2 Concord 8D (258 AH each)Freedom 25 Inverter-Charger (130 amp)Trimetric 2025 GaugeI'm dry camping and charging my batteries. They were 30% discharged. My Concords call for 14.2-14.4v absorption and 13.2-13.4v float. My charger (20 years old) is set as close to those numbers as I could get at the wet cell cold setting which is supposed to yield 14.4v bulk-absorption and 13.5v float. I just started my generator (10K) and see that the charger is only putting out 13.5 volts and 47.7 amps. (same after a half hour or so) Shouldn't I be seeing the maximum bulk voltage right now? While waiting for some input an hour has passed. The charger is now supplying 14.1v, still substantially less than the 14.4 I had expected.Thanks.jor

what is the AC voltage reading from the generator into the Freedom inverter chargerDC voltage at batteries should rise, as the amps into the batteries decreaseshould keep rising until it reaches setpoint, then drop to float

Battery voltage rising with constant amps is good. (bulk stage) Keep it going and see if the voltage settles at the set Vabs.I don't know your equipment but the amps are well below 130a at 47a. Is that deliberate by some setting you did? Some of those have reduced 120v amps you can choose that affects the DC amps output. Otherwise it seems your batteries are higher in SOC than you thought, so only accepting lower amps or they are at much less capacity than you think, (sulfation?) so they have a lower acceptance rate at 70% SOC and 14v than you would think.

You will not see absorption set point voltage until amps begin to taper.I recommend running the generator one more hour after the amps are tapering.

Moderator, thanks for moving my post to the proper forum.what is the AC voltage reading from the generator into the Freedom inverter chargerI can't get to it right now. I'll be home tomorrow and I'll be able to get that measurement at the inverter. I have a Progressive Industries EMS unit on board. It indicates the generator is producing 110vac on each leg. The Trimetric now shows a steady 14.1v and, as you indicated in your reply, the amperage has dropped from its starting point of 49 amps 34 amps (2 hours after start). I understand the relationship between voltage and amperage but shouldn't I see the full bulk-absorption voltage right away with 30% discharged batteries? Thanks.jor

Bulk-Absorption Charging Voltage | Good Sam Community

BFL13
Explorer II
Feb 27, 2015
No, you should see amps taper at an SOC depending on the charging rate.

The charging rate is the charging amps/battery capacity in AH. Higher charging rate means you get to Vabs faster and at a lower SOC.

With a high charging rate you can reach your Vabs at 65% SOC. At a low charging rate you might not see amps taper till at 90% SOC.

So if you are already at reduced amps at 70% it means you have a fairly high charging rate and are already on the tapering curve (caused by reducing battery acceptance as SOC rises)

Which means your battery bank is lower in AH than you think, which would jack up the charging rate (same as if the bank were smaller in size) Sulfation reduces bank AH capacity. So does cold temperatures.
joraz
Explorer
Feb 27, 2015
ou will not see absorption set point voltage until amps begin to taper.

Well, I did not know that. Thanks for this information. It's a steady 14.1 now so I guess, as the amps decrease, it should rise to the 14.4 setting that I have selected. Thanks.
jor
joraz
Explorer
Feb 27, 2015
Is that deliberate by some setting you did?

No. Never have made any adjustments.

Otherwise it seems your batteries are higher in SOC than you thought

I don't think so. I have a shunt mounted right at the batteries and the Trimetric 2025 which is supposed to be pretty darn accurate.

sulfation

I guess it's possible but these babies are only a year old and have not been abused.

Thanks.
jor
joraz
Explorer
Feb 27, 2015
Moderator, thanks for moving my post to the proper forum.

what is the AC voltage reading from the generator into the Freedom inverter charger

I can't get to it right now. I'll be home tomorrow and I'll be able to get that measurement at the inverter. I have a Progressive Industries EMS unit on board. It indicates the generator is producing 110vac on each leg.

The Trimetric now shows a steady 14.1v and, as you indicated in your reply, the amperage has dropped from its starting point of 49 amps 34 amps (2 hours after start).

I understand the relationship between voltage and amperage but shouldn't I see the full bulk-absorption voltage right away with 30% discharged batteries? Thanks.
jor
time2roll
Nomad
Feb 27, 2015
You will not see absorption set point voltage until amps begin to taper.
I recommend running the generator one more hour after the amps are tapering.
BFL13
Explorer II
Feb 27, 2015
Battery voltage rising with constant amps is good. (bulk stage) Keep it going and see if the voltage settles at the set Vabs.

I don't know your equipment but the amps are well below 130a at 47a. Is that deliberate by some setting you did? Some of those have reduced 120v amps you can choose that affects the DC amps output.

Otherwise it seems your batteries are higher in SOC than you thought, so only accepting lower amps or they are at much less capacity than you think, (sulfation?) so they have a lower acceptance rate at 70% SOC and 14v than you would think.
MrWizard
Moderator
Feb 27, 2015
what is the AC voltage reading from the generator into the Freedom inverter charger

DC voltage at batteries should rise, as the amps into the batteries decrease
should keep rising until it reaches setpoint, then drop to float
MrWizard
Moderator
Feb 27, 2015
moved from technology corner

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