Outback FM80 End Amps vs FlexNet Return Amps

Hi All,
I'm just in the process of building/installing my new solar system and before I start commissioning everything I want to make sure I've understand sensible starting values for it. One thing in particular that has me puzzled is the methods of ending the absorb phase of the charge. I've forked out for the whole 9 yards - Mate3, FlexNet DC, Hub and two shunts - so I'm hoping that I can set the thing up to behave relatively intelligently. Ideally, I'd like to have it end the absorb stage based on the end amps measured by the FlexNet DC - which hopefully compensates for what is being pulled out via the inverter, if I understand correctly. I get that this won't be perfect, but hopefully it would be slightly less of a crapshoot than just putting a time limit in.
Unfortunately, nothing that i've found so far in the manuals explains the relationship (if any) between the "return amps" that you configure for the FlexNet and the End Amps value that you set for the CC itself. Is there a way to make the CC go into float based off the value from the FlexNet? Or am I just stuck with trying to approximate the background load and/or putting a time limit in?
Cheers,
Lucian
I'm just in the process of building/installing my new solar system and before I start commissioning everything I want to make sure I've understand sensible starting values for it. One thing in particular that has me puzzled is the methods of ending the absorb phase of the charge. I've forked out for the whole 9 yards - Mate3, FlexNet DC, Hub and two shunts - so I'm hoping that I can set the thing up to behave relatively intelligently. Ideally, I'd like to have it end the absorb stage based on the end amps measured by the FlexNet DC - which hopefully compensates for what is being pulled out via the inverter, if I understand correctly. I get that this won't be perfect, but hopefully it would be slightly less of a crapshoot than just putting a time limit in.
Unfortunately, nothing that i've found so far in the manuals explains the relationship (if any) between the "return amps" that you configure for the FlexNet and the End Amps value that you set for the CC itself. Is there a way to make the CC go into float based off the value from the FlexNet? Or am I just stuck with trying to approximate the background load and/or putting a time limit in?
Cheers,
Lucian
Outback VFX3048E, Outback FM80, Outback FNDC, Outback Mate3, Outback Hub4, 15x Munchen 250W panels (5x3), 8 x Rolls S605 (48V system)
Comments
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--vtMaps
Thanks for the responses, I understand that the FlexNet DC can measure the actual battery current - what I was looking for was some Outback-specific guidance on the correct configuration to make sure that the FM80 uses the value measured by the FlexNet to terminate charging rather than its own current measurement. At the moment I can't find anything conclusive in the manuals. There's an advanced setting for the FlexNet called "Enable Charge Termination Control", but the description says "allows the battery charging to be stopped for all inverters on the system, once the charging parameters of the Flexnet DC have been met" (emphasis mine). Not sure if this is just bad wording or whether this setting really does only apply to inverters and not charge controllers.
Do I need to head over to the Outback forums to get an answer to this?
Cheers,
--vtMaps
Cheers!
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Hi Lucian,
Am certain that you have seen the FNDC Topic on the OB Forum. There does appear to be some general disappointment with the functionality of the FNDC, there. Just in case, here is a Link:
http://www.outbackpower.com/forum/viewforum.php?f=28
I Agree, that EA is a very good way of ending Absorb, and have used EA, for over a decade on all systems here -- first with the OB MX-60s, and now with MidNite Classics and the WBjr current monitor, paired with the Classics. Just needed to tweak the Vabs and EA settings, quite recently, due to battery aging.
Good Luck, Vic
I am not saying that this is something to gloss over but it is the biggest advantage of flooded! You can measure SG and slight overcharges of voltage and time are not going to be a problem. Keep water above the plates, do your EQ's and keep the tops clean and you will be in the cat birds seat for many years.
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