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LFPSWSP-8000 Fan will not turn on.


Kyle Anders
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I have a brand new PJ LFPSWSP-8000 inverter, the main board is V11.1, and the fan never turns on. I have had large loads on it that eventually cause the inverter to shutdown, but the fan never turns on. I have checked the fan itself and it will power up when power is directly applied to it. also this is a 2021 model with the fan plugged directly in to the main board. Does Anybody have any ideas as to what might be wrong with this unit, this is actually the third one i have bought that behaves this way, i have returned the other two.

 

Thanks,

Kyle

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Does yours have the fan toggle switch?

FWIW, if you know how to power it manually, you can probably buy a cheap thermistor switch for the appropriate temperature and just put that in series with it, touch it against the hottest part of the transformer. Sometimes it's better just to improvise... -_-

 

Edited by NotMario
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5 hours ago, Kyle Anders said:

I have a brand new PJ LFPSWSP-8000 inverter, the main board is V11.1, and the fan never turns on. I have had large loads on it that eventually cause the inverter to shutdown, but the fan never turns on. I have checked the fan itself and it will power up when power is directly applied to it. also this is a 2021 model with the fan plugged directly in to the main board. Does Anybody have any ideas as to what might be wrong with this unit, this is actually the third one i have bought that behaves this way, i have returned the other two.

 

Thanks,

Kyle

What's the rated fan voltage?  EDIT: and the inverter battery voltage?

also...what's the part number on the CPU?  PIC18F87K22....or is it an 87K90...or is it an 86K90...??

I updated code for PJ last year to control the fan from BOTH thermistors (as their original code would ONLY switch the fan from ONE thermistor), but if they're using the original 87K22 processor, it will still only control the fan from ONE thermistor.  Any of the later processors (i.e. anything except the 87K22) SHOULD be able to control the fan from both.

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1 hour ago, Kyle Anders said:

It says 24V on the fan.

That might be a bit of a problem, as the control board is only going to give it +12v.  However, it still should run...just not very fast.

If you can test the fan on 12v and it doesn't run, then that's likely the problem.  Fortunately, there's a pretty easy workaround: the FET on the board only connects the fan negative wire to battery negative.  This means that you technically can cut the fan positive wire off of the connector (leave the negative wire intact!), and splice the fan positive wire to battery positive (= +24v).

Test the fan on 12v first (before cutting the fan positive wire!)

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48 minutes ago, Kyle Anders said:

I see what your saying. If i cut the positive wire and put it to battery positive, is there a chance of damaging anything, such as the FET you mentioned?

What's the part number on the FET near the two 2-pin fan connectors?

On the 11.1 board I have here, it's NCE80H15, which is an 80v, 150A FET--if that's what you have, running fan positive to battery positive won't hurt it at all.

Worth noting that the 80H15 is a terrible choice for the provided control signal, as that FET barely turns on at 4.5v--and the CPU runs at 5.0v.  At best, that FET will BARELY be turning on.  They should have used a logic-level FET for the fan control.

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46 minutes ago, Kyle Anders said:

When i apply 12v to the fan it spins up, but not very fast. But when the inverter is hooked to 24v batteries and a load is applied i dont get anything out of the fan.

Fan control is based on measured temperature, not load.  But if the inverter is shutting down due to overheat, then it most definitely should be running the fan(s).  If the inverter shuts down due to overload, that won't cause the fan(s) to run.

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The FET nearest the fan connector is a RU7088R, looking at its data sheet, it should be fine to run the fan+ to 24V battery? but i still have the issue that it does not seem to turn on at all. I understand what you are saying about overheat vs overload, i believe that the problem is overheat. I have had the exact same model inverter bake cookies in an electric oven with out issue, but this one cant even get it preheated before it shuts down.

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1 hour ago, Kyle Anders said:

The FET nearest the fan connector is a RU7088R, looking at its data sheet, it should be fine to run the fan+ to 24V battery? but i still have the issue that it does not seem to turn on at all. I understand what you are saying about overheat vs overload, i believe that the problem is overheat. I have had the exact same model inverter bake cookies in an electric oven with out issue, but this one cant even get it preheated before it shuts down.

Yes, the RU7088R is a 60v FET--so a 24v potential across it (when it's off) will be just fine.

However, it also has a relatively high gate threshold voltage...which means it'll BARELY turn on with the 5.0V the CPU can provide.

image.png.7e6df96080ef9d840a90fb457ebf6253.png

Note that the ideal gate drive voltage for a standard MOSFET is 10-15v.  I put a red line @ 5v on the above graph--note that based on temp, it MIGHT be partially turned on with a 5v gate drive.

If the FET is barely turning on, that will cause the PCB's default 12v to be even lower (which could cause the fan not to run).  PJ really should have used a logic-level FET for this one...

 

There are several tests you can do to figure out the cause of the problem if you're game to feel like a technical electronics detective 😉.

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1 hour ago, Kyle Anders said:

I have had the exact same model inverter bake cookies in an electric oven with out issue, but this one cant even get it preheated before it shuts down.

Remember, you bought a PJ..........

That means that the model number means basically nothing.  Published specs pretty well mean absolutely nothing.

If it works for your needs, great.  If it doesn't...well...you bought a PJ 😉.  I've heard a lot of reports from customers saying that the PJs with the v11 board all alarm/shut down at far lower loads than prior models did (and of course many times less than the "rated" load).  That's an overload shutdown, not necessarily an overheat shutdown.

 

If it's overheat shutdown, the main MOSFET heatsinks and/or the transformer will be extremely hot to the touch afterwards.  These type of shutdowns usually take 5 minutes for the heat to build up.

An overload shutdown usually happens in 30 seconds or so--and there will be little if any significant heat inside.

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So far i am pretty happy with PJs, especially considering the price. I have had a couple of them and when they died it was my fault. I had one of the stainless steel 8000W models that had a significantly larger transformer and it worked great until i let the smoke out. 

 

As far as this model goes, i am pretty sure it is a thermal shutdown, it takes about 5min with a heavy load, water heater or oven. i have not done this with the top cover off, so i cant speak to the internal heat. I would love to feel like a technical electronics detective, let me know what to test please.

 

Thank you so much for all the help!

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1 hour ago, Kyle Anders said:

i have not done this with the top cover off, so i cant speak to the internal heat.

After an overload shutdown, you can turn the inverter off, and remove the cover to feel for heat; especially with no fan running, it'll take a few minutes to cool down.

 

I just checked the 11.1 board and found that the DID run the fan positive line all the way to the battery positive (through the very thin FET cables).  So the fan SHOULD be getting 24v (not 12v as in all prior versions.)  EDIT: that means there's no need to cut/splice battery positive to the fan positive lead.

Making matters doubly worse is the completely inexplicable fan connector design.  There's 2 connectors...and THEY'RE BOTH OPPOSITE POLARITY from each other! 

In other words, plugging the fan into one connector might work fine.  Plugging it into the other connector will reverse-bias it.  Best case, it just won't run; worst case, it'll blow the fan out and/or melt inverter wiring, etc.  Saving grace here might be that the FET is barely turned on in the first place.......!

Your best bet here is to match up the fan polarity (red/black) with the connector that has the corresponding proper polarity.

image.png.9cb13bfc3fef5a69c65e5311d2144133.png

 

Once you're sure the fan is plugged into the correct polarity port, then you can continue testing:

  • experiment bypassing the MOSFET (with battery connected, but the inverter does not have to be running).

image.png.5077fa2d34d2421bdb36c451bceaf645.png

             When you short the 2 leads out, the fan should run. 

             If it doesn't, there's a power/wiring issue to the fan.

 

  • If the inverter did an overheat shutdown, it's prime time for a measurement with a voltmeter (digital preferred!)  You have to be careful with this one...as shorting this FET lead to the adjacent one will likely blow the FET (and possibly the CPU).  With the inverter ON and complaining about overheat, measure the voltage from the gate of the MOSFET to battery negative (note: only positive meter probe shown here):

image.png.aca4b6d9cb6bc7f821a0a94d56524aa1.png

               If this is 0v, then the CPU isn't even turning the MOSFET on.

               If it is close to 5v, then we have a MOSFET issue.

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OK, so when i shorted the FET, the fan did turn on, but the next problem i am experiencing is trying to heat up the inverter, it seems that a couple car batteries borrowed for testing do not have enough juice to run a space heater. I guess I will have to use my main battery bank. 

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1 hour ago, Kyle Anders said:

Also, are you someone i can buy replacement PJ parts from?

Not me, but @Sean Genetry Solar has SOME replacement parts (all older, none of the new v11 stuff AFAIK).  Don't think he's gotten any new replacement parts from PJ though; you probably are totally at the mercy of PJ as to whether you can buy replacement parts.

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Hi Kyle,

I figured out some years ago that it was much easier (and more reliable) to just go around powerjack's flaky fan controls.  Even when they work they turn on the fan at unpredictable times and frequently much higher inverter temps than I wanted. (The sooner your fan turns on, the less heating your inverter endures, and therefore the longer it will last - my theory anyway!)

To that end I don't interfere with powerjack's fan controls.  Instead I add two of these:

https://www.ebay.com/itm/194245273137?hash=item2d39eba631:g:1lgAAOSwHONg8tW-

You need 12v to power them.  I tuck one sensor into the fins of the same heatsink that powerjack mounts its sensor, and put the second sensor on the transformer near where powerjack puts their transformer sensor.  One controller now displays transformer temp and the other displays mainboard heatsink (mosfet) temp.  You can then set on and off temps for your fan based on actual temp readings from both sensors.

If your inverter has just one fan you just parallel the switch connections on both temp controllers and then connect that in parallel to powerjack's temp sensor on the transformer.  That may not work on your inverter Kyle so you could alternatively connect to the two pins of the mosfet you shorted to make your fan run.

This setup not only allows very definite fan control, it also gives you a constant temp reading of your inverter.

If you need a 12v power supply, there are many to choose from.  I use this one as in addition to powering the temp controllers, it can also power 2 or 3 12v fans easily (in case you want to add cooling to your inverter)

https://www.ebay.com/itm/152240514307?hash=item23723de503:g:0nUAAOSw6C5hCCkK

I have been using both of these exact items for years without a single one failing.  Sadly the price of them has doubled since I last bought some, but still a fairly cheap and more reliable fix for your problems.  Below is a pic of my temp controllers mounted in front of my inverter.

Hope this might be useful to you.

temp controllers.png

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44 minutes ago, dochubert said:

Hi Kyle,

I figured out some years ago that it was much easier (and more reliable) to just go around powerjack's flaky fan controls.  Even when they work they turn on the fan at unpredictable times and frequently much higher inverter temps than I wanted. (The sooner your fan turns on, the less heating your inverter endures, and therefore the longer it will last - my theory anyway!)

To that end I don't interfere with powerjack's fan controls.  Instead I add two of these:

https://www.ebay.com/itm/194245273137?hash=item2d39eba631:g:1lgAAOSwHONg8tW-

You need 12v to power them.  I tuck one sensor into the fins of the same heatsink that powerjack mounts its sensor, and put the second sensor on the transformer near where powerjack puts their transformer sensor.  One controller now displays transformer temp and the other displays mainboard heatsink (mosfet) temp.  You can then set on and off temps for your fan based on actual temp readings from both sensors.

If your inverter has just one fan you just parallel the switch connections on both temp controllers and then connect that in parallel to powerjack's temp sensor on the transformer.  That may not work on your inverter Kyle so you could alternatively connect to the two pins of the mosfet you shorted to make your fan run.

This setup not only allows very definite fan control, it also gives you a constant temp reading of your inverter.

If you need a 12v power supply, there are many to choose from.  I use this one as in addition to powering the temp controllers, it can also power 2 or 3 12v fans easily (in case you want to add cooling to your inverter)

https://www.ebay.com/itm/152240514307?hash=item23723de503:g:0nUAAOSw6C5hCCkK

I have been using both of these exact items for years without a single one failing.  Sadly the price of them has doubled since I last bought some, but still a fairly cheap and more reliable fix for your problems.  Below is a pic of my temp controllers mounted in front of my inverter.

Hope this might be useful to you.

temp controllers.png

So the new v11 boards DO use a larger TO-220 FET (my suggestion I guess!) and power the fans off battery voltage.  A slight modification to the CPU firmware makes it so both thermistors will control the fan--meaning that they have gotten rid of the (frankly terrible) thermal switches.  They've also removed the "fan override" switch.

One small step forward anyway.

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So the new v11 boards DO use a larger TO-220 FET (my suggestion I guess!) and power the fans off battery voltage.

I think PJ  hire you  as their  real design  engineer  as they use many of your  design  and I think more in the future  to make the PJ inverter even better  as my  PJ never blow up  FETs  anymore any never  overheat again .    

 

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