Xantrex SW Plus 5548 problem. any ideas?

6bicks
6bicks Registered Users Posts: 7 ✭
in Advanced Solar Electric Technical Forum #1
First off, new to solar living and off grid.

I have enough knowledge to know what I am doing hooking things up and how they operate.

I purchased a refurbished SW plus 5548 from Tekris to power my home. They have tried to help me but the only solution they can come up with is to replace the unit. Problem is, I live off grid, it is in Montana, winter time and I have no back up or money to replace the unit.


The problem is, it reads DC voltages erratically. It shows a six volt or so swing/flash on the ICM display. This causes the lights to flicker as it is trying to adjust for varying voltage. I have used my MM to check that my DC voltage is steady. I have tried different things with Tekris( resetting, powering down etc..)
It will even read erratic temps on the Batt temp sensor.

It seems to be getting a dirty reading somewhere and I really need to figure it out.

Looking for any ideas
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Comments

  • NorthGuy
    NorthGuy Solar Expert Posts: 1,913 ✭✭
    #2
    Re: Xantrex SW Plus 5548 problem. any ideas?

    I assume the voltage is not varying too fast for your voltmeter to detect variations.

    Start by measuring the at battery terminals, then move to inverter terminals, then inside the inverter as the wires go (be careful with that). If you find a varying voltage at some point, you have just passed the problem point. Could be a bad contact or some failing part.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #3
    Re: Xantrex SW Plus 5548 problem. any ideas?

    Welcome to the forum.

    DC Voltage tends to be very stable, especially under load. A 6 Volt swing on a 48 Volt system is unlikely without some highly noticeable wiring problems.

    Unfortunately it sounds like your refurbished inverter is defective, and no amount of investigation of the rest of the system will change that. These are not user-friendly for service. It needs to be replaced. Let me guess; one day out of warranty this started? The company that sold it should step up to the plate here and exchange it. That is not to say they will.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,631 admin
    #4
    Re: Xantrex SW Plus 5548 problem. any ideas?

    One other question--Have you used a good volt meter to monitor the battery bus voltage on the input of the AC inverter? We are talking about some pretty heavy currents and too small of cable, too long of cables, poor connection somewhere, bad or too small battery bank, etc. can all create the apparent issue you are seeing too--Even if the inverter is running perfectly.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • 6bicks
    6bicks Registered Users Posts: 7 ✭
    #5
    Re: Xantrex SW Plus 5548 problem. any ideas?

    Tekris will warranty the inverter, however, they do not have another one of these units and I need an additional $1K for a replacement, and the house build has tapped me.
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  • 6bicks
    6bicks Registered Users Posts: 7 ✭
    #6
    Re: Xantrex SW Plus 5548 problem. any ideas?

    6 foot 2/0 cable with soldered ends. Very light load on the inverter with a small fridge being the only real demand.
    I have a good meter and see no changes in DC voltage going into the inverter at any point in the system. Next step will be to check internals at varying points as has been suggested.
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  • SkiDoo55
    SkiDoo55 Solar Expert Posts: 414 ✭✭✭
    #7
    Re: Xantrex SW Plus 5548 problem. any ideas?

    Where your ends crimped before being soldered?
    may want to inspect them for cold joint or high resistance across joint.
    Inverter may still have failed but something to inspect.
    GT3.8 w/4600W Trina 230W, TX5000 w/5000W ET-250W, XW4024 w/1500W ET-250W, 4 L16, 5500W Gen. (never had to use) Yet!!
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #8
    Re: Xantrex SW Plus 5548 problem. any ideas?

    I could have sworn the OP indicated he had measured the DC Voltage at the inverter and it was not changing the 6 Volts the inverter thinks it is.
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #9
    Re: Xantrex SW Plus 5548 problem. any ideas?
    6bicks wrote: »
    ... I have used my MM to check that my DC voltage is steady ...

    Marc, you are CORRECT .. the above from the first post. Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • SkiDoo55
    SkiDoo55 Solar Expert Posts: 414 ✭✭✭
    #10
    Re: Xantrex SW Plus 5548 problem. any ideas?
    Cariboocoot wrote: »
    I could have sworn the OP indicated he had measured the DC Voltage at the inverter and it was not changing the 6 Volts the inverter thinks it is.
    Kind of depends on where he is probing the connection?
    agree he probably has an inverter problem. I have gotten brand new battery cable and they have enough connection to show correct voltage but fail to pass current.
    soldering only is looking for problems as wire terminal can get hot enough to melt the solder out, should be crimped and then soldered if desired.

    just suggesting that the terminals are inspected for problems.
    GT3.8 w/4600W Trina 230W, TX5000 w/5000W ET-250W, XW4024 w/1500W ET-250W, 4 L16, 5500W Gen. (never had to use) Yet!!
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  • 6bicks
    6bicks Registered Users Posts: 7 ✭
    #11
    Re: Xantrex SW Plus 5548 problem. any ideas?

    I will triple check the cable connections. I don't pull enough load on the cable to begin to heat them up. My fridge is the biggest draw at 1.1KWH for the entire day. Everything else is lights, PC and occasional TV.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #12
    Re: Xantrex SW Plus 5548 problem. any ideas?
    6bicks wrote: »
    I will triple check the cable connections. I don't pull enough load on the cable to begin to heat them up. My fridge is the biggest draw at 1.1KWH for the entire day. Everything else is lights, PC and occasional TV.

    SkiDoo55 is correct that solder is problematic because if a connection heats up the solder may melt. But there is another issue with solder... it causes metal fatigue (micro fissures) in the copper just outside the solder joint. This takes time to develop and may be a cause of erratic and difficult to diagnose behavior.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • halfcrazy
    halfcrazy Solar Expert Posts: 720 ✭✭✭
    #13
    Re: Xantrex SW Plus 5548 problem. any ideas?

    The guys at Tekris are good. Have they had you pop the cover off and check voltages inside? It sure sounds like a bad connection internally. My brain is foggy on the SW+ but there may have been a few ribbon cables. I would hope they have had you pop the lid and try reseating everything and check some voltages?

    I also agree with soldered cables being bad in my opinion. Maybe try a different set of cables? Or what you can do is take the meter and hold one lead on the threaded stud of the inverter and the other on the battery terminal itself at the battery. Now have some one turn on some larger loads and watch and see if you see the volts climb to check for voltage drop. Try this on the positive side and then on the negative side.

    Ryan
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  • 6bicks
    6bicks Registered Users Posts: 7 ✭
    #14
    Re: Xantrex SW Plus 5548 problem. any ideas?

    Tekris had me open it up, unplug all ribbons cables and reset them just to be sure.
    I will get with them on Monday to have them walk me through some places to check voltage. He was pretty leery about me opening it up (with his blessing/knowledge) with voltage connected.

    Odd thing is, it stops its flickering when the fridge turns on, it seems to mellow out and perform fine under load.

    I have never even came close to pushing this thing or getting it warm, outside of charging. I bought a larger inverter than needed for future expansion.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #15
    Re: Xantrex SW Plus 5548 problem. any ideas?

    Do you have the Search mode set to high maybe and it's dropping in and out ?? Try turning it off. Mine can do some really weird things when it on. The controller on the door of refrigerator will flash on and off and the CFL lights will flicker.
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  • boB
    boB Solar Expert Posts: 1,032 ✭✭✭✭
    #16
    Re: Xantrex SW Plus 5548 problem. any ideas?

    Have you tried smacking the unit on the top with your hand ? Does it make the voltage stay one way or the other ?

    Sometimes this will help figure out if it is an intermittent that you can locally tap around to find out exactly where that
    intermittent might be.

    boB
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  • Ralph Day
    Ralph Day Solar Expert Posts: 1,022 ✭✭✭✭
    #17
    Re: Xantrex SW Plus 5548 problem. any ideas?

    "Have you tried smacking the unit on the top with your hand ?"

    I love it! From the guy who has designed/engineered/built the best stuff on the market for years! Hit it! If that's boB's suggestion, I'd go for it.

    Ralph
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  • 6bicks
    6bicks Registered Users Posts: 7 ✭
    #18
    Re: Xantrex SW Plus 5548 problem. any ideas?

    I have only been operational for 2 months, fatigue should not be occurring yet.
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