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Re: PIP inverter repairs and hardware modifications

Posted: Sat, 14 Nov 2015, 00:33
by coulomb
offgridQLD wrote: I looked at the small rocker switch at the bottom of the PIP and wondered if there would be any harm in extending that to the garage and placing a switch on the wall near the car charger.

I happen to have traced that part of the schematic (plus there were some fragments in a PDF published earlier in this topic):


I can't see a problem extending that by 30 m. There may be issues with false starts caused by transients, which would be minimised by using twisted pair wire of any kind.

[ Edit: Use your browser's "view image" or similar facility for greater detail of the schematic ]
[ Edit: extended schematic trace to include Q36 and TX9. Some more detail can be found in the Axpert MKS Charger/ Inverter Service manual. ]
[ Edit: added U8 opto and current sense components. ]
[ Edit: added regulator U6 and opto U11 for sensing the battery voltage. ]
[ Edit May 2019: Q10 may actually be a BSX53. Also, many of the components around UTIL_PS_OUT may be missing on all but the oldest models, since that whole power supply doesn't exist in later models. ]

Re: PIP inverter repairs and hardware modifications

Posted: Sat, 14 Nov 2015, 05:07
by lopezjm2001
offgridQLD wrote:"Maximum operating distance of the remote module is 15m connected via RJ45 network cable. "

Hi Kurt,
I have just installed a remote module for my PIP4048MS. Could not get the 5Vdc supply from the PIP to work even after changing the jumper setting, probably due to the new communications board not being compatible, the remote unit is about a year younger than the PIP, so I had to use a separate 5Vdc mini-USB supply to power the remote module. It also worked with a better quality 20m network cable which I bought separately. My remote unit has two switches, one to switch the 5Vdc and the other to switch off the PIP. Neither one of the two switches works so I assume they have both been bridged out inside the remote unit. Other than that the two switches do nothing and the remote unit works fine. Luckily I did not buy the remote unit for the intention to switch the PIP remotely as the PIP runs 24/7 to the whole house. Just for monitoring.
PS - I am thinking of installing a grid inverter inside my Plug In Prius to take power from the 220Vdc PHEV battery to supply 220Vac to the house which in turn would be used to charge the Off-grid 48Vdc battery via charger. I would just need to run a cable with a three pin plug to the AC side of the house to the nearest GPO. Just for when the off-grid battery is near flat.

Re: PIP inverter repairs and hardware modifications

Posted: Sun, 27 Dec 2015, 16:32
by coulomb
coulomb wrote: Fri, 28 Aug 2015, 03:18
Scott wrote: The inverter ships with the same RJ45 to DB9 connector, as well as a USB A-B cable.

So what's the USB port for?

I've since read that the USB port is a very basic one with poor support for operating systems other than windows. For example:

But it should work with Windows, saving the need to use a USB to serial adapter. The new PIP MS (Axpert MKS 5KVA etc) models seem to come with both RS232 (using an RJ-45 socket) and USB, so nothing is lost.

[ Edit July 2017: But it seems that the USB port can only be used for monitoring / commands; it sadly can't be used for firmware updating, at least with presently available firmware updating software. ]

Some other models seem to come with USB only. They may have trouble on operating systems other than Windows.

Re: PIP inverter repairs and hardware modifications

Posted: Thu, 31 Dec 2015, 00:09
by coulomb
coulomb wrote: Sun, 27 Dec 2015, 17:01 So either they are very fast at delivering from Taiwan to Sydney, and slow to send the dispatch confirmation, or they have stock in Sydney (the Toll Priority tracking information started with "freight pickup" from "Sydney bulk" just after 4pm on the 23rd).
Well, I have the inverter now. It came from "Winit Au Trade, Dock 1, Regents Park NSW". Aha! A Dock! So it did come from... China. Yes, designed in Taiwan, but made in China. (A sticker on the box says made in China.)

But when I look up Regents Park, it's in Western Sydney. Nowhere even a river, let alone the Pacific Ocean. It might be an importer, or a warehousing company, or something else.

The box:

Image     Image

It has a USB cable, as well as an RJ-45 to serial cable. There is a CD with WatchPower 1.07, a paper manual (version 1.06 of the manual), and the box. The box is 460 x 300 x 120 mm (rounding up). The top is smooth; no heatsink there. No 80 A solar charging.

When I power it up, I get the first surprise:


The firmware hasn't been updated for a while. Well, that's good; I don't need to patch anything newer. Now to look inside.

Image     Image

To anyone familiar with the 2013 and 2014 models, this is quite different. The Solar Charge Controller (SCC) is now distributed along the top end of the case (the two inductors), and down the middle between the two main heatsinks. One gets the impression that these SCC heatsinks run the full length of the SCC printed circuit board, but that can't be the case. In the earlier models, this is where the large (55 x 55 x 75 mm tall) transformer is located, along with two quite large capacitors and four smaller ones. They've really packed it in there. This makes me really wonder how the triple SCC version fits everything in! (I think the main trick is a deeper case, perhaps 194 mm deep). You can see the rounded top in the second photo above.

I couldn't get a good photo of the heatsinks without taking out a fan. I decided I wanted to try the original fans merely turned around to blow upwards (they still blow downwards as supplied). I'll follow up with a post on the "fan rectification" soon. So here is a view with one fan removed:

Image     Image
So basically, both fans face pretty much packed heatsinks. In this last photo, you can see what I believe are the SCC FETs.


[ Edit 1: large inductor -> large transformer; SCC heatsinks likely don't extend full length ]

Re: PIP inverter repairs and hardware modifications

Posted: Thu, 31 Dec 2015, 00:43
by weber
Fascinating. Thanks Coulomb.

Re: PIP inverter repairs and hardware modifications

Posted: Thu, 31 Dec 2015, 03:02
by offgridQLD
That sure solves a few things I was wondering about regarding the SCC layout.

I'm not sure if I like the new layout or not. I kind of don't know why they did it? Perhaps to so they can loose the fly wire and stand off that was often not tight. Edit: Now I see the pic on my pc I see they still use the two long fly wires for the SCC.

Though the SCC heat sink could perhaps be heating the inverter components? I guess the direct fans on the sinks should stop that.

Thanks for the pics .


Re: PIP inverter repairs and hardware modifications

Posted: Thu, 31 Dec 2015, 04:05
by coulomb
Fan "Rectification"

This post is for those who agree with me that the fans in any electronic equipment, if they act vertically, should blow air up from below, not suck out from below. Performing this modification will likely void your warranty, despite the fact that in my opinion, it will improve the cooling of the unit.

[ Edit: The other consideration is that dust tends to collect where the fans draw air into the unit. This is more readily accessible at the bottom of the unit, where the cable access cover can be removed with just two screws. ]

The top cover comes off easily, but you'll have to sacrifice part of the sticker with the year of manufacture. This is what you need to aim for, in order to be able to access the bottom two screws of the left hand fan; they're right behind the serial PCB:


NOTE: It's been shown that the following is the hard way to access the fans. I leave the following for historical interest and for the reader's enjoyment at my expense. Take out the serial board for much easier access.

If you don't get the plate holding the two fans this high up, then you'll never be able to remove and replace the bottom two screws on the left fan. Well, unless you have an amazing Z screwdriver that has a very short straight part. The two screws holding the fan plate to the box sides are easy to remove, but unlike earlier models, the PV input terminal block is now holding the plate firmly in place. The terminal block is screwed to a seat, as shown below:

Image     Image     Image

The second photo shows the pegs that together with the screw and the tight fit hold the PV terminals in place. The third photo shows the three screws that you need to remove: one in the middle that screws into the seat, and the two holding the straps that connect the PV inputs to the SCC PCB. The other end of the straps is soldered to the SCC PCB; it would be a lot of effort to undo those, and these is no need. The terminal block comes out with a bit of wiggling and choice words.

At this point, the fan plate still doesn't come up, because of the two toroids marked 1 and 2 on the photo below, trapped under the printed circuit board marked 3:


By pushing the fan plate towards you, you can carefully work the two toroids out from under the printed circuit board. Finally, the fan plate can come up. Using a full sized #2 [ edit: was #3 ] Philips head screwdriver, the fan screws can be removed.

Oh, I've neglected to mention another test of dexterity and patience. There is a small cable tie at the bottom of the left hand fan, which restricts movement of the right fan. Using long nosed pliers, I was able to pull the cable for the right hand fan through the cable tie, but not far enough to be able to rotate that fan. I found the best way to cut the cable tie was to use a small flat bladed screw driver to rotate it slightly so that the bulge on the cable tie was facing away from me; I was then able to cut it with medium sized side cutters from above.

It is then a matter of taking the fans up, rotating them about the vertical axis (so they now blow inwards rather than outwards), and putting them back. You will be cutting new threads into what was the back of the fans (now the front), so that's another reason you need good access to all eight fan screws, and the need for the large #3 Philips screw driver.

Manipulate the toroids back under the printed circuit board, carefully as before. Replace the PV terminal block, screw the fan plate back, and replace the lid.

Edit 1: in retrospect, it might have been easier to remove the serial port board. You could cut the new thread in the fan plastic while the fans are out of the unit. I may try it that way if I decide to replace the fans with quieter ones.

Edit 2: Weber just reversed his fans without having to remove the metal plate that they are mounted on at all. Removing the serial port board is definitely the way to go. He may have rotated one of the fans 90 degrees to make the cables fit. He didn't even have to cut the troublesome cable tie.

Re: PIP inverter repairs and hardware modifications

Posted: Fri, 01 Jan 2016, 02:55
by coulomb
I'm playing around with my inverter, watching the temperature with various loads, and I see that the temperature sits at 44-52°C now. On 52.02 it would make a lot of noise (with original fans) but keep the temperature around 32-35°C.

The other thing I notice is that the lower temperatures happen with *higher* load. So there must be a feed forward term there ("load is 40% - set the fans up higher, don't wait to measure the temperature rise, we know it's coming"). The lowest temperature I measured was 41°C immediately after a moderate load (2.3 kW) came off.

With ambient load (100-120 W), I'm getting 47-51°C; with the microwave running (1.8 kW total), I'm getting 44-46°C; with a 2.3 kW total load, 42-43°C. At this ambient temperature (24°C), it's slightly over compensating. The actual junction temperatures will be higher than measured, so that's good.

So far, the stock Adda fans have been quite quiet. Only once did it run the fans at a moderate huff, but only for less than a second, and nowhere near as loud as with the older firmware.

I think eventually I'd like a lower average temperature, but for now, the stock fans and fan algorithm will do.

[ Edit 9/Jan/2016: I had the PIP horizontal, which really invalidated the test. I noticed that the front cover was getting warm; with later tests and a vertical PIP, this did not happen. ]

Re: PIP inverter repairs and hardware modifications

Posted: Sun, 03 Jan 2016, 15:50
by paulvk
Coulomb have you turned the fans around it would be good to see the difference if any ?
Also if you get a flexible driver you can remove fans without taking the units apart

[ Edited Coulomb: linkable URL ]

Re: PIP inverter repairs and hardware modifications

Posted: Sun, 03 Jan 2016, 20:30
by coulomb
I don't think that one would be nearly flexible enough for two of the fan screws. [ Edit: this was while I wasn't considering taking out the comms board. ] There is only about 15 mm clearance to the back of the serial comms board.

Re: PIP inverter repairs and hardware modifications

Posted: Sun, 03 Jan 2016, 20:35
by coulomb
paulvk wrote: Coulomb have you turned the fans around it would be good to see the difference if any ?

Yes. But I foolishly didn't do measurements before I turned them around. Weber has promised me to do the before and after measurements on his recently ordered PIP. It should arrive in a few days.

Re: PIP inverter repairs and hardware modifications

Posted: Sat, 09 Jan 2016, 20:26
by coulomb
paulvk wrote: Coulomb have you turned the fans around it would be good to see the difference if any ?
Ok, now that Weber's PIP is here and it's Project Day, I can rectify my lack of a scientific comparison.

We set up his PIP almost vertically (another mistake I made); ambient temperature was 26°C. We loaded it with 3.8 kW before and after the fan reversal. PV panels were connected; it was a cloudy day with intermittent full sun.


To cut a long story short, with the fans in the original direction (blowing out of the bottom of the unit), at 3.8 kW load, it quickly reached 57°C. With the load reduced to 100 W (to compare better with my results), the temperature actually increased to 58°C, and remained there for at least 3 minutes. With zero load, it fell to just 57°C.

To prove this wasn't some artifact, we re-connected the 3.8 kW load, and the temperature went down to 56 then 57°C.

After the fans were reversed, with the 3.8 kW load, the highest temperature reached was 45°C. With the 100 W load, the temperature went up to 46°C (with the fans off), then reduced to 41°C after 5 minutes.

We were pretty slack about checking the PV charging power. With the original fan direction, the two measurements we noted were 300 W and 1200 W. At the end, with the 41°C figure, the solar input was about 300 W. So we waited for some sun; it rose to 1.2 kW. This only ran the fans a little harder, and reduced the temperature to 40°C.

It seems that with the fans blowing down as standard and 100 W of load, the main effect of the fan was to precisely cancel the benefits of natural convection Image .

In summary, the fan direction change gives a 12°C improvement at high loads. At 50% load, there is an improvement, but only four degrees.

Re: PIP inverter repairs and hardware modifications

Posted: Sat, 09 Jan 2016, 20:35
by solamahn
Good. I will continue to turn all my fans upside down pre installation. I have some msd and mst coming next week.

Re: PIP inverter repairs and hardware modifications

Posted: Sat, 09 Jan 2016, 21:26
by paulvk
It is good to have real data.
Today with temps here at 27deg I had the air con running and then boiled the kettle this had the unit at 3200watts for about 4 mins .
As the top of the inverter heat sink had gone past 42deg the two 125mm fans mounted on the sides at the top were running (my add on external), with the load up the two internal fans were running almost flat out the temperature stayed at 40deg.
This is the older unit with heat sink at the top there was also 48amps from the solar panels.
Now I have my temperature probe from the controller (similar to this ... pCYnLGZCpo) at the top of the inverter heat sink.
How are you measuring the temperature, the inverters sensor on my unit appears to be at the bottom so blowing air at it from the bottom would maybe not give good results.

Re: PIP inverter repairs and hardware modifications

Posted: Sat, 09 Jan 2016, 23:52
by coulomb
paulvk wrote: How are you measuring the temperature
This is using the QPIGS command, with AccessPort. That's presumably the same measurement that the firmware is using.
The inverters sensor on my unit appears to be at the bottom so blowing air at it from the bottom would maybe not give good results.
An interesting question. It seems to take the maximum of about 3 measurements, and I think one of those is bolted to the heatsink.

Weber seems to recall a bead thermistor physically under the main transformer. It may have been lower than the main transformer, which means without the reversal it would have gotten the heat from that transformer, but with the reversal, it might not be registering that heat.

It would be good to know where the sensors actually are. I can check on a spare board when I get home, for the 2013 model.

Re: PIP inverter repairs and hardware modifications

Posted: Sun, 10 Jan 2016, 05:13
by coulomb
coulomb wrote: Weber seems to recall a bead thermistor physically under the main transformer.
He remembers well:

Image     Image

The above photo is of a 2013 model, kindly donated for spare parts by forum contributor dockarl. The transformer doesn't look much like a transformer from this angle; most of what can be seen is something shiny on the side of its ferrite core. It may be plastic tape, varnish, or a lacquer coating.

NTC.Txt probably stands for Negative Temperature Coefficient thermistor, Transformer Temperature. You can see that there is no thermal connection between the transformer and the tiny thermistor. Indeed, the transformer appears to be thermally isolated from the printed circuit board by the white plastic material. (Some heat would conduct to the PCB tracks by conduction along the leads.) So it must sense by radiated heat, or conduction through air. I imagine that radiated heat would dominate.

The thermistor is towards the bottom of the unit when mounted normally, so that indeed blowing colder air from below may in fact change how the transformer's temperature is sensed. This is not something I'm an expert at, so I don't know whether this is serious or not.

There are also two more standard thermal sensors of some sort bolted to the two main heatsinks. So there are at least four temperature sensors: two on the heat sinks, one or more on the Solar Charge Controller, and this thermistor.


[ Edit 1: I decided the shiny surface could be plastic tape as well as varnish/lacquer. ]
[ Edit 2: I found that the transformer sensor read 5-6 °C cooler 4 seconds after the fans came on at 30% after a 60-160 W load. It "bounced back" 4 seconds after the fans came back on. This suggests to me that reversing the fan air flow direction may be causing the transformer to heat up some 5 °C more than it would have with the standard fan direction, under certain unusual conditions. ]
[ Edit 3: Added heatsink sensor photo. ]

Re: PIP inverter repairs and hardware modifications

Posted: Mon, 11 Jan 2016, 16:48
Hi All,
I have recently purchased a 4048 inverter. Just wanted to ask opinions on if I should change the caps on the DC side now?.....Thanks in advance!

Re: PIP inverter repairs and hardware modifications

Posted: Mon, 11 Jan 2016, 23:28
by paulvk
Is it under warranty?
If it is why void the warranty.
I have units here working 24/7 for over 12 months have had no problems with the caps and as they are still under warranty (2 years on my ones) I will wait till that ends.
I have lead acid batteries connected to the units.

Re: PIP inverter repairs and hardware modifications

Posted: Mon, 11 Jan 2016, 23:41
Yes, the unit is new, so still under warranty. Waiting until the warranty ended was my thinking also, however, I don't want it breaking down if it's a simple case of changing them now to help solve an issue I would be happy to do that. I was a little concerned by the quality of the caps, reading about other peoples experiences.

Re: PIP inverter repairs and hardware modifications

Posted: Mon, 11 Jan 2016, 23:58
by weber
It is possible that in recent models the caps have been upgraded, and/or that voltage overshoots are better controlled. I'm unwilling to disassemble my new unit enough to find out.

Re: PIP inverter repairs and hardware modifications

Posted: Sun, 24 Jan 2016, 06:58
by rinaldoparaipan
rinaldoparaipan wrote: Hello everyone.
It seems that the new type of 4048MS(which is build in a new case, without the black heatsink at the upper side)has problems with the 3300uF capacitors.
I had problems with my inverter, a friend of mine has the same fault: with only 500W load the inverter collapsed after 5min.The capacitors exploded and the device stopped functioning.

Hello everyone.
Regarding my post, MPP Solar send me (two months ago) the replacement boards:main board and MPPT board.The cost was 70USD.
So far, so good.

Re: PIP inverter repairs and hardware modifications

Posted: Sun, 24 Jan 2016, 15:07
by coulomb
I had a post here questioning whether the above photo was of a late 2015 model like mine, but there were so many errors and confusions, I've decided to delete the post.

Rinaldoparaipan, thanks for the update on the replacement boards. It's good to know that MPP solar looks after its customers, that the replacement boards aren't extremely expensive. The US$70 mentioned may be more about expedited shipping than the true cost of the boards, so we might not all be able to buy spares at that price, but it's still a good sign. It's also good to hear that the boards are performing well. Hopefully, you were just unlucky to get one of the first 2015 models before the kinks were completely ironed out.

Re: PIP inverter repairs and hardware modifications

Posted: Sun, 24 Jan 2016, 23:06
by rinaldoparaipan
The cost of 70USD was for shipping.They send me the boards under guarantee terms.The real value is bigger, for sure.Image
I had also the same problems with the generator connected to AC in.
I use the method to start the generator with a small load.
Now, reading the forum,I see that is the only way to use it for 52.30 firmware version.

Re: PIP inverter repairs and hardware modifications

Posted: Thu, 28 Jan 2016, 03:11
by coulomb
Northland wrote: I opened it up, did the fan swap. Could not see anything abnormal. Nothing smelly.
It seems the smoke must have come from elsewhere, then. Weird.
I noticed 6 relays inside. 3 on the main board, 2 on the mppt board, 1 on the comms board. All 12v coils. Anyone know what they do?

There's 4 on the main board; according to the service manual, two are designated "safety relay" on the mains input (active and neutral). The "inverter" relay isolates the inverter from the mains, and the "output relay" isolates the load from the mains. I think if you have a generator and it's out of spec for voltage and/or frequency, you need to disconnect the mains and run the load from the inverter. Perhaps the load relay goes off if a short circuit is detected on the load.

Block diagram.png
Block diagram.png (48.79 KiB) Viewed 2429 times
I'm guessing the MPPT switches both positive and negative of the PV inputs. [ Edit: I've found that at least for the 2015 model, the two relay contacts are in parallel, connecting the output of the MPPT section with battery positive; see this later post. ] The one on the comms board is the "dry contact" that can be used for generator starting or other purposes. I believe it can be programmed to turn on at a particular battery voltage, but I've never looked into it.

[ Edited July 2020: added inverter current detection to block diagram. ]

Re: PIP inverter repairs and hardware modifications

Posted: Sun, 31 Jan 2016, 23:42
by rinaldoparaipan
I think is useful.
PIP 4048 Service Manual 06.2015 Part1