converting meanwell power suply into Lipo charger

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Re: converting meanwell power suply into Lipo charger

Post by NeilP » Apr 24 2011 5:49am

Ah. looks like I cross posted with you

Yes, totally different board to the S and SE series.

Although looking at the first pic and the top left hand corner...is that the voltage adjuster trimmer I can see? with an upright resistor next to it that could well be the same sensing resistor that the fecther cc/cv board taps in to to control the PSU..as for current limiting and fan mods..totally different beast...but I am no expert, we just ahve to hope one of the others has used one of these

Looks like 450v capacitors on there...so good to up the voltage on
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Re: converting meanwell power suply into Lipo charger

Post by wojtek » Apr 24 2011 6:01am

ok i managed to unscrew it - so i will add more pics in few minutes to the previous post to keep them in one place...
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Re: converting meanwell power suply into Lipo charger

Post by sico » Apr 24 2011 6:22am

Yep, Wojtek's psu looks quite different to the s350. I suppose it might use the same switching circuit "brain" though? Would need to see the schematic I suppose.

Neil, I've no particular desire to have the fan running constantly on my work (under desk) charging unit. If I knew I could safely leave the fan off at 5A, that would be my preference. I'd even take a current penalty to keep it quiet. Any guess at a safe non-fanned current for an s350 48V? Next best thing is thermally activated, but why should it affect the current limiting? Does Comanda's transistor-pin-shorting-mod leave the thermal activation of the fan intact or make the fan constantly on?

Nice setup, by the way :)

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Re: converting meanwell power suply into Lipo charger

Post by wojtek » Apr 24 2011 6:26am

sico wrote:Yep, Wojtek's psu looks quite different to the s350. I suppose it might use the same switching circuit "brain" though? Would need to see the schematic I suppose.

Neil, I've no particular desire to have the fan running constantly on my work (under desk) charging unit. If I knew I could safely leave the fan off at 5A, that would be my preference. I'd even take a current penalty to keep it quiet. Any guess at a safe non-fanned current for an s350 48V? Next best thing is thermally activated, but why should it affect the current limiting? Does Comanda's transistor-pin-shorting-mod leave the thermal activation of the fan intact or make the fan constantly on?

Nice setup, by the way :)
OK i added more pics..
Re fun, mine is using fan non- stop and it is LOUD!

Re schematics all i can find is here: http://www.meanwell.com/search/spv-1500 ... 0-spec.pdf

re voltage adjustment , it is prob this blue screw in front - so no need for unscrewing to change the V
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Re: converting meanwell power suply into Lipo charger

Post by www.recumbents.com » Apr 24 2011 8:24am

Hi Sico,

The pictures showing which resistor was replaced with a pot on the genuine S-350-48 seem to be missing in the thread you referenced. That mod is exactly what I have been looking for. Can you take a picture of your mod or can somebody point to the resistor that controls the current in this PSU?

Thanks,

-Warren.

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Re: converting meanwell power supply into LiPo bulk-charger

Post by NeilP » Apr 24 2011 9:03am

The current mod is in one of these threads:

"Repairing Meanwell Power Supplies" (healthyoung, 2 pages)
http://www.endless-sphere.com/forums/vi ... 14&t=21156

"How-To: Meanwell 63-84V CV/CC Charger" (Kingfish, 3 pages)
http://endless-sphere.com/forums/viewto ... 14&t=20118

"Fechter's Mini Meanwell Limiter Board" (fechter, 11 pages)
http://endless-sphere.com/forums/viewto ... 68&start=0

"Switch mode supply mod" (Jeremy Harris, 26 pages)
http://endless-sphere.com/forums/viewto ... =14&t=4125

"CC/CV Mod+Review - Meanwell S-350-48 from SureElectronics.net" (mwkeefer, one page)
http://www.endless-sphere.com/forums/vi ... =4&t=14212

"Making a CC/CV charger" (Tiberius, 3 pages)
http://www.endless-sphere.com/forums/vi ... =14&t=6749

but open up your S-350 and with output on the LHS, look at top RH corner ...look for resistor R33 there may be two components not marked on the board I think R37 and SVR2. If they are both fitted they parallel R33

R33 is the current limit resistor and its value set the supply up to deliver 135% of rated current. If you reduce the value of that resistor, the output current reduces to that level proportionally

there are other current restriction mods, that include chopping the shunts and either leaving them out or repacing with single strands of multicore wire...and then curttng the strands to get the value of current you want.

Fitting a 5k multi turn potentiometer ( I used a 16 turn cermet) gives you god control of the current from it max of 135% all the way down to probably zero...but I never tried it as the unit starts making that horrible buzzing associated with SMPSU's under stress

I'll post this now, and try scanning the threads for the picture, if no one else chips in before then, i'll post up what I find

or some of my own pics
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Re: converting meanwell power suply into Lipo charger

Post by NeilP » Apr 24 2011 9:19am

s-350.jpg
SVR2.jpg
SVR2.jpg (70.04 KiB) Viewed 2716 times
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Re: converting meanwell power suply into Lipo charger

Post by NeilP » Apr 24 2011 9:35am

All this is from memory, but I seem to remember R33 being 330 Ω..that gives 135% of rated power = so 472 watt...so at 48 volts that is 9.84 amps

Since the rated output is 350W 100% at 48 volts would be 7.29Amps

If you adjust the voltage down to 41.5 volts then 350Watt is 8.43amps

8.43amps divided by the 135% current (9.84 amps) is 85%

so at 41.5 volts R33 needs a resistor 85% of the initial value
So
330Ω x 0.85 =280Ω

so you need a resistor in parallel with R33 equal to 1848 Ω to give a parallel resistance of 280Ω

http://www.sengpielaudio.com/calculator-paralresist.htm

if you go down more in voltage say to 38 volts then R33 value needs to be 307 Ω...so a 4404Ω (4.4kΩ) resistor in parallel...so a 5k pot just about covers all eventualities

This is all covered in more detail in the threads I linked to earlier...although it does take a lot of digging through that 39 page thread to find it
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Re: converting meanwell power suply into Lipo charger

Post by sico » Apr 24 2011 9:44am

Warren,
here are before and after shots of the mod as I copied it from boost:

Before:
before_793x600.jpg
before_793x600.jpg (117.79 KiB) Viewed 2722 times
After:
after_701x600.jpg
after_701x600.jpg (117.27 KiB) Viewed 2716 times
The trimmer is 500ohm. Neil's post shows the location to look for the components :)

Simon.

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Re: converting meanwell power suply into Lipo charger

Post by NeilP » Apr 24 2011 12:04pm

Yes, you can use 500 Ω but if you are planning on turning the voltage down to below 41 volt or so, go higher, I went for a 5kΩ pot, that gives you a greater range of adjustment. You still have the 0-500Ω that the 500Ω pot gives you ...but can continue the adjustment up to well beyond that...meaning that you can get higher currents at the lower voltages.

I can give some definite info on the current mod and how it interacts with ( but not why) the fan. as I have just this second tried it

Just come back from a ride and the battery was down to 74 volts so 3.7volt per cell

With both menawells set to 41.5 volts ...therefore 83 volt total, and the fan in the normal auto position ( as factory produced) the current to the batteries was 7.62 amps.
If i flick e the switches ( so shorting out the collector to emitter of the Q5 resistor...this forces the fans to run...and the current to the battery pack jumps up to 8.3 amps

BUT when the fan is in Factory standard ( no fan mod) auto mode and the fan kicks in, current stays the same...so in standard auto mode the current output is not affected...So I would say give the fan mod a miss.

I can not explain anyof the above effects, I am not an electronics engineer, I can only report what I see.

This is some function of the current limiting...but it does not change the output voltage
If the two meanwells are run with no battery connected, the output of the two is 83 volts...flicking the fan resistor override switches to the override position...and the voltage is exactly the same....83 volts

When under load and the battery is drawing 8 amps...then the voltage is 76 volts at the output, again staying constant when the an override switches are toggled so fan come on/off. Have not seen if this is the same effect when the fan cuts in in the normal automatic way or not
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Re: converting meanwell power suply into Lipo charger

Post by Racer_X » Apr 24 2011 1:32pm

This is very informative thanks NeilP and all other contributors,
I am wondering what the limits are of using a MeanWell as a standalone charger for Lipos.

My question is how accurate is the limiter for example can you charge to 4.1v a 15s pack to 61.5v?
Can you go as high as 74v to charge a 18s pack?

The reason I ask is that I think it is cumbersome to be bringing a whole bunch of charging accessories every time I go on a trip with possibities of charging on the spot, And I have been following this thread with that goal in mind. I live in the outskirts of town and find it a hassle to bring 16ah just so i can make it back without recharging. It is trips like these where the ping battery really shines, just plug and play.
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Re: converting meanwell power suply into Lipo charger

Post by NeilP » Apr 24 2011 1:58pm

Racer_X wrote: My question is how accurate is the limiter for example can you charge to 4.1v a 15s pack to 61.5v?
Can you go as high as 74v to charge a 18s pack?

The reason I ask is that I think it is cumbersome to be bringing a whole bunch of charging accessories every time I go on a trip with possibities of charging on the spot, And I have been following this thread with that goal in mind. I live in the outskirts of town and find it a hassle to bring 16ah just so i can make it back without recharging. It is trips like these where the ping battery really shines, just plug and play.
See my links above..the big one that is 39 pages is really a must to read though...take it in stages though!!

This thread seems to be going away from the OP's question about the charger he has bought and gone back to the old topic about the S-350-48 series...partially my fault I suppose
but to answer your question...( sort of) a 48v Meanwell maybe able to go above 60 volt or so...but lots of mods...changing capacitors etc and it seem to cook them

I am doing my 20 s pack with two S-350-48's turned down to 41.5 volts each and then have the two of them in series.

struggle through all those links I posted earlier...and cut and paste out the usefull bits...that is the only way to make sense of it all

This 1500 Watt Meanwell that the OP mentioned SPV-1500 -24 is also available in 48 volt...with a stated range of up to 56 volts...maybe this can be tweaked up a bit? who knows? not me

http://www.meanwell.com/search/spv-1500 ... 0-spec.pdf
Last edited by NeilP on Apr 24 2011 3:07pm, edited 1 time in total.
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Re: converting meanwell power suply into Lipo charger

Post by wineboyrider » Apr 24 2011 2:04pm

Racer_X wrote:This is very informative thanks NeilP and all other contributors,
I am wondering what the limits are of using a MeanWell as a standalone charger for Lipos.

My question is how accurate is the limiter for example can you charge to 4.1v a 15s pack to 61.5v?
Can you go as high as 74v to charge a 18s pack?

The reason I ask is that I think it is cumbersome to be bringing a whole bunch of charging accessories every time I go on a trip with possibities of charging on the spot, And I have been following this thread with that goal in mind. I live in the outskirts of town and find it a hassle to bring 16ah just so i can make it back without recharging. It is trips like these where the ping battery really shines, just plug and play.
First, thanks for trying to help me on one of my threads. I have another thread where I am talking about using the meanwell power supply(ies) to charge my ping battery through the bms (or maybe not), but I also have lipo and want to be able to opportunity charge those too. If I could use one I would be able to adjust the voltage (if I learn how) so I can charge my 36v ping or my 12s 11s lipo quickly. One at 7 or 8 amps would be a real nice quick charge for either battery chemisty I think. On the ping I would balance charge it at home with my balance charger and hope the cells all balance up etc. My ping has many miles on it and it is very reliable. I haven't had as good of luck with lipo, but most of the mistakes are my own doing.
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Re: converting meanwell power suply into Lipo charger

Post by www.recumbents.com » Apr 24 2011 2:30pm

Thanks NeilP and Sico.

Yeah I was exaggerating a bit when I said 500 pages earlier :wink:. NeilP you scared me a bit when you posted all those other threads!

With this information I should be able to modify the S-350-48 MW to charge my 12S pack to 49V at a reasonable 5A or so without frying the PSU. The existing pot next to the LED gives plenty of range to adjust for that voltage. Because the voltage is close to stock specs, it sounds like the 500 ohm pot should work well.

Sico, its a bit hard to tell from the photo, did you remove the remove the 330 ohm resistor and replace it with the 500 ohm pot or put it in parallel as NeilP noted?

Also at that low a current I should not need the fan mod. I'll give it a try and let you know how it goes.

Thanks again,

-Warren.

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Re: converting meanwell power suply into Lipo charger

Post by NeilP » Apr 24 2011 3:25pm

wineboyrider wrote: If I could use one I would be able to adjust the voltage (if I learn how) so I can charge my 36v ping or my 12s 11s lipo quickly. One at 7 or 8 amps would be a real nice quick charge for either battery chemisty I think. On the ping I would balance charge it at home with my balance charger and hope the cells all balance up etc. My ping has many miles on it and it is very reliable. I haven't had as good of luck with lipo, but most of the mistakes are my own doing.
Yes , a S 350-48 would probably do that, but I think one of those threads does mention cooking the Meanwell when it is turned down below 36 volts.so careful

Warren wrote:With this information I should be able to modify the S-350-48 MW to charge my 12S pack to 49V at a reasonable 5A or so without frying the PSU. The existing pot next to the LED gives plenty of range to adjust for that voltage. Because the voltage is close to stock specs, it sounds like the 500 ohm pot should work well.
Problem with using a 500Ω pot is that if you find the current you set is too low then you will not be able to turn it up without removing the pot. A 5k one wont cost any more and will give you adjustment all the way back up to the original 135% If you put zero ohm ( a short) across R33 then you would shut the PSU down completely ( it would make the total parallel resistance with R33 zero ohm). if you put an infinite resistance across R33, then it will remain at the same value.
The 500ohm across the 330 will give about 195 ohm...so 60% of the original current...5.5 amp or so. ok for current needs...

Warren wrote:Sico, its a bit hard to tell from the photo, did you remove the remove the 330 ohm resistor and replace it with the 500 ohm pot or put it in parallel as NeilP noted?
you can do either..as long as you calculate the resultant resistance. if you scrap R33 then a 330 ohm pot would do the job exactly the same. make it multiturn, 16 turn minimum...gives you much more accurate control

From what I have seen, i'd forget the fan mod too. the auto action seems to work well
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Re: converting meanwell power suply into Lipo charger

Post by Alan B » Apr 24 2011 3:31pm

One function missing on a modified power supply is an auto shutoff. Do you just do that manually? Or let them "cook" a bit??

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Re: converting meanwell power suply into Lipo charger

Post by Ykick » Apr 24 2011 3:35pm

Alan B wrote:One function missing on a modified power supply is an auto shutoff. Do you just do that manually? Or let them "cook" a bit??
Bathroom off timer wired into an extension cord. There's a digital one out there that offers 1, 2 and 4 hours IIRC. I'll try to get the details for you when I get to my workshop.
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Re: converting meanwell power suply into Lipo charger

Post by NeilP » Apr 24 2011 4:01pm

Fecthers board offers a current to the battery shutoff...it reduces the output to zero amps...with a pre settable limit pot...you set it so when the current drops below a threshold (0.4 amps or so) then the output voltage drops by a volt or two, and stops the battery from taking any further charge, but keeps the PSU on and at a high enough voltage to keep it from taking getting a reverse current from the battery
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Re: converting meanwell power suply into Lipo charger

Post by Alan B » Apr 24 2011 5:58pm

NeilP wrote:Fecthers board offers a current to the battery shutoff...it reduces the output to zero amps...with a pre settable limit pot...you set it so when the current drops below a threshold (0.4 amps or so) then the output voltage drops by a volt or two, and stops the battery from taking any further charge, but keeps the PSU on and at a high enough voltage to keep it from taking getting a reverse current from the battery
Sounds good. Have to get some of those.

What happens if the AC power fails while it is hooked up. How do those power supplies like reverse power? Does it hurt them, and how much does it draw from the battery??

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Re: converting meanwell power suply into Lipo charger

Post by icecube57 » Apr 24 2011 6:16pm

Yes the pack can reverse feed back into the power supply but the amount of current is very small. It will basically top the pack off... cut off.....it slowly reverse feeds and then it cuts back on and tops it off again.

I used a 10k 15turn pot on svr 2 and I can go down to 18v

I used the same current limit mod and I get get 9.5-10.5A regardless of voltage. It kinda fluctates and osciallates up and down a little bit but at 50.4v Its able to put out 9.5-10.5A continuous duty well above the rated 7.3.

I did the fan resistor mod to make it stay on .

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Re: converting meanwell power suply into Lipo charger

Post by wineboyrider » Apr 24 2011 6:19pm

Ykick wrote:
Bathroom off timer wired into an extension cord. There's a digital one out there that offers 1, 2 and 4 hours IIRC. I'll try to get the details for you when I get to my workshop.
Awesome idea! I am going to use a turnigy watt meter to monitor the ah's, wh's, voltage to get and idea of what I am putting in,but the timer idea is just bad ass. 8) 8) 8)
Once I know how much I am putting in I can time it for shut down... 8) 8) 8) 8) 8) 8) 8) 8) 8) 8) 8)
@NeilP: The ping battery is like 45volts hot off the charger so I was thinking about setting it for around 42-44 volts.....
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Re: converting meanwell power suply into Lipo charger

Post by sico » Apr 24 2011 9:15pm

Hi Warren, Neil. Sorry Wojtek for the hijack!

THe 500 ohm trim resistor replaces r33 in boost's mod. I had the pot set on about half when I installed it and when I checked the current limit it was 5A, so I didn't adjust it again. The original r33 looks like a yellow blue black, which would be 46 ohms unless I'm mistaken.

Neil, my experience of the fans effect on the current limiting is outlined in my first post on this thread. When you have two meanwells in series, both with the current mod, if one has the fan on and the other off, the one with it off will limit the current to the lower value. That might explain the difference in our observations. When both fans are on (either because of thermal switch or because of the Commanda mod) I think the current will be the higher value. The two values for my 50V, single meanwell were 5A and 6.5A.

The behaviour changed again when the voltage on the pack got low enough for the "natural" current flow to be smaller than the current limit. Then I observe that when the fan switches on the current goes to zero. After the fan switches back off it will show some lower-than-5 number of amps, like 2A or whatever (depending on the pack voltage). This continues until the amps taper off to zero, when the pack voltage is 50V.

I emphasise that this fan behaviour has not affected the usabiliy of the psu for my purpose (except I'd rather it was always off), but it is a poor reflection on the designer I think :)

Simon.

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Re: converting meanwell power suply into Lipo charger

Post by NeilP » Apr 24 2011 9:52pm

icecube57 wrote:Yes the pack can reverse feed back into the power supply but the amount of current is very small. It will basically top the pack off... cut off.....it slowly reverse feeds and then it cuts back on and tops it off again.
Is that with a cc/cv board or just the stand alone mod'ed pack?

icecube57 wrote: I used a 10k 15turn pot on svr 2 and I can go down to 18v.
Do you mean SVR 1? for the 10k pot , as that is the one for voltage control, or did you put a 10k pot on both SVR 1 and SVR2
icecube57 wrote: I used the same current limit mod and I get get 9.5-10.5A regardless of voltage. It kinda fluctates and osciallates up and down a little bit but at 50.4v Its able to put out 9.5-10.5A continuous duty well above the rated 7.3.
Good luck, hope you do not let the magic Chinese smoke out of those Meanwells, from reading all those threads, it has happened many times to many people, but I have no idea how much over rated power they were running

icecube57 wrote: I did the fan resistor mod to make it stay
Does fan resistor mod still give auto speed control or does it override that



sico wrote: Neil, my experience of the fans effect on the current limiting is outlined in my first post on this thread. When you have two meanwells in series, both with the current mod, if one has the fan on and the other off, the one with it off will limit the current to the lower value. That might explain the difference in our observations. When both fans are on (either because of thermal switch or because of the Commanda mod) I think the current will be the higher value. The two values for my 50V, single meanwell were 5A and 6.5A.

The behaviour changed again when the voltage on the pack got low enough for the "natural" current flow to be smaller than the current limit. Then I observe that when the fan switches on the current goes to zero. After the fan switches back off it will show some lower-than-5 number of amps, like 2A or whatever (depending on the pack voltage). This continues until the amps taper off to zero, when the pack voltage is 50V.

I emphasise that this fan behaviour has not affected the usabiliy of the psu for my purpose (except I'd rather it was always off), but it is a poor reflection on the designer I think :)

Simon.
Cheers for more fan info Simon
I gotta get one of my fans out anyway. It only starts up now if I shove a pen in it and give it a flick....and it only ever seems to fun at one speed whereas the fan on supply no.1 runs up to areally noisy level and you can feel the draughts off it, no.2 is very quiet and sluggish. So Mayer be there is another source of problem. The faulty fan could be pulling more current than designed for
Last edited by NeilP on Apr 25 2011 2:24am, edited 4 times in total.
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Alan B   100 GW

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Re: converting meanwell power suply into Lipo charger

Post by Alan B » Apr 24 2011 9:55pm

One rule of thumb for electronics gear in continuous service is not to exceed 80% of the max rating. A little derating goes a long way, especially if operating in warm temperatures. If ambient is really hot then derate even more.

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NeilP   10 GW

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Re: converting meanwell power suply into Lipo charger

Post by NeilP » Apr 24 2011 10:10pm

Alan B wrote:
What happens if the AC power fails while it is hooked up. How do those power supplies like reverse power? Does it hurt them, and how much does it draw from the battery??
I think not well. Again I am sure I have read of people smoking the Meanwells by plugging the batteries into them before they were not powered up. It was either not powered on or reverse polarity.... sorry can't remember so hou 'll have to scan those earlier links to find the answer. I would not go with the electronic timer idea till an answer is given on this one. Or use big diode between pack and PSU and tweak the voltage up a bit to take account of this


I would second that 80% of rated power rule. I'd rather the charge time be an extra 20 minutes than the expense of frying a Meanwell and either having to repair it or wait another 3 weeks or more for another to arrive from China if you can afford it or have another kicking around in standby, then do some continuous over rated charges for us and let us know how well they cope. If you could maybe find a constant load like a big reohstat of stack of bulbs and can run one for a few days at 100%. 120% etc and see if they fry or not then that would he great to know
:) Only Irish coffee provides in a glass all four essential food groups: alcohol, caffeine, sugar, and fat :)

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