The question is when the load is removed does the voltage recover?
There is what is known as sitting voltage, and charging voltage. This is that immediate voltage drop,and the true state of charge is when the battery is sitting.
Your charger/charge controller should be set based on the label or literature that came with the battery. This is very important for safety when lithium is your battery of choice. You will read that the charger should be a cvcc voltage source. This means you set your charger to nickel/iron, nicad, or custom, depending on your charger. The setting should be where bulk,and float setting are at the bulk voltage. Further, the equalizer function should be turned off. If you can't turn it off,then set it to the bulk voltage. All this translates to cvcc that your battery manufacturer has told you is Best practice for their product.
Voltage drop is normal! Even the shunt works on this principle. To ensure best possible readings the shunt should be as close to the bank as is possible. And as long as the voltage recovers when no load is applied your good to go! Your voltage meter should be connected directly to the batteries, or the battery buss.
Hope this clears your concerns!
Good am, Kevin
thank you kindly!
well, i can only tell you that as per last night....I am in an area where the storm "Debby" has wreaked some havoc on shore power, so this has been an illustrative night.
I do understand the points about "sitting and charging" voltage...and thanks for making that point.
I would not be concerned about it, understand it as I do, but last night, as case in point, when shore power went off, and the fridge and a few 12 volt lights were all that were the load on the batteries, and that meant the amperage draw was about 25-27 amps, it only took minutes for the voltage to drop from 13.2, to not just "13", but it was clear from the flickering, that it was about to drop below "13".
looking at specs on these batteries, even at "13 volts", the batteries are said to be a mere fraction of their full charge capacities, so it sure appears, that the precipitous drop from resting ("silent") at 13.6, to "13.2", without any load (meaning I am still on shore power while all that is happening) continues as a "precipitous drop" when shore power goes off and there is only a modest load (fridge and 12 volt lights).
so it would appear that had I not run the generator, or had shore power not come back on quickly (and at night so the solar panels are not generating any real amount of power...this whole process goes a bit more more slowly during the say when the panels are producing normal amounts of current), that with only a small load, had I not applied additional power...in this case via the generator....those batteries would have quickly dropped below 13 vots and (I assume, but did not want to let it go to that extreme) quickly gotten to a cut off voltage as set via the magnum panel (I think it is set to cut off at 12.5....I am a recent lung cancer patient...nasty surgery.....and have not closely checked all those settings recently, but if memory serves, the cutoff as set at the magnum level before some kind of external charge is called for, is 12.5 volts (in any event, all the settings, having gone thru them MANY times with battleborn, are where they should be at all times).
so net, net, I don't seem to get much out of these batteries, unless the ride down from a "flickering" 13 vots to 12.5, takes a much longer time than would appear).
I hope this all makes sense and I really appreciate your help....due to my health issues, things that may seem like molehills to someone else are "mountains" right now, to me.
many thanks!!
