Need assistance from Schneider/Xantrex experts: MPPT80 issues

creosote · October 2020

Greetings,
I have an XW6048 Inverter with two CC's (MPPT60 & MPPT80) and Combox setup in a hybrid system. I recently discovered that my MPPT 80 is not sending voltage to my battery bank. I've checked the incoming lines from the PV array at the bottom of the MPPT80 and I've seeing almost 400 volts, but on the Combox it's reading only around 8v. The smaller MPPT60 array is working fine with no issues.

I've rebooted the MPPT80, did Factory Reset & finally upgraded the firmware (per suggestion of Schneider tech support). But none of this made any difference.. still not get any power from the pv array into my battery bank. No matter what it continues to show the "Charger Enabled" status as: Disabled (see below)

I haven't been able to try and contact Schneider again since they make it very difficult to contact them if you aren't a solar contractor.
Hoping that others on this forum may have experienced this and might know what the issue could be. I'd be very grateful for any help
or suggestions.

Cheers.

Image: https://us.v-cdn.net/6024911/uploads/editor/ll/kgbyqc1h2ff9.png

Dave Angelini · October 2020

You should be seeing array voltage in system. Did you measure it around noon? This may be why tech support stopped with you, if they did. This is really an installer issue, did you install it? You can always start a new product support request. This is long out of warranty.

Things I would try are, remove combox from the network and try with the SCP to enable the charger. It should be enabled.

Do you have surge protection? If there is (good) array voltage with an external voltmeter then you may have a damaged mppt. More below.

This can be tough for you to test as you need at least 200 vdc to test the mppt. You also need to verify the 400v array really is good. The 400v may not be a true indication of good, Can it supply current? and is the wire run to mppt is good? You need to load this 400vdc somehow. Easy for me to say as I have a spare. Maybe others can think of a way to load 400vdc, safely!

The wire run could be damaged and breaking down from rodents or connections. I have to go for a day or so. Where are you?
Bad time of year to lose an array ! Good Luck !

BB. · October 2020

Original poster is probably around Daytona Beach FL area...

To load a 400 volt array--I would start with 4x 120 VAC filament lamps in series (whatever you can find wattage wise--Don't use LED/CFL or other electronic lamps).

There are voltmeters that have an internal resistor loading option (600 Volt max input for LoZ):

https://www.amazon.com/gp/product/B019CY4FB4

Low Impedance / LoZ mode... Won't draw much current--But usually enough to show that it was not a "static elecric" or other leakage current...

-Bill

creosote · October 2020

Hi Dave/BB,
Thanks for the replies.. Just to clarify, I was using my Fluke meter to test the voltage coming in from the PV array. I used the Fluke probes to measure at the bottom of the MPPT80 where the Pos/Neg cables come in. I didn't even think about that voltage being too high for the meter, but the Fluke seemed to handle it with no issues. I'm located in central FL and tested around mid day. I installed this 2nd PV array about 5 years ago and it's been working fine since, just stopped all of a sudden.
Also, I do have Surge protectors installed.

The Schneider tech just said that sometimes the MPPT80's will need to be reset or upgraded if they are not handling the voltage correctly. He said to try those things and it should resolve the problem, if not try to call them back.

If I'm testing the voltage directly where the PV cables come into the MPPT80 doesn't that show everything (wiring, panels, fuses, etc) is all good up to that point? I'm getting around 360-380 volts showing on the Fluke depending on the sun.

When you talk about "Need to Load this 400vdc somehow" ... Are you saying it's not good to have the panels producing that
much energy and no where to send it?

Also, it is possible the MPPT80 is just broken? I really hope not, but not sure how to test.

Appreciate the help!

thanks,

mike95490 · October 2020

But that meter reading has no load.

Do what Bill says ( I'd use 75 watt bulbs):
> To load a 400 volt array--I would start with 4x 120 VAC filament lamps in series
> (whatever you can find wattage wise--Don't use LED/CFL or other electronic lamps).

(edit to correct bulbs to 75watt)

BB. · October 2020

I think Mike means 75 Watt bulbs (not 75V)... Whatever filament type bulb you can find (getting difficult to find any higher wattage filament bulbs these days).

-Bill

PS: 3x 120 VAC = 360 VAC--So 3 in series would work OK with the 368 VDC open circuit voltage you measured.

creosote · October 2020

Ok.. 75W bulbs makes more sense..... I was searching everywhere for 75v bulbs?? I'd never heard of them before.

I'm still a bit confused though.. So I need to try and put 3 lightbulb sockets (120v) in Series to achieve a 360v total. Then put
75w bulbs in each socket and try to wire it up to my incoming PV array Positve/Neg cables? If the bulbs all light up then
we are getting current/load from the PV array and know it's good?

Any additional info or how to test would be appreciated..

mcgivor · October 2020

The image in post 1 shows the device status, have you gone into settings and attempted to toggle it it enable then update?

creosote · October 2020

mcgivor said:

The image in post 1 shows the device status, have you gone into settings and attempted to toggle it it enable then update?

I can't find any place in the settings that allows you to toggle that setting (Charger Enabled). It seems like that's determined
based on other dependencies. If anyone knows where that setting is please let me know.

BB. · October 2020

The bulbs provide a (relatively heavy) load vs the typical DMM which draws only 0.00000001 of an amp or so....

They just draw enough current (~0.5 Amps or so) to ensure that there are "solid" electrical connections all the way from the panels to the solar charger's array input terminals. If there is a poor electrical connection somewhere, you will probably see the voltage drop to near zero with the lamps/load resistors connected.

Not specifically needing to see the bulbs light--They are just a quick, cheap, and dirty set of load resistors. Although, in this case, yes I would expect them to light (or glow) and measure around 300 Volts with a DMM (assuming 368 Volts is Voc, and Vmp is closer to ~300 volts and you have "enough sun").

-Bill

mcgivor · October 2020

On the Combox display there are drop down menus on the left of the devices, this will lead to devise settings where the controller can be toggled to enable, you will need to update after the selection, be careful not to read the current settings
P.S. I'm going on,memory, if you have trouble I'm willing to log on to my system and provide more details, I don't do this on a regular basis, but am willing to help the best I can.

Dave Angelini · October 2020

The second thing I asked the OP was to do this BTW. However, the wrong voltage is on the array input on his screen. The 400v voltage should be there no matter if the charger is enabled or not. This is not a sign that there is much hope for the mppt.

Since it now sounds to me like this could be a user issue, he should make sure the solar disco is off, make sure the battery connection disco is off to mppt. Let the unit sit with zero power for an hour. Then repower. Schneider probably told him to do this but I always question this as people forget to shut down the array and the unit may not clear the slate and repower from non volatile memory.

I also asked about surge protection and would be nice to know what make SPD and where it is installed.

creosote · October 2020

Hi Dave, I tried powering off the Combox and using just the SCP to adjust the settings. When I navigate through the MPPT80 settings I can not find any place to "Enable or Disable" the Charger.. There's an option to set "Operating or Standby" mode but that's all I can find. The Schnieder tech never mentioned anything about disconnecting all power to the MPPT80 and letting it sit for an hour to clear the nvram. I just tried this and will test again in an hour..

Also, I have a Delta Lightning arrestor installed on my system (at the incoming fuse box next to inverter) but that was already installed when I bought the house so not exactly sure how it's connected.

It is common that these MPPT's just die or stop working? That's my biggest fear at this point.

Thanks,

Dave Angelini · October 2020

The setting is called operating on the SCP in mode on mppt-80. If you change it to standby, it will disable the charger.

I have installed over 200 of these and it is very rare that they fail. In places like Florida, the lightning capital, you need active surge protection. This is indicated by an LED to inform you that it is operating. The unit you have is a poor choice. Midnite makes an excellent SPD and they sell them in the store here. I asked as if it was operating and you saw the blue led, it would indicate that the array was working to some extent.

Buy another one if it still is dead. Chalk it up to the cost of doing business and improve it for next time. There is alot more you can do, and you need to in that part of the world. Disconnect the hi voltage when strikes can be heard and use an AM radio or detector if you are home. The SPD in your area is for insurance when you are not home

I have a client there who came home and said the blue led was not on and he could only find the metal nut that help the SPD. Everything else was gone.

Need assistance from Schneider/Xantrex experts: MPPT80 issues

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