diy solar

diy solar

Outback Power Flexmax 60 80 stuck in "Charged"

snoobler

Solar Honey Badger
Joined
Jul 10, 2020
Messages
8,390
Location
HBR, AZ
This is intended for Outback Flexmax 60 or 80 owners.

My neighbor went with dual FM80 units for his 4kW array (2X 2kW) and 24V 24kWh battery. One has been working for maybe 3-4 months. The second was just installed this last weekend to work with his 25 year-old 1500W array because - that's what he had, and it was sitting unused.

I'm accustomed to my Victron behavior - once absorption termination is reached, it immediately goes to float mode. The FM80 differs from this by have a "charged" state where it's between the end of the absorption charge but above float voltage. In normal operation, this is usually barely a flicker of "charged" on the screen before it goes to float.

About 5 or 6 times, the FM80 has been stuck in the "charged" state. Even if the battery drops below float (27.1) and even the re-bulk voltage (25.2), it stays in the "charged" state and provides no solar power for charging or loads.

The installation of the second charge controller was done primarily to assess the health of the old Siemens panels (they're hurting - maybe 500W capable out of 1500W) AND provide a "backup" option in case the primary charge controller gets stuck in "charged" again. The thinking is that it's much less likely that TWO units will do it simultaneously.

Has anyone ever seen their FM60 or FM80 get stuck in the "charged" state?
 
Yes, my fm80 did exactly the same. It drained my batteries in full sun! Rebulk didn’t work...
I took me a while before I noticed it.
3600€ of batteries died because of this!
Fm80 was still under warranty. New one is just delivered...
 
Thanks for the info. When did this happen? I'm thinking it's a software bug, and it's fixed in a FW update, which can only be done at the factory.
 
I have firmware 003.003.000. That is the latest,no? I don't think it is a software related problem. It got worse over time. At the end it happened every few days. Tech support analysed the data from my mate 3 and they confirmed the weird behaviour. They checked my setup and we did a bunch of test because they wanted to exclude that It had something to do with the other components in the system, nothing solved the problem, and they send me a new one. I'll install it next week and let you know how it worked out... I found other posts about this on other forums, so more people have this problem.
Force float fixes the problem, untill the next time it happens...
 
Thanks. This is a standalone unit w/o Mate 3. Not sure of the firmware.
 
I have firmware 003.003.000. That is the latest,no? I don't think it is a software related problem. It got worse over time. At the end it happened every few days. Tech support analysed the data from my mate 3 and they confirmed the weird behaviour. They checked my setup and we did a bunch of test because they wanted to exclude that It had something to do with the other components in the system, nothing solved the problem, and they send me a new one. I'll install it next week and let you know how it worked out... I found other posts about this on other forums, so more people have this problem.
Force float fixes the problem, untill the next time it happens...

@Elephantbud

Any update?
 
No, but it's essentially not an issue anymore.

With two running, I can't recall it happening to both, and my neighbor would only notice if he saw his battery SoC or voltage go low. Has a trimetric indoors. Even less likely now that both have 1980W on them.

One will always show "charged" every day during absorption as the battery can't take output from both, but at least one has always picked up and maintained float.
 
interesting. I am learning since adding a victron into the mix. I might need to switch the load dump over to the victron, as the outback will remain in the charged state for quite some time before ever going into a float now. Especially if the outback finishes the absorption before the victron. The victron will easily maintain the float without any need for the outback to come online.
 
I had two FM80's and it seems like if I remember that the units would occasionally be in the charged state with the panels still producing power and nothing going into the batteries. I think that i dealt with it by keeping the units from going into the charged state in the first place.

Bulk mode is just constant current. It uses the maximum current from the panels up to 80 amps unless you set the current lower. Set the Absorb voltage to a setting where the batteries are happy and not to high as to destroy them. Go in the advanced menu and set the Absorb timer to 8 hours or so. This will keep it in absorb and not go into the float mode.

I think that once the sun went down then it went back to Bulk again the next day and I didn't see the charged state error. I also played with the rebulk voltage. Mine was a 48 volt system. I think if you work along the thought pattern of keeping it from float and the charged state and just keep it in either Bulk or Absorb then you will have your problem solved.
 
Last edited:
Back
Top