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


  1. Joost Wilterdink says:

    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.

    • kg4cyx says:

      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.

      • johnathan says:

        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. Joost Wilterdink says:

    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. R J says:

    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

    • kg4cyx says:

      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. Pat McLeod says:

    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.

  5. Dale VE3AAM says:

    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. Pat McLeod says:

    Any onw repairing these XW controllers?
    Have two that look perfect, just dead.

  7. 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).

    • kg4cyx says:

      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.

  8. 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.

  9. 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.

  10. Joost Wilterdink says:

    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.

    • kg4cyx says:

      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.

  11. melford says:


    • kg4cyx says:

      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.

    • Joon says:

      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.

  12. daniel says:

    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.

    • kg4cyx says:

      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.

    • Joon says:

      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?

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