Fechter's Mini Meanwell Limiter Board

[NeilP]

What is the white JST style multipin connector, looks like a LiPo balance lead socket?

Are you running the supplies in series or parallel


Try connrecting to a pack that is only a little discharged and see if the supply still drops out

[steveo]

I tried a pack that approx 5v difference between supply and battery and it cutout...


I gues if its 2-3v difference it wouLd not

However when charging a batter i can not keep tweaking voltage to keep charger going , it just has to work!

Hopefully i can get the limiter board wired in there

Steveo

[NeilP]

or try the other type of current limit mods, if you can find the control rrsistor on this new board type

What exact model is this ?

[fechter]

Here's the datasheet for the switching controller chip:
http://www.onsemi.com/pub_link/Collateral/SG3525A-D.PDF

Looks like the error amp inputs are pins 1 and 2.

If I stare at the pictures long enough, I can probably trace it out.
I also see an optocoupler. These usually tie into the feedback,

[steveo]

Here's the datasheet for the switching controller chip:
http://www.onsemi.com/pub_link/Collateral/SG3525A-D.PDF

Looks like the error amp inputs are pins 1 and 2.

If I stare at the pictures long enough, I can probably trace it out.
I also see an optocoupler. These usually tie into the feedback,

I will give pin 1&2 a try

I measured 2.5v on each, which is jusy my old psu that has limiter board

[fechter]

It's pretty hard to trace from the pictures. Do you see anything that looks like a shunt?

My guess is raising the voltage on pin 2 will reduce the output. You could possibly try using a resistor like 100k from pin to the positive output and see what it does to the output voltage. You really want to feed just a little over 2.5v to pin 2 so you need to be careful with jumpers during testing. I think the chip fries if you put a little to much into there. There is probably another part of the regulator circuit that uses the LM358 and that feeds into pin 2.

Near the adjustment pot, there is a spot marked OVP. That might be the 2.5v reference spot.
On most meanwells, the sensing line is connected to one side of the adjusment pot.

The connector has pins marked S+ and S-. These might be remote voltage sensing inputs. You might see what the voltages on those pins look like.
The pins marked RC seem to go to the optocoupler and must be a remote control of some sort. Feeding voltage into the RC input might lower the output voltage. I suspect it's a 5v signal there.

[steveo]

It's pretty hard to trace from the pictures. Do you see anything that looks like a shunt?

My guess is raising the voltage on pin 2 will reduce the output. You could possibly try using a resistor like 100k from pin to the positive output and see what it does to the output voltage. You really want to feed just a little over 2.5v to pin 2 so you need to be careful with jumpers during testing. I think the chip fries if you put a little to much into there. There is probably another part of the regulator circuit that uses the LM358 and that feeds into pin 2.

Near the adjustment pot, there is a spot marked OVP. That might be the 2.5v reference spot.
On most meanwells, the sensing line is connected to one side of the adjusment pot.

The connector has pins marked S+ and S-. These might be remote voltage sensing inputs. You might see what the voltages on those pins look like.
The pins marked RC seem to go to the optocoupler and must be a remote control of some sort. Feeding voltage into the RC input might lower the output voltage. I suspect it's a 5v signal there.

hey fechter

I see the shunt wires on the opposite side of the capasitors, 3 shunt wires on this psu

do you mean use use a 100k resistor connected to pin 2 on that chip & connect it to the 48v dc output of the power supply?

sounds like that will make things crispy...

-steveo

[fechter]

hey fechter

I see the shunt wires on the opposite side of the capasitors, 3 shunt wires on this psu

do you mean use use a 100k resistor connected to pin 2 on that chip & connect it to the 48v dc output of the power supply?

sounds like that will make things crispy...

-steveo

Yes, that's probably a risky way to test it.

Measure the voltage on that 'OVP' pad near the voltage adjusting pot. I think it goes to the pot wiper. Otherwise try to get on the pot wiper somehow. That's really where you want to tie in the limiter. On most supplies it's around 2.5v, but some run 5v or more.

What you really want is to feed the reference point with just a little more than 2.5v. Up to 5v should be safe for the input. Depending on the resistances, 100k to the 48v might be in the safe range, but better to not risk that. I use a resistor to feed test points to limit the current.

Take a pic of the shunts. I saw something that sort of looked like one, but I think it was a jumper.

[steveo]

Hey Everyone

i just purchased 2 1000w meanwell 48v psu

i am having the issue where i connect the psu to a load (my batteries) and the psu powers down.. I've had the same issue with a small 250w psu which i fixed with one of fechters mini meanwell limiter boards....


I was wondering if anyone could help me on where to connect the sense wire for the limiter board on the 1000w meanwell

here is a couple photos of both sides of the psu board

thanks
-steveo

Hey Everyone,

I just want to say that i have gotten the 1000w meanwell to work with fechter's limiter board, The sense wire must tap into the "OVP" spot on the board, right next to the voltage turn pot..

I will post a video on my youtube of it working shortly, stay tuned..

....

Fetcher does the limiter board limit the current at 14amps?.... thats what i maxed out at!

-steveo

[fechter]

It should be close to that. It depends on what value resistor was used above the pot. The shunt should be good for 20A in theory, but will get hotter than hell. I think it will be OK at 15A. It can run pretty hot without damage.

[steveo]

Could anyone specify how to increase current limit for the limiter board?, my power supply is 20amp at 48v however i only get 14amps at 48v off the limiter board...

thanks
-steveo

[fechter]

Could anyone specify how to increase current limit for the limiter board?, my power supply is 20amp at 48v however i only get 14amps at 48v off the limiter board...

thanks
-steveo

The 160k R3 controls the upper limit. You could replace it with 100K or just stick another resistor in parallel with it. The shunt is rated for 20A max and will run very hot. It can take the heat, but keep wires away from it.

[NeilP]

It is a matter of changing the resistor network / string where the at the high end of the fixed part of the pot that controls current limit.

Is it the single adjuster Fechter version board you have? or the version from tppacks with three adjustment pots?
assuming the single pot variant as pictured at the start of the thread

then change R3 the 160K pot to 100k

[NeilP]

Ah Richard, you just beat me to it. must have cross posted

[fechter]

Update: Sold Out
I'll see about getting another batch done.

[PaulD]

Bump. Just checking to see if these will be available again.
thanks!

[NeilP]

If fechter does not have any, try Gary Goodrum at tppacks
He has the slightly more advanced ones with three pots on them . Same basic design, I believe they both colaborateed on designing them any way

The three pot design has the current limiting as does fechters board, but it also has end of charge cut off, that monitors charge current, and drops output voltage once current flow goes below a setpoint

You may have to mail tppacks directly, they are not on the site

Oh, and make sure you can get a Meanwell S-350 first, a few of us have all ordered them from Sure electronics on E bay and beeen sent NES model Meanwells, not the S model Meanwell
Sure electronics tell me the S series are no longer being sold

[PaulD]

Cool, thanks for the info, NeilP.

[fechter]

You don't want the 3 pot version. There were a lot of issues with that design.

The basic version is sold out and I was not really planning to do more, but if I can find enough money, I could possibly do another batch. Most supplies can be modded to have the same function without using the board. The SP versions are an exeption to this.

If anyone is interested in spending the money to make a batch of boards and sell them, pm me.

[NeilP]

I would say it works fine...once the BC107 is installed the correct way around...it works perfectly every night, since I had the issues with it...many months back.

Still produces a buzzing on the Meanwell it is connected to , but other than that it works great.

[hillzofvalp]

has anyone just used an arduino as a cut-off? I don't think I need current limiting for my a123 pack.. but if the arduino sensed battery voltage and tripped a contactor when it got to say 3.42V, then I would be in business.

[etard]

The current limiter is for the power supply not for your batteries.

I am interested in a couple, so there are none available? Dammo!

[hillzofvalp]

Yeah that's what I was talking about.. I do not need to limit charge limit cause a123 m1 cells handle 4C alright

[Arlo1]

Yeah that's what I was talking about.. I do not need to limit charge limit cause a123 m1 cells handle 4C alright

IF your power supply runs at more amps then its rated for you will blow the power supply up. I know this because i have blown 8 or more mean wells up! You need this board or to mod the shunt!!!

[hillzofvalp]

I would like to use a single 220v 2950W esp120 hp server suPply. It outputs 51.4V at like 57A if I remember right.. This would be perfect