Constant voltage/float voltage for 12v FLA settings?

[Martinjmpr]

Trying to set up my Renogy DC-DC charger and I wanted to tap into the group wisdom here for the settings on the DIP switches.

Looks like the Renogy can do 3 different Constant Voltage/Switchover voltage settings: 14.4, 14.1 and 14.7, and 3 Float voltage settings, 13.8, 13.5 and 13.2. These settings are controlled by 4 DIP switches S1 though S4. The 5th DIP switch, S5, according to the manual, should be "on" for a lead/acid and "off" for lithium-Ion.

My battery is a FLA (wet battery, not sealed or AGM.) Default setting (S1 though S4 in "on" position) is: Constant/Switchover at 14.4 and float at 13.8. Does that sound right for a FLA?

Wanted to post this as a separate topic in case anyone else had a similar question,

Thanks!

EDIT some sources I'm looking at seem to say 14.1 for bulk charge phase and 13.8 for float. Does that sound right? Default is 14.4 for bulk but I can set it to 14.1

 

[rayra]

13.8 seems high to me. and I keep reading about how AGM need the higher voltages to operate properly and to not sulfate / die early. So the inference would be lesser settings for your battery type.
The manual should say, though.

I also note as an aside when I got my 'new & improved' high Amp rated alternator for my Sub, that it's base voltage is 14.6ish and my original 130A Bosch alternator was more like 14.1 and my batteries rarely held at over 12.9/13.0. But my Renogy PWM will bulk charge at 14.6 as well, even though it is set for SLA. Floats at 13.2 though.

 

[john61ct]

Every model of quality deep cycling battery has detailed spec sheets if not full user docs, plus easy to contact expert tech support.

The charge profile specific to your model is what you need the profile to match.

There is no "one size fits all" set of parameters, that work for all FLA, any more than GEL or AGM.

link to your battery?

 

[jonyjoe101]

for FLA lead acid it's 14.4 volts, the 2 agms I have a full throttle and also an odyssey both require 14.7 volts. But the specs call for 14.7 volts at 77 degrees, at 50 degrees it specifies 14.8 volts, and at 104 degrees it specifies 14.3 volts. So ultimately it depends were your battery is going to be and the temperature to fine tune the voltage.

Also you need to take into account any voltage drop. Measure the voltage at the battery terminals to see if your getting the proper voltage, you don't want to undercharge your battery. The renogy might read a voltage of 14.4 volts but the battery terminals might actually be at 14.2 volts and this will cause it to switchover too early to float.

 

[john61ct]

The only voltage reading that matters is one taken directly from the battery terminals with a known accurate volt meter or DVM.

Temperature compensation should be automatically handled by a good charger.

And again, you should not generalize about the voltage setpoint, not all FLA are the same, get the specs for **your** battery.

And often adjustment up or down is appropriate depending on usage patterns, how fast the cycle desired vs sitting on shore power, current level etc.