ex absorb

Discussion about the FM100, FM80, and FM60 Charge Controllers

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mikecmt4@gmail.com
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ex absorb

Post by mikecmt4@gmail.com » Sun Sep 08, 2019 7:16 am

cant get an answer from support so , can anyone explain how to resolve the ex absorb issue, i have read manual and there is no solution offered

raysun
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Re: ex absorb

Post by raysun » Sun Sep 08, 2019 8:40 am

What is the ex Absorb issue?

pss
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Re: ex absorb

Post by pss » Sun Sep 08, 2019 10:34 pm

From the Flexmax manual:

EX-Absorb
There is an external DC source other than PV keeping the battery above the Absorbing voltage set
point. The FLEXmax will stop charging because it is not needed.

So this would suggest that you have improper wiring configuration or your inverter or other DC source is charging your batteries.

Let us know please.

mikecmt4@gmail.com
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Joined: Tue Sep 03, 2019 4:56 pm
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Re: ex absorb

Post by mikecmt4@gmail.com » Mon Sep 09, 2019 7:38 am

batt bank is not getting full charge so when generator comes on it bulks for a few seconds then goes to ex absorb, i ran gen 4 hours to charge full and couple hours after, gen came back on , i am set for 50% discharge, batt bank is new 400amph 6 volt agm, i have reset fm80 3 times with same results, i have to think it is not set up right or i need an upgrade, have used this fm80 6-7 years and only recently experienced this issue, to include the former batt bank

sparksalot
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Re: ex absorb

Post by sparksalot » Mon Sep 09, 2019 8:16 am

Too high off resistance through total battery circuit/connections gives false or inaccurate charge results...lower resistance to improve both charge and discharge.
Clean tight connections on thick copper of shortest length...this allows battery to be best it is capable of...

raysun
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Posts: 755
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My RE system: Flexpower One: FX3048T, (2) FM80, MATE3s, FlexNetDC
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Suniva 330 watt panels (12 - 6 Strings @ 2 Series)
Hyundai 355 watt panels (6 - 3 strings @ 2 series)

Re: ex absorb

Post by raysun » Mon Sep 09, 2019 9:14 am

pss wrote:
Sun Sep 08, 2019 10:34 pm
From the Flexmax manual:

EX-Absorb
There is an external DC source other than PV keeping the battery above the Absorbing voltage set
point. The FLEXmax will stop charging because it is not needed.

So this would suggest that you have improper wiring configuration or your inverter or other DC source is charging your batteries.

Let us know please.
When using multiple chargers, the FM80 needs to be set so that it has priority. In Absorb and Float, the voltage needs to be set higher than the Absorb and Float voltages of the other charger(s) by 0.1 per 12v. For example a 48V battery might have an Absorb setting of 57.6V on the FM80 and 57.2 on the other charger, and a Float setting of 54.4 and 54.0 on the other charger.

This works fine if: both chargers are using temperature compensation at the same rate; and there is enough solar PV harvest to complete the charge cycle.

pss
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My RE system: 8330 watts in three strings, Flexmax 60 x 3, Radian 8048A, GSLC load center, Mate 3S, Hub 10.3, FN-DC and 900 Amp, 48V Trojan T105-RE battery bank.

Re: ex absorb

Post by pss » Mon Sep 09, 2019 10:03 am

Lots of good points being made. I am still a little confused. You say your generator comes on and charges the batteries. Your inverter and battery bank appear to be 24 volt. How exactly does your generator charge your batteries? Or did you mean your generator supplies AC power to your inverter and the inverter's charger then charges up the batteries. If that is the case, then the information provided to set the voltages higher for the Flexmax to supercede the inverter's charger are very important.

As for wiring to your batteries, make certain all connections are tight. Also, if you can, use a laser pistol grip type thermometer. Compare the temperature of the wires with a load being supplied to ambient temperature of a surrounding surface. Also, obtain the temperature of each battery terminal. They should all be the same and not elevated. If you spot a high temperature anywhere, make sure the connection is secure. Also, refer to your battery owner's manual to make certain charged voltages, absorb voltages, float voltages, and times are correct as well as the maximum charging amperage your battery bank can receive so as to not charge too quickly. Set these into the Flexmax and then set the inverter's parameters lower by about 0.2-0.3 volts and shorten the times on the inverter's absorb timer.

Let us know what happens.

mikecmt4@gmail.com
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Re: ex absorb

Post by mikecmt4@gmail.com » Mon Sep 09, 2019 10:45 am

thanks pss, the gen is set to come on when batt v gets low, 50% discharge, all fittings clean and tight, when ags turns gen on it runs inverter but none to little batt charging taking place,that is when i get ex absorb on fm80, i use magnum remote, no hub or mate, just checked batt bank is at 25.95 , cloudy day getting 68v and 4 amp in today, absorb is done at 1.5 hours, i have fm80 and magnum remote set at the same values?

pss
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Posts: 273
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My RE system: 8330 watts in three strings, Flexmax 60 x 3, Radian 8048A, GSLC load center, Mate 3S, Hub 10.3, FN-DC and 900 Amp, 48V Trojan T105-RE battery bank.

Re: ex absorb

Post by pss » Mon Sep 09, 2019 11:29 am

25.95 is charged, reduce voltages on the magnum inverter below absorb of flexmax and set float to about 25.

Make sure absorb is about 3 hours in flexmax.

Question: how exactly does generator know when 50% amperage capacity of batteries has been withdrawn?

mikecmt4@gmail.com
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Re: ex absorb

Post by mikecmt4@gmail.com » Mon Sep 09, 2019 12:08 pm

it is a network ags unit and is plugged in to inverter and set to 23.8volts to come on, was told that was 50% discharge

mikecmt4@gmail.com
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Re: ex absorb

Post by mikecmt4@gmail.com » Mon Sep 09, 2019 12:28 pm

ok , set as you suggest , will let you know, thanks pss

mikecmt4@gmail.com
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Posts: 7
Joined: Tue Sep 03, 2019 4:56 pm
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Re: ex absorb

Post by mikecmt4@gmail.com » Mon Sep 09, 2019 6:14 pm

thanks pss, that seems to help my problem, i am adding another array, do i need a hub to manage 2 fm80s ?

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