When charging, the electrical pressure ( voltage) is higher, and as such, incandescent and many LED bulbs will be brighter and run hotter and will have their lives shortened somewhat.
Some cheaper LED bulbs might start flickering at 14.4v, because they are getting too hot with the extra voltage. Not really a huge deal as most LEDs are pretty cheap.
Some converters come wired with separate wires to a DC fuse panel, some only have wires feeding a battery, and the battery feeds the fuse block. Circuit wise, there is little difference. It is not as if one output terminal is for DC loads only, and one output terminal is for the battery only and both are moderated separately by the converter. If so, i have never seen it, on any RV converter. I am not including 500+ dollar programmable chargers or $$$ marine chargers in this statement.
Whether DC loads are hooked directly through RV converter, or directly to battery terminals, the only real difference is the circuit length. IF the DC fuse panel is hooked directly to converter, and converter is also hooked directly to battery, when converter is not plugged into 120vAC, then DC loads get their juice from battery through converter output terminals, then to fuse block, a longer distance than if the fuse panel was wired directly straight from battery.
Though NO converters working properly, will go above 14.8v, flooded batteries benefit from the occasional equalization charge, which is an intentional overcharge bringing the batteries to as high as 16.2 volts. When performing this Equalization, loads should be disconnected from the batteries as 16.2v could damage some 12v electronics.
Also note that marketers have bastardized the term 'equalization' because it sounds good. a 15 minute bump to 14.4 or 14.8v from float/maintenance voltage, causes bubbling, which destratifies the electrolyte, as denser acid would otherwise sink to bottom of cells and eat the plates at a faster rate. This 4th 'Destratification' stage is unneeded on AGM batteries. This fourth stage also only occurs after the converter has been plugged in for more than 16 hours.
And these 'stages' that charger/converter makers are all so happy to throw around, are simply different voltages the charger seeks.
"Bulk" stage is when the charging source outputs its maximum amperage until it voltage at charger output terminals reaches 14.x volts. It is a constant current 'stage'. The wiring thickness is important, as converters do not account for voltage drop, meaning the converter output terminals might see 14.8v, while the battery terminals is only 14.2v. Iota only holds 14.8v for 15 minutes before dropping to 14.2v, so it slows charging even more so.
Absorption stage is a constant voltage stage. Some converter/chargers like Iota, will drop from 14.8 to 14.2 for this stage. Others like PD will maintain 14.4 or 14.8v.
How long absorption stage is held is the Key to proper battery charging. Most every Charging source ends this absorption stage too early. Not a huge deal if one is still plugged in as 13.2v will eventually fully charge the battery, but it is if one is running a generator.
Float maintenance stage is another constant voltage stage. the converter only makes enough amperage to hold the voltage at 13.2v, or whatever number the manufacturer decided upon.
At Any time/stage , with a converter, the DC loads while charging, are no issue. With regular smart chargers these loads might confuse the charger and it could shut itself off thinking there is a problem with the battery.
In bulk mode and in the early absorption stage, DC loads will reduce charging amps into battery, which might or might not be a detraction.
Iota dropping from 14.8 to 14.2v 15 minutes after it first reaches 14.8v, does slow battery charging, but is more gentile on the battery. It will use less water, but take longer to fully charge.
Progressive Dynamics charger/converters will hold 14.4( or 14.8*) for 4 hours, and can also be manually forced into the stages by holding a button.
This manual forcing of stages is beneficial for those with limited time to recharge.
Here is why. Say one drove for 15 minutes with depleted batteries, then started generator/plugged in to finish recharging batteries to full. The alternator would likely have had battery above 13.2v, and when plugged in the converter would see 13.2v and think the battery is full, and seek to hold only 13.2v. But the batteries are still 50% charged, and perhaps only 15 amps are required to hold 13.2, if the charger were seeking 14.8v, 55 amps would be flowing.
With the PD one could press a button and the charger would seek and then hold 14.4( or 14.8) for 4 hours, drastically reducing recharge times and filling the batteries to a much higher state of charge before one unplugs/shuts down generator.
*PD converters now offer models with a 14.8v absorption voltage rather than the standard models which only go to 14.4v.
The higher the voltage the faster the recharging.
If time is a factor, and it often is in this lifestyle, then a converter which seeks and holds a higher voltage will reduce generator run times, and get the batteries to a higher state of charge faster, when 120vAC is time limited.
The Iota is a good converter, but the PD of the same amperage might better suit those with limitations on time, and for those who want the option of some manual control.
I really recommend that people have an Ammeter in addition to a voltmeter.
How many amps are flowing into battery from charging source is a great indicator as to state of charge.
This product requires no shunt. Just run one wire through the round Hall effect sensor.
https://www.amazon.com/gp/product/B01DDQM6Z4/ref=s9_dcacsd_bhz_bw_c_x_3_w
Say voltmeter shows 14.4v and 45 amps, this means batteries have just reached absorption stage and are likely ~80% charged.
Say voltmeter reads 14.4v and 3 amps. This means batteries are likely 95%+ charged.
Location of hall effect sensor might or might not include DC loads in the display. It depends on how ones system is wired whether it displays total amperage from converter, or total amperage into or out of battery.
