MSPAE4440 Magnum 48V inverter faults under small load

Jogotta · July 2016

Hello,

New to the forum, new to inverted power. Here is my setup:
2300W Solar Panels running into Magnum PT-100 Charge controller to feed 8 6v Trojan T-105 (225AH) batteries which feed a 48v Magnum 4400W inverter. I have the remote control ARC as well.

Last night I completed the AC side of the wiring and hooked up my first 110 outlet.. so today I wanted to test what I expect my largest power sink to be.. my portable AC unit. I plug it in and it runs fine but the second the compressor tries to start the inverter faults and recycles power.

Specs on the AC: LG 12000btu portable AC, 1340W, 12 Amps
Now I know I won't be able to run this a lot but it should be able to start right?
Specs on the inverter are:

Trying the portable AC unit out on the inverter setup. Every time the compressor tries to come on .. the inverter faults and recycles.

it's a 4400W inverter. Specs are :

MS4448PAE

5 sec surge power (real watts) 8500

30 sec surge power (real watts) 6000

5 min surge power (real watts) 5400

30 min surge power (real watts) 4800

Continuous power output at 25° C 4000 VA (L-L) 4400 VA (L-L)

Maximum continuous input current 266 A 144 A

Waveform Pure Sine Wave Pure Sine Wave

Vic · July 2016

Hi Jogatta, Welcome to the Forum.

Your batteries need to be fully charged, or nearly so.

What size interconnections for the battery jumpers and inverter DC cables? Measure battery SGs with your Hydrometer, check cable connections, and retorque all electrical connections, and so on.

That A/C is a LAGRE load, with a very large surge. Your batteries are bordering on tiny. We run 10K BTU LG window A/C. It works fine, but, on a larger system.

Also, in general, if one can have balanced loads on the AC side of the system can help some issues. ie 240 VAC loads can be better than the same load (and twice the current) on 120 VAC.

Also the cable size on the AC output from the inverter is important. And, NO extension cords, even for temporary setups,

Just to try to help get you started. Vic

SolarMusher · July 2016

If your small battery bank was not fully charged, it maybe that your voltage dropped too much under the LBCO setting.
It's not really a Magnum fault but rather a protection to not discharge your batteries too deeply. Check your LBCO and lower it a bit in the 44V range.
Magnum recommends a minimum 400Ah battery bank with a PAE, if you need to run these loads it would be better to add another string of T105.
What are the length and diameter of your inverter cables?
A+
Erik

SolarMusher · July 2016

Jogotta said:

The batteries are fully charged 48v system has over 50v of charge right now. All of my wiring is 1/0 welding cable.. the distance between the battery bank and the inverter is 4' ..

1/0 is not large enough, a Magnum 4448PAE needs 2/0 minimum for 5-6 feet, usually I prefer to wire it with 4/0 for 10 feet and avoid heat and voltage drops.
50V doesn't mean that your batteries are full charged, you 'd better check your specific gravities.
Anyway, you're really too short on battery capacity if you want to run large loads at night. Add a T105 string...
A+
Erik

Vic · July 2016

Hi Jogotta,

Do you have a Hydrometer, to measure the actual SG of the batteries? As was noted by Erik, voltage is not a good indication of battery SOC. In your previous you mentioned that your battery voltage was "over 50 V", but it was not clear what charge stage the CC was in (we have no real clue just where on this Planet you are located). And depending on loads on the system, PV power available, and battery temperature, 50 V is a bit of an unknown, regarding battery SOC.

And, those interconnecting cables are a bit small. But, really, for an inverter rated to deliver over 4,000 watts, a 225Ah battery, with a L A R G E 120 VAC A/C as a load, you are starting behind the curve.

Just to restate what has already been said. Good Luck, and please let us know how you are doing.

Vic

Photowhit · July 2016

Jogotta said:

The batteries are fully charged 48v system has over 50v of charge right now. All of my wiring is 1/0 welding cable.. the distance between the battery bank and the inverter is 4' ..

Well a 48 volt battery bank at rest fully charged should be at 50.8 volts 50 volts represents about 80% charged. Roughly with out looking at a chart.

Photowhit · July 2016

Math, running the air conditioner, a 12 amp 120 volt load or lets us the lesser 1340 watts, must use the inverter which is @91% efficient, so the load at the batteries is 1340 x 110= 1475 watts. 1475 ÷ 50 volts = 29.5 amps. You have a 225 amp battery bank, you should expect a serious voltage drop drawing 13% of it's 20 hour rating. In effect these batteries act as @ 205 amp hour battery bank at a 8 hour rate, again with out checking.

Photowhit · July 2016

"...2/0 won't fit in the shunt for the battery monitor..."

Not sure what shunt you are using, all the ones I've seen have nice large bolts to bolt into on the top. here's mine, other heavy cable is going to the large breaker.

Not sure what breaker you are talking about when you say "...way too big. wouldn't fit in the breakers.. "

Midnite doesn't recommend using their Din Rail Breakers for inverters. Though I have in the past for small inverters. ...but 4400 watts ÷ 48 = 91amps, throw in some surge and you are above their single din rail breakers.

Photowhit · July 2016

Jogotta said:

Here is a reading AT the inverter, there is no voltage drop. What you're saying is I just spent $7000 building an off grid system that can't power a refrigerator without adding another quarter ton of batteries.

Well it should run a fridge. Doubt that large of an A/C for long.

I designed my system for a 3500-4000 watt inverter, that I haven't purchased yet. I have a 24 volt system since I had the battery from a previous system. I run a small window unit all the time. As in any good design, you need to look at the loads you intend to run and build a system around that.

Would you like to give us some idea about the loads you intend to run?

I would suggest with a pretty good size system, you invest in a few tools; A DC clamp meter, it can likely double as a good digital read out meter, note most clamp meters don't measure DC current.

Midnite imports a pretty neat simple to use hydrometer.

Photowhit · July 2016

Jogotta said:

NOTE: Adding another 600lbs of batteries isn't an option.

Is not using your $7000 investment an option?

Figure out what you need to run then look at what you need to do to run it.

If the sun was out and your batteries were at 50 volts while charging, they might well be at 50% State of Charge or less!

Photowhit · July 2016

Okay, I read your other thread in "Off Grid" and saw;

"...8 - 285W LG Panels wired in 4 parallel sets (To obtain the 48v input required for my charge controller)..."

http://www.lg.com/us/commercial/solar-panels/lg-LG285N1C-G3

...but you have a;

"...Magnum PT-100 Charge controller..."

http://www.magnum-dimensions.com/file/1751/download?token=w-_CgWQj

The Magnum Pt-100 is a MPPT type charge controller. So it needs some 'head room' above the voltage needed to charge your batteries. The Solar modules speced LG 285watt have a NOCT VMP of 28.9volts so 2 in series is 58.8 volts. This is not a high enough voltage to operate the charge controller efficiently if at all at some stages of charging.

See page 21 of the manual link above. Most MPPT type charge controllers work best at about 2x the battery bank voltage. So strings of 4, if the VOC will fit under the max VOC for cold temps in your area.

The Magnum PT-100 is a new Charge controller so some of the information is confusing, on page 71 it gives PV operating Voltage (This would be voltage from your array) = Voltage of Battery +8 volts... This would be voltage presented to the battery so if it's charging at 58.6 volts it needs 66.6 volts coming in from the array.

Photowhit · July 2016

Jogotta said:

My wire is bigger than what you're showing in this picture .. I am using 600Amp welding wire .. I'm using 100amp DC rated breakers

Likely that breaker is a lot bigger than you think, It's about 8 inches long, 250 amp breaker. That is 2/00 wire going to it and the shunt. Here is an over view. The pink wires are 6 gauge, I think the next smallest is 4 gauge. You are likely using little din rail breakers like those on the top left.

You could put a 4/0 cable on the panel mount breakers on the top right, an certainly on the large breaker on the left and on the shunt. In fact they are 90 or 100 amp breakers so I could max out the charge controllers.

Photowhit · July 2016

Jogotta said:

I checked all of the batteries .. each individual cell but one.. because the fuses for the connection are on one and I don't want to fool with removing the terminal connections in the dark.
2 batteries tested in the blue level meaning fair
1 battery tested in the red level
all the rest pegged the meter into green.

Does this mean the batteries are bad or does this mean I need to run an equalization charge?

Yes, With batteries that out of balance you would want to run an equalizing charge, but fix your array configuration first.

You can get a simple glass hydrometer at most auto part stores that you can read the Specific gravity (SG) for <$10. Midnite imports a nice simple one that is temperature corrected for $30 here;

http://www.solar-electric.com/midnite-solar-battery-hydrometer.html

zoneblue · July 2016

OP, your issues are something of a canary for your overall system design. The forum guys here are pretty good at giving (fairly gentle) second opinions, so suggest you put up a couple of pics so we can see what youve got going on.

The rule of thumb for inverters is that the rated capacity should not draw more than 0.2C from the battery. This works out as 100Ah of battery per 1kW of inverter at 48V. The purpose of this is to be able to provide the surge loading demands of an inverter that size.

The pics PW has put up are industry standard disconnect systems, so if yours look too much different, then chances are improvements can be made. Look at this as part of the fun, our system now looks quite a bit different than how it started out, almost completely due to wisdom gained from this forum.

You are going to need a better voltmeter. The difference in cell voltages is often 10s of millivolts, and having one that you are confident in being 0.5/0.1% accurate or better is what we call a good thing.

Again, PW is spot on about your array configuration. 2S 60 cell modules will not properly charge a 48V bank. The ideal for 60cell/48 is 3S, so you needed to buy an odd number of panels. (4S lifts the Voc quite high and will lead to more heat losses.) The reason is pretty simple , Vmp of 31.6V*2 is 63.2V. Most array home run cables will lose a few percent, the controller will lose a bit more, your breakers a bit more, your other cabling a bit more, then when the array gets hot the Vmp drops even further. End result: it will bulk fine, but controller will not hold absorb or EQ properly, unless its real cold.

For battery and inverter cables, we tend to use 'the fatter the better' sized cables (but not array cables). The reason is simple, they are short, thus cheap, and hundreds of amps at low voltages disappear fast in cable. Our system uses 50mm2, (1/0), and if they are short this can work good. In your case you have, about 0.1V drop with 4 foot http://www.calculator.net/voltage-drop-calculator.html?material=copper&wiresize=0.3224&voltage=48&phase=dc&noofconductor=1&distance=4&distanceunit=feet&amperes=108&x=34&y=10, which is actually ok. All the joints between the battery and the inverter should be crimped.

zoneblue · July 2016

Also your array to battery ratio is bit high for FLA.
= 2280W*0.77/48V/225Ah = 0.16C

0.1C is what youre aiming for there.

Doubling your battery to 450Ah, would give you a charge rate of 0.08C, and a discharge rate of 0.24C, so it will fix two problems. Of course ideally that inverter would use L16s.

SolarMusher · July 2016

Jogotta said:

I started with 4/0 .. it was too big .. way too big. wouldn't fit in the breakers.. I bought and tried everything down to 1/0, where does it say that it needs 2/0 minimum? If you look at voltage drop calculations.. running 1/0 for less than 4 feet is more than acceptable .. Let me go out and take a reading at the inverter for voltage.. be back in a minute

A 500A shunt is made to break a large negative line, in fact you could even connect up to two 4/0 wires on plate to this shunt for large 8kw inverter system. If you need to add a battery monitor to the shunt, just connect a negative bus to the load side of this shunt. Midnite sells a neg bus/plate that you can easily mount on the load side of the shunt to connect all your loads
Magnum speces 2/0 minimum for 5 feet, mounted with a 175A DC disconnect, they know what they are talking about they build it.
2/0 is not that expensive but you will know quickly that batteries are not cheap when it's time to change.
Look at closely to the pics below (right), there are two batt monitors in this Magnum system (WBjr plus BMK) with 2/0 wire/175A disconnect.
Read your manual and do it safe.
A+
Erik

Image: https://us.v-cdn.net/6024911/uploads/editor/du/u3nxuz6awi8b.jpg

Jogotta · July 2016

Photowhit said:

Okay, I read your other thread in "Off Grid" and saw;
"...8 - 285W LG Panels wired in 4 parallel sets (To obtain the 48v input required for my charge controller)..."
http://www.lg.com/us/commercial/solar-panels/lg-LG285N1C-G3
...but you have a;
"...Magnum PT-100 Charge controller..."
http://www.magnum-dimensions.com/file/1751/download?token=w-_CgWQj
The Magnum Pt-100 is a MPPT type charge controller. So it needs some 'head room' above the voltage needed to charge your batteries. The Solar modules speced LG 285watt have a NOCT VMP of 28.9volts so 2 in series is 58.8 volts. This is not a high enough voltage to operate the charge controller efficiently if at all at some stages of charging.
See page 21 of the manual link above. Most MPPT type charge controllers work best at about 2x the battery bank voltage. So strings of 4, if the VOC will fit under the max VOC for cold temps in your area.
The Magnum PT-100 is a new Charge controller so some of the information is confusing, on page 71 it gives PV operating Voltage (This would be voltage from your array) = Voltage of Battery +8 volts... This would be voltage presented to the battery so if it's charging at 58.6 volts it needs 66.6 volts coming in from the array.

You're wrong about the ability to power the charge controller.. HERE is a link to the spec sheet for my panels:http://www.lg.com/us/commercial/solar-panels/lg-LG285S1C-G4

vtmaps · July 2016

Jogotta said:
You're wrong about the ability to power the charge controller.. on a sunny day
.. Full sun I have 70vdc coming in from each set of two.. and there are

Depending on the state of your system, that 70 volts may mean nothing. Two of those panels in series can put out 78 volts when the cell temperature is 25° C. In order to know what that 70 volts means, I need to know how much power the panels are producing while at 70 volts.

The reason we recommend against trying to charge a 48 volt bank with two 60 cell panels in series is that under typical hot conditions, the Vmp of your two panels is less than 58 volts (as has been explained to you).

Perhaps you live in a cold climate... I get much higher voltages in the winter, but I also need to get the batteries equalized in the summer... therefore I have my 60 cell panels in strings of two for a 24 volt system. For a 48 volt system, I would put my panels in a string of three.

--vtMaps

Photowhit · July 2016

Jogotta said:

You're wrong about the ability to power the charge controller.. HERE is a link to the spec sheet for my panels:http://www.lg.com/us/commercial/solar-panels/lg-LG285S1C-G4

If you don't like mine read your own Dag gum link....

I went and found the NOCT (Normal Operating Cell Temperature) values, FROM YOUR LINK

MPP voltage (Vmpp) = 29.5 Volts

2 - 29.5 volt panels in series does not get you to 66 volts! or 8 volts over the charging voltage. In fact if you think this is a finite number of 8 volts over the charging voltage. YOur panels in series can produce 59 volts so 51 volts would be the maximum voltage when charging. This won't get you close.

You might also learn something from those trying to help you!

We don't need help, YOU DO!

If you know it all, don't ask! I didn't post all that for my health!

Dave Angelini · July 2016

They tend to be much nicer when you are billing them.........Sorry Happy 4th Photowhit

Photowhit · July 2016

Dave Angelini said:

They tend to be much nicer when you are billing them.........Sorry Happy 4th Photowhit

God Bless you! Have a Great 4th!

Jogotta · July 2016

Please don't start attacking me, if you only knew the HELL i have gone through to get this system built and the total ruin I am facing because it's worthless you'd not attack me. I am FRUSTRATED because I followed direction and built what I expected to be a good system and am now finding out that it's worthless for anything other than charging my cell phone. ALL of the decisions I have made were from another forum.. so to come here and ask for help and have you tell me that all of it is garbage .. I am ready to blow my fucking brains out right now. So please.. don't attack me. Or make jokes.

Jogotta · July 2016

Or go ahead.. attack away .. if it makes you feel good .. or superior .. or gives you a chuckle.. go for it...

vtmaps · July 2016

Jogotta said:

built what I expected to be a good system and am now finding out that it's worthless for anything other than charging my cell phone.

It is by no means worthless. The panels need to be reconfigured. Some cables need replacement. Show us some pictures of your setup... I'm not sure exactly what you've got for breakers, bus bars, etc.

--vtMaps

Photowhit · July 2016

I actually felt attacked myself, I'm still wanting to help! It's the reason I did those search's and follow up.

Dave is a professional and does charge for his services, but is kind enough to help out people here as well, Gratis! Consider his remark a confirmation, that I'm not lying to you.

I'll let you do the research, look at the Pt-100 specs and see what the maximum VOC is. Then find the VOC of the panels and multiply x4 and see if you can use strings of 4 panels. This will be the simplest way to get you charging properly. If it's under by a close amount say 15% you will want to check to see what the coldest temperatures are in your area, to see if the VOC will rise enough above the rated VOC to create a danger for your system. Likely you can hook them up this way at least temporarily during the summer to gt your batteries charged!

I'm sorry about other forums, I've spent too many hours correcting "SunGOD" to try to play nice with him any more.

I suspect that there is no reason your system would not work for a fridge and likely a small A/C at least when you are in float or sunny days, You likely won't want to run it continuously over night certainly on Multiple cloudy days. Think of your inverter as a 200 watt inverter, at least for the time being.

I was heating water too late on Friday and have had minimal charging all weekend, but 6" of much needed rain. My battery is currently at 50% SOC and I'm just running a fridge and a few things around the house, throw in a couple loads of laundry and ... I need to be careful for the next 24 hours or so... It should be sunny tomorrow! All systems have limites, it's easier when you've had to live within the constraints of a system, rather than having them forced on you, not knowing what to expect.

Most of your issues appear to stem from your batteries not being completely charged. Your system is not small, but if you hope to run the large A/C I think you are out of luck.

animatt · July 2016

I have a similiar setup except a smaller solar array.
I have magnum 48v inverter as well as their 100 amp charger. And if I remember correctly 235ah battery bank [crown]

I have successfully used it with air conditioners, 1hp well pump, 7 inch angle grinder, smalls jack hammer.
All with fairly decent sucess. What really helps in my case is system is used almost exclusively during the day.

This way solar array greatly helped increase run times . I do have a backup generator. Actually 2
A small one and a large one. Small 3500 watt champion generator is the main battery charging generator. The 7500ish watt Honda engine generator is to run the really demanding items.

System will upgrade to more solar and more batteries but probably not until I start living there and needing night time power.

Main point is you should be able to get your system working for you. Just keep at it. Rules of thumb are very helpful starting point. But you can venture fairly far from them if you understand principles and willing to make tradeoffs /live with system strengths and weaknesses.

Last note. I do have 4/0 inter connects. Bigger the better.
If having problem fiting wire into a connection you can just cut a few wire strands of copper off the last inch of your cable. This way your think cable can enter tight terminals. And still have the benefit of large cables.

Matthew wright

SolarMusher · July 2016

Jogotta said:

Please don't start attacking me, if you only knew the HELL i have gone through to get this system built and the total ruin I am facing because it's worthless you'd not attack me. I am FRUSTRATED because I followed direction and built what I expected to be a good system and am now finding out that it's worthless for anything other than charging my cell phone. ALL of the decisions I have made were from another forum.. so to come here and ask for help and have you tell me that all of it is garbage .. I am ready to blow my fucking brains out right now. So please.. don't attack me. Or make jokes.

All the advices which were given in this thread are excellent and Photowhit is absolutely right in all he said.
Your system is not garbage but really needs to be reconfigured and improved as Vtmap said.
Magnum PAE are built strong and I'm pretty sure that their PT controllers when used in a PAE system are very good too.
There's no reason for you to feel attacked, just take a breath and do it right. All you need to know is already in this thread.
Take the time to read.
A+
Erik

Thom · July 2016

Your system will work fine . Reconfigure the panels and get the batteries charged up. I have always bin given great advice from the volunteers at this website.

zoneblue · July 2016

Jogotta said:

You're wrong about the ability to power the charge controller.. HERE is a link to the spec sheet for my panels: http://www.lg.com/us/commercial/solar-panels/lg-LG285S1C-G4

So, 60 cell panels, with a Vmp of 32.3V.

Please don't start attacking me, if you only knew the HELL i have gone through to get this system built and the total ruin I am facing because it's worthless you'd not attack me.

Solving your problem will involve listening.

I am FRUSTRATED because I followed direction and built what I expected to be a good system and am now finding out that it's worthless ... So please.. don't attack me. Or make jokes.

And learning. I was really surprised at how involved building your own system is. It requires a commitment to take on the level of research.,i found i needed to do. Without that your vulnerable to whichever salesman comes your way. Persevere mate, youll get there.

Photowhit · July 2016

I went on a little hunt, and it would appear "Jogotta" is installing this system on a bus. I suspect that it the reason for the level of frustration. The added weight is a non-starter. I think the hope was to A/C when boon docking, but I don't want to speak in Jogotta's stead. It's likely, a smaller A/C could be run during the day. The system is large enough to run a small window unit over night or at least long enough for sleeping, particularly if there will be sun the following day. Though I'd suggest partitioning off an area of the bus for this, there will be little or no insultation so a long "Duty cycle".

Hope Jogotta will allow us to help! Once the fireworks are over!

Photowhit · July 2016

I went back and checked and the Magnum PT-100 is rated for 200 volts + battery bank voltage or 240 volts max.

Your panels have a VOC of 39 volts, so you should be able to connect in strings of 4 with no fear, even in winter.

This would be a quick way to correct the panel configuration, just unplug and reconnect, You do have a pretty good gap between a couple pairs of your panels, so you might need a small connector, but just one wire. You should be able to take a volt meter and check the wires going to your power center for continuity and just leave the other wire there.

In the winter time you have an operating voltage limit of 187 volts, so on very cold mornings you might not start charging until the solar panels warm up.

MSPAE4440 Magnum 48V inverter faults under small load

Comments

Categories