Yet Another Converter Question

[Roll With The Changes]

You missed the part where I said that I charge the battery first, before leaving on a trip. At that time, there is basically nothing in the camper drawing current from the 12V system. Also, tail current is not based off of battery capacity, it is based off of the total output capacity of the charger. In my case, the NPB is capable of 43 amps, so down to 4.3 amps will trigger float mode

I understand that your battery is almost always almost fully charged. Mine is as well. We live in it full time, so the battery is never off a charger except when the truck is shut off at a fuel stop. Pretty much the only time current is moving out of my battery is when I run the jacks which exceeds the output of the converter.

If you use 4.3 amps as the changeover point to float mode, that makes the situation worse. I typically measure about 4 amps just with refrigerator control, furnace/AC thermostats and antenna amplifier. That is the house basically off. It would be unlikely to get the current low enough to make the switch without actually forcing it to as I think you do. You're also using a FLA charge profile with a lithium battery to prevent over charging (as do I).

My point for this whole thread is that no charger that I have found can differentiate between house and charge current. Maybe Victron has a $1000 system that can actually take care of a battery, but I already have a $1000 battery that the popular chargers can't hurt.

[Roll With The Changes]

You missed the part where I said that I charge the battery first, before leaving on a trip. At that time, there is basically nothing in the camper drawing current from the 12V system. Also, tail current is not based off of battery capacity, it is based off of the total output capacity of the charger. In my case, the NPB is capable of 43 amps, so down to 4.3 amps will trigger float mode

Also, I'm not trying to be nitpicky about terms, but it is important to speak a common language in technical discussions.

Tail current is defined as the current at which a battery is considered fully charged. Tail current is expressed as a percentage of battery capacity. That comes from Victron's website.

Whith that in mind, ideally, the tail current should be a settable parameter for any given system. For example, if you had 400 amp hours of battery capacity, you would expect a higher fully charged current than a small single battery.

[Roll With The Changes]

In a perfect world, you would also want to allow the lithium to draw down to a predefined level and essentially disconnect from the circuit until needed.

That is a good point. And that is just a firmware change. We are told so often about so many products that this or that is a "smart device". Most things are not, and in this case all the smartness that they advertise is based on a measurement of something irrelevant.

In the case of converter/ chargers, I wish they would add 20 or 30 dollars to their production costs, charge another 100 dollars and we would end up with a device that actually functions as intended.

One step closer to that perfect world.

[xrated]

Also, I'm not trying to be nitpicky about terms, but it is important to speak a common language in technical discussions.

Tail current is defined as the current at which a battery is considered fully charged. Tail current is expressed as a percentage of battery capacity. That comes from Victron's website.

Whith that in mind, ideally, the tail current should be a settable parameter for any given system. For example, if you had 400 amp hours of battery capacity, you would expect a higher fully charged current than a small single battery.

Mine is the 750 watt, which produces a maximum of 43 amps out. The manual clearly states that in 3 stage charging (which is how mine is setup) that it starts out in CC mode, then goes to Constant Voltage. As the battery is being fully charged, the current will then decrease as the voltages are matched....battery voltage and applied voltage. When the current reaches 10% of the "rated current" (43 amps), it will shut the charger down if it is set to 2 stage charging, or if in 3 stage charging like mine is, it will go into float mode voltage....13.4V

I did misspeak earlier though, I said that bulk voltage level was 14.4........I meant that to be 14.2V