XW6048 Question

PeteNora · March 2011

Hello being a new guy here I want to say this site has some very good information and help. I have a bunch of questions on my plans and I hope I can get the needed help.

First off I have a remote off grid camp that I want to set up. Most use will be fall months on weekends and aprox 2 weeks in november for deer hunting. I bought an used 2 year old xw6048 inverter with a midnight solar install kit. I have access to 8 6 volt golf cart batteries. My present Onan is a 4,000 watt 120 volt, 33 amp propane powered. This will be my set up at first. Next will be some sort of solar charging which I will need help selecting. I will address the solar in another post at a later date. Here are my questions.

What size battery cables do I need to link the batteries? The inverter system came with 4/0 leads.

How many amps are needed to power the inverters charge system?

Is the XW6048 a good choice or overkill?

Thanks in advance for any info or help.

Cariboocoot · March 2011

Re: XW6048 Question

Welcome to the forum.

PeteNora wrote: »

Hello being a new guy here I want to say this site has some very good information and help. I have a bunch of questions on my plans and I hope I can get the needed help.

First off I have a remote off grid camp that I want to set up. Most use will be fall months on weekends and aprox 2 weeks in november for deer hunting. I bought an used 2 year old xw6048 inverter with a midnight solar install kit. I have access to 8 6 volt golf cart batteries. My present Onan is a 4,000 watt 120 volt, 33 amp propane powered. This will be my set up at first. Next will be some sort of solar charging which I will need help selecting. I will address the solar in another post at a later date. Here are my questions.

What size battery cables do I need to link the batteries? The inverter system came with 4/0 leads.

If I recall correctly, the 6048 will draw at most 150 Amps. So if you were going to use it at its peak capacity you'd need '0' AWG on the DC side. But so long as the fuse is rated properly for the wire size and you don't exceed that capacity there should be no problem. 4 AWG should handle 60 Amps - roughly 2500 Watts. What size fuse/breaker came with it? Something like 75 Amps?

How many amps are needed to power the inverters charge system?

This depends on how many Amps it has to put out. The golf cart batteries are probably around 225 Amp hours, so you're looking at a maximum of approximately 23 Amps @ 57 Volts - around 1300 Watts, not including system losses or loads.

Is the XW6048 a good choice or overkill?

That would depend on what you need to run with it. It's just about the biggest single battery-powered inverter you can get (also has grid tie capacity). I suggest you visit Xantrex/Schneider and get a manual for it if you haven't got one (I did a quick search - couldn't find it on their site). There's a lot of programming you'll need to know about.

One issue you have: the XW requires 240 Volt input from the gen. I believe some of the guys here were exploring feeding it off 120 only, but either a step-up transformer or a 240 VAC gen may be in order.

niel · March 2011

Re: XW6048 Question

i'd go with the heaviest wire you can and make the lengths as short as possible due to voltage drops.

in addition to solar you do have the option of feeding power into the inverter from a generator if it is stable enough and run the built-in charger. it is capable of 100a at 48v and i don't know how far back the charger can be cut back on amps for it to be used with smaller gennies that can charge smaller battery banks.

is it overkill you ask? only you can answer that as only you know how much power you use.

PeteNora · March 2011

Re: XW6048 Question

Thanks for the replies. This is my first inverter. My camp is propane heat, fridge, hot water, coooking. In the past its been all generator for lights, tv, satellite dish, microwave, ect. Generator is propane fired, 4,000 watt, 120volt, 33 amps. This is all Greek to me. I was looking to achiece 24/7 power with the generator running no more than 3 hours a day.

I would not of bought such a big inverter. But the price was so right I could not turn it down. I only asked about the xw6048 so I could get a feel on its track record and reliability. I was told 48 volt was the most efficient operating.

This is the install panel kit that it came with. The main DC breaker is rated at 250 amps.

http://www.midnitesolar.com/pdfs/XW%20E-Panel%20instructions.pdf

I was asking about the cables because of the size of the entrance cables at 4/0 which is huge. So from what you guys claim 0 or 00 would be fine on linking the 8 batteries togeather. Also keeping them as short as possible.

I am pretty sure I will upgrade to a 5,000 or 6,000 watt Onan with 120/240 at about 26 amps per leg. I hope that will be enough to power the inverters charger properly?

After I get this working I would like to get into the solar to assist in keeping the batteries fully charged. With the usage as I posted above what charge controller and what solar panel requirements will I need.

Thanks for the answers.

Cariboocoot · March 2011

Re: XW6048 Question

I was of course referring to the minimum wire size. Sorry that wasn't clear. the 4/0 is the biggest you can get and will handle 300 Amps - which is for the XW's huge surge rating of 12 kW. If you can, keep the big wire and the big breaker. If you do feel you have to downsize the wire you must reduce the breaker size.

One option for recharging from your existing gen is to skip the XW's AC in and go with a stand-alone charger like this: http://www.solar-electric.com/iodl48vo15am.html

Ideally, those golf cart batteries are going to want 12-24 Amps so that Iota charger above would be a minimum. As for panels, with the existing battery bank (assuming its 225 Amp hour) you'd be looking at something like this:
12 Amps minimum @ 57 Volts charging = 684 Watts, less "typical" 77% derating: 888 Watt array.
22.5 Amps "ideal" @ 57 Volts charging = 1282 Watts, less 77% derating: 1665 Watt array.

So somewhere in the neighborhood of 1 kW of panels would probably be good, with a corresponding charge controller (you would probably be better off with the more expensive MPPT type, but it is not strictly necessary).

NOTE: just rough calculations and not specific recommendations, okay?

Another possibility is flogging the XW to someone for enough $ to buy a more suitable-to-needs system.

That's some pretty big generator capacity you've got too. Sure it's necessary? You could be burning more fuel than you actually need to. On the other hand, replacement costs can buy a lot of fuel for a long time.

Addendum: that battery bank should be capable of 4.8 kW hours of power, which is quite a bit for off-grid use. About double what I use with all the stuff that runs off my meager system.

PeteNora · March 2011

Re: XW6048 Question

So I should consider linking the batteries with 4/0 cable?

I have thought about the possibility of making some trade. I may just get the gen set up, then the inverter and batteries and see how it reacts.

So 1 kw is what you forsee on the solar panel. Can you advise me on the panels, controller at 48 volts and a wiring guide.

I hate to ask and reask but I am green on this and need to understand terms and abbreviations ect. Thanks for the patience and advice.

Cariboocoot · March 2011

Re: XW6048 Question

I'd follow Niel's advice and keep the cables as large as possible, since you've already got them.

To really understand this stuff you have to do a lot of reading. We even have a section for that:
http://forum.solar-electric.com/forumdisplay.php?f=14
That's where you'll find lots of basic info like the glossary of terms and links to important resources like the Voltage drop calculator.
The battery FAQ's are vital too: http://www.windsun.com/Batteries/Battery_FAQ.htm

Again I'll point out that the XW is expecting 240 VAC input, not 120. Basically its internal battery charger isn't going to work with your existing gen. You will need either a step-up transformer, stand-along battery charger, or different generator.

In terms of panels, whatever name brand you can get a good per Watt price on (delivered - delivery is $$ on panels because they're large, heavy, and fragile). For reference: http://www.solar-electric.com/hiposopa.html Charge controllers: http://www.solar-electric.com/chco.html

You need to look over some of this stuff yourself so you can get a "feel" for what is involved. Remember too that the panels will require mounting, wiring, and circuit protection (fuses).

PeteNora · March 2011

Re: XW6048 Question

Thanks again. I agree lots of reading. All greek stuff to me so it takes quite a bit of craming for my bean to understand and absorb it. I sure do apreciate the help.

BB. · March 2011

Re: XW6048 Question

Also be aware that a 6kW 48volt system is HUGE... That is more than enough to run my entire suburban home with a family of four.

Very typically, people live very nicely with a 300-1,800 watt inverter (no fridge/electric fridge) and ~400-800 watts of solar panels.

For a cabin--Most often, it makes more sense to run everything you can from propane (heating, cooking, propane fridge/etc.) and run just a few lights, radio, laptop, cell chargers from solar/battery bank.

Basically, if your cabin is occupied less than 9 months of the year, look at a minimal solar PV system (especially if much of the occupation is during low sun / poor weather months).

If you are living there > 9 months, or have to carry in fuel, then a larger solar PV system can make sense and run the fridge from electricity.

During poor solar irradiation months, you will, most likely, need a genset anyway. Keeping the entire system small, means smaller genset and less fuel to haul.

Without knowing your electrical loads, it is really hard to size the system.

And with very large systems, you can have more losses and require more solar panels, and larger gensets just to keep the batteries charged.

-Bill

PeteNora · March 2011

Re: XW6048 Question

Thanks again. My camp has propane generator,fridge,heat, hot water,cooking. Electrical is basicly lights, water pump, microwave, tv, sat dish, and misc. My Onan 4,000 watt basicly sits at a 1800 rpm of governor idle unless the pump runs which does work the gen into the governor. well is 225 foot with the 110 pump at 125 feet. It has a fair amp draw. The Onan is rated at 33 amps. I would say the average use is in the 10 to 15 amp range. I average about 175 to 200 hours each year on the generator. My intentions were to use the inverter and cut the gen run time to 50 hours aprox per year. My propave usage for the whole year is slightly less than 200 gallons. The camp is very efficient.

I agree the xw6048 is overkill. I only have about 1,000.00 into it with the install panel. So as said I should consider trading it off for a more rounded system for my needs.

Maybe one out you gurus could outline a system that would be better for me? Thanks.

mike95490 · March 2011

Re: XW6048 Question

Water pump. do you have pressure tank system where the pump runs for 2 minutes and then shuts off, or a gravity feed tank overhead, that when it gets low, the pump runs for 20 minutes to refill ?
For running a water pump, the xw6048 is NOT overkill.

Recharge: using the 240VAC from the genset is good to do the BULK part of the charge, where you can pump in the amps pretty quickly, and stay pretty efficient with the genset.
The ABSORB phase, takes a couple hours, and much less power, so your genset will be burning quite a bit of fuel idling. I've found the IOTA charger, to be good for bulk, bu it does not do so well with absorb, and cannot equalize.

Absorb is where the battery electrolyte bubbles and gets mixed up, so at least once a week, you will have to run the genset for a full charge to mix the batteries, 1KW of solar may not be enough for a 200AH bank

PeteNora · March 2011

Re: XW6048 Question

Thanks for the replies. Yes I do have a pressure tank. Pump runs for a couple minutes and shuts off.

More info for me to check out and understand.

mike95490 · March 2011

Re: XW6048 Question

PeteNora wrote: »

Thanks for the replies. Yes I do have a pressure tank. Pump runs for a couple minutes and shuts off.

More info for me to check out and understand.

OK. That means it's likely the pump will be running on the batteries after dark, and so the entire starting surge will have to be supplied by batteries, not the genset.
If it was a overhead storage tank, you could pump enough while the genset was running, to last till the next scheduled runtime.

Also, the 6048 has on "AC in 2", "Generator Support", which is a fancy way of saying if the gen is running, and a big load comes on, the inverter will assist the generator as needed, then go back to recharging the batteries.

And another bit of advice, use the xw6048 to power the pump, and it's readout will indicate what it's true comsumption is. My 1//2 hp pump takes 1,000 w dead even. Assume Starting Surge is at least 5x running. (which puts mine at 5,000w startup for 2 seconds). If you ever pull the pump, you (your electrician) may be able to switch the wires to a 240V configuration, which lowers the loss in the 150' of pump wire, and puts more power to the pump, and easier starting.

Just don't be so quick to get rid of the 6048 quite yet.

XW6048 Question

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