sw 5548 charging hicup

arby · October 2017

Hello,
After all summer of no genny I heard it kick in last weekend at the cottage. Great I thought everything is working as it should. After about an hour and a half I hear the genny go offload. I went into the shed to see what was up and the green light was flashing and then the bulk charge light came on. Almost immediately it went off and did the same thing again a few times so I just shut the genny down.
Next day I started the genny and the bulk light stayed on and continued to charge the batteries. Since it was sunny that day I just shut it down.
Seems to me that when the charger drops into float that is when the genny is turned off. But when it was kicking in and out it had not reached float and it was not shutting the genny down like it should if it was in float.

Any ideas what might cause this situation. My guess is that something in the inverter is overheating but I have no idea what or if that's what's happenning.
TIA, arby

mcgivor · October 2017

Could it be a conflict between the charge controller and the inverter charger? The charge controller adding current periodically, in partially cloudy conditions, confusing the inverter charger when close to the float settings. Are the setpoints for both identical? The reference to the green light flashing, is this on the SW 5548, an older Xantrex unit? Has the system worked in the past without issues? Are there any error codes indicating temperature issues?

Personally I'm not a fan of AGS, strange things can occur, which could be when nobody is there, charging all the way to float with a generator is not the best use of fuel, shutting down when the current is around 3-4% of battery capacity and allowing solar to finnish the job, if possible, is in my opinion, a better idea.

arby · October 2017

It was pretty cloudy that day so I don't think it was a conflict between the CC and the inverter. Yes it is an older Xantrex which works great in all other things. I shut my inverter off when I leave the cottage so no AGS when not there. No error codes or error lights flashing.
IIRC the genny always shut down when reaching float before or if a breaker on the genny popped. Last year I doubled the size of my panels from 1600 watts to 3200 watts and since then have not heard the genny until this weekend that was very rainy and cloudy with a full house for Thanksgiving using everything they could find that runs off electricity. )))
The only difference in the settings between the CC and inverter is the bulk/absorb voltage which I had lowered on the CC to 58.8 from 60 for the winter. The inverter remained at 60 since it will most likely never come on as the place is only used 3 or 4 times for a day and a half in the winter.

Estragon · October 2017

Just to clarify, when you say the genny went "offload", do you mean the genny continued running, but with no load?

I use one of a couple of generators to charge occasionally, depending on circumstances. One is a little Honda eu2000 and the other is a 4kw diesel, and I need to adjust Outback inverter settings when switching or I can get generator overload issues, which would be something like what you may be describing. When set properly, the inverters will cut back on charging output to accommodate live loads up to the limit set for total generator input. There are a couple of settings, one for total generator input, and another for max charging current.

The little Honda will indicate an overload condition if I don't get the settings right. The diesel won't though. Either a breaker pops, or the inverter drops the input because the voltage goes out of spec.

mcgivor · October 2017

Could be load related, judging from the full house everything being used statement, what is the recharge voltage set at? 25v is usually the default, which could be drawn down by excessive loads, hence the bulk reappearing. I'm thinking along the lines that this is not a normal situation, having many people using more than normal loads. Perhaps testing under controlled conditions, without added guests, would reveal if there is in fact a problem, my guess is everything is good, just a situational problem.

bfitzgerald · October 2017

I have an XW4548 inverter, a Xantrex MPPT charge controller, and a Champion 5000 watt generator. I have had a number of issues with this combination, some of which I've figured out.

The inverter charger would go off line and not requalify the generator power. I discovered that the generator will go over 65 hz under a light load, under 1000 w. This can happen when I start charging under cloudy conditions and the sun pops out. The inverter charger scales back as the solar charge controller ramps up. The only way to get it back to qualify is to plug a 1500w heater into the generator. I now make sure that I have a useful load (like a hot water heater) to keep the frequency in range. (I should fix the generator problem). Could your generator be off frequency, maybe too low under load?

The inverter charger stops charging and by passes to power the loads. It took me a while to clue into this one. It appears to happen when I start charging under cloudy conditions and like the scenario above, the sun starts to shine. The inverter charger load drops to below 2%C and the charger turns off. It will not come back on line until the battery voltage reaches recharge voltage. Even if the sun disappears again, it can take a while for the battery bank to drop to the recharge volt setting. Although I haven't changed anything yet, I think I could work around this by 1) setting the battery bank size in the inverter settings to indicate a very large bank and that should keep the charger online or 2) set the recharge voltage to 59 (from 50), maybe not a good idea with a auto gen start or for the solar charger contoller or 3) boost the inverter charger bulk and absorb settings higher than the solar charge controller. This will shut down the solar charging before the inverter charger shuts down. This might be best done in conjunction with 1) above.

Inverter qualifies power, starts to load up the charger, but then stops charging, and cycles between charging and not charging. The power seems to remain "qualified". This happened just recently (I've been using this setup for 4 years) when I ran the generator mostly for the purpose of running the generator. I rarely need the generator in the summer so I was basically burning off the old fuel from last winter. The charge controller had been in absorption mode for some time, but not up to full absorption voltage. When the generator started to add charge, the solar charge contoller was able to reach it's (temperature compensated) absorption voltage which was, I thought, set the same as the inverter charger aborption setting. I have battery temperature sensors connected to both chargers but I noticed that the charge controller reads 3 degrees C lower than the inverter. When the inverter charger kicked out, the voltage dropped and the inverter charger restarted and this cycle would repeat every 10 seconds or so. I lowered the absorb voltage in the solar charger and that seems to solve the problem. This may also solve the problem discussed in the previous paragraph.

Not sure if any of this could apply to your issues. Good luck.

Brian

Estragon · October 2017

One way to get around the charger shutting down prematurely might be to set the float voltage to the same as absorb. I assume you wouldn't normally float using the generator anyway.

sw 5548 charging hicup

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