Fechter's Mini Meanwell Limiter Board

[number1cruncher]

Part One
I have ordered two Meanwell S-350-48's and was planning on running two in series and bringing the voltage down on both to 41 volts.

Pack is 20s LiPo. 5A 1C charge 82 volt is 410Watt..not 350..is that driving them too hard or can they cope?

I understand that for current limiting..one board is fine. But what about the voltage.
What range of control will this board give?

Can I leave one PSU at 48 and bring all the voltage down with the board on the other?

Or easier to just buy and use two boards? or mod one with a multi turn pot to bring voltage down, and then do fine control with the other PSU with the board?


Part Two
To complicate things...I am hoping to use these PSU's in two rolls. In series as above at 82 volt...4 or 5 amp, and also occasionally for a balance charge in parallel as a 38 volt PSU to drive a iCharger 3010b 1000W balance charger.

How can I achieve this as well the initial charging in series?

Neil,

410watts should be okay, but you may want to tune it closer to 350W. The board voltage is dependant on the zener diode used. If less than 24V, no diode is neccessary. I think you can derive the rest of the answer to part 1, from page 1 of this thread:

So for a 100V solution (4 x S-350-24) this would not work?

It would work, but could run out of compliance if the pack was really dead. If you installed limiter boards on two of the 4 supplies, it would have more compliance.

I'll try to explain differently: At 100v the supply with the limiter can only drop by about 10v when the current tries to exceed the set point. This still leaves you with 90v, which might give you more than the desired current and throw things into hiccup mode. You could also run the risk that one supply shuts down and gets fed in reverse by the other ones (causing failure). This would not necessarily be the supply that has the limiter board on it. All of these things would only happen if the pack voltage was significantly below 90v.

As for part 2, not sure if you can lower the 350-48 down to 38V. Seems a bit much, but I could be mistaken. Also, running two 350W units at 500W each to get 1000W is not a good idea. I'd go for 3 units in this case.

[fechter]

The limiter board itself does not set the output voltage.
A 48v supply will probably go down to 44v or so without modding.

To make it go lower, it will be necessary to add a resistor in series with the one right behind the adjuster pot.
There is another resistor on the board that you could parallel another one with to make the voltage go lower too, but the location of that one varies.

Yet another way to lower the voltage would be to place a resistor from the sensing wire to the output+ connection. I don't know exactly what value would be needed, but it would be fairly high, like over 10K I think.

Other than the need to add a resistor, the supply should be perfectly happy with 41v. I think you could take it down as low as 36v or so with no issues.

[NeilP]

Ah, I mis understood, I thought the board did have voltage limiting, i read this...:

the supply with the limiter can only drop by about 10v when the current tries to exceed the set point.

and sort of assumed that there was voltage control...so this voltge drop is merely a by product of th current limiting?


As for going below 36 Volts..I am pretty sure I have read that it can go much lower....I read the 38 page Switch Mode supply Mod thread the a few days ago. Am sure there was mention of taking them down way below. I seem to remember it was a case of replacing the voltage adjuster pot on the front LHS with a 10 turn pot ....1k...10k can't remember.

Maybe it is Garys boards from tppacks that do the voltage control?

[number1cruncher]

Maybe it is Garys boards from tppacks that do the voltage control?

No, its the same design. I'll check my s-350-48 when I get home tonight and see how low the voltage can be set. If I remember correctly the 48 volt model had the widest voltage range of all the MWs I own. We'll see...

BTW - I got my genuine MWs at http://www.sure-electronics.net. Shipping takes a while, but they have great products.

[NeilP]

Thanks for checking...The Meanwell as standard will NOT go down below ..I think..40 volt...but the mods do allow it to go down lower...have you modd'ed yours?

[wineboyrider]

I would like to buy one of these DIY if all the parts come with it.
PM sent

[NeilP]

Not sure if they are available any more. tppacks do not have them listed, I had got one by placing an ad in the Wanted section of the forums

[fechter]

I still have a bunch of boards.

I generally don't like to 'kit' them, since sorting out all the parts takes about as much work as fully building it. I'll get something for wineboyrider.

[NeilP]

I will take a spare board or two as well


Gary, do you know anything about the Meanwell SPV 1500 series of SMPS units?
Wondering if they can be controlled with your board in the same manner, I'd via the voltage sense resistor.
They have a much wider range of voltage adjustment straight out of the box, seem to remember the 48 volt unit has range of 9.6 volts to 56, and they have built in load sharing port to allow units to be run in parallel with auto load sharing.
Another big plus is the 1500 watt capacity....... Thinking 2 in series at 83 volts @ 30 amps for my nano tech 20s4p 20Ah pack

[auraslip]

Babies first circuit



I don't think I clipped the component wires (?) short enough. Don't have the proper tool for that.
I used my 25w radioshack iron and I think it was too hot.

Three questions:
I used the BOM for the 24v boards. I didn't get the zener diode.... is that a necessary part for 24v boards?

Second, instead of using a trim pot to adjust the current limiting resistor inside the meanwell itself could I jump it and use the current limiting boards only? I ask because I've been using the pots to control current, but with the proper cooling I'm at the limit at which the stock meanwell limits to.

Where/how on the board does it tie into the sense line?

[NeilP]

Apologies for the next string of my posts, have really screwed up the editing trying to post from the F ing iPod

[NeilP]

Deleted

[NeilP]

[NeilP]

gone too

[NeilP]

Something worth checking before you apply power

The Q1 MOSFET ....... double check the pinout of the legs against a datasheet for the exact component you have.

I have spent more than 2 months pestering both Richard and Gary with PM's and e-mails because my boards did not work ( I have three of them) It seemed that the circuit was faulty and was not doing what it was supposed to. I even bought more, and built from new, and the problem was still there...three times. It turned out to be a component specification change issue.

I finally solved it a few days ago, the new versions of the MOSFETs BS107P's have pins 1 & 3 swapped on the component, so although the component was fitted correctly according to Richards instructions, in reality it was in backwards


Richard originally used a BS107A, but that is now obsolete and Mouser now supply a BS107P. The Source and Drain are swapped when compared to a BS107A.
So if you have a BS107P, you will need to fit it the other way around.
Pin 3 three where the board is marked Pin1 or the square pad. If you have any other components as an equivalent, then check a data sheet for it and make sure the Source and Drain are corrct way round

I used the BOM for the 24v boards. I didn't get the zener diode.... is that a necessary part for 24v boards?

Depends what voltage you are running your Meanwell at. if you are running over 24 volt then you will need it to control the supply voltage to the LM78 voltage reg
Check back a few pages of this very thread, half way down
viewtopic.php?f=31&t=21768&start=15

For over 35v operation, we just add the 24v Zener diode and no longer use the FET or 100K resistor.

For under 35v, place a piece of wire through the 24v jumper holes. You can use a piece of wire snipped off of one of the resistors. The jumper goes here:

24V jumper location.jpg

For over 35v, place the zener diode like this:

Zener Diode placement.jpg

It won't hurt if the zener diode is installed and the 24v jumper is added. It will be in the under 35v mode with the jumper.
For odd voltages, the value of the zener might need to be changed. To calculate, take the highest output voltage for the supply the board is connected to, and subtract 35v. This is the value you should use for the zener. If this doesn't work out to an available value, use the next higher zener voltage. Multiple zeners can be put in series to increase voltage. Try to keep the input of the LM78L12 between 24v-35v.

Second, instead of using a trim pot to adjust the current limiting resistor inside the meanwell itself could I jump it and use the current limiting boards only? I ask because I've been using the pots to control current, but with the proper cooling I'm at the limit at which the stock meanwell limits to.

yes you can use this board as current limit instead of pot in the Meanwell, that is what it is designed for. But I would not jumper the original resistor on the meanwell, that will be final safe guard if the board failed for any reason.

Where/how on the board does it tie into the sense line?

you can just see the picture of the red wire going off the board, into the Meanwell, and you can just make out where it is soldered to the resistor behind the voltage adjustment pot. on to a leg of the resistor, the outer leg, closest to the case side

[auraslip]

Thanks neil - you are the boss and have practically taught me everything I've needed to know about these damn things.

[NeilP]

Hey, thanks for that, but all I have really done is collated the info in my mind from all the multitude of sources, then spewed it back out when asked.

I have built my own twin Meanwell unit recently, so have all the info immediately to hand, I can't take credit for any of the work

Here is a link to recumbents page with all the info set out

http://www.recumbents.com/wisil/e-bent/ ... efault.htm

go bak to his home page, he has loads of other interesting useful stuff there too

[auraslip]

That site is legit - his black and yellow recumbent trike is probably the most bad ass electric vehicle I've ever seen!

[fechter]

There's a better picture of where the sensing line attaches on page 4 of this thread.

When using the limiter board, you can leave the limiter resistors in the Meanwell in their original configuration. If you modded the resistor in the Meanwell, it will limit at whichever one is set lower.

[NeilP]

Thanks Richard...I knew I had seen a better one somewhere, I just posted a re link to the first one I came across

[Gregory]

That site is legit - his black and yellow recumbent trike is probably the most bad ass electric vehicle I've ever seen!

I think you are confusing Mr bad ass Matt Schumacher Recumpence with this website guy who is on ES but I don't remember his name.

[TylerDurden]

Website guy is Warren.

memberlist.php?mode=viewprofile&u=6456


Yellow trike is Matt.

memberlist.php?mode=viewprofile&u=6262

[hillzofvalp]

Here's my situation.. I built a 24V supply from two esp114 server supplies for my 1420i. However, for my 14s5p pack I would like faster charging. Could I split the pack into 7s10p for a quick charge? My supplies max out at around 50A. If necessary I could put in the original server fans for better throughput.

There are some pots inside that may adjust the voltage.. but I've never messed with them. Is 24 volts or a little less okay to charge a pack that is 23.1 nominal? I guess fully charged would be 3.42V/cell... but that's probably over 90% charged. I could then balance on the 1420i

If I need a current limiter, which one would be best from a member of ES? OR-- how could I build one from radioshack parts?

[fechter]

I think we'll have to see a picture of the board on that one to make any guesses. I have no experience with that model. There should be some way to do it.

When charging at high rates like that, be careful that no cell group goes over voltage toward end of charge. Bad things could happen fast. 3.65v is the nominal target, but some commercial systems go even higher. 3.42v should be pretty safe and near 90% as you estimated.

[hillzofvalp]

I will take it apart tonight and post some pics. I'm hesitant not having a cut-off because I would like to walk away from the charger every once in while...

WHat guage wire do you guys use over 6 foot to charge at 35-45A? I've got some 10 gauge I thought I might try.

Also, when the battery reaches psu voltage, does the current go to 0?