Newb Xantrex 6048 questions

utahwilson · October 2010

Hello,

Just joined the forums, neighbor up North. I have a Xantrex XW6048 with 24 6volt deka batteries in a 48v configuration.

Next spring we will install solar panels, however, until then I will use a Generator to charge the battery banks. I have a Honda 6500 watt generator. XW6048 qualifies the Gen just fine. However, when I switch over to the charger the Generator starts to load up and the XW6048 bypasses the charger and the qualification cycle starts again. I have measured the Hz coming off the Gen at 56Hz. While under initial load from the charger you can see the Hz drop. I have decreased the Hz threshold on the XW6048 to the minnimum of 52Hz and still didn't make a difference.

Question1: Anyone else seen the issue? Is the difference between the Gen running at 56Hz verses 60Hz enough to keep the charger from kicking in?

Question2: Does the size of the motor on the generator make a difference to handle the initial load?

Question3: Even though I manully charge the battery banks and the remote config panel for the XW6048 indicates 50Volts. The battery meter still indicates empty. Any suggestions on why this would be?

Again, thanks in advance for any information.

BB. · October 2010

Re: Newb Xantrex 6048 questions

Have you reduced the programmable charging current drawn by the XW? Perhaps you should start at 1/2 the genset's rated output and work up to 75%.

I don't know the details of the XW battery monitor function... Many of the battery monitors require the batteries to charge up to near 100% capacity (a few hours at ~58+ volts) before they will reset/display "Full"/correct capacity... Right now, the XW may not have a clue at what capacity the battery bank is at.

When/how are you measuring the 50 volts? (resting, charging, discharging, DMM, XW meter, etc.).

-Bill

RCinFLA · October 2010

Re: Newb Xantrex 6048 questions

utahwilson wrote: »

Hello,

Question1: Anyone else seen the issue? Is the difference between the Gen running at 56Hz verses 60Hz enough to keep the charger from kicking in?

Question2: Does the size of the motor on the generator make a difference to handle the initial load?

Question3: Even though I manully charge the battery banks and the remote config panel for the XW6048 indicates 50Volts. BY The battery meter still indicates empty. Any suggestions on why this would be?

1) The XW has a phasing lock system that has a finite bandwidth to avoid it jumping on spurious zero crossing.

When a sudden load is dropped on a generator it will slow down for a moment as engine thottle is opened and brought back to regulated speed. The rate of this drop in frequency may not be tracked by XW causing it to disconnect.

It is worse while initially aquiring lock. Some generator control loop wobble when generator is unloaded. This is very difficult for XW to lock to.

The generator may also be dropping in voltage with the sudden load. If it drops too far the XW will release connection. This is usually rare, compared to speed/frequency issue.

As mentioned, back down on the max charging rate so XW will not dump such a heavy load on generator.

2) A larger engine will normally not bog down as much, but a larger engine, not well matched to alternator power rating, is going to have more fuel consumption. 3600 rpm gas engines are already oversized in HP to help this situation, running close to 2 HP per 1 kW of generator size.

3) XW battery gauge is based on computed input and output current and programmed battery AH rating targeted from its last fully charged reference.

Voltage is not a good indicator of SOC as battery current flow greatly impacts the voltage/SOC relationship. When your battery gets to absorb voltage you should be approaching full charge. When at absorb voltage, and current tapers off to about 1-2% of AH rating current the XW will reset its 100% full reference. If you never let it get to this fully charged point, or at absorb voltage for a period of time in the case of solar charging, the XW's input/output calculation of % full will have cummulatively more error for each charging/discharge cycle.

utahwilson · October 2010

Re: Newb Xantrex 6048 questions

WOW!

thanks for the information. I have been communicating back and forth with Xantrex support for over three months and ramping back on the charge amperage has never been mentioned. I emailed my contact yesterday with your suggestion and below is the reply.

"Yes, if you have an undersized generator, or simly want to reduce the draw on it, you can reduce the Max Charge Rate from 100% (100Adc for an XW6048) down to 10%.
Advanced Settings / charger settings / Max Chg Rate"

lol, I have provide numerous emails with exact same questions and I get the answer on these forums. Fantastic. Heading up tomorrow and I'll let you know the results. When I first started this 3 months ago I found solar-guppies site, however didn't see an obvious link to register. Frustrated yesterday, I found this forum. Suprised, I had not come across it before in my google searches for support. Or, reading through the manuals lightbulb never clicked on pertaining to the Max Chg Rate.

again, thank you very much for the suggestions.

utahwilson · October 2010

Re: Newb Xantrex 6048 questions

Set Max Chg rate to 10% worked great. 20% worked Great. 40% not so much. Settled around 30%.

Thanks for the suggestion

RCinFLA · October 2010

Re: Newb Xantrex 6048 questions

utahwilson wrote: »

Set Max Chg rate to 10% worked great. 20% worked Great. 40% not so much. Settled around 30%.

Thanks for the suggestion

That's only about 1700 watts, I'd expect Honda 6500 should do better than that.

Check the gen voltage and frequency at charge setting level that you start to have trouble.

Simple DVM that has frequency counter option should do. You can also use the XW readout but XW meters only work when unit is locked on generator.

mike95490 · February 2011

Re: Newb Xantrex 6048 questions

I'm going to expand on this question a bit, as I was told by another 6048 owner ( a plumber ), that

while the XW needs 240VAC to qualify the generator, it only charges off one leg @ 120V ??

crewzer & Solar Guppy, can you confirm ?

I'm also thinking / considering, about a 240V phase/load equalizing transformer, to eliminate problems with loading one leg of the XW, while the other leg is empty. I've heard just a 240V CT autotransformer will accomplish this, at 2x the inverter rating, since one leg may be called to deliver nearly the full 6KW capacity.

Dave Angelini · February 2011

Re: Newb Xantrex 6048 questions

Mike, this sounds crazy and why would you listen to a plumber? Use a good generator, split the loads correctly as any electricican would do when wiring a house and eventually get enough solar so you don't need a generator.

mike95490 · February 2011

Re: Newb Xantrex 6048 questions

Dave Sparks wrote: »

.....eventually get enough solar so you don't need a generator.

for 5 day long cloudy/rain spells ? not practical.

Solar Guppy · February 2011

Re: Newb Xantrex 6048 questions

Mike, XW-6048 uses 240 single phase ...

mike95490 · February 2011

Re: Newb Xantrex 6048 questions

Solar Guppy wrote: »

Mike, XW-6048 uses 240 single phase ...

That's what I thought, but someone that claimed he owned one, apparently didn't know how they worked internally. Just double checking.

Still don't have my genset bolted down, or wired up yet. Poured 3 gallons into the battery bank last weekend, plates were still covered, but boy they take a lot of water every other month. May be considering AGM's - save an hour of watering and mop up each month.

RCinFLA · February 2011

Re: Newb Xantrex 6048 questions

Another thing you might try is putting some load directly on generator before XW load. Start with a 60-100 watt light bulb and work your way up in wattage (hair drier, toaster).

Sometimes this stabilizes the generator enough to reduce its rate of change in frequency with load surges.

You should also be able to increase the charge rate (in moderate steps) on XW after it has connected to generator. This is manual operation and is a pain, but will allow you to milk more power out of the generator. 50%-80% VA rating load on generator gives best fuel efficiency. Less then 20%-25% VA load is really poor fuel efficiency. On that sized generator you should be able to achieve 5-5.5 kWH's per gallon of gasoline while bulk charging.

I would not recommend going over 90% of generator VA rating just to ease the wear and tear on generator. Make sure you are referencing continuous load generator rating. I believe Honda rates their generators based on peak short term load, not continuous load. They have the continuous load rating in the fine print, probably about 5000 watts for their 6500 watt advertised generator.

When recharging batteries from generator, I usually stop the gen when absorb voltage is reached. This will bring batteries to about 85% SOC but avoid the poor fuel efficiency of absorb stage where load on generator is reduced. Every 4 or 5 days do a full absorb cycle to bring battery up to full SOC.

Dave Angelini · February 2011

Re: Newb Xantrex 6048 questions

mike90045 wrote: »

for 5 day long cloudy/rain spells ? not practical.

Learn to lower your useage! I know it seems "not practicle" now but the appliance problems, noise, and hassel will someday. It is not like you live in Alaska?

Newb Xantrex 6048 questions

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