v stock.
If you put supplies in parallel, you can get the current to add (but the voltage must be the same on both). Unless the voltages of the two are exactly equal, one supply will tend to carry all the load when they are not in limiting. This is not a big problem, but reqires both supplies to have CC limiting.
Another option would be a pair of 27V supplies in series. I think you can get these up to 30v without changing any parts (not tested).
I have a 48v supply that I cranked up to 60v, but it required changing the zener. It could do about 54v stock.
NeilP
1 GW
What mod do I need to turn down two 48v supplies to 38V each, is it just changing SVR1 for a multi turn pot?...or is there something else?
OK, I know I'll need to limit the current also, so I may do a current mod via the 'shunt mod' I want 38 volt to run as a PSU for an iCharger 3010b. This has "Supply Protection" buitl in, so I can limit the current it tries to draw from the PSU.
I may go for a CC/CV board also, as Backup protection. Set that a little higher than the limit on the iCharger.
If I do a Fan Always On Mod, I had thought to try the 'remove the Q5 transistor and bridge the collector -emitter link
OK, I know I'll need to limit the current also, so I may do a current mod via the 'shunt mod' I want 38 volt to run as a PSU for an iCharger 3010b. This has "Supply Protection" buitl in, so I can limit the current it tries to draw from the PSU.
I may go for a CC/CV board also, as Backup protection. Set that a little higher than the limit on the iCharger.
If I do a Fan Always On Mod, I had thought to try the 'remove the Q5 transistor and bridge the collector -emitter link
NeilP
1 GW
Anyone?
have trawled the 38 pages of this thread, but just cant find it.
Anyone remember what the value of the pot that you replace SVR1 with? I remember mention of a 10turn pot...but what value?
This is for a Meanwell S-305-48 going down to 36-38 volt. Upper limit 42 volt
Neil
have trawled the 38 pages of this thread, but just cant find it.
Anyone remember what the value of the pot that you replace SVR1 with? I remember mention of a 10turn pot...but what value?
This is for a Meanwell S-305-48 going down to 36-38 volt. Upper limit 42 volt
Neil
docnjoj
1 GW
Hey Neil
Perhaps this post will help
otherDoc
http://endless-sphere.com/forums/viewtopic.php?f=14&t=24992&p=361394#p361394
Perhaps this post will help
otherDoc
http://endless-sphere.com/forums/viewtopic.php?f=14&t=24992&p=361394#p361394
NeilP
1 GW
Yep, thanks...got it...knew it was here somewhere...just could not find it
10k 15 turn
10k 15 turn
number1cruncher
1 kW
NeilP said:
Neil,
Sorry for the delay. I've been sick and my wife is very close to having a baby.
Anyway, I checked my s-350-48 and it tunes down to 38.4V. The only mods I did was clip one of three shunts to reduce the current and replaced the thermistor with a resistor to keep the fan constantly on. I do not think either mod affected the voltage range. I could be wrong. Good Luck!
Bryan
NeilP
1 GW
Hi Bryan , thanks for the reply...and good luck with the baby
NeilP
1 GW
Well my S-350-48's arrived.
I took SVR 1 out...measured at 1k...so I put in a single turn 2k ...that is enough to turn it down to 33 or so volts...
Somewhere in this thread there is a mention of turning below 33 volt tends to let the magic smoke out anyway after a period of running...so down to 33 volt is fine for me..I only need 36 volt anyway
I took SVR 1 out...measured at 1k...so I put in a single turn 2k ...that is enough to turn it down to 33 or so volts...
Somewhere in this thread there is a mention of turning below 33 volt tends to let the magic smoke out anyway after a period of running...so down to 33 volt is fine for me..I only need 36 volt anyway
icecube57
10 MW
Ive tuned my 48v Meanwell as low as the high teens by switching out for a 10k 15turn precision pot. I charged at 25.2v for a short period of time.
NeilP
1 GW
oh well...maybe be the poster that mentioned frying his just got unlucky?/..I wont be trying though
Hyena
10 GW
Anyone played with higher current units ?
I just came across 500w ones on ebay that claim "Current Limit Control VR"
http://cgi.ebay.com.au/500W-24V-20A-Switching-Power-Supply-Radio-Charger-/250777384280?pt=AU_Security_Equipment&hash=item3a637f3558
I get 18 amps out of my 24v 350w unit reliably so I wonder if there's too much different in these. Probably just an additional fet, but having an adjustable current limit out of the box could make them worth the extra.
I just came across 500w ones on ebay that claim "Current Limit Control VR"
http://cgi.ebay.com.au/500W-24V-20A-Switching-Power-Supply-Radio-Charger-/250777384280?pt=AU_Security_Equipment&hash=item3a637f3558
I get 18 amps out of my 24v 350w unit reliably so I wonder if there's too much different in these. Probably just an additional fet, but having an adjustable current limit out of the box could make them worth the extra.
