Generator to maintain batteries

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jarmstrongnelson
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Generator to maintain batteries

Post by jarmstrongnelson »

I have read many of the posts concerning generators in conjunction with Outback systems. I haven't found an answer to my question and neither emails or phone calls have gotten and answer from Outback, so I will try here.
I have a 240 volt Outback Radian GS8048A system fed by two 3500 kw panels. I was planning to maintain battery charge with a Champion 7kw dual fuel generator wired for 30 amp 240 volts.

During a recent outage I fired up the generator for the first time with the radian and hooked it up to my inverter(wired in by licensed electrician). Side note, I ran the whole house with this generator prior to installing the solar system with no issues. I kept getting frequency too low or too high from the Mate3. Frequencies varied from 59.4 to 60.5 and apparently was not close enough for the inverter. I have decided to purchase an inverter generator and need to know if a 30 amp 120 volt generator will work with the system if I change the settings in the Mate3. I haven't been able to find a dual fuel inverter generator with 240 volt capability in the 4kw to 7 kw range. Thanks for any advice you might be able to give me.
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Greg T Fordan
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Re: Generator to maintain batteries

Post by Greg T Fordan »

With your Champion 7kW generator, are you setting up your Radian for AC Input Priority to Generator and Gen Input Mode to Generator? Those two fields are needed to accept the AC coming from the generator with more tolerance. There should be no issue in accepting the frequency range that you mentioned.


The other generator that you just purchased (120V 30A) will not work with the Radian, because the Radian needs a full 240/120 wiring input, which your Champion generator is supposed to provide.
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jarmstrongnelson
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Re: Generator to maintain batteries

Post by jarmstrongnelson »

Thanks for your help. I was hoping my existing generator would work. Still pretty new with little run time on it. I haven't purchased another yet, just had two smaller inverter generators for my RV, but only 120 volt.

I have changed the Gen Input Mode to Generator so next time it should work okay. Fingers crossed. AC Input Priority was already set to Generator. Installers didn't really seem to know how to set it up for me. I appreciate your expertise.
Joe Armstrong-Nelson.
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Re: Generator to maintain batteries

Post by Buy_Bitcoin »

Does your system receive incoming solar PV electricity while your generator is operating? If i turn everything on in my building, i use considerably more than my solar array, so after my batteries are drained to the threshold, my generator kicks on and runs until its at 90%. While the generator is running opticsRE does not show any incoming solar. Is this because my generator is providing more power than the inverter can handle? My inverter is the 8048 and my generator is a 15KW Eco-Gen.
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Re: Generator to maintain batteries

Post by raysun »

Buy_Bitcoin wrote: Tue Jul 27, 2021 12:36 pm Does your system receive incoming solar PV electricity while your generator is operating? If i turn everything on in my building, i use considerably more than my solar array, so after my batteries are drained to the threshold, my generator kicks on and runs until its at 90%. While the generator is running opticsRE does not show any incoming solar. Is this because my generator is providing more power than the inverter can handle? My inverter is the 8048 and my generator is a 15KW Eco-Gen.
The Flexmax charge controller works autonomously, and uses the sensed battery voltage to determine its charging state. (A bit oversimplified but appropriate for this response.)

When the inverter accepts the generator input, AC IN is routed to AC OUT to service the "house" loads, the inverter switches to charger mode, and charges the battery (autonomously) in parallel with the Flexmax. It uses sensed battery voltage to manage charger states as well.

Small differences in the sensed battery voltage will cause one charging source to have "priority" over the other.

To allow the Flexmax to have priority (so maximum solar harvest can be attained) the Absorb Voltage and Float Voltage on the inverter charger should be set 0.4V lower than the equivalent voltages on the Flexmax.

For example, if the charging specs call for 58V Absorb Voltage, set the Flexmax Absorb Voltage = 58V, and the Inverter charger Absorb Voltage = 57.6V. Do the equivalent with Float Voltage.
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Re: Generator to maintain batteries

Post by Buy_Bitcoin »

I set the charging specs on the Flexmax for both absorb voltage and float voltage to 57.6V, which is recommended by battery manufacturer. I set my inverter charger to 57.2V, and it did nothing different. any other suggestions?
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Re: Generator to maintain batteries

Post by raysun »

Buy_Bitcoin wrote: Wed Jul 28, 2021 12:21 pm I set the charging specs on the Flexmax for both absorb voltage and float voltage to 57.6V, which is recommended by battery manufacturer. I set my inverter charger to 57.2V, and it did nothing different. any other suggestions?
That's the most unusual float spec I think I've ever seen. What sort of battery is it?

Is there an FNDC in the system?
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Trojan AGM batteries 375 AH x (2) = 750 AH

Re: Generator to maintain batteries

Post by Buy_Bitcoin »

FNDC.. I googled it and still unsure what that is... Finally put it together, Flexnet DC. Yes, my systems is a 48volt, and has solar array, outback inverter 8048, (2) 1000Flexmax charge controllers, a Flexnet DC, a hub, and a Mate3s. My batteries are Trojan, and for charging, it recommends 57.60 volts for absorption and 54.00 volts for float. I misunderstood your post, so i tweaked the settings again and will try it. I'm curious why you asked about the FNDC... Should I try to use it for AGS in lieu of the inverter? I thought i read somewhere that the FNDC was more accurate on voltages and SOC readings?
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Re: Generator to maintain batteries

Post by JRHill »

Buy_Bitcoin wrote: Wed Jul 28, 2021 2:00 pm Should I try to use it for AGS in lieu of the inverter? I thought i read somewhere that the FNDC was more accurate on voltages and SOC readings?
Huh? Please clarify. You've got a really nice system. What are you trying to do?
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Re: Generator to maintain batteries

Post by raysun »

With the FNDC, two advanced charging parameters could be enabled:
Global Charge Control (Mate)
Automatic Charge Termination (FNDC)

Are either enabled?
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Re: Generator to maintain batteries

Post by JRHill »

For me I use the inverter for the generator. But it all depends on how your generator starts. I like the inverter: 12vdc in and generator runs. 12vdc gone generator shuts down. Simple. It works. I still have to run a cheap automotive relay to change 12vdc to open/closed. I have hade one relay fail a few years ago. Dang, it was less than $4 with free shipping and I bought a few extras.

Still I ask, what is the problem?
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Trojan AGM batteries 375 AH x (2) = 750 AH

Re: Generator to maintain batteries

Post by Buy_Bitcoin »

raysun wrote: Wed Jul 28, 2021 5:13 pm With the FNDC, two advanced charging parameters could be enabled:
Global Charge Control (Mate)
Automatic Charge Termination (FNDC)

Are either enabled?
Both the Global Charge and the Automatic Charge Termination are both set at their defaults, which is DISABLED. What kind of subsection is Global Charge? If there wasn't a clear instruction on how to or why to or what to use/change, then i left settings at default. Being that it's disabled by default, i assumed it wasn't something i needed to mess with.

Seems like there's so many settings, I need to be a genius to put it all together.
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15kW Generac Eco-Gen Generator
Trojan AGM batteries 375 AH x (2) = 750 AH

Re: Generator to maintain batteries

Post by Buy_Bitcoin »

JRHill wrote: Wed Jul 28, 2021 2:22 pm
Buy_Bitcoin wrote: Wed Jul 28, 2021 2:00 pm Should I try to use it for AGS in lieu of the inverter? I thought i read somewhere that the FNDC was more accurate on voltages and SOC readings?
Huh? Please clarify. You've got a really nice system. What are you trying to do?
Hello. I'm probably not replying or posting correctly, i'm new to this site. This is what I'm trying to do: When my AGS kicks on to charge batteries back up, my system appears to stop incoming solar... I'd like to have solar incoming while the AGS is running so it tops off my batteries off the batteries sooner, uses less fuel, and obviously uses the solar that I know it should be producing.

As an example. I'm at 95% on the batteries, and I turn everything on. Now i'm using 7000 or 8000 watts per hour, and it drains my batteries quickly. When SOC gets to 75%, my generator kicks on automatically. My generator is set to run until the SOC on batteries are 90%. My system apparently stops the incoming solar when the generator kicks on. So I'm left with a dilemma. Do i change the SOC to 85% or 80% and let the generator kick on and off a bunch of times, or do I just let the generator run a lot longer even though it's sunny and I could have incoming solar. I feel like I'm not articulating very well. I don't need my generator running when the SOC is 85% and I have full sun and using 3500 watts of electric, because the solar could handle that 3500 watts, no problem.
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Re: Generator to maintain batteries

Post by raysun »

Both the Global Charge and the Automatic Charge Termination are both set at their defaults, which is DISABLED. What kind of subsection is Global Charge? If there wasn't a clear instruction on how to or why to or what to use/change, then i left settings at default. Being that it's disabled by default, i assumed it wasn't something i needed to mess with.
Disabled for now is good. They are both useful, but can complicate things when trying to resolve a charging issue.
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Re: Generator to maintain batteries

Post by JRHill »

Buy_Bitcoin wrote: Fri Jul 30, 2021 8:06 am
JRHill wrote: Wed Jul 28, 2021 2:22 pm
Buy_Bitcoin wrote: Wed Jul 28, 2021 2:00 pm Should I try to use it for AGS in lieu of the inverter? I thought i read somewhere that the FNDC was more accurate on voltages and SOC readings?
Huh? Please clarify. You've got a really nice system. What are you trying to do?
Hello. I'm probably not replying or posting correctly, i'm new to this site. This is what I'm trying to do: When my AGS kicks on to charge batteries back up, my system appears to stop incoming solar... I'd like to have solar incoming while the AGS is running so it tops off my batteries off the batteries sooner, uses less fuel, and obviously uses the solar that I know it should be producing.

As an example. I'm at 95% on the batteries, and I turn everything on. Now i'm using 7000 or 8000 watts per hour, and it drains my batteries quickly. When SOC gets to 75%, my generator kicks on automatically. My generator is set to run until the SOC on batteries are 90%. My system apparently stops the incoming solar when the generator kicks on. So I'm left with a dilemma. Do i change the SOC to 85% or 80% and let the generator kick on and off a bunch of times, or do I just let the generator run a lot longer even though it's sunny and I could have incoming solar. I feel like I'm not articulating very well. I don't need my generator running when the SOC is 85% and I have full sun and using 3500 watts of electric, because the solar could handle that 3500 watts, no problem.
Ah, no, it not an articulation problem but one of getting a handle on the environment. Back further you were asked about hardware involved. Most of us put a semi-detailed list in our profile so it shows up in our posts on the right sidebar instead of scrolling back through messages to see if it was listed earlier within a message. Please do this if you will, its not a security risk. And please say which Trojan batteries you are using.

But before we go much further please consider using ONLY the 2 min voltage start for AGS, for a while. Pick the average bottom voltage you want for your batteries (I used 50.5 with my Trojans but didn't have your loads). Disable the SOC start. Why? Regardless of how old your batteries are, how maintained, and how accurate the SOC displayed is at the moment your batteries will call for help based upon voltage and that number doesn't lie. Then tune your charge parameters for the CC and the inverter. For the inverter pick an Absorb voltage for the approximate equivalent SOC you want from Trojan's data sheet for your battery and a minimal Absorb time. For the charge controller set it to fully charge the batteries since the power is free.

The above is how I did AGS with the Trojans and I do the same with lithiums now. No SOC start/stop. If you try this please tell us how it is working or not.
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Re: Generator to maintain batteries

Post by raysun »

During a "normal" charge cycle, charge controller charging current and inverter charging current will combine, using both sources to charge the battery. This is especially so during the Bulk phase, which is putting as much current as is permitted into the battery. Bulk is referred to as a constant current phase.

During the Absorb phase, the battery is held at a constant voltage. The charging current varies to maintain the constant voltage state. If both chargers are active, their combined charging current may not be needed and one or the other may drop out. A small voltage rise above the charger's Absorb setpoint causes it to go idle as it has nothing to do.

The above is the same for the Float stage. Once a battery has been fully charged, the chargers will idle until the battery drops to the Float voltage. The Flexmax charge controllers, once a charge cycle completes, will stay in Float until the sun sets.

I don't use AGS so someone else will have to fill in the blank here, but I assume when the generator is triggered, it starts a new charge cycle, starting with Bulk. If this causes the battery voltage to rise above Float, the Flexmax could go idle.

The older FM charge controllers (60, 80) show status on their front panels. IDK how the FM100 shows its current status, but checking the state of the controller when it stops producing may give a clue.
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Re: Generator to maintain batteries

Post by JRHill »

raysun wrote: Fri Jul 30, 2021 9:24 amI don't use AGS so someone else will have to fill in the blank here, but I assume when the generator is triggered, it starts a new charge cycle, starting with Bulk. If this causes the battery voltage to rise above Float, the Flexmax could go idle.
This is true. When the AGS is triggered the inverter will start a complete charge cycle - but a charge cycle as you define it. That is the key in the programming. You want the gen to come on and shut off but not too often. You want the solar to carry the load (Charge controller programming).

If the genset comes on (dang, a 15kw) too often it can be tuned to your liking.
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Re: Generator to maintain batteries

Post by raysun »

An old app note, but useful background info on some of the more arcane aspects of battery charging, as well as overview of basics.)
https://www.outbackpower.com/downloads/ ... p_note.pdf

Again, I have zero hands on AGS knowledge, so all that follows is supposition...
• The trigger point for AGS, in this case using SoC, is set at a battery voltage above the REBULK voltage setting for the FM charge controllers. If such is the case, the FMs may simply be staying in Float mode, rather than resetting to Bulk mode to follow along with the inverter charger. If in this case, during AGS charging, the battery rises above the FMs' Float voltage setting, the FMs will go idle, with nothing to do.

Remember, the FM charge controllers are actually servicing battery charging, not servicing loads necessarily. If they think the battery doesn't need their charging service, they go idle.

You may wish to, as Jim pointed out, switch to AGS 2 minute start triggered on voltage, not SoC, and set the trigger voltage below the FMs' REBULK voltage. I'd expect doing so would cause the FMs to start a new charge cycle in sync with the inverter charger.

Hopefully, someone will read the above and amend it as needed.
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Re: Generator to maintain batteries

Post by JRHill »

raysun wrote: Fri Jul 30, 2021 11:45 amHopefully, someone will read the above and amend it as needed.
Yup. Com'on people. I know how I use AGS. It will probably not be the same this winter. It changes every winter. But can we get Mr Buy_bitcoin up and going?

He doesn't want to know that it may all change this winter. But we don't know his area. He might pucker at this. Yup. It may surely happen. Summer profile and winter profile. Go through it all again. But then he'll know what to do as the seasons change.

Sorry if I'm short. It's 103f. It's hard to do chores.
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REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
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Re: Generator to maintain batteries

Post by raysun »

The "here and now" is a good place to start.

AGS or not, getting the charge parameters right is necessary for inverter charger / charge controller coordination. In practice, its a matter of the voltage setpoints being compatible, the devices properly calibrated to accurately read the battery voltage, and the charger states being in sync.
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Re: Generator to maintain batteries

Post by sodamo »

Quote from OP
“ Do i change the SOC to 85% or 80% and let the generator kick on and off a bunch of times, or do I just let the generator run a lot longer even though it's sunny and I could have incoming solar.”

Using AGS, I favor running the gen to get the battery back to acceptable level then let the PV do the major work. While I’m hopeful that is a single run, if due to weather that proves not to be the case then the gen just runs again. Had this discussion with my installer when I did my upgrade and he agreed that was preferable to charging too much via gen and wasting the PV. I don’t think a battery really cares if charged by gen or PV or sees a difference.
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Trojan AGM batteries 375 AH x (2) = 750 AH

Re: Generator to maintain batteries

Post by Buy_Bitcoin »

This is really good info regarding the SOC settings for the AGS. Based on this, it makes a lot of sense that the SOC seems to be all over the map, but the voltage is the voltage, and that is accurate? The only issue i have with the 2 MIN start, is that i could get a big surge in loads where the voltage would fall below for, 5 or 10 minutes, and then it would be fine (or clouds come and go and the solar array isn't quite large enough to sustain). When the mini splits or pump or whatever is shutoff, the voltage immediately spikes back up. So it's hard for me to tell voltage because it doesn't seem like the voltage is accurate either.

I've been using the SOC on the AGS settings only. When batteries fall to 72-75%, the generator kicks on and runs until it's back at 90%.

I just learned about the 2 MIN start, 2 HR start, and the 24 HR start, so I just started to fiddle with them. It's just super unclear on what settings I should use, as it seems like the voltage will swing wildly depending on what is running or not running, and I can't see how there isn't anything more than just a big guessing game and trial and error hundreds upon hundreds of times. I'm shooting at a moving target, but the target is in a room full of mirrors. A lot of settings are left on default because my brain can't learn everything in one sitting, let alone the hundreds of hours i've spent learning and messing around.

I'm using Trojan batteries (SOLAR SAGM 06 375).

For my absorb voltage on the inverter, i have it set at 57.2. For the dual charge controllers, i have them set at 57.6 for absorb voltage..

JRHill wrote: Fri Jul 30, 2021 9:03 am
Buy_Bitcoin wrote: Fri Jul 30, 2021 8:06 am
JRHill wrote: Wed Jul 28, 2021 2:22 pm
Huh? Please clarify. You've got a really nice system. What are you trying to do?

Hello. I'm probably not replying or posting correctly, i'm new to this site. This is what I'm trying to do: When my AGS kicks on to charge batteries back up, my system appears to stop incoming solar... I'd like to have solar incoming while the AGS is running so it tops off my batteries off the batteries sooner, uses less fuel, and obviously uses the solar that I know it should be producing.

As an example. I'm at 95% on the batteries, and I turn everything on. Now i'm using 7000 or 8000 watts per hour, and it drains my batteries quickly. When SOC gets to 75%, my generator kicks on automatically. My generator is set to run until the SOC on batteries are 90%. My system apparently stops the incoming solar when the generator kicks on. So I'm left with a dilemma. Do i change the SOC to 85% or 80% and let the generator kick on and off a bunch of times, or do I just let the generator run a lot longer even though it's sunny and I could have incoming solar. I feel like I'm not articulating very well. I don't need my generator running when the SOC is 85% and I have full sun and using 3500 watts of electric, because the solar could handle that 3500 watts, no problem.
Ah, no, it not an articulation problem but one of getting a handle on the environment. Back further you were asked about hardware involved. Most of us put a semi-detailed list in our profile so it shows up in our posts on the right sidebar instead of scrolling back through messages to see if it was listed earlier within a message. Please do this if you will, its not a security risk. And please say which Trojan batteries you are using.

But before we go much further please consider using ONLY the 2 min voltage start for AGS, for a while. Pick the average bottom voltage you want for your batteries (I used 50.5 with my Trojans but didn't have your loads). Disable the SOC start. Why? Regardless of how old your batteries are, how maintained, and how accurate the SOC displayed is at the moment your batteries will call for help based upon voltage and that number doesn't lie. Then tune your charge parameters for the CC and the inverter. For the inverter pick an Absorb voltage for the approximate equivalent SOC you want from Trojan's data sheet for your battery and a minimal Absorb time. For the charge controller set it to fully charge the batteries since the power is free.

The above is how I did AGS with the Trojans and I do the same with lithiums now. No SOC start/stop. If you try this please tell us how it is working or not.
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sodamo
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My RE system: Totally off grid - Hamakua side, Big Island, Hi

36 Trina 280 & 16 Phono 250 in 48 volt array (fixed) 14080w
Radians GG8048/GS4048 w GSLCs
4 FM 80 charge controllers
Hub 10.3
FNDC w/3 shunts
Mate 3s
OpticsRE - MMKL - Ninole Hi
12 SimpliPhi 3.8
14Kw Kohler 14RESA Propane

Charging Only
2FX3048T
Hub
FNDC. - shared shunt feeds from Radian FNDC
Mate 3s
10Kw MEP 803a Military gen

Honda EU7000i

Davis VantagePro2 Wx Station
On line at: https://www.wunderground.com/dashboard/pws/KHININOL2
Location: Ninole, Hi

Re: Generator to maintain batteries

Post by sodamo »

AGS also has a Load start setting. I’ve no experience with it but maybe it is appropriate for your surge concerns. I considered it briefly for my hot tub, but as I only run during sunshine, I haven’t needed. Maybe someone here has experience using.
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My RE system: VFXR3648, FM80, 3k panels, Mate3s, FNDC, 4ea 3.8 PHIs. EU7000is AGS. X240 with big Bertha way off in the shop. Off grid.
Location: PNW
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Re: Generator to maintain batteries

Post by JRHill »

I hear your points. Let me reiterate: choose the lowest 2 minute voltage you are comfortable using. You are using lead batteries so the voltage drop is less than with, for example, lithium. In my system with LI my loads are light and I choose a voltage that works with my typical load pattern. Yours are heavier and you have lead but I suspect the load is somewhat consistent/predictable day by day so you choose a voltage you want when the load hits and the voltage drops due to load. Also keep in mind warm up time which will be a delay. I have no idea where you are weather wise and what is good for your generator longevity for warm up. For me, I have 3 minutes in the summer and 5 in the winter. So under a loaded voltage to the batteries you need to factor in the connection delay due to warm up. [Plz note my warm up times are completely based upon an eu7000is that runs year around in ECO mode so I need to allow extra time before it connects. Yours will be different but I'm making a point.]

I may still add another start up parameter for the winter as an experiment. We lose most of our direct sun for 3 months. I am looking at the Must Run on weekdays and weekends for a few hours in the morning. Then maybe I can get some cloud edge, etc. to add to the charge from solar through whatever I can harvest. I haven't found what happens if the charge is completed during the Must Run but still has time left to shut down time. I hope the inverter parameters rule and the genset shuts down. Who would know? Anyway, after that if the battery voltage drops later (snow covered panels) then the 2 min AGS kicks in if needed and runs a defined inverter charge cycle. I have never had the 2 or 24 hour voltage start execute. I don't bother with them.

Lastly: "let alone the hundreds of hours i've spent learning and messing around." What a useful way to use your time that goes way past a hobby. You will probably never have a non-participatory system on a regular basis.

Hope this helps.

Best, Jim
JRHill
Forum Emperor
Posts: 1875
Joined: Thu Feb 17, 2011 11:12 am
My RE system: VFXR3648, FM80, 3k panels, Mate3s, FNDC, 4ea 3.8 PHIs. EU7000is AGS. X240 with big Bertha way off in the shop. Off grid.
Location: PNW
Contact:

Re: Generator to maintain batteries

Post by JRHill »

sodamo wrote: Tue Aug 03, 2021 11:32 amAGS also has a Load start setting. I’ve no experience with it but maybe it is appropriate for your surge concerns. I considered it briefly for my hot tub, but as I only run during sunshine, I haven’t needed. Maybe someone here has experience using.
I have tried Load Start. Like the 2 hour and 24 hour settings I never had it execute. And again, if the genset is starting cold, it has to go through the warm up. by then the big surge may be done. So If I have a big load planned I just fire up the generator and run it for that time. Fortunately I don't have big loads that I am not in control over.
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