eSmart-3 Controller

I am trying to set up this controller for a 12 volt Lithium battery, but the terminology is somewhat confusing.
I believe that what they are calling BOOST is actually Absorption, which I am setting to 14.5V, however, there is another setting they call Constant Voltage, which I have no idea what to set that to.
The other confusing issue is that they have BOOST Charge Time setting, which given that BOOST equates to ABSORPTION, why would there be a timer. Might be easier if I show the whole menu:

The parameters that I can set are as follows:
Constant Voltage: (14.5?)
Float Voltage: (0.0?)
Boost Voltage:
Boost Charge Time: ????
Bat. O/voltage: (14.6?)
Bat. O/voltage recovery:
Bat. U/voltage: (10.8?)
Bat. U/voltage recovery:
Max. discharge current: (100A?)
Maximum charge current: (40A?)

The figures I have filled in are based on the following:
The Solar Controller is 40A
Battery supplier info: (not a lot, waiting for more)
Charge voltage: 14.6
Discharge cut-off voltage: 10.8V.
Max. Discharge current continuous: 100A
Max. Charge current: 100A

Have a look at the graph on page 8/9 in the manual, available here:

The terminology mess is likely due to the charger being designed mainly for lead acid batteries, but also with support for other kinds of batteries, including Lithium. Most features are simply unnecessary (possibly harmful) for Lithium batteries.

"Constant voltage" is called "absorption stage" in lead acid chargers. I don't know the specific chemistry/configuration of your Lithium battery, so can't say if 14.5V is suitable.

"float stage" is generally not necessary for lithium batteries, so it should be disabled (set to the same voltage as "constant voltage").

"Boost voltage" (p9, 1.5b) normally called "equalization stage". Once a month, with default settings the battery get overcharged by 0.2v for 60 minutes. The idea being to dissolve any stubborn sulfation that may have started to develop in the lead acid battery. Almost certainly harmful for lithium batteries, so should be disabled by setting to the voltage as "constant voltage".

To sum it up, set everything to the same value as in "constant voltage". Make sure that voltage is suitable for your specific battery - you may want to go ~3% lower than the official max voltage to increase lifespan. Also, the charger may not be correctly calibrated, so check the actual voltage with a good multimeter.

ajw22 said:

Have a look at the graph on page 8/9 in the manual, available here:

https://www.solartex.co/tienda/wp-content/uploads/2019/04/eSmart3-User-manual.pdf

The terminology mess is likely due to the charger being designed mainly for lead acid batteries, but also with support for other kinds of batteries, including Lithium. Most features are simply unnecessary (possibly harmful) for Lithium batteries.

"Constant voltage" is called "absorption stage" in lead acid chargers. I don't know the specific chemistry/configuration of your Lithium battery, so can't say if 14.5V is suitable.

"float stage" is generally not necessary for lithium batteries, so it should be disabled (set to the same voltage as "constant voltage").

"Boost voltage" (p9, 1.5b) normally called "equalization stage". Once a month, with default settings the battery get overcharged by 0.2v for 60 minutes. The idea being to dissolve any stubborn sulfation that may have started to develop in the lead acid battery. Almost certainly harmful for lithium batteries, so should be disabled by setting to the voltage as "constant voltage".

To sum it up, set everything to the same value as in "constant voltage". Make sure that voltage is suitable for your specific battery - you may want to go ~3% lower than the official max voltage to increase lifespan. Also, the charger may not be correctly calibrated, so check the actual voltage with a good multimeter.

Click to expand...

Thank you very much for that detailed explanation, it makes things a LOT clearer.
I was led to believe that Boost on this unit is the Absorption stage, so the timer had me really confused.
I will read the link you posted too.
F.Y.I. it is LiFePo4, manufacturer recommends 14.6 charge, so I was going for 14.5, mainly so I could set the O/Voltage to 14.6 to avoid tripping, but I am now guessing that if I set it the same as Absorption, the battery BMS will look after O/voltage?

EDIT:

I have since found some more information on this charger, as follows:

a) Constant Current Charging_CC(Bulk Charging) In this stage, the battery voltage has not yet reached constant voltage (Constant or Boost Voltage), the controller operates in constant current mode, delivering its maximum current to the batteries (MPPTCharging).

b) Constant Voltage Charging_CV( Constant and Boost Charging) When the battery voltage reaches the constant voltage set point, the controller will start to operate in constant voltage charging mode, this process the charging current will drop gradually. The constant charge voltage will increase 0.2V on the basis of constant voltage at 1st of each month, charge time is 60mins. ( The data of boost charge voltage can be set via PC software and APP)

c) Floating Charging_CF After the constant voltage stage, the controller will reduce charging current to maintaining the battery voltage on the Floating Voltage set point. Charging the battery with a smaller current and voltage on Floating Voltage stage, while maintaining full battery storage capacity.

I think I might be finally getting my head around this charging subject.
I have been trying to figure out how to set the chargers two stages (for LiFePo4), but I am now thinking that the first stage, Constant Current, is not something I have to "set", it is determined by the available power from the panels, up to the 40A max.
If I set the 2nd stage (Constant & Boost) to 14.6V (or a little less, 14.5) and the Float to a lower setting so it doesn't do anything (13.5V) that should be all I need to do.
IF that is the case, my settings would look like this:

Constant Voltage: 14.5
Float Voltage: 13.5
Boost Voltage: 14.5
Boost Charge Time: 0
Bat. O/voltage: 15V
Bat. O/voltage recovery: Not needed?
Bat. U/voltage: 10.8
Bat. U/voltage recovery: Not needed?
Max. discharge current: (100A?)
Maximum charge current: 40A

Please confirm or correct as necessary.
Cheers.

Best to set the target (ie 14.5V) in the charger, and the BMS limit slightly higher and avoid tripping.
Having the BMS trip should really be the last resort, as chargers often do not like operating without a battery (ie. can be damaged).

Again, make sure to check the actual voltage. I have 4 units running in parallel, and the actual voltages were all over the place.

ajw22 said:

Best to set the target (ie 14.5V) in the charger, and the BMS limit slightly higher and avoid tripping.
Having the BMS trip should really be the last resort, as chargers often do not like operating without a battery (ie. can be damaged).

Again, make sure to check the actual voltage. I have 4 units running in parallel, and the actual voltages were all over the place.

Click to expand...

I will certainly check the actual voltages when it is all running and adjust as necessary.
The BMS is internal in the battery case, so I won't be able to set that, so can I assume that as the manufacturer recommends a charging voltage of 14.6, setting my target to 14.5 should be O.K.?