Outback AC Source Charging Issues |
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Observations on some odd results when charging lead-acid batteries by generator on Outback equipped off-grid systems. |
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The proper charging of lead-acid batteries is very time-dependant. Those chemical reactions aint gonna happen instantly. A typical setting for absorption of VRLA (UnigyII) batteries is 57.6 to 58.4 for three hours. for flooded lead acid it is about 58.0 to 59.0 for 3 hours. The Outback inverters do not seem to be holding the absorption for the programmed absorption duration. |
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| Below are graphs of the a generator charging cycle on 5 Outback sites. They have a variety of inverters and a a mix of Radian and FX derivative inverters. The yellow ellipse points to the peak voltage during charging. That peak is maintained for about an hour. In all cases the peak should actually be a plateau of 3 hours duration. Click any thumbnail for a larger image. | |
Client DH. Four Radian inverters charging 2900AH of UnigyII |
Client JRM. 4 VFX3648 charging Deka 2 volt flooded cells. |
Client PV. Two Radian 44048A charging VRLA ~1800AH UnigyII VRLA |
Client SC. 4 FXR3648 charging 16 MK L16 flooded. |
Client TT. 2 Radian 8048A charging ~1500 AH UnigyII VRLA. |
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| Below is a screen shot of typical settings for battery charging on these inverters. | |
Typical charge settings. Note 3 hour absorb setting. |
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| As an experiment I performed a 3 hour equalization on one of the systems. The inverter did hold voltage for the prescribed 3 hours. See graph below. | |
EQ period of 3 hours indicated within yellow ellipse. This is the kind of curve that should be seen during absorption charging. |
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| Some of these systems have FNDC battery monitors and some do not. In none of the cases is the FNDC programmed to control generator start/stop. One Outback tech support person suggest I unplug the FNDC from the hub and after doing so there was no change in the charging profile. | |
| Outback also told me the firmware on the Radians at client PV was one step too advanced to be compatible with a Mate3 and I was instructed to downgrade the inverter firmware. In my opinion this recommendation is not appropriate. Many sites with the correct firmware are exhibiting this same problem. | |
| I will be reaching out to Outback to put some more serious thought into what may be causing this problem I invite them to look into the settings and configurations for all of these system to see if I might have set something wrong on all of these systems or what else it might be. | |
| I am also asking colleagues in the industry to share any experience they may be having that might be similar, and to look at the charging profiles on their own systems to see if any incidence of this unusual behavior is observed. | |
