Progressive Dynamics PD9270. What voltage is required to activate boost mode?

[Ampster]

When referring to "constant current", where in the system is current being measured?

Constant Current only applies to the current during charging. Therefore it is implicit that it is measured between the charger/charge controller and the battery. As I have said earlier; there are only two relevant measurements during charging; Voltage and Amps. Bulk, Absorb, Boost and Float are descriptions of the above devised by battery and charger manufacturers to dumb down the physics.
I presume from your comments that you have not read the Stickies. Do you need a link? The information is very useful. You may want to get another explanation beside mine to improve your understanding.

[checkthisout]

Constant Current only applies to the current during charging. Therefore it is implicit that it is measured between the charger/charge controller and the battery. As I have said earlier; there are only two relevant measurements during charging; Voltage and Amps. Bulk, Absorb, Boost and Float are descriptions of the above devised by battery and charger manufacturers to dumb down the physics.
I presume from your comments that you have not read the Stickies. Do you need a link? The information is very useful. Since I am the only one responding to your questions you may want to get another explanation to improve your understanding.

There is lots of different info online. I basically don't think I have a constant current charger as the amperage output varies to reach the target voltage.

If I let my battery voltage drop to 11.8 and then apply power to the charger, I get 80-100 amps for a few minutes until the battery stops accepting the initial in-rush of current and the charger and the voltage begins to rise. The voltage is rising because the battery is rising voltage and and thus the battery's voltage difference between whatever the limit is on the charger and the battery becomes less. This is in boost mode.

If my battery is at the same voltage 11.8 and and I apply power to the charger and then quickly take it out of boost mode and into "normal" mode, I get 80-100 amps.

That's all. I think each manufacturer does things differently which makes it ok to call the different modes whatever one wants because they unfortunately have no universal meaning when it comes to each manufacturer. I think that was Mike's point, more or less. Thanks for chatting with me. I wasn't trying to be pointlessly argumentative, but only discuss things in lively way. It's how I learn.

[Mike90250]

Constant current applies to POWER SUPPLIES fed by Hover Dam.

Solar charge controllers will supply as much current as they can, from their solar panels, to charge the batteries in the BULK or initial portion of the charge.
( AKA Max Smoke portion )
When the battery voltage finally rises to the specified absorb voltage, then the controller tapers off the current to allow the voltage to stabilize.
( a 60A MPPT controller connected to 200W of panels won't magically deliver 60A to a 24V bank. )

[Ampster]

There is lots of different info online. I basically don't think I have a constant current charger as the amperage output varies to reach the target voltage.

Mike is correct to clarify solar charge controllers as distinct from power supplies or grid powered chargers. I presume your charger is grid powered? As I mentioned the terminology used by manufacturers may be unique to each device.
Constant Current is a phase of charging during the charging cycle not a type of charger.. Almost every power supply or charger has some limit on the current it can supply. That limit may be adjusted by the user. You can describe your charger any way you want but it most definitely has a phase in which it is limiting current to a user or manufacturer setting. For that reason it is defined as a Constant Current phase.

If I let my battery voltage drop to 11.8 and then apply power to the charger, I get 80-100 amps for a few minutes until the battery stops accepting the initial in-rush of current and the charger and the voltage begins to rise. The voltage is rising because the battery is rising voltage and and thus the battery's voltage difference between whatever the limit is on the charger and the battery becomes less. This is in boost mode.

What you are describing appears to be the constant current phase even for the few minutes which you describe. As I explained earlier the charger will begin to reduce the current to prevent the voltage from rising above the setting for Constant Voltage phase.

If my battery is at the same voltage 11.8 and and I apply power to the charger and then quickly take it out of boost mode and into "normal" mode, I get 80-100 amps.

What are the settings for boost mode and "normal" mode? Are they expressed in terms of Volts or Amps? Your measurement of 80-100 Amps may very well be an example of Constant Voltage mode, especially if the Amps are reducing from 100 Amps to 80 Amps. The only way to detect if you are in Constant Current phase is to measure Amps and Voltage over time. If voltage increases and current stays the same then the charger is in the Constant Current phase. If the voltage stays the same and current reduces then the charger is in Constant Voltage phase. Boost has become a term used differently by different manufacturers and I have no idea what "narmal" mode is. I will add that normally most chargers start in Constant Current phase and then transition to Constant Voltage phase.

That's all. I think each manufacturer does things differently which makes it ok to call the different modes whatever one wants because they unfortunately have no universal meaning when it comes to each manufacturer. I think that was Mike's point, more or less. Thanks for chatting with me. I wasn't trying to be pointlessly argumentative, but only discuss things in lively way. It's how I learn.

No worries, I was not sure you understood it from a physics perspective. My comments are also directed to other readers who may stumble across this topic. We all have different learning styles. Physics can be daunting and that may be why manufacturers come up with various descriptions for simple measurable things like voltage and current.
Yes, manufactures do thing differently and some chargers have additional settings such as rebulk, refloat et cetera. I can't keep track of the various descriptions each manufacturer uses so it is easier for me to think in terms of simple physics measurements like voltage and current.