Hi All,
New here, and have a question about my new system. Xantrex XW 4548-grid tied with 14 Canadian Solar, 250w panels, output around 60 volts at 56 amps. Using Midnite Solar XW E-Panel with all MS breakers and GFI. Solar charge controller is a Xantrex MPPT 60-150 with a 60 amp max output.
The problem is that about mid day when things really get hopping, The output on the charge controller shows to be about 51 volts and 30 amps, and the 63 amp MS breaker gets hot to the touch and trips. The input breaker to the controller from the PV is the same 63 amp unit and stays cool and never trips. Driving me nuts.
Any thoughts?
Hi Emerald .,
The first thing to check is that the screws on the popping breaker are TIGHT. A poor connection will cause heating at these connection points. In time, this heating will make the breaker more prone to pop as the current through it increases.
The second thought is that if the cable that connects the CC to the breaker and/or the cable on the output of this breaker, connecting to the battery is too small gauge, its heating 'might' cause the breaker to pop.
Just a couple of things to check. Vic
QUESTION
You do have the negatives isolated right? So the PV negative goes straight to the XW? I ask because they use the negatives to measure current.
Keep in mind that 14 panels at 250 watts is 3500 watts and at say 48v that is 73 amps. The XW does not current limit real well so it will over shoot the breaker size. I would wire it for an 80 amp breaker. But I would also make sure the PV- is direct to the XW controller so it can measure current properly
Hey Vic,
The connections have been re-torqued and are tight. The manual called for #6 wire, but I used #4 instead. The infrared thermometer says the outside of the breaker is at about 135 degs f when it trips. I also swapped the MNEPV63 used for the input to the output position and had the same results. Both breakers are new.
Hey Halfcrazy,
The negatives run from the panels to a MS Disco combiner then directly to the PV negative bussbar in the MS E-Panel. From there it goes directly to the XW controller. The only other connection to the PV negative bussbar is the negative from a MS DC Lightning Protector.
Do you have a clamp on amp meter? I suspect the XW is not telling the truth on Amperage and it is actually more like 65 amps
Wait you say you are using a midnite solar GFI?? This is not on the PV side of the XW is it?
Hey Half crazy,
I don't have a DC ammeter at the moment, just an AC. I ordered a DC clamp on meter a couple of days ago and will have it Monday. I suspect the same thing, that the XW controller is lying to me. But why?
About the Midnite Solar GFI. Yes, it is on the input side of the PV. The MS instructions said it did not matter which side it was installed on. Is this incorrect? I did a test by taking the GFI out of circuit completely and jumping the input breaker directly to the XW controller. Had the same results with the breaker heating.
Why should the GFI be on the controller side of the breaker?
I am not sure what to say other than the amount of PV you have is capable of more than 63 amps. You swapped the breakers did the problem stay with the breaker or with the location (IE battery Side)?
Quote from: Emerald Power on March 13, 2014, 12:40:19 PM
I did a test by taking the GFI out of circuit completely and jumping the input breaker directly to the XW controller. Had the same results with the breaker heating.
When you disconnected the GFI, did you disconnect the small breaker that is ganged to the 63 amp breaker? Where am I going with this... I'm wondering if the small breaker (1 amp or less) part of the GFI is bonding your PV negative to ground.
--vtMaps
Hi Emerald Power,
Thanks for the added info.
Ryan, thanks for reminding me about the XW SCC's required PV negative wiring. AND, I had not considered that tying the bat and PV neg together away from the CC could cause the SCC to output excessive current.
Vic
Hey Halfcrazy,
It is a puzzler. This unit is grid tied and the output on the inverter display is reading only about 2.7kw when the breaker pops. The local load in only another 300 watts or so. So I am far below overloading the unit with input. After swapping the breakers, the problem remained with the battery side, input from the XW controller.
I know there is something amiss, because there is 800 watts difference in the readings between the watt displays on the controller and the inverter. The inverter being the higher of the two. You can't get something for nothing.
Hey vtMaps,
I did completely isolate the MS GFI, disconnecting all of it's wires. The XW controller has it's own GFI which uses a jumper and pins to disable or enable. This XW GFI uses a standard 1amp fuse that is not resettable, hence the reason I went for the MS units.
Quote from: Emerald Power on March 13, 2014, 05:52:22 PM
Hey Halfcrazy,
It is a puzzler. This unit is grid tied and the output on the inverter display is reading only about 2.7kw when the breaker pops. The local load in only another 300 watts or so. So I am far below overloading the unit with input. After swapping the breakers, the problem remained with the battery side, input from the XW controller.
I know there is something amiss, because there is 800 watts difference in the readings between the watt displays on the controller and the inverter. The inverter being the higher of the two. You can't get something for nothing.
Yes thats about what I would expect is 3000 to 3200 watts and that coupled with the fact the XW does not current limit well would explain it to me. I would swap to an 80 amp breaker if ti where me.
Ryan
Hey Ryan,
Could you explain to me more about current limiting. The XW has a manual setting for limiting the current, and I can set it at 60% and it will put out about 2400 watts (as reported on the inverter display) , all day long and not trip the breaker. If I adjust it up to 65% it will eventually heat up the breaker to about 120 degs and it will trip. Isn't a MS MNEPV63 supposed to be rated at 63amps continously? I don't think I am anywhere near that, but won't know for sure until I get my new meter on Monday.
The XW inverter has a percentage setting. I thought the XW charge controller had a numerical setting up to 60 amps?
I guess I need to back up and ask questions?
Is the breaker in question between a XW charge controller and the battery?
When you swapped the tripping breaker for another breaker did the new breaker trip?
You are not using this breaker on the Inverter in any way are you?
Hey Ryan,
I see you know your stuff. The XW controller does display amps, but I am using the optional remote system monitor which displays percentage of capacity. In this case that's 60 amps.
The breaker in question is between the XW controller and the battery.
I have tried 3 brand new MNEPV63 breakers on this problem. The all get warm and trip. BTW, I understand the polarity of these type of breakers and the + side, or bottom connection is connected to the battery buss bar. The - side or top of the breaker is connected to the output of the controller. This is the way that the instructions stated to connect the "most positive" side to the battery.
I am not using this breaker for any purpose other than what is intended, that is, protection between the output of the XW controller and the + battery buss bar on the MS XW E-Panel.
QuoteI have tried 3 brand new MNEPV63 breakers on this problem. The all get warm and trip.
Thus, your problem lies elsewhere!
Also the % adjustment is for the inverter. I need to go plug my XW charge controller in but it has a number you set. The XW inverter has a % you set. It is a 100 amp charger and 60% of that is 60 amps but that's from the inverter not the charge controller. 2 separate items
If you have tried 3 different breakers than the issue is 99% for sure what I told you. The charge controller for some reason is not showing the current correctly and the breaker is to small. So I would
A- change to an 80 amp breaker simply because the 63 is to small mathematically
B- get a clamp on DC amp meter and verify the amperage
C- call Schneider after A and B are done and ask them why the amperage is reading half or so
Hey Ryan,
The XW system remote display can control the functions of the XW controller or the inverter. When the controller is selected, the percent value on the remote mimics the actual amp value on the controller's LCD screen. If you change one, the other will follow suit.
A. Can I use the two 63 amp breakers I have and build a parallel type breaker as the MNEPV80 is, or would that be overkill for my #4 wire.
B. DC Clamp on meter is ordered and will be here Monday.
C.Have already been in touch with Schneider/Xantrex and a tech fellow as reviewed all my info but has yet to come up with a solution. He has also suggested I buy the clamp on DC meter to verify the output before he can send out a replacement unit.
Emerald Power,
Personally, would avoid paralleling two of the 63 A breakers. As I read the tables, #4 AWG cable has an Ampacity of about 85 Amps (at 75 F). So, this cable might be stressed in the event of a catastrophic event.
And, I know nothing about just how the breakers are selected when CBI makes breakers that are paralleled for double Ampacity, but, perhaps they are selected for very close curves ... dunno.
Just my $0.0001, FWIW, Vic
Yes #4 in free space is good for over 100 amps but the pair of 63 amp breakers wold land you a 126 amp breaker. This is more than I would recommend. Schneider recommends an 80 amp breaker.
Hey Guys,
Thanks for the input. I have ordered the 80 amp breaker and will let you how it goes.
Hey Ryan and others,
Today my new clamp on DC ammeter arrived and I checked the output from the XW controller to the battery buss bar. It reported 53.1 amps on the new meter and the XW's display reported 32.3. Wow, over 20 amps more being delivered that what it says! This accounts for the ability to blow the MNEPV63 breaker way more easily than one might think. So Xantrex will replace my controller under warranty.
Now on to the breaker. I have the manual current limiter the XW controller set so the breaker is not blowing, but it is getting fairly warm to the touch. The infrared thermometer says 118 degs. Anymore than this and it will trip. So that would be around 54 amps when the MNEPV63 trips. Midnite Solar says all of their breakers are rated for full labeled amps continious duty, as opposed to thermal breakers that must be de-rated by 20%, so I should be able to put 60 amps through this. I have tried 3 new breakers, and they all trip around 54 amps. I am now thinking that Midnite Solar lies about their breaker ratings. Am I missing something here?
I have ordered a new MNEPV80, but this ordeal has cost me some bucks that could have been avoided.
EP
Well I can say we do not LIE about our breakers and I am so positive about that I am willing to personally pay shipping both ways and get those 3 back to test myself.
My real suspicion is the Clamp on is not spot on as well. Does it show absolute 0 before installing it? Then try this take the wire and loop it around and run it through the meter 2 times and see what it measures. Some DC clamp meters are not extremely accurate.
I would be more worried about the fact the XW is reading so Wrong.
Ryan
Hey Ryan,
I appologise for being so blunt. I didn't realize you were part of the company. I am just frustrated that I keep spending money for something that seems so simple.
I just tried your suggestion and made a loop of #4 wire and ran 2 wires through the inductive pick up of the meter and this just doubled the amp reading. At the moment it was reading 49 amps on a single wire and it doubled to 98 with the additional loop. The meter I bought has a zero function button, so it was at zero before the test.
I would be happy for you to test 2 of my MNEPV63 breakers after I install the new 80 amp model. I need to keep one because that is the PV input to the XW controller and it is working fine.
Kind Regards,
EP Tom
Hey Ryan,
My new meter is a Craftsman model 82369. While reading through the owners manual and specs, it states the accuracy is +or- 2.5% while reading 0 to 300 ADC. At 50 amps this is only about 1.25 amps if it is at the far end of the inaccuracy range. My MNEPV63's are tripping at 54 ADC as read on the meter, so I kind of doubt the meter is that far off. Just trying to get to the bottom of things. Your help and suggestions are greatly appreciated.
Kind Regards, EP
Quote from: Emerald Power on March 18, 2014, 06:15:57 PM
I have ordered a new MNEPV80, but this ordeal has cost me some bucks that could have been avoided.
It would have been avoided if you designed and specced the breaker correctly in the first place!
Still lesson learnt, good old clampmeter is an essential part of your kit. Keep it handy.
BTW clampmeters are funny things. Try this:
positive lead, one way, then facing the other way.
negative lead, ditto.
Four diff readings, yippee. To get the best reading (at least according to my ones manual)
- measure on the positve lead, with the positive side of the meter should facing bat pos. wire positioned at the mark point, as far from other wires and magnetic objects. delta 0 just before you start each reading.
And using it right near a water pump or other motor will give you real whacky results!
Emerald,
And, with these inexpensive DC Clamp meters, zero is quite the moving target. Zero the meter, and note if it is really zero. Then, open the jaws and close them ... is it still zero?
Also, they are sensitive to radiated noise, and to external fields, as zoneblue mentioned.
Regarding breakers that you mentioned, have you looked at any ambient temperature de-rating? These are NOT Thermal breakers, but there still may be a de-rate for ambient temp. BTW, what IS the ambient temp in the area where the breakers are operating?
Will look for curves for these breakers ... But as also mentioned the 80 A breaker really IS called for.
EDIT, and since you appear to have a IR Thermometer, have you measured the temperature of each of the Lugs on this breaker? The thermometer may not have a small enough spot size to really see the connection screw, or the contact foot (shoe?).
In looking at the breaker spec, the temperature noted, was 30 C, FWIW
Vic
Hi zoneblue,
This appears to be beyond my comprehension. I admit I am a bit slow. I have a controller that has a 60 amp max output, but I screwed up and only used a 63 amp breaker and should have used an 80 amp breaker to start with. Do I have this right?
EP
Emerald,
I am not a real Code expert, however, in looking at the XW SCC manual -- 975-0400-01-01, dtd 3/09 Rev B, the following is stated, regarding Output circuit breaker size,
... " Battery Circuit
The NEC requires the battery circuit to be protected with a device rated for 125%
of the rating of the circuit. The DC-rated fuse or circuit breaker between the
battery and the XW SCC must be rated for 1.25 × 60 A (the maximum current
rating of the XW SCC) ... "
Also noted in this manual is the statement that the maximum wire size is #6 AWG.
So, seems that they are saying that they believe that a 75 Amp CB would be needed.
All FWIW, Vic
Yeah i know, i know 60 amp breaker on a 60 amp controller sounds reasonable but heres why sometimes reasonable isnt reasonable:
- you have 3500Wp into a 60A controller at 48V nom. Thats 72 Amps give or take.
- on cold clear days that could go another 20% higher, so 88amps.
- the way mppt controllers work is that they do timed sweeps and in between those sweeps some quite biggish surges are able to pass through the controller in some cases.
- And; the din rail breakers are polarised, which means that they can only be fitted in one direction.
- when fitted to a CC, they are in "backwards", positive to the battery, negative to the CC.
- this is so that in the worst case scenario, (CC blows), the battery is more positive
- if in your case you blew it by over powering the CC with your PV, so the CC is more positive, and thats not a good way to trip those breakers.
- even though they say load rated, doesnt mean i would run one at load for long periods
- with your overpanelled setup, you WILL be running that controller hard for long periods (make sure you have plenty of airflow around it.
- maybe even consider adding a computer fan if your ambient is over 25*C.
- make sure to retorque the breakers one hour after you install them. Running 60A through a loose connection will make it heat up mighty quick, and mighty hot.
Anyway youre doing the right thing, the panel mount breakers are not polarised, have better fittings, and 80A should see you right.
Quote from: Emerald Power on March 18, 2014, 11:53:30 PM
This appears to be beyond my comprehension. I admit I am a bit slow. I have a controller that has a 60 amp max output, but I screwed up and only used a 63 amp breaker and should have used an 80 amp breaker to start with. Do I have this right?
I'm no expert on breakers but I sort of agree with the logic that a 63A breaker should be good for a circuit that moves 60A. Despite the NEC requirement for larger breaker the logic of 60amps through a 63A breaker works for me.
I also seem to remember that the KID manual said something about 30A breakers since the maximum battery current it can produce is 30 amps. Nothing about a larger breaker being required
Then again when I look at the Carling surface mounted breakers used by MN and Outback they specify an FL current which is the breaker rated current, eg 30A I'm not sure what FL means - Full Load?
Then there is a Trip current specified, in the case of 30A breaker this is 37.5A
So does this mean the 30A breaker is intended for continuous full load of 30A but will not open until the Trip current of 37.5A is reached.
Same for the DIN CDi breakers made in Lesotho, I'm looking at a 50A one with Trip current 65A.
So back to the 63A breaker, does it open at 63A or is 63A the max load rating? and does it open at a higher Trip current?
Maybe a breaker guru can explain this?
And does it mean the 100A breaker I use between my Classic 150 and battery bank is sufficient? Would that fail NEC requirements and I would need a 120A breaker?
dgd
In reality the breaker is to small. The Schneider regulates very slow and is capable of over 80 amps output. I have seen this personally. I would never install a XW 60 amp controller with less than a 80 amp breaker.
You see it all boils down to how fast the controller can regulate that 60 amps. Some are a LOT faster than others. I have no idea why the meter reads 53 and the breaker trips but in my mind its a non issue as the Charge controller or something is massively wrong.
Install the 80 amp breaker and a new charge controller and lets see what happens.
I do know I run our breakers continuous from time to time and have no issues so I am wondering if the ripple from a single cylinder charge controller is introducing an issue with the amp meter?
Simple Math tells us it should be closer to 70 amps not 50 so I am still suspect of the meter.
Ryan
Hey dgd,
I am looking at one of my extra 63 amp breakers and it states max volts is 125 but MNS has relabled it for 150 vdc. The trip amps are marked 81.9. It also says "polarity sensitive do not reverse feed". Maybe ratings are different in Africa than they are here.
EP
Hey zoneblue,
I wanted to thank you for your wordy explanation.
EP
Emerald,
MidNite has had these breakers ETL ( I believe it was ETL) Tested for 150 VDC, when used in a MidNite box, IIRC. So they ARE good for 150 VDC.
Know that you have ordered an 80 A breaker ... Personally would not dwell on this issue too much, until you get the new breaker and replacement CC. FWIW, Vic
No worries! Too bad you dont have a classic, you wouldnt have had those problems... and, you would be able to harvest all of your array output!
Quote from: Emerald Power on March 19, 2014, 12:47:05 PM
Hey zoneblue,
I wanted to thank you for your wordy explanation.
EP
Hey Ryan , Vic, All,
Thanks for all of your input. It has made me research and learn much about my system. Schneider/Xantrex has agreed to replace the controller under warranty. When it and the new breaker are all in place, I will report back here with the results.
Kind Regards, EP
hopefully it is not a repaired unit... ::)
Hey All,
Just thought I would send in an update for my controller problem.
Xantrex sent me a brand new XW MPPT60-150 controller and I installed it with the new MN 80 amp breaker and all is well. Appearenty, the controller was delivering about 30 percent more amps than it was reporting. There were also spikes that would trip the 63 amp breaker. The new unit delivers a nice constant amperage that I think would work with a 63 amp breaker, but since I have the 80, I will continue to use it. Output ramps right up to 60 and stays there. I also measured this at the battery output wire with the new clamp on ammeter, and they are within .1 of each other. Very satisfied now with my system.
Thanks for all of your input. Really made me dig into how this system works.
Kind Regards, EP