So my new inverter shuts off when the sun comes out....

Plowman
Plowman Solar Expert Posts: 203 ✭✭✭✭✭
I bought a new inverter, little Xantrex PROwatt 300 on Fleabay. The main thing that attracted me to it was the very low no-load draw (0.18 amps, about half of my current inverters).

Hooked it up last night, worked fine, and no load draw was even less than advertised. Then the power suddenly went out late this morning. I assumed it had something to do with the new inverter, so I swapped it out for one of my old inverters and power was back up.

Then tried my new inverter on my truck battery and another deep cycle battery, and it worked, no problem. But as soon as I plug it into my battery bank, it dies. Battery bank is charged with solar, sun was strong, charge controller was putting out 14.8-14.9V, typical for absorption stage.

The manual says the Xantrex has a high voltage cut off at 15V. It's apparently being tripped.

I'm assuming the only thing I can do is use a different inverter? I could adjust the CC absorption voltage down, but that has problems of its own.

Comments

  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: So my new inverter shuts off when the sun comes out....
    Plowman wrote: »
    I bought a new inverter, little Xantrex PROwatt 300 on Fleabay. The main thing that attracted me to it was the very low no-load draw (0.18 amps, about half of my current inverters).

    Hooked it up last night, worked fine, and no load draw was even less than advertised. Then the power suddenly went out late this morning. I assumed it had something to do with the new inverter, so I swapped it out for one of my old inverters and power was back up.

    Then tried my new inverter on my truck battery and another deep cycle battery, and it worked, no problem. But as soon as I plug it into my battery bank, it dies. Battery bank is charged with solar, sun was strong, charge controller was putting out 14.8-14.9V, typical for absorption stage.

    The manual says the Xantrex has a high voltage cut off at 15V. It's apparently being tripped.

    I'm assuming the only thing I can do is use a different inverter? I could adjust the CC absorption voltage down, but that has problems of its own.
    Well, .1 -.2 could be a +/- error. 14.8 - 14.9 is a little high for t-105's, they just don't need that much on a daily basis unless the SG's are coming out low, I'd drop them to more like 14.6 or so especially in the summer, they'll last longer.
  • Plowman
    Plowman Solar Expert Posts: 203 ✭✭✭✭✭
    Re: So my new inverter shuts off when the sun comes out....
    Well, .1 -.2 could be a +/- error. 14.8 - 14.9 is a little high for t-105's, they just don't need that much on a daily basis unless the SG's are coming out low, I'd drop them to more like 14.6 or so especially in the summer, they'll last longer.

    This is another question I had. Trojan's page on charging lists 14.8V as the "daily charge" (absorption) for flooded batteries. But their data sheet on T-105s says 2.35-2.45V per cell, which is 14.1-14.7V for a 12V system.

    So data sheet doesn't match their other information on battery charging. Not to mention that 14.1 to 14.7V is a rather wide spread. Maybe I'm being too precise in my thinking about charging voltage and that it doesn't matter all that much as long as it's within a specified range?

    I might try dialing down the absorption voltage and see if I can't find a happy medium. My new inverter still won't work during equalization (>15V), but that's infrequent enough that it won't really matter. It sure would be nice to get this inverter to work, I have an inverter on 24/7, the reduced no-load draw would be helpful, especially in winter.
  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: So my new inverter shuts off when the sun comes out....

    I used to have similar problems when I was running the Outback MX-60. It would allow uncontrolled voltage overshoots during MPPT sweeps, but you're not using an MPPT controller, and besides, it wasn't a problem with my Morningstar TS-MPPT controllers, just the MX-60.
    You could try reducing the absorb voltage, but you'd have to keep a close eye on your batteries for sure.
    I ended up with inverters that could handle at least 16 volts, as in Winter when the batteries were really cold, the controllers would shove the voltage too high for the lower voltage inverters anyway.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: So my new inverter shuts off when the sun comes out....

    Big (50 Amp) diode to knock half to three-quarters of a Volt off the inverter input.
    Many of these inverters not only scream and shut down at 15-ish Volts but also wait until deadly 10.5 Volts to turn off. Adjusting the Voltage at the inverter downward a tad helps both problems.
  • Plowman
    Plowman Solar Expert Posts: 203 ✭✭✭✭✭
    Re: So my new inverter shuts off when the sun comes out....
    Big (50 Amp) diode to knock half to three-quarters of a Volt off the inverter input.
    Interesting, I'll look into this.
    Many of these inverters not only scream and shut down at 15-ish Volts but also wait until deadly 10.5 Volts to turn off. Adjusting the Voltage at the inverter downward a tad helps both problems.
    Yeah, the voltage limits don't make sense on a lot of inverters. My new Xantrex has a low voltage shut off at 10.0V, which is possibly even dumber than the 15.0V max. I believe the battery would be irreversibly damaged by the time it reaches 10.0V.

    This Xantrex inverter was designed to be used in a car, it came with cig plug, which I cut off and replaced with Powerpoles. I'm pretty sure many (most?) vehicle alternators will put out >15V.

    I never had this problem with the other cheapo car inverters I have, a little Sima 150W and a Cobra 400W. The Sima overheats pretty bad in summer, and the Cobra has a gluttonous no load draw.

    Probably should have saved my shekles for a decent little true sine.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: So my new inverter shuts off when the sun comes out....

    Actually 15 Volts on a vehicle is a recent thing; for a long time the system Voltage was regulated to 13.8 Volts +/- 5%. Seems with all the added do-dads they're ranging upwards. Still better than the old generator systems that were all over the place depending on whether the engine was idled or revved.

    Now someone's going to tell me that "recent" is "for the past 40 years". Time keeps passing.
  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: So my new inverter shuts off when the sun comes out....

    Now someone's going to tell me that "recent" is "for the past 40 years". Time keeps passing.

    Haha I'd never do that :D
    But seriously, here in Nova Scotia, for at least the last 40 years, the standard automotive voltage with engine running, battery charged or almost charged and alternator properly charging, has been 14.5, that may well have been upped in the newest cars, haven't had reason to get involved with the newest. Yet.
  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: So my new inverter shuts off when the sun comes out....
    Plowman wrote: »
    My new Xantrex has a low voltage shut off at 10.0V, which is possibly even dumber than the 15.0V max. I believe the battery would be irreversibly damaged by the time it reaches 10.0V.

    The components (including wires and bus bars) in an inverter are rated to handle a certain current. When a manufacturer tries to get an inverter listed, there must be a way to prevent more amps flowing than the components can handle. That way is the LVD. The default LVD is designed to protect the inverter, not the battery. A high quality inverter will have an adjustable LVD so that you may protect the battery.

    There are times when you should be grateful to have a very low LVD. For battery technologies other than lead acid, and also for 48 volt systems where it is possible to remove a defective 2 volt cell and function on 46 volt nominal battery.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • Plowman
    Plowman Solar Expert Posts: 203 ✭✭✭✭✭
    Re: So my new inverter shuts off when the sun comes out....

    I adjusted my charge controller down to the next lowest setting, which is 14.6V absorb. I've had my Xantrex inverter running all afternoon and it's been working fine. Just checked my meter and actual voltage is jumping between 14.6 and 14.7 depending on load, but that seems to be low enough for the Xantrex. Hopefully I won't have the problem Wayne mentioned about higher voltage in winter. That's when I'll need the low no-load draw of this inverter the most.

    Vtmaps, interesting info on LVD. Always wondered why it was so low on inverters. I've heard of people running their inverters until the low voltage alarm goes off, which is obviously a terrible idea. I get worried if my batts get below 75%.
  • Plowman
    Plowman Solar Expert Posts: 203 ✭✭✭✭✭
    Re: So my new inverter shuts off when the sun comes out....

    It's been about a month since I dialed the voltage down on my charge controller, from 14.8V to 14.6V in absorption stage. The inverter has been working fine since I did this, it's been in near 24/7 use with no problem.

    However, my batteries don't appear to like the lower voltage. I added two more panels to my system a couple days ago. I was hoping that might solve the problem, but I kind of figured it wouldn't since absorption amps are usually in the 1.5-2.5 range even when the panels are getting full sun.

    My four 158W panels were charging my two Trojan T-105s all day today with almost no load (couple amp-hours at most). I checked my batteries at 5:30 pm, specific gravity was 1.270 and 1.260 (testing middle cell in each battery). That's only 95% and 90% charged based on Trojan's chart. That's about average for what I've seen since I reduced the absorption voltage.

    When I saw this I equalized the batteries for about 2 hours. At the end the SG was 1.275 and 1.265. 100% and 95% charged based on Trojan's chart, about as good as I've seen with these two batteries. I'm measuring SG with a Hydro-Volt, which has automatic temp compensation. It was hot today, 90 outside, maybe a bit hotter in the trailer in which I keep my batts.

    I'm thinking if I hike the absorption voltage back up to 14.8V, I'll see my charge controller actually achieve float, which I almost never see. I haven't seen it in float mode for more than a month or two. That seems like a problem.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: So my new inverter shuts off when the sun comes out....

    SG readings sound good. You are usually aiming for >90% SOC once to several times a week (when actively cycling the lead acid batteries).

    How much water are you using? If these are the Trojan RE batteries--They have been reported as using less water than their traditional batteries. So, in 1 month, you may not see much water usage.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CDN_VT
    CDN_VT Solar Expert Posts: 492 ✭✭✭
    Re: So my new inverter shuts off when the sun comes out....
    Actually 15 Volts on a vehicle is a recent thing;

    The new Charging systems can bring the voltage up to 16V + temp adjusted DC !! but just that the battery sees , the computers now know with CAN.LIN,LAN,LEN protocols that with PWM the voltages are 13.9-14.2 so bulbs and stuff is not smoked.

    The ACL )Alternating Controlling Module ) sends the CAN code to all computers to do this.

    In a few more years , WE WON' T have the Jetsons cars !!

    VT
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: So my new inverter shuts off when the sun comes out....

    And CDN_VT reminded me--Watch what happens when the weather turns cold to the equipment in the trailer.

    The charge controller is going to increase the battery charging voltage by 5 mVolts/C*Cell as it falls below 25C in the trailer.

    As temperatures drop, you will probably see the charge controller bumping the voltage up by:

    0.005 V * 25C drop (from ~25C standard temp to 0C) * 6 cells (12 volt battery) = +0.75 Volts over room temperature set point for battery charging voltage.

    If your inverter is "that sensitive" to elevated voltages--You may have to look for a replacement that goes 16+ volts (for a 12 VDC input inverter).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Plowman
    Plowman Solar Expert Posts: 203 ✭✭✭✭✭
    Re: So my new inverter shuts off when the sun comes out....
    BB. wrote: »
    SG readings sound good. You are usually aiming for >90% SOC once to several times a week (when actively cycling the lead acid batteries).

    Are the SG readings good before or after equalization? Before they were 1.27/1.26, after they were 1.275/1.265.

    I can usually achieve >90% SOC, but not >95% since I dialed down the absorption voltage. The highest I've seen since late June was ~1.28 after a couple hours of equalization and when I had absorption set at 14.8V.

    One battery has always been weaker than the other since I got them in April. Thread here.
    How much water are you using? If these are the Trojan RE batteries--They have been reported as using less water than their traditional batteries. So, in 1 month, you may not see much water usage.

    -Bill
    I recently watered the batts, but I don't have a good sense for how much I'm using. They were lower than expected, I'd only watered them a couple times since I got them in the spring. Still learning that side of battery maintenance, I was using an AGM batt previously.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: So my new inverter shuts off when the sun comes out....

    Well Trojan batteries do want higher Voltage than a 12 Volt system likes to run at. That's one problem.
    Most 12 Volt inverters do not like these high Voltages and especially do not like equalization Voltages; they scream and shut down. That's another problem.
    Raising the Absorb Voltage will not increase Float time. More likely the opposite as it takes longer to reach a higher level which means there is less daylight time for completing that cycle and entering Float (it has nothing to do with the actual SOC). This is yet another problem and it sounds like one of lacking insolation.

    Run the gen & Iota first thing in the morning before the panels start to produce. Then let them take over and see if Float is achieved. Measure the time for Absorb (the TriStar may be set for too long) and watch the current. If you can't achieve a full charge on a good day something is wrong (especially with light loads). And it may be the batteries.

    BTW getting around the problem of inverters shutting down due to 'high Voltage' on 12 Volt systems is a recurring discussion. If the inverter is small enough you can put a diode (must be able to handle the maximum current) or two in-line with it to drop the Voltage to less-than-warning levels. This also has the advantage of effectively raising the LVD which keeps the batteries from being drained too low.
  • Plowman
    Plowman Solar Expert Posts: 203 ✭✭✭✭✭
    Re: So my new inverter shuts off when the sun comes out....
    Well Trojan batteries do want higher Voltage than a 12 Volt system likes to run at. That's one problem.
    Most 12 Volt inverters do not like these high Voltages and especially do not like equalization Voltages; they scream and shut down. That's another problem.
    Raising the Absorb Voltage will not increase Float time. More likely the opposite as it takes longer to reach a higher level which means there is less daylight time for completing that cycle and entering Float (it has nothing to do with the actual SOC). This is yet another problem and it sounds like one of lacking insolation.
    My panels get full sun all day, no shade at all. It's been hot and sunny lately, very few clouds. So insolation isn't a problem. I'm wondering if the Tristar charge controller has an absorb time that's set too long, as you suggested. I don't know what that time is or how to change it. How low should the amps go before it should switch from absorb to float?
    Run the gen & Iota first thing in the morning before the panels start to produce. Then let them take over and see if Float is achieved. Measure the time for Absorb (the TriStar may be set for too long) and watch the current.
    I'll try this, hopefully will have time this weekend.
    BTW getting around the problem of inverters shutting down due to 'high Voltage' on 12 Volt systems is a recurring discussion. If the inverter is small enough you can put a diode (must be able to handle the maximum current) or two in-line with it to drop the Voltage to less-than-warning levels. This also has the advantage of effectively raising the LVD which keeps the batteries from being drained too low.
    I switched back to my little Sima 150W inverter, which has no problem with 14.8V, or even equalization voltage (15.3V).

    Might try the diode trick. I know nothing about them and have no idea how to wire one into my inverter circuit, but always good to learn new things. What size?
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: So my new inverter shuts off when the sun comes out....

    Recently I went over the TriStar manual closely and could not find any detail about its Absorb time or how to change it. It was a different problem where the controller wasn't 'following' a parallel charge source, but the results were the same; no Float when there should have been. Either the manual is written badly or I'm getting too old and missing too much. It seems you can only really program these things with the MS View software & computer interface.

    A diode will usually drop about half a Volt in a circuit. You need to find one that will handle the maximum current of the inverter and wire it in series on the positive cable. Don't ask me which one or where to get it as I'm not in the same country and don't buy things like that these days. It would be nice if NAWS or somebody offered V-drop diodes specifically for 12 Volt inverters (the only ones that seem to need them), but talk about a niche market!
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: So my new inverter shuts off when the sun comes out....

    Not that this is the exact diode you need (very high voltage rating, you need much less), but to give you an idea about a 200 amp diode:

    http://www.amazon.com/POSITIVE-DIODE-MOUNT-200AMP-800VOLT/dp/B00BF36NHU

    And if you have 200 Amps * 1 volt drop, you are looking at 200 watts of heat--You need a big heat sink to dissapate that much energy. Also, the heat sink will be at +Vbatt so you have to make sure it is insulated.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: So my new inverter shuts off when the sun comes out....
    Recently I went over the TriStar manual closely and could not find any detail about its Absorb time or how to change it.....

    I think that's all covered in the MS View software, which is where you have to go to change it. Otherwise, you are just using the DIP switches and their chart to set up charge voltage.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • bill von novak
    bill von novak Solar Expert Posts: 891 ✭✭✭✭
    Re: So my new inverter shuts off when the sun comes out....
    Plowman wrote: »
    It's been about a month since I dialed the voltage down on my charge controller, from 14.8V to 14.6V in absorption stage. The inverter has been working fine since I did this, it's been in near 24/7 use with no problem. However, my batteries don't appear to like the lower voltage. I added two more panels to my system a couple days ago. I was hoping that might solve the problem, but I kind of figured it wouldn't since absorption amps are usually in the 1.5-2.5 range even when the panels are getting full sun. . . .I'm thinking if I hike the absorption voltage back up to 14.8V, I'll see my charge controller actually achieve float, which I almost never see. I haven't seen it in float mode for more than a month or two. That seems like a problem.

    Before you do that verify that you are really seeing 14.6 volts at the batteries. Poor connections, undersized cabling etc might mean that you are only getting 13.8 volts or something at the batteries.
  • Plowman
    Plowman Solar Expert Posts: 203 ✭✭✭✭✭
    Re: So my new inverter shuts off when the sun comes out....

    My CC was finally in float mode when I got home from work yesterday. I switched back to 14.8V absorb a couple days ago. Checked SG and it was 1.27/1.26 yesterday, which is pretty much 100% for my batteries. So at this point it looks like the 14.6V absorb may have been the problem.

    I'm pretty sure the only way to adjust the TS-45's absorb time is with Morningstar's software, but I think I may also need their meter, which I don't have. I'll have to experiment with it. I have the software, but have only hooked my computer up to the CC once. I'm running Linux, so MSView doesn't run all that well on it (have to use Wine, which is super slow on my machine).
    Before you do that verify that you are really seeing 14.6 volts at the batteries. Poor connections, undersized cabling etc might mean that you are only getting 13.8 volts or something at the batteries.
    Voltage is good at batteries as measured with multimeter. I'm also using voltage sense wires to the CC.
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: So my new inverter shuts off when the sun comes out....
    Plowman wrote: »
    I'm running Linux, so MSView doesn't run all that well on it (have to use Wine, which is super slow on my machine).
    If you have enough RAM memory, try VirtualBox, a free software virtual machine platform. It will allow you to run an actual Window instance if you can come up with a licensed copy of Windows to install in the virtual machine.
    It allows you to control access to the various I/O and hardware resources, etc. Not as good as VMWare, but the price is right.
    SMA SB 3000, old BP panels.
  • Grinnin
    Grinnin Solar Expert Posts: 39
    Re: So my new inverter shuts off when the sun comes out....
    Plowman wrote: »
    My new Xantrex has a low voltage shut off at 10.0V, which is possibly even dumber than the 15.0V max. I believe the battery would be irreversibly damaged by the time it reaches 10.0V.
    Your 300W inverter would be designed for a small system with a small battery bank. Actually drawing 300W would be over 25A @ 12V which would cause significant voltage sag in most small batteries.

    I had always thought of the inverter hitting the LVD after long use and moderate draw. Yes, 10V would be far too low. In my house the LVD screams only when there's an occasional high-amp draw, i.e.power tools. I changed the LVD from the high setting to the low setting and I can use those tools now at night instead of only during the day.

    For a larger inverter designed for a larger battery bank, a higher voltage for LVD would make sense.

    On the high voltage end I suspect that Xantrex is being more careful than the other unnamed plug-in inverters you've tried.