Best Off-Grid Inverter/Charger

david3
david3 Solar Expert Posts: 37 ✭
in Solar Product Reviews & Opinions #1
I'm researching right now, trying to figure out what I'd need to put a system together.

I'm in the Philippines, and the situation here is that there is no grid-tie, and the power is of low quality with many power outages and low voltage conditions. And electricity is expensive at about $0.20 USD per kWh (even more expensive in some areas), and I expect it will continue to increase in cost.

Since there's no grid-tie, I'd need to use batteries. I'd like to stay off the grid as much as possible to avoid the low voltage conditions, too.

Ideally, I'd use solar panels to fully charge a set of batteries when there's sunshine, and use the grid to automatically recharge the batteries if there's not enough sunshine and they drop too low. I may want to add a generator at some point, too, in case there's no sunshine and no grid power.

I need 110/220 (or 120/240) 60hz split-phase power. My house is wired for 220 with 2 hot lines and no neutral, with a ground to my own grounding rod (no neutral or ground to the transformer on the pole).

Any suggestions as to which inverter would be best to use in this situation?

So far I've checked out these:

Xantrex XW6048 - Rated for 6000 watts continuous, 12,000 watts surge and provides 110/220 with a single unit. I looked through the manual, and read various posts about it, and it doesn't seem to have a way to charge batteries from the AC2 input based on their voltage or soc, though.

The only way I could think of to do it would be to get the automatic generator module and find some third-party relay to connect/disconnect the grid from the AC2 input.

I wouldn't want to use the AC1 Input on it, since it would be synced with the grid all the time, then, which I really want to avoid as much as possible. And from what I hear, even with Sell Mode off it still takes a certain percentage of it's power from the grid.

Outback FX3048T - I'd need two of these wired in series to produce 110/220 6000 watts continous, 9600 watts surge. I looked through the manual, but couldn't really find much useful information about it's charging functions.

Magnum Energy MS4448PAE - This looks like the most promising one so far. One would have 4400 watts continous, 8500 watts surge, with 110/220 available with a single unit. Two could be wired in parallel for 8800 watts continuous, 17,000 watts surge.

According to the manual the unit can be set to connect to the grid power only when the battery voltage drops to a set level, and charge until the voltage reaches a second set level. I don't see any way to charge based on the soc/state of charge, though, so it would probably only be able to bulk charge from the grid and would shut down before it gets to the Absorption phase. A full charge from the grid would require manual intervention.

Any comments on these, or things I've missed, or other inverters I should check out?

Thanks.
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Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    Re: Best Off-Grid Inverter/Charger

    Cost wise--You might still want to look at connecting to the grid if it is at all stable:

    XW Xantrex 4024

    Batteries, when they cycle, do experience "wear" and will not last as long. And there are the losses of charger to battery to inverter which can cost you 30% or more in power losses.

    The above thread (and another linked thread) would seem to be the "optimum" of a poor set of choices to make.

    The batteries really are the weak portion of any power system and you need to look at how long they will last in your usage (how deep you cycle them, how good quality the batteries are, etc.). And you should probably plan on replacing the inverter (and other electronics) after ~10 years or so (at least have money saved in the bank)...

    In many places with "afternoon outages"--they just get a set of batteries and connect an AC charger to the grid... Most of the time, the grid is up and functioning, and when it goes down for 4-8 hours, you run the home/business from the battery bank. AC Power comes back, switch over to AC power and recharge the battery bank.

    You can always add a backup generator and/or solar panels to the battery bank to help the power last longer and (perhaps) reduce some power/fuel costs.

    It is a tough project to do "cost effectively"... Generally, my first suggestion is that you look at energy conservation first--It is almost always less expensive to conserve energy (insulation, new energy efficient appliances and lighting, new Air Conditioner, smaller laptops instead of desktop computer, etc.).

    Once you have your usage cut as much as practicable--then start by measuring your AC power needs to design your power system around (including when outages happen--summer only, monsoon season--Need generator backup, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • david3
    david3 Solar Expert Posts: 37 ✭
    #3
    Re: Best Off-Grid Inverter/Charger

    Thanks Bill.

    I can only connect to the grid one-way. There's no net metering here, unfortunately. There's talk about it, so perhaps sometime in the future it will be a possibility, but I'm not holding my breath.

    So if I want to use solar panels, I'll need to cycle batteries.

    I could just use a generator, but I'd still have to deal with power cuts when the load is transferred back and forth. And I doubt my neighbors would be happy listening to a generator start up in the middle of the night.

    I could also skip the solar panels and just get an inverter/charger and batteries and keep the batteries float charged from the grid and only drain them during power outages, as you mentioned. That way the batteries will last longer. That may be the most cost effective thing.

    Adding solar panels to that setup would be mostly useless, with no way to sell the power and no way to store it in batteries that are already fully charged.

    So I still want to find a way to use solar panels, even if it's more expensive than grid power right now. My main reasons for this are to have a clean, reliable source of power for my home and to hedge against future increases in the cost of electricity and decreasing grid reliability.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #4
    Re: Best Off-Grid Inverter/Charger
    david3 wrote: »
    I could also skip the solar panels and just get an inverter/charger and batteries and keep the batteries float charged from the grid and only drain them during power outages, as you mentioned. That way the batteries will last longer. That may be the most cost effective thing.

    Adding solar panels to that setup would be mostly useless, with no way to sell the power and no way to store it in batteries that are already fully charged.

    You can let the solar panels charge the batteries instead of using grid power (i.e., only use grid power to recharge the batteries if they are below 75% or 50% state of charge (the longer the batteries spend below ~75% state of charge, the quicker they will sulfate and die (basically, you probably don't want the batteries setting below 75% state of charge for more than 12-24 hours).

    Depending on what you need and your experience level--you might tackle this in two parts..

    Part 1 is a smaller battery bank, with enough battery and inverter to to power your loads for the "typical" 1 day outage (draw the battery to 75% or 50% state of charge. First recharge with AC Battery Charger--and add solar panels + charge controller after you have a "stable system" and you know how much power you need per day. Then you can let the solar panels recharge the bank (or start with AC power and finish with solar array).

    Part 2; the XW hybrid inverter in Load Shaving Mode should do what you want (or pretty closely what you want). And depending on the size of your solar array and loads--you can use AC power during the day and the XW inverter will "assist" the AC Grid power (keeps grid AC draw down to ~50 Watts--I think). And the XW will help the AC power up to the amount of solar panel power currently being collected.

    It looks like the XW is about as close to a "perfect" match to your requirements--But it is a complex device and I am certainly no expert.

    The system (XW, charge controller, battery bank, wiring, solar panels, etc.) is not cheap and I (personally) would want to be sure it meets your needs (load shaving, you can justify the battery bank + solar panel investment, etc.).

    If you do not have experience with the large/higher end solar power systems--I would be real hesitant to make this your first project with support a 1/2 a world away.

    There are companies here that configure and test systems before they ship overseas (like our host Northern Arizona Wind & Sun).

    For the first system, it may be worth paying for the XW system to be configured and tested before it ships to you... After you have experience, perhaps you can buy just the components and configure on your own for subsequent installations.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,894 ✭✭✭✭✭✭
    #5
    Re: Best Off-Grid Inverter/Charger

    I would just do what Bill suggested. Buy a good generator and configure it for autostart. Bad power is a very real enemy of any inverter charger. The reason offgrid equipment lasts so long is it is not connected to the grid, or bad generators...
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • jeffkruse
    jeffkruse Solar Expert Posts: 205 ✭✭✭
    #6
    Re: Best Off-Grid Inverter/Charger

    I wish the Xantrex inverter would let you set how much you want to draw from the grid with Grid Support on. Mine is drawing 50 – 100W when the load is less than 200Watts. When the load is higher than that the power coming from the grid is about 20-30% of the load.

    I thought there wouldn’t be many people wanting to do this but with all these threads about it I was wrong. Xantrex should “fix” this issue or change their manuals.

    The Xantrex inverter/charger is a good choice. For your situation and mine (although my grid is a bit more reliable) this setup will provide about 2/3rds of your power from the batteries and 1/3rd from the grid. However, if your grid power is unstable I don’t know how the inverter will qualify it and what effect it will have. My guess is it will get more of the power from the batteries. This all assumes you have panels to recharge them.
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  • david3
    david3 Solar Expert Posts: 37 ✭
    #7
    Re: Best Off-Grid Inverter/Charger
    BB. wrote: »
    You can let the solar panels charge the batteries instead of using grid power (i.e., only use grid power to recharge the batteries if they are below 75% or 50% state of charge (the longer the batteries spend below ~75% state of charge, the quicker they will sulfate and die (basically, you probably don't want the batteries setting below 75% state of charge for more than 12-24 hours).

    Right, that would be the plan, to let the batteries charge from solar panels during the day, and then drain them to 50% state of charge until the sunshine the next day. If it's cloudy, then the inverter should detect the 50% state of charge and charge the batteries from the grid automatically.
    Dave Sparks wrote: »
    I would just do what Bill suggested. Buy a good generator and configure it for autostart. Bad power is a very real enemy of any inverter charger. The reason offgrid equipment lasts so long is it is not connected to the grid, or bad generators...

    Yeah, that would probably be the least expensive thing to do.
    jeffkruse wrote: »
    I wish the Xantrex inverter would let you set how much you want to draw from the grid with Grid Support on. Mine is drawing 50 – 100W when the load is less than 200Watts. When the load is higher than that the power coming from the grid is about 20-30% of the load.

    Having 20-30% of the load coming from the grid when I'm trying to run from the batteries doesn't seem ideal. The Magnum inverters seem better on paper since they're supposed to be able to disconnect from the grid to run on batteries and only connect to the grid when the battery voltage drops to a certain level.
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  • jeffkruse
    jeffkruse Solar Expert Posts: 205 ✭✭✭
    #8
    Re: Best Off-Grid Inverter/Charger
    david3 wrote: »
    Having 20-30% of the load coming from the grid when I'm trying to run from the batteries doesn't seem ideal. The Magnum inverters seem better on paper since they're supposed to be able to disconnect from the grid to run on batteries and only connect to the grid when the battery voltage drops to a certain level.

    Ha, thats what the Xantrex says on paper in multilple places!
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  • david3
    david3 Solar Expert Posts: 37 ✭
    #9
    Re: Best Off-Grid Inverter/Charger

    I started reading through the Outback "Mate" manual and it looks like the Outback inverters can also be set to only connect to the grid to charge the batteries when the voltage drops to a certain level by using the "HBX" mode.

    I'd need two of those, though, and their surge capacity isn't as good as the Xantrex and Magnum inverters.
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  • david3
    david3 Solar Expert Posts: 37 ✭
    #10
    Re: Best Off-Grid Inverter/Charger

    There's a new inverter out now to consider, too: The Outback Radian GS8048. It's more expensive:

    http://www.solar-electric.com/ourags8wain.html

    Though it's rated for 8,000 watts. Looking through the manual, it has a "Mini Grid" mode that will run off the batteries, disconnected from the grid, until the battery voltage falls to a certain level. Then it will connect to the grid and recharge the batteries until the solar panels are outputting enough power to take over again.
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  • Shane Jackson
    Shane Jackson Solar Expert Posts: 49 ✭
    #11
    Re: Best Off-Grid Inverter/Charger

    You might want to look at the Apollo TSW4048

    http://apollosolar.com/Products/SolarInverters/OffGridTrueSineWaveInverterCharger/tabid/176/Default.aspx

    It has split phase (120/240) and a built in charger. No need in paying for a XW6048 if you can not sell back to the grid....

    Shane
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #12
    Re: Best Off-Grid Inverter/Charger

    I don't know about the new Radian, but Outback has a well-deserved reputation for being extremely reliable even under harsh operating conditions. The only problems I've ever seen people reporting around here have been due to the programming complexity or hooking things up wrong (which will doom any inverter) and one case of lightning strike (which will also doom any inverter).

    Just my opinion, but I think they're more dependable than any other brand - even if they are complicated to set-up and "old tech design" without all the "bells and whistles" of fancier units.
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  • Mangas
    Mangas Solar Expert Posts: 547 ✭✭✭✭
    #13
    Re: Best Off-Grid Inverter/Charger

    Bill's very good advice. "If you do not have experience with the large/higher end solar power systems--I would be real hesitant to make this your first project with support a 1/2 a world away."

    Even with our solar people a couple hours away, I had difficulty managing inverter programming and troubleshooting. What was routine for them was not for me.

    Given your location and unless you have convenient access to tech support, I would keep your system as simple as possible coupled with a conservation first discipline.

    After living with Outback, Xantrex, Trojan and Sharp for 6 years, I have become comfortable with these manufacturers products and technology.
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF Custom House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
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  • david3
    david3 Solar Expert Posts: 37 ✭
    #14
    Re: Best Off-Grid Inverter/Charger
    Shane Jackson wrote: »
    You might want to look at the Apollo TSW4048

    http://apollosolar.com/Products/SolarInverters/OffGridTrueSineWaveInverterCharger/tabid/176/Default.aspx

    It has split phase (120/240) and a built in charger. No need in paying for a XW6048 if you can not sell back to the grid....

    Shane

    I ruled out the Apollo early on due to reports of unreliability.
    Cariboocoot wrote: »
    I don't know about the new Radian, but Outback has a well-deserved reputation for being extremely reliable even under harsh operating conditions. The only problems I've ever seen people reporting around here have been due to the programming complexity or hooking things up wrong (which will doom any inverter) and one case of lightning strike (which will also doom any inverter).

    Just my opinion, but I think they're more dependable than any other brand - even if they are complicated to set-up and "old tech design" without all the "bells and whistles" of fancier units.

    Thanks -- hopefully their new Radian inverter will be as reliable as their older models.
    Mangas wrote: »
    Bill's very good advice. "If you do not have experience with the large/higher end solar power systems--I would be real hesitant to make this your first project with support a 1/2 a world away."

    Even with our solar people a couple hours away, I had difficulty managing inverter programming and troubleshooting. What was routine for them was not for me.

    Given your location and unless you have convenient access to tech support, I would keep your system as simple as possible coupled with a conservation first discipline.

    After living with Outback, Xantrex, Trojan and Sharp for 6 years, I have become comfortable with these manufacturers products and technology.

    Reading through the Xantrex and Outback manuals, it doesn't seem like rocket science, but I'll defer to those with the experience. I'll admit that inverter setup complexity wasn't even something I'd considered as a potential issue.

    I'm more concerned about getting equipment shipped here without damage, and choosing equipment that will be reliable.

    I will have an electrician to do the wiring and help me with everything, but he doesn't have any special experience with solar setups.
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  • Shane Jackson
    Shane Jackson Solar Expert Posts: 49 ✭
    #15
    Re: Best Off-Grid Inverter/Charger

    Could you point me to some of the reports of it being unreliable? I have searched and cant find any....

    Shane
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #16
    Re: Best Off-Grid Inverter/Charger

    As far as I know--the discussions on the forum here were about the Apollo MPPT Charge Controller, not any other Apollo products.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • david3
    david3 Solar Expert Posts: 37 ✭
    #17
    Re: Best Off-Grid Inverter/Charger

    Well, here's one reference:
    Windsun wrote: »
    Just a heads up - we no longer carry the Apollo stuff for the simple reason that far too much was coming back on warranty.

    Have you seen any positive reviews of Apollo inverters being reliable?
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  • Dapdan
    Dapdan Solar Expert Posts: 330 ✭✭
    #18
    Re: Best Off-Grid Inverter/Charger

    David,

    I personally have a TSW4048 setup at home with no problems as yet. It was in place for about 2-3months so not a long time. I have set up about 2 as well in the same time frame and those are working 24/7 and no problems there as well. I personally know two other persons that have two setups using the apollos as well.

    If you check their website they offer a loaner inverter should their inverter breaks down in the field while they repair or replace you inverter under warranty which is 5 years. I think that is an indication that they are willing to stand behind their product. How long will the company last...who knows but, it must have some kind of reliability built in or they would have to have alot of loaners going through the door and that can't be good business sense.

    All in all my experience so far for the past 3months with them has been great. I have had good experiences with there technical department as they have fielded all my queries in person and solved any issues I may have had. I have had no real issues except clarification and technical advise.

    The TSW series is now my go to inverter. Good luck.

    Cheers...
    Damani
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  • david3
    david3 Solar Expert Posts: 37 ✭
    #19
    Re: Best Off-Grid Inverter/Charger

    I'm happy to hear that. Thanks for the report.
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  • Fullpower
    Fullpower Solar Expert Posts: 69 ✭✭
    #20
    Best Off-Grid Inverter/Charger

    I have an OUTBACK FX2024 inverter in continuous service since early 2003.
    This inverter runs my entire house, to include a deep well pump, clothes washer, audio, video and communications equipment, full kitchen with microwave oven, full size refrigerator, chest freezer and seasonal use of engine block heaters.
    The FX2024 has not missed a cycle nor shut down for any reason in 8 years, occasional overloads of 3 times rated capacity have been observed.
    I can without reservation recommend Outback power equipment for off grid residential power systems
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,894 ✭✭✭✭✭✭
    #21
    Re: Best Off-Grid Inverter/Charger
    BB. wrote: »
    As far as I know--the discussions on the forum here were about the Apollo MPPT Charge Controller, not any other Apollo products.

    -Bill

    Right and it was the low voltage CC. I have a customer with the HV CC and it has been fine.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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