FM80 snoozing when it shouldn't
I've owned an Outback FM80 for about three months. Initially it worked perfectly. Recently it has decided to go into snoozing mode in the middle of the day with the batteries are partway through the bulk cycle. Batteries are not overheated, plenty of sun. My settings for 24 volt system are 27.6 float 29.8 bulk absorb 2 hours end amps zero. Typical charging amps range from 25 to about 60 so well within the 80 amp limit. My building uses on average 5 Kw-hr/24 hour day which so far has been replaced daily. Since sun hours are now starting to diminish, I would love to halt this peculiar behaviour.
I've visited the Outback forum but it presently has locked me out; can't change password etc.
FWIW the unit will reset itself and go back into tracking and bulk charge modes but will then inexplicably go back into snooze mode sometimes within a few minutes.
Do I have a lemon here?
I've visited the Outback forum but it presently has locked me out; can't change password etc.
FWIW the unit will reset itself and go back into tracking and bulk charge modes but will then inexplicably go back into snooze mode sometimes within a few minutes.
Do I have a lemon here?
Island cottage solar system with 2500 watts of panels, 1kw facing southeast 1.3kw facing southwest 170watt ancient Arco's facing south. All panels in parallel for a 24 volt system. Trace DR1524 MSW inverter, Outback Flexmax 80 MPPT charge controller 8 Trojan L16's. Insignia 11.5 cubic foot electric fridge. My 29th year.
Comments
https://forum.solar-electric.com/discussion/10407/outback-flexmax-80-always-snoozing
https://forum.solar-electric.com/discussion/18280/mx-60-controller-stuck-in-sleeping-mode
https://forum.solar-electric.com/discussion/3472/fun-with-mppt-whats-causing-this
You can search the forum by typing into Google, duckduckgo, etc. (you can change the site tag to any website):
site:https://forum.solar-electric.com outback controller sleeping
This has been a going back 12 years:
http://www.outbackpower.com/forum/viewtopic.php?f=29&t=3142&p=18784&hilit=current+sense#p18784
I do not know what the "present sleeping issues" may be... Contacting Outback service may be a good start.
-Bill
Let us know what cures its ills!
-Bill
When the CC is Bulking, what is the Vin, then ?
Thanks, Vic
Some things Change back but a lot of my setting stayed the same.
And it worked .
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Rethinking, I think you need to rewire, just because you saw mide 30's on the solar does not mean that it dipped and triggered snooze. If it is not hard to do this, I would. Even a decent logging voltmeter might miss a cloud voltage drop. They are fast. The loss at 2 panel in series when charging is almost negligible offgrid for 24v.
It would drive many of my clients nuts to see a load come on in the day and not be covering it with the solar. If you rewire you will have less drop on the wire run and can add even more panels.
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Re: FM80 snoozing
Unread post by pss » Sun Jul 26, 2020 9:12 am
Your battery bank has 740 amps at 24 volts. That's 17,760 watts. If discharged by 50%, that's 8,880 watts. You have 1980 watt array, split into 2 directions, so really a 1K watt array at any time. Therefore, YOU CANNOT CHARGE YOUR BATTERIES WITH PV.
Next, you have an inverter that does not communicate with your charge controller. And you are reliant on what little PV you get PLUS either generator or grid or both to properly charge your batteries. It is necessary to put the Flexmax 80 at the "head of the class" when PV is present by making certain that the voltage settings for bulk/absorb are 0.2-4 volts higher on the Flexmax than on the inverter or generator. Set your absorb time to 4 hours.
Since your system can be termed 'unbalanced", meaning too little PV to support the size of the battery bank, you can either remove one of your strings of batteries and charge it with a different source entirely or add PV. For that size battery bank, about 6K watts of PV depending on your location would do the trick with another Flexmax 80, add a Outback hub and a Mate 3S too.
Now for your question, the charge controller may just be experiencing voltages that are too low or amps too low and deferring to the charger on say an inverter if that is present and heat is not an issue. That is why it is important to make sure settings on both chargers are correct. Your inverter has a 25 amp AC charger, that is 3,000 watts, at say 28 volts, that would be 107 amps into your battery bank. That would overwhelm your Flexmax 80 capacity. And your batteries should have their maximum charge current set properly which is about 13% of the C20 hour rating. In your case this is roughly 96 amps of charging current at one time from all sources.
Would like to hear more about your settings then to add further insights.
Re: FM80 snoozing
Unread post by 706jim » Tue Jul 28, 2020 12:51 pm
While I don't disagree with Trojan's 10-13% charging current recommendation, I should point out that I ran a 660AH battery (12 GC's in series parallel) for 19 years (6 month seasons) with only 400 watts of solar charging them. So you CAN charge a large battery with less current if you don't kill them with excessive DOD. When I started PV in 1994, panels were awfully expensive and batteries relatively cheap. That minimal system usually reached float by the end of a sunny day as well. I increased panels and batteries two years ago to allow an electric fridge to be used.
As for grid tie, I'm on an island in Lake Superior. There will never be grid power out here so PV will be doing all of the charging.The Trace has a 35 amp charger that could be used with generator backup but I'm sure this is 35 amps at nominal 24 volts; about 700 watts.
Re: FM80 snoozing
Unread post by pss » Tue Jul 28, 2020 1:04 pm
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The other side of your current problem is as the temps go down in the fall, the system may operate fine the way it is currently wired. A chess game for sure.
What make of guitar? Looks like one of Malcolm Young's old gretches
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Back to the solar wiring, we use this place from May until the end of October. After that the only loads will be the current needed to run the charge controller. The panels are set 30 degrees from vertical so will shed snow for part of that 6 month period.
See what Outback says. INO you are too close from 30vdc bulk and solar in at 35vdc. Maybe I am wrong but I would always wire a 24v battery with at least 5o vdc solar or more on mppt.
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