Help with Trace SW 4048 Generator Auto Start

crstainbrook · June 2012

I'm new to both this forum and to alternative energy systems. I have recently installed a Xantrex 4048 inverter/charger, 8 6v Energizer GC2 batteries and a 4.0 Onan Genset propane generator. After much toying with converting the generator to propane and tweaking the inverter I have the system functioning but have been unable to dial in the generator auto start function. What I am witnessing is that when I activate the quiet time mode of the inverter, I can only get the generator to turn on remotely when the voltage drops to my Low battery cut out setting. I can't figure out how to set my inverter to turn my generator on at the same time each day to go through the full charge process. Does anyone have any suggestions? I am completely frustrated and am not sure where else to turn...Thanks in advance!

BB. · June 2012

Re: Help with Trace SW 4048 Generator Auto Start

What is your low battery cutout setting? In general, I would start with ~46 volts as the floor--But because battery voltage varies with temperature, loading (and charging), it is not really possible to estimate battery state of charge just from battery voltage.

And, it sounds like you are only using a generator for recharging the battery bank at the moment? Do you have a time when you have loads on the system (water pumping, A/C, etc.) such that you can both charge the battery bank and run your loads (trying to save fuel--Batteries, once they reach around 80-90% state of charge, reduce their charging current acceptance--change from bulk charging to absorb charging--So, as the battery charging current goes down, most gensets become fairly fuel inefficient during the last couple hours of fully charging the battery bank).

Combining a genset + even a smaller solar array can help--Run the generator for bulk charging (typically in the morning, although, some people run gensets in evening because they have their other AC loads at that time), and let the solar array take care of the absorb to float charging cycles.

Sorry this does not really address your question (don't have any off grid systems).

-Bill

Cariboocoot · June 2012

Re: Help with Trace SW 4048 Generator Auto Start

Not sure how the Xantrex gen controls work, but "quiet time" on the Outback system means the generator absolutely will not be started.

Normally you would have a start parameter for the gen at 'X' Volts; battery Voltage drops to that point, generator starts and runs until 'Y' Volts shutoff.
Quiet Time is programmed as hours of the day when then generator will not be started even if 'X' Volts occurs. This is so it won't fire up at 2 AM or such. Evidently Xantrex has a LVD over-ride.
Outback has a "must run" mode when the gen will fire and boost the batteries up regardless of the 'X' Voltage setting.
They also have an "exercise" mode which starts the gen for maintenance purposes (to make sure it will start and its battery is charged) regardless of battery SOC in case the panels are doing the whole job. This is for remote locales which may not be attended; start once a month to be sure it will in case it is needed.

As far as I know the generator should not start during quiet time, although Xantrex terminology may be different from Outback.

Ralph Day · June 2012

Re: Help with Trace SW 4048 Generator Auto Start

I have one of these old darlings, though never ran the generator on auto (diesel, needs pre-heat in the winter).

To get the auto start function to work on a daily basis I'd suggest you set the 2 hr start voltage to just above (edit below) what you usually wake up to in the am. If your battery voltage is usually at 48.2v then set the 2hr start parameter for 49.8v or so. Once your quiet time end is passed the generator should start and go through a charge cycle.

*Remember your quiet time timer is on a 24hr clock, not am-pm*. Your "start" quiet time should be 21:00 for instance, "end" quiet time 08:00 or so (generator will start at 8:00am if required, stop at 9:00pm or whatever you set for start quiet time). Setting 8:00 for pm start and 8:00 for am end will disable the function.

Generator Menu should be selected to Auto. To program the above parameters you must press the red and green buttons at the same time to get past menu number 8 and into the setup menus. Auto start functions are at menu 12. (sorry if this is below the threshold of your working/functioning with your 4048; you never know from initial posts sometimes

)

Let us know how things work out.

niel · June 2012

Re: Help with Trace SW 4048 Generator Auto Start

a sidenote here. the ripple on the batteries may be a bit high as it is generally a good idea for it to have 100ah capacity for each kilowatt of power. if you don't the life of the batteries could possibly be reduced.

Ralph Day · June 2012

Re: Help with Trace SW 4048 Generator Auto Start

Hi Christopher
After further thought I've come to the conclusion that you can't ask the SW to do what you want...sort of. What I've come up with is this. Since the SW will charge when it senses power on the AC2 inputs (the generator inputs) you just have to arrange for power to be there at the same time every day. How?...

If your generator is a 2 wire start it's relatively easy. Get it to run at the same time every day. To do that you need a plug in timer and a relay. Set the timer with a program that turns on and off each day. That powers the relay which starts the generator. To keep the controls simple just run a parallel set of wires from the low voltage generator control circuit. Parallel so you can over ride the timer control with the inverter/charger controls. I did this before and used a light switch to turn the generator on and off. To limit the run time of the generator you just limit the time the timer is "on". When it shuts off, the relay opens and the gen shuts down (system in float by then?)

The plug in timers with a battery backup will keep the programming information in case of outage, unplugging etc. An electrical supply house could furnish you with a relay appropriate to requirements...120v from the timer, not sure it matters what voltage on the generator control side.

That's all I could think of as a work around without grid power and Energy Management Mode (pg 90 in the manual).

Ralph

ps I can't make my previous method suggested work. I have grid power and generator, but feeding the inverter through the same wire (generator panel, one or other selected). There's always power on AC2 if I don't shut a breaker off. Might work if there's only power once the gen starts. Hope so.

denisseattle · November 2013

Re: Help with Trace SW 4048 Generator Auto Start

I have a SW5548 off grid with a generator on autostart. I'm assuming you have Quite Time set correctly (not overlapping so it's quiet all day) and all your Gen Autostart Setup voltages set for 24 hour, 2 hour, and 15 minute starts. In that case it should be working when the 3 conditions are met. You don't need to rig up external relays or timers, your SW does all that but it's not easy to figure out.

Try disabling Quiet Time and using 15-minute start voltage as a test.

If what you want is simply for the generator to start every day, try setting Exercise to 1 day. It will start up at your End Quiet Time. I've found that it doesn't always stop after Exercise Minutes, it can go into Bulk for the prescribed Absorption Time, I leave it up to you to figure out the conditions of this undocumented feature (or consult Xantrex).

If you want it to run only on condition of low battery, carefully study the various sections of the manual about the battery voltage settings other than LBCO. You have to set a voltage and then wait 24 hours (or 2 hours, or 15 minutes), and wait until it is not Quiet Time, and somehow know the VDC has stayed below your setting, before you can really test the autostart. A cheap USB DC voltage logger can be handy.

Help with Trace SW 4048 Generator Auto Start

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