The Phi Season Changes

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JRHill
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The Phi Season Changes

Post by JRHill »

In the October-Feb frame I run the genset in the evening while at the highest load on the day and wake up with them at ~80%. They have an easy life and I don't charge until full (55.6) and I'm good until the next evening's run. Day in and day out without solar, or only a few watts incoming. It's a 2.5 hour run at 20AAC.

Then come the longer days with clear sky like right now. At this early season with a clear sky and cool temps for the panels I'm full by noon. At that time Absorb hits its target and charging is done as the Phis fall toward float (52.9). I have moved rebulk up to 52.7. I try to steal away some solar input doing things like running the washing machine on its Allergen cycle which hogs 1.5kW for electric heating. Also a cheap space heater in the back rooms. But not at the same time - that's a bit much. All I'm trying to do is move 'full' a bit later so I head into night at a higher SOC. During these times I drop into the high 50's for SOC. At least SOC reset as determined full at 55.6. I do a full recharge at 56.4 every few weeks for cell balancing. A full 56.4 doesn't make that much difference in the next morning's numbers as those extra few watts into them don't amount to much other than balancing.

Yesterday I loaded the heck out out the system with loads and actually hit rebulk. That was an act of intentionally loading the system to excess. And go figure, it was too late to rehit the Absorb. In the morning I was at the same high of 58%.

My question is what do you do to extend the absorb set point to later in the day IF you have the input? I don't want to do a dump load and it would be a mess. This goes to the old conversation of "What does one do with excess?"
raysun
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Re: The Phi Season Changes

Post by raysun »

If I had a 5 gallon bucket that I wanted to fill and keep at 4¾ gallons, I guess I have two choices:
• Start pouring slowly, adjusting the rate so the bucket hits the full mark at the end of the day.
• Fill the bucket to the mark, then add a bit over the course of the day to maintain at that level.
The first option is a bit "fiddly" and time-consuming. At some point, someone's going to ask what I'm doing out there. Other chores are waiting.
The second option is what our tools are designed to do.
Charging to less than 100% is fine. Since the battery isn't deeply discharged, cell balancing isn't even much of an issue, but good housekeeping practice.
The key, IMO, is adjusting Float to meet the average workload after the Bulk charge has completed (as indicated by "Absorb" terminating.) 52.9V as a "floor" leaves a good deal of upward adjustment. I feel I've hit the bullseye when the day concludes with the same charge on the battery as when Bulk/Absorb completed. Alternately, you may simply pick a "ballpark" voltage target.
I'd try raising the Float Voltage a bit.
JRHill
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Re: The Phi Season Changes

Post by JRHill »

"I'd try raising the Float Voltage a bit."

But, but, they are already at 100%. And holding them high is a no-no. I get what you mean Raysun. Holding them at 56.4 is the no-no, no? (wink)

"• Fill the bucket to the mark, then add a bit over the course of the day to maintain at that level." And that is the issue. Adding a bit more. The only way to do that is to raise the float. So I'll take it to 53.1.... Rebulk to 52.8.

You said Phi's don't count cycles only time since commissioning. Is that still true?
raysun
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Re: The Phi Season Changes

Post by raysun »

When I talked to Phi a few weeks ago, they only wanted to know when the battery was put in service, not how many charge cycles was on it.
raysun
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Re: The Phi Season Changes

Post by raysun »

Charging some with gas today.
Screenshot_20240316_155949_VRM.jpg
Passing the same point on discharge.
Screenshot_20240316_170625_VRM.jpg
JRHill
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Re: The Phi Season Changes

Post by JRHill »

raysun wrote: Sat Mar 16, 2024 7:22 pm Charging some with gas today.
Screenshot_20240316_155949_VRM.jpg
Passing the same point on discharge.
Screenshot_20240316_170625_VRM.jpg
That's an interesting comparison. Esp catching the up and down at the exact same instant.

I increased the float to 53.1 and can see some watts going into the batteries before sun down on some days now. But it has made little noticeable difference to the SOC in the morning. But two days ago I noticed I left a light on in the shop at bedtime but shrugged it off. But I had also left the air compressor on and it cycles every so often due to a small internal leak down. Oops. For some reason the Victron was beeping at me while I was nuking some coffee the next morning.
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