Xantrex XW-MPPT-60-150: Squeezing 60 amps through a toothpick

It doesn’t smell too great in my office right now…. some Xantrex XW-MPPT-60-150 charge controllers just came back that are completely, totally burned up. SCORCHED. OWNED. PWNED. TEHPWNZRIATED.

All images are clickable for full resolution, as always (4000×3000 px)

First off, here’s why I think these blew up. Note the four small pins on the back of each contact of the large screw terminals. Each of them is probably 18 gauge… if even. It’s hard to judge since they’re square pins.

Up to 60 amps of current will flow through these little four-legged pieces of Chinese scrapmetal when the controller is running full tilt.

FYI, National Electrical Code requirements would call for AT LEAST 6 AWG assuming the conductors are copper — which they are not, they’re tin plated steel.

Aaaaaaand now, the results.

Burnt components and pieces of plastic fall out of the controller whenever it’s handled, and it’s left a wretched smell to permate my workspace. The copper PCB traces are still there and didn’t fuse, but the solder has melted away on them from the heating, and several components in the vicinity desoldered and fell right out of the controller.


Topside. The top of the terminal block and delaminated PCB

33 thoughts on “Xantrex XW-MPPT-60-150: Squeezing 60 amps through a toothpick”

  1. I was wondering if repair of these electronics is still possible. I have the same charge controller but he quit completely after I miswired the battery connectors.

    What would you advice, look for spar parts, find and replace the wrong component or throw the whole thing away.

    Your opinion will be depreciated.

    Best regards.

    1. Hard to say really. Open the controller up and look to see if anything is visibly burnt. On power inverters, the switching FETs tend to blow out from reverse polarity.

      When you remove the top cover screws, the transistors will be stuck to a sort of melted green pad on the cover. This is normal, just try to pry them off the green stuff carefully.

      I may have some spare power boards for these sitting around from some units where bad capacitors destroyed the CPU board (the small one under the display, with the microcontroller, xanbus interface, aux out, and battery temp sensor connectors). My workshop is being moved right now but I’ll look around once it’s all unpacked.

      1. Hi I saw your post, and I am having a similar problem.. I connected the DC negative and positive in reverse. Blowing the controller chil. Would u happen to have a spare one of those u would be willing to sell. Or maybe have any advice on how to fix it. Because it looks like only the two 100v 47uf capacitors blew..

  2. Thank you for your responds.

    There are no burned or broken parts of funny smells,
    My guess is that the CPU board is gone. Because I think the FETs only get current when the relay is switched on, and I think the relay is controlled by the CPU board, only after a delay of a few seconds after connection.
    And because I can measure power going to the CPU board.
    But I am only guessing because electronics is not my profession.

    Much appreciated.

  3. I work on a/c units for a living and it looks to me your problem was caused by loose wires over heating. With that kind of amps and volts its real easy to fry a board. I see it all the time with breakers not being tight enough. I’m going to check my MPPT this afternoon for loose wires. thanks Rod

    1. Thanks… months later I am just starting to realize, gee, it’s suspicious the customer just happened to return two that were damaged exactly the same way. Gotta put some oomph behind that screwdriver!

  4. one would think that the input limitation would be about 43 amps, 48 X 1.25 but even then these “leads” are to small, as mentioned in the stringing calculator.

    I had a HOT termainal condition, where the lead was not tight tight and ran hot under load, sniff it out as it smelled like burning PCB during operation. Found it before damage and reset the connection and been running daily for two years without fail. But a loose connections can have the same result.

    1. It looks like someone has replaced the fuse with a new one because you would think the smoke stains would be on the fuse like the board around it. Maybe not using proper fuse. These units are rated for 60 amps but they will only allow 3500 watts to the battery’s so 3500 watts divided by 140 volts = 25 amps on the in put and depends on the out volts

  5. Looking for some info on Getting info to and from the Contoller.
    I understand that they use the CAN protocol…Maybe Modbus imbeded in packets?? I would like to interface these Charge Controllers to a PC or embeded controller like a MICROCHIP CAN PIC18xxxx Any ideas or help? Cant find nothing on internet!! 10 billion hits and pages to read!! The internet is now somewhat Useless….Always the same stuff…Cheers

  6. I am getting ready to buy one or two of these units. I think that is the solar panel input side at least I hope it is), and the input is usually a higher voltage and lower current, such as 5 ea 27.5 volt panels in series (for 137.5 VDC @ ~7.5 amps max), then they can be paralleled with up to 3 more sets of 5 for max current of 30 amps in, at the same 137.5 VDC. Then the MPPT unit does its Magic (which must be the the first ‘M’ in MPPT), and converts the voltage DOWN and the current UP to charge a set of 48 or 60 volt batteries with currents as high as 60 amps on the other, much larger terminals. AT least I HOPE the other terminals are much larger! . – Cool Blog. I like the colors and graphics, too. Futuristic. I to will be interfacing to a PC (one way or another).

    1. Unless you are already planning an entire Xantrex XW system, I would strongly recommend you look at the MidNite Solar Classic instead. It’s a much better controller and has built in Ethernet — with the OutBack you’d need a MATE to add PC connectivity.

  7. I have a XW-6048 Charger/Inverter and have been running some test with it (using its on-board charger), and the solar panels/charger is the next logical step in my tests. I’ve seen a picture of a 6048 installation with the Midnight Solar unit used directly in place of the XW-MPPT. It looks like it takes up the same footprint on the wall, too. I wonder if they had trouble with the XW units and went to the MS, or went MS first (I’ll have to look through my Browser history to see if I can find it).

    I have read only positive things about the Midnight Solar units. But I’ve seen two other negative on the XW MPPT, and your pix make 3. And it looks like you have first hand experience with them, and “strongly” usually means strongly. I’ll have to dig into the communications issues with the MS being used with 6048. The Midnight units look neat, too.

  8. Doing more detailed searches, I found quite a few people using the Outback units with XW-6048 – and they all seem happy. But I still need to look into the communications issues. I also saw your review of the 80, and that appears to quite a nice design.
    I will probably end up going for the Flexmax-80 since I need more charging juice and I didn’t like the larger Xantrex Charger to begin with – I want about 24KW of batteries (60 VDC). But to be honest I am still in “phase 2” of my plan which is reducing power consumption (all LED lighting, move the HW-Heater off the house power, new Super Duper Windows, New High Efficiency A/C) – all of which has taken us 2 years to get the cash to do it all. Good Windows – what a difference – now the trains (3 blocks over) don’t sound like they are in bed with us. Training a teenager will be the most difficult task.
    Thanks again for your advice. You have obviously been doing this for a while. All of the Flexmax/XW users seem to be happy as clams.
    I appreciate it immensely.

  9. Here is an other MPPT60-150 with burned out FETs. After two years of non-stop working my MPPT60-150 just stopped (low-light). I disconnected the batteries and I heard loud noises of flashing coming from the inside.

    Two pairs of the 8 FETs were burned out, $500,- down the drain.

    What is wrong with those chargers, and can they be fixed?

    Love to hear you opinion.

    1. Unfortunately I’m not sure that just changing the FETs will always bring these guys back. I’ve seen a lot of problems on Xantrex gear that appear to actually be internal shorts between layers of the circuit board they use – in one case it was a mighty XW6048 that just completely turned to CHARCOAL!!

      Sad but true… 🙁

      Contact Schneider Electric tech support.


    1. Ouch!! Sadly that may be the end of the line for that controller. I saw a few that had suffered reverse polarity; extensive damage was done, especially in the low voltage supply and microcontroller board.

      I recommend the MidNite Solar Classic as a replacement, unless you still need the xw system connectivity.

    2. Hi Melford,

      Before you replace, make sure you had checked all your protection equipments are in place and doing their job, eg Fuses, CB. and check the last Fault Code in ComBox. If not the next replaced item may face the same fate.

  11. I have a Xantrex mppt60-150 charge controller with a fault code of “low batt vol” which will not reset as described in the manual. The battery bank is fully charged with both batt reading 12.6 V and 12.5 V connected in a series reading 25.4 V. I have tried all reset options as described in the manual but the unit will not erase the “low batt vol” fault. Please advise.

    1. Is the battery voltage configured correctly?

      If it is and that’s still showing up, make sure the controller’s displaying the correct battery voltage. If the controller’s reading and the reading with a meter are far in disagreement, the controller’s going to need to go to Schneider for repair.

    2. Hi Daniel,

      What is the LBCO you have set?
      What is the Battery Cable size and Fuse Rating you had used?
      What is the Battery Cable length you had used?

  12. My XW mostly works, but only reads the battery temperature incorrectly. I can’t find anyone to repair it. Any ideas other than replacing it with something new?

  13. Hello. I had need to replace the FR120N and accidentally i lost the R32 . please would somebody tell me the value off this resistor .
    Thank you so much

  14. By the way, THANK YOU SO VERY MUCH for your recommendation on the Midnight Solar. What nice units. They REALLY do care about quality all the way around on those things. They do some real magic in those, I think .

    That XW-MPPT-60-150 is TOAST! BIG TIME! And yes, I’ll bet it stinks to high heaven anywhere near it.

    And I was worried about communications for nothing since the Midnight solar does all the work for you on the batteries and the 6048 plays DUMB as it hums away pumping out the juice. I got it for the 230 VAC split with the the MASSIVE over rating of power and especially on startup current – I basically over rated the whole system so much that the 6048 was only doing just over half of its rated power 40% of the time, and 20 to 25% MOST of the time, and never more than 65% at ANY TIME. But we really downgraded EVERYTHING that uses AC power) And with 1700 amp hours of batteries @ 48 VDC I have juice to spare for an extra day or three. But my timing SUCKS WATERMELONS since my roof qualified for total insurance replacement due to damage from Hurricane Matthew (at no cost to us since my wife was smart enough – God love her – to pay for replacement cost insurance on the roof back when we applied for it), BUT, they just finished the job that was scheduled the first few days of LAST November a month after the hurricane… (yes, the roofers are THAT far behind down here). And now all of my mounts are gone since my solar system and all of its hardware were NOT covered on insurance since I did the design and installation myself (they don’t trust DIY-ers at all… sad but true) . At least I was lucky enough to have the time before it hit to pull all of the panels down off the roof (but the lag bolts were zinc plated garbage so I left them for the roofer to rip out and throw away) and there was no time to unscrew all of the brackets and cross members that were lagged into the trusses anyway). I will buy REAL galvanized this time – I already had a big bag of those so I used them (sadly)… And I have NO idea when I can get this sucker up and running again, but at least I have my 5500 watts of Evergreen panels stacked and ready when I clone myself to get it all done… (again). All my batteries will be worthless before I do, I suspect although I for over 5 and half years out of our backup battery bank at the office (albeit much smaller with a dozen 21 amp hour AGMs. And they are still good for 60% or more after almost 6 years, but they don’t get the use the BIG bank does (or did did for a year, each evening drain by 20% or so).
    I am TEMPTED to go DC on EVERYTHING in the house (including the A/C unit), and pitch the inverter in the trash (well.. I’d sell it for CHEAP). The idea is calling to me. I am experimenting with water cooled Peltier modules for whole house A/C (somewhat inefficient UNTIL you go with WATER-EVAP cooling for the hot side of the modules – I am playing with misting large aluminum fins with forced air ducted fan cooling, then the efficiency goes WAY UP to just “crappy” from “abysmal”). But I am just dumb enough to try it with 220 watt panels DIRECT to a Peltier A/C unit. I’ll send you the design. You can have a good laugh while we sweat in our sleep if my plan fails (but I hope it won’t…)

    Thanks again for the VALUABLE information you provide to everyone. It is mighty generous and kind of you, and I wanted to let you know that we DO appreciate it.
    KA1BOU ( a Four man stuck with a One, and happy to be back in Four land, But I had to keep the BOU because it fit so nicely as: Kilowatt Alpha ONE, Big, Ornery and Ugly@!)

    1. Normally I’d skip the Peltier modules due to low efficiency (they generate more waste heat per btu removed than refrigerant systems), but hey… If the power is free, go ahead 😀

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