Fechter's Mini Meanwell Limiter V.3

[fechter]

I'm starting a new thread here specifically for the Version 3 Mini Meanwell Limiter board.
The thread on the older versions is here: http://endless-sphere.com/forums/viewtopic.php?f=31&t=21768

NOW IN STOCK

Just to let everyone know in case you were not following the previous thread. Fetcher has entrusted myself with the distribution of the bare boards. I should have them some time early next week and will start shipping as soon as I get them.
The bare boards will cost $10 each. Basic USPS shipping including the cost of a padded envelope pretty much anywhere in North America should be $3-5. I'll get to the post office in the next couple of days and find out exactly how much the shipping will be to different parts of the world. I'll start taking payments as soon as I find out the exact shipping rates. At this point there are only 34 boards for sale so don't think about it for too long.

Email and paypal info fcarcao@gmail.com.

100_0176 Build 9.jpg (86.93 KiB) Viewed 3139 times

What it does:
Attaches to the output terminals of a power supply, monitors the current and automatically reduces the output voltage when the current tries to exceed an amout dialed in by the adjustment pot on the limiter board. This results in constant current operation when the load exceeds the current setting.

The limiter board has a bi-color LED that will go red when the charging current is at the limit. When the pack reaches the CV setting of the supply, the LED goes out, indicating the pack is nearly full. In addition, there is an input for cell level HVC alarm that will also drop the charging current and light the LED green. HVC alarm can be from CellLogs or most previous HVC boards that monitor individual cell voltages.

The board can be configured for most switching power supplies, not just Meanwells. The basic configuration is rated for up to 20 Amps charging, and there is a provision for an additional shunt that can raise the limit to 40 Amps. The adjustment pot goes from the maximum current to near zero, allowing a wide range of charging current.

The idea is you want to dial down the current on the supply so that the power remains below the supply's rating so nothing overheats or blows up. In some cases, the charge rating of the pack may be the limiting factor, not the supply.

Here is the schematic:

Mini Limiter Board v.3 schematic prod 1.jpg (48.07 KiB) Viewed 3139 times

[fechter]

Parts ordering:

All the parts for the board can be obtained from Mouser Electronics. The parts are all pretty generic and I'm sure you could find them from any number of other distributors.

On Mouser's web site, there is a feature called BOM import. You need to set up an account with Mouser to use this feature. With BOM import, you can copy and paste from the list and it will automatically place the items in your cart. The left side is the part number and to the right of the bar symbol is the quantity. If you don't want to use the BOM import function, you can simply copy/paste the parts numbers one at a time and pay attention to the quantities.

Mouser BOM screen shot.jpg (63.13 KiB) Viewed 3039 times

For all versions, the following parts are recommended:

652-3362P-1-102LF|1
594-K104K15X7RF5TH5|1
78-1N914|2
66-OAR5R005FLF|1
270-4.7K-RC|3
270-1K-RC|1
512-LM358AN|1
512-LM78L12ACZX|1
604-WP59SURKSGC|1

Next, choose your zener. This depends on the maximum voltage the supply with the limiter is going to be used with.

Up to 35V- no zener - use a jumper wire.

Up to 40V (5.1V zener)
771-1N4733A,133|1

Up to 48v (15v zener)
771-1N4744A,133 |1

Up to 59v (24v zener)
771-1N4749A,133 |1

Up to 65v (30v zener)
512-1N4751A |1

Next, choose R4 for the current adjustment range. The following values are for a single shunt.

For 11 Amp range
270-220K-RC|1

For 15 Amp range
270-160K-RC|1

For 20 Amp range
270-120K-RC|1

By adding a second shunt resistor (p/n 66-OAR5R005FLF) the current range will be doubled.

Attached is a MS Word document with the part numbers in table form:

Mouser BOM for mini limiter 3.doc

(46 KiB) Downloaded 97 times

[fechter]

Building the board:

Building the board is not that difficult. If you have never built a circuit before, this is a good beginner project. You will need a soldering iron with a fine tip and temperature controlled is a plus. Always double check the part to make sure it's going in the right holes. It also pays to double check the values of the resistors with a meter. More than once I got the wrong parts from Mouser. Some parts are polarized, so it matters which way they go. Square shaped pads on the board indicate the orientation of the polarized parts.

Here's the bare board:

100_0165 Build 1.jpg (74.59 KiB) Viewed 3037 times

I like to start by inserting all the resistors/diodes/cap that are in the central row.
The striped end of the diodes go to the square holes. The other parts can go either way.

100_0166 Build 2.jpg (60.12 KiB) Viewed 3037 times

Bend the legs of the parts outward to hold them in place while soldering. You can solder one row, then spin the board around to do the other side. Snip off the legs after you finish soldering both sides.

100_0167 Build 3.jpg (60.51 KiB) Viewed 3037 times

Next install the LM358 op amp. Pin 1 goes to the square hole. Pin 1 is on the side with the notch in the case. It is not necessary to snip the legs on the chip after soldering, they will be short enough.

100_0168 Build 4.jpg (68.95 KiB) Viewed 3037 times

Next, I installed the adjuster pot and the Zener. Like the other diodes, the banded end goes to the square hole. If using at below 35v, take one the snipped off legs from a resistor and use it as a jumper wire in place of the zener diode. There are multiple holes for the pot to accomodate a variety of types depending on availability. Use whatever holes fit the pot best.

100_0170 Build 5.jpg (71.91 KiB) Viewed 3036 times

Next, I installed the LED. The LED can be installed straight up, or bent at 90 deg. depending on the orientation of your supply's terminal strip. The LED could also be installed on the bottom of the board (which is the top when used with horizontal terminals found on some clones supplies). I went for the 90 deg. mounting in this case. The shortest leg on the LED is the green anode, which goes to the square hole regardless of orientation.

100_0171 Build 6.jpg (56.96 KiB) Viewed 3036 times

Next goes the LM78L12 regulator. With the markings toward you, the left pin goes to the square hole.

100_0172 Build 7.jpg (80.35 KiB) Viewed 3036 times

The shunt resistor goes last. If using a single shunt, I suggest mounting it on the inside pair of holes so it can be bent over later.

100_0174 Build 8.jpg (87.06 KiB) Viewed 3036 times

Once the shunt is soldered in, it can be bent over to keep the profile low. With two shunts, it will be necessary to leave them upright.

100_0176 Build 9.jpg (86.93 KiB) Viewed 3036 times

The negative output wire comes off the hole in the board. The positive output wire comes straight off the Meanwell terminal.
Here's what it looks like on a real Meanwell with vertical terminals (ver.1 board shown)

100_0184 Build 11.jpg (59.69 KiB) Viewed 2990 times

With some clones, the terminal block is horizontal, so it is necessary to mount the board face down. If your supply is like this, you could mount the LED and pot on the bottom when building the board (which becomes the top when installed). If you mount the adjuster pot on the bottom, keep in mind this will reverse the adjsutment direction (clockwise will lower the current).

100_0183 Build 10.jpg (63.04 KiB) Viewed 3036 times

Here's a photoshopped picture of what the dual shunt install would look like:

100_0174 Build 8 double shunt.jpg (73.71 KiB) Viewed 2990 times

to be continued....

[Farfle]

nice! been using your mini v2 board for quite some time, I like the status LED, what is the parts cost difference for these boards compared to last version?

[fechter]

The additional parts will add less than $1 to the parts cost.

To install, it is necessary to attach a jumper wire from the OVP pad on the limiter board to the OVP point on the supply. On most of the common Meanwells, this is the end of the resistor behind the green LED.

Here is a S-350

S-350 OVP.jpg (51.68 KiB) Viewed 3031 times

SP-320:

SP-320-24 voltage adjustment.jpg (57.23 KiB) Viewed 3031 times

NES-150:

NES-150-24 voltage sense.jpg (46.4 KiB) Viewed 3031 times

Clone S-350:

Clone S-350-48 wire location.JPG (60.25 KiB) Viewed 3031 times

Condor power supply:

Condor PS voltage sense.jpg (101.16 KiB) Viewed 3031 times

Most switching power supplies will have a corresponding point. Some even label the spot "OVP". This spot typically measures a little under 2.5v when the supply is running.

TESTING:

For testing, I would suggest mounting the board on the supply, turn the adjustment pot about half way and fire it up. Look for smoke.
If no smoke, that's a good sign.
Next, use a voltmeter and measure across the HVC pins. You should see 12v across these pins. This tests the output of the voltage regulator.
Next, try shorting the HVC pins. You can use a little piece of wire or some tweezers. Shorting the HVC terminals should make the LED light up green.

If all that works, then you're ready for a load.

I find it easiest to just use the intended battery as a load. To avoid a big spark when connecting the charger, plug in the AC line first before connecting the battery. Once connected, the red LED should light up. You can adjust the current using an ammeter or by measuring the voltage across the shunt on the limiter board. Voltage across the shunt will be 5mV per Amp, so if you want 10A, you should adjust until you see 50mV. Alternately, the pot range should be quite linear, so if you built for a 15 Amp range, and put the pot exactly half way, you should be quite close to 7.5A.


Here is an example diagram of connecting multiple supplies in series:

Meanwell Series Connection.jpg (34.5 KiB) Viewed 2717 times

This shows 4 supplies in series. You can use two or possibly 3 in series with one limiter board.

The Diode shown on the supply output is optional. It is there to protect a supply in the event it loses power while the others are still running, which could potentially send enough reverse voltage into the output to cause destruction. The more supplies used in series, the more likely the diodes will be needed. During normal operation, the diodes won't do anything. The diodes need to be rated for the supply's voltage and current.

In the unlikely event a pack gets connected backwards to the supply(ies), the diodes will short out and possibly prevent damage to the supply, but no gurantees in that event (but please be sure to have a video camera rolling if you do this).

[nicobie]

Thanks Fechter. These little boards are needed if running meanwell or meanwell clones. The one I got from you still works great. I now need another charging system and was wondering what I was going to do. I was thinking of getting a small variable dc power supply, but these boards will do the trick cheaper.

[Andje]

Fetcher, how good are the v3 when using multiple meanwells? I plan to turn down 4 48v meanwells to 41v each and run them in series for 164v. Would one v3 board work?

[neptronix]

Awesome, i'm assuming this is tested & works on the meanwell NES models ..?

[fechter]

Fetcher, how good are the v3 when using multiple meanwells? I plan to turn down 4 48v meanwells to 41v each and run them in series for 164v. Would one v3 board work?

4 supplies in series might take 2 boards. There is a limitation to compliance, or how much a supply can drop its voltage in response to over current. If a pack is really low and only one supply has a limiter, it's possible it will try to drop it's voltage so much that the limiter circuit runs out of voltage to power itself. If the zener on the limiter is dialed in properly, you should be able to get up to 20V of compliance on a single 48V supply.

When compliance is exceeded, I think the current will limit at a lower than normal level until the pack voltage rises enough to restore full current. This may actually be a good feature. If compliance is grossly exceeded to where the output voltage drops below where the limiter is able to run, the supply would revert to it's factory limit.

Any time using multiple supplies in series, regardless of type, you should place a hefty diode across the output of each supply to prevent reverse current. If one supply loses power or is overloaded, the other supply(s) could drive its output reverse polarity and damage the output capacitors etc. Normally the diodes don't do anything, but if the string tries to drive one supply backwards, it will conduct to save the low supply.

[Doctorbass]

Fechter, These board are really interesting!.

Did you ever managed to test them on the RSP meanwell serie?

I know their PWM board are appart and vertical mounted on the main baoard and they seem a little more complex..

The only way i found to play with the max current of my meanwell RCP and RSP serie is to remove some paralleled shunt DALE resistor... but i would like to have a pot instead!

Doc

[fechter]

I tested a SP-320, which only has hiccup mode current limiting. It works great on that model but the compliance was limited. On a 24V supply, the minimum voltage output was around 17V.

I have not tested on the newer NES models, but have no reason to think it won't work the same.

[JohnC]

Thanks for the tutorial Fechter. My 16 year old is building a bike now with a MW S-350-48 and that looks like a soldering project he can handle. When your V.3 bare boards are available we are in.

[Degull]

Just to let everyone know in case you were not following the previous thread. Fetcher has entrusted myself with the distribution of the bare boards. I should have them some time early next week and will start shipping as soon as I get them.
The bare boards will cost $10 each. Basic USPS shipping including the cost of a padded envelope pretty much anywhere in North America should be $3-5. I'll get to the post office in the next couple of days and find out exactly how much the shipping will be to different parts of the world. I'll start taking payments as soon as I find out the exact shipping rates. At this point there are only 34 boards for sale so don't think about it for too long.

Email and paypal info fcarcao@gmail.com.

[nicobie]

Will there be a parts kit or a link to one available?

[Degull]

The Mouser BOM import feature works very well. Look at post 2 at the top of this thread. Fetcher has taken the time to format the bill of materials list for the Mouser parts tool and it makes ordering the parts very easy. If you are asking if we plan on selling a parts kit with the boards, no there are no plans for that right now. If there is a demand for it then I could put a few kits together. If you want to build one now, order the parts on your own. At this time I only ordered enough parts from Mouser to make myself a couple of boards.

[nicobie]

Thanks, somehow I missed the first part of the thread.

[Degull]

Hi everyone! I'm excited to announce that Fechter's Mini Meanwell Limiter V3 boards arrived at my place this afternoon! I am ready to take payments and start shipping tomorrow.

In case anyone missed it, the boards are $10 each. Shipping/handling per shipment anywhere in North America will be $5 and $10 for the rest of the world. All prices are US dollars. I will be shipping the boards with USPS and according to the post office, it should take one week for North American addresses. The rest of the world is a coin toss because it is dependent on your country's postal system. If you require FedEx shipping please send me an email and I will look into shipping case by case.

My PayPal address is:

Fcarcao@gmail.com

Please make sure that your correct address is in the PayPal invoice. USD only please!

Thanks

Fernando

[JohnC]

Okay, thanks. Payment sent.

This is for my 16 year old son’s new build, e.s. dude. He joined the forum yesterday.

[nicobie]

Thanks,

Put me down for one.

I already ordered the parts from mouser ( they were out of the 78-1N914B diodes).

[fechter]

Diodes:
Mouser Part #: 78-1N914
Stock: 26,948 Can Ship Immediately

[Degull]

Everyone who sent their payments yesterday and today, your boards are shipped!

[nicobie]

Diodes:
Mouser Part #: 78-1N914
Stock: 26,948 Can Ship Immediately

I saw that too. However when I placed the order they came up as 'back ordered'. We'll see what they ship. Maybe I'll get them. If not, no big deal as they can be found all over the net.

[nicobie]

I now see what happened. In the original BOM the diode was listed as a 512-1N914B. That's what they said was out of stock. It has since been restocked and already shipped out to me. Meanwhile I ordered the 78-1N914 and it will be here in a couple of days too. Does it matter which one I use? one was listed as 200mA and the other as 300mA.

Sorry to be such a pain...

Nick

[fechter]

Either one will work fine. The 78- version is a little cheaper

[JoeG]

Hey Fletcher,
I'm thinking of using 3 Meanwell PSP-1000-48 , 19A supplies in series to charge my 162V peak charge voltage EV pack. Do you know if your limiter board has been used sucessfully on the larger Meanwell supplies? Or this version in particular? Also, I've heard some of the supplies don't do the hiccup mode limiting, that they have constant current ablity. Does anyone know how to tell the difference?
Thanks for the info,
Joe