Looking for Synonyms

[PhillT]

Hi, first post here, and new to the LiFePo4 world, but learning day by day.
I have replaced the AGM in my caravan (trailer) with a 135AH 12V LiFePo4, and in setting up and trouble shooting the biggest hurdle I am encountering is the seemingly inconsistent terminology used by manufacturers and others.

For example, I was instructed by someone to "lower the bulk", but my S.C.C. does not give me a definable parameter called "BULK" so that term must have one or more "other name/s"
Other terms like "Absorption" and "Constant Current" also don't appear on my S.C.C.
So I guessed that I can't be the only newby who is confronted by this double-speak, so I tried good old google and came up short there too :-(
Is there a list of the terms used, and their possible synonyms out there, and if not, can someone here please post with at least some of the common ones?

Just for the record, the S.C.C. that I am using (eSmart-3 by ipanda) has only the following user definable parameters:
Constant Voltage:
Float Voltage:
Boost Voltage:
Boost Charge Time:
Bat. O/voltage:
Bat. O/voltage recovery:
Bat. U/voltage:
Bat. U/voltage recovery:
Max. discharge current:
Maximum charge current:

 

[sunshine_eggo]

Hi, first post here, and new to the LiFePo4 world, but learning day by day.
I have replaced the AGM in my caravan (trailer) with a 135AH 12V LiFePo4, and in setting up and trouble shooting the biggest hurdle I am encountering is the seemingly inconsistent terminology used by manufacturers and others.

For example, I was instructed by someone to "lower the bulk", but my S.C.C. does not give me a definable parameter called "BULK" so that term must have one or more "other name/s"
Other terms like "Absorption" and "Constant Current" also don't appear on my S.C.C.
So I guessed that I can't be the only newby who is confronted by this double-speak, so I tried good old google and came up short there too :-(
Is there a list of the terms used, and their possible synonyms out there, and if not, can someone here please post with at least some of the common ones?

Just for the record, the S.C.C. that I am using (eSmart-3 by ipanda) has only the following user definable parameters:
Constant Voltage:

?

Float Voltage: 13.6
Boost Voltage: 14.4
Boost Charge Time: 30 min

Below down to "---" likely applies only to load ports:

Bat. O/voltage:
Bat. O/voltage recovery:
Bat. U/voltage:
Bat. U/voltage recovery:
Max. discharge current:

---

Maximum charge current:

^Likely an option to restrict charging if the charger controller has the potential to send more current than the battery can handle.

Generally, bulk/boost/absorption all refer to the same voltage. "Boost" seems most commonly used on Chinese made hardware.

"Constant voltage" is a curiosity. It implies it means the same thing as absorption, but I'm not certain, but it might mean something else. I'm wondering if that has the option to regulate output voltage to load ports. Link manual?

 

[PhillT]

?



Below down to "---" likely applies only to load ports:

---



^Likely an option to restrict charging if the charger controller has the potential to send more current than the battery can handle.

Generally, bulk/boost/absorption all refer to the same voltage. "Boost" seems most commonly used on Chinese made hardware.

"Constant voltage" is a curiosity. It implies it means the same thing as absorption, but I'm not certain, but it might mean something else. I'm wondering if that has the option to regulate output voltage to load ports. Link manual?

I am thinking now that what they call "Constant Voltage" is the trigger voltage that stops the C.C. (1st. charging phase), and starts C.V. (2nd charging phase). The term they are using for this second phase is "Boost Voltage" which has a timer function which ties in with my understanding of multi chemistry chargers.
Does that sound like a plausible interpretation?

 

[sunshine_eggo]

I am thinking now that what they call "Constant Voltage" is the trigger voltage that stops the C.C. (1st. charging phase), and starts C.V. (2nd charging phase). The term they are using for this second phase is "Boost Voltage" which has a timer function which ties in with my understanding of multi chemistry chargers.
Does that sound like a plausible interpretation?

Possibly, but it just sounds like two names for the same thing. Would set both to 14.4 if that's the case.

 

[PhillT]

O.K. Cheers.
Thanks for pointing out that those 4 parameters apply only to the load port. That makes sense, but I am not using the load port so can safely ignore them.

The link you asked for: (it muddied the waters further for me, good luck ;-) )

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

 

[timselectric]

My take on this.
CC (constant current) is the bulk charging/first stage. It charges the battery until a set voltage is reached. This will get you to approximately 90% SOC.
Then CV (constant voltage) is the float/absorption is the second stage. It holds the charging voltage at a set point, until the battery takes no more amps in.
This is just the general description. The details of what the settings should be depends on the battery and needs of the system.

 

[PhillT]

My take on this.
CC (constant current) is the bulk charging/first stage. It charges the battery until a set voltage is reached. This will get you to approximately 90% SOC.
Then CV (constant voltage) is the float/absorption is the second stage. It holds the charging voltage at a set point, until the battery takes no more amps in.
This is just the general description. The details of what the settings should be depends on the battery and needs of the system.

If so, what do you think the BOOST voltage is?
C.V. and FLOAT both have their own individual settings, but you are suggesting that FLOAT & C.V. are one & the same? This is doing my head in :-( I am starting to wish I had stuck with A.G.M. L.O.L.

 

[iRondo]

If so, what do you think the BOOST voltage is?
C.V. and FLOAT both have their own individual settings, but you are suggesting that FLOAT & C.V. are one & the same? This is doing my head in :-( I am starting to wish I had stuck with A.G.M. L.O.L.

Boost is (I believe) synonymous with Bulk. Constant Current, I think, is also used to describe Absorption and Float is not needed with LiFePo4 so can be set to the same voltage as Constant Current, in effect eliminating the Float stage.

 

[PhillT]

IRondo, going back to my original post, which of the available settings would set the voltage of constant current?

 

[iRondo]

Sorry, I mispoke. Bulk/Constant Current are the same (14.4V). Constant Voltage is Absorption (Boost? (typically 13.6 or 13.8V). There is no float, but if your charger wants a float setting, set it to either the same level or lower than your Absorption stage and set the time to float to a short time.
Not really sure what Boost is. Sounds foreign. I'm in Canada eh

 

[iRondo]

Okay, now you got me Duckle-ing charge currents and seeing stuff I've never seen before. No wonder you're confused. Now I am too lol
Here's a link that explains the stages. He's not talking about lithium chemistries at all but the voltages I gave above are safe for LFP.

What are the three stages of battery charging?

The iTechworld 20A Battery Charger has three key charging & maintenance stages to maximize the power and lifetime of the battery. The iTechworld 20A Battery Charger can be attached to the battery indefinitely if required without risk of over or under charging. Click the following link to view...

itechworld.com.au

A site with good and extensive info is marinehowto.com.

 

[Ampster]

Constant Current and Constant Voltage are not manufacturer’s terms. They are actual descriptions of the nature of the electrical energy going into a battery. Think of it as two stages. The first stage is Constant Current and in that stage the current is fixed and the battery voltage increases until the Constant Voltage setting is reached. Then the current tapers off until the battery reaches a timed setting or a minimum voltage. This is the second stage.
To answer the question of @PhillT about which setting would set Constant Current just look at the value in the setting. Most chargers connected to an AC source ave a fixed current that they can produce so voltage is the only setting available. Bulk is typically a Constant Current stage but the Bulk voltage setting is actually the point of transition from Constant Current to Constant Voltage. Boost, Absorb and Float are typically Constant Voltage settings and take place in the second stage.

 

[PhillT]

@Ampster I have a good understanding of the charging process for a 12 volt LiFePO4 battery, but the issue is the terminology used on my "Not a.c." Solar Charge Controller.

You said, "To answer the question of @PhillT about which setting would set Constant Current just look at the value in the setting." If you look at my original post you will see that there is no Constant Current setting to look at the value.

I have only two available (relevant) settings, they being Constant Voltage, and Boost Voltage (timed)
I think that the setting called "Constant Voltage" on my charger, is where I can define the voltage reached during the constant current stage of charging, at which point the charger goes to stage 2 which is the constant voltage stage (timed) but they are calling it "BOOST"

Given that there are only two relevant settings, the only other option is that what they are calling "Constant Voltage" is actually that, which makes it stage 2, un-timed, and what they are calling "BOOST" (timed) is the constant current stage, which makes no sense to me, if for no other reason than that it is a timed setting.

The only other possibility which doesn't make sense to me, is that stage 1 (Constant Current) has no definable setting, but is factory set to whatever voltage they decided.
That could make stage 2 the setting they call "CONSTANT VOLTAGE" (un-timed) which leaves the setting they are calling "BOOST" (timed), for what?

 

[timselectric]

You're probably going to have to play with the settings to figure out what they are calling what.

 

[PhillT]

You're probably going to have to play with the settings to figure out what they are calling what.

I think so. If, as most people say, BOOST = BULK = ABSORPTION, then it should not be a timed function surely?
Am I correct in thinking that the only stage that should be timed is constant voltage?

 

[timselectric]

I think so. If, as most people say, BOOST = BULK = ABSORPTION, then it should not be a timed function surely?
Am I correct in thinking that the only stage that should be timed is constant voltage?

Yes, I agree.
I think that it's mislabeled.

 

[timselectric]

Bulk is stage one. (Constant current)
Absorption, AKA float is stage two. (Constant voltage)

 

[PhillT]

Bulk is stage one. (Constant current)
Absorption, AKA float is stage two. (Constant voltage)

No wonder I am confused. If BULK is stage one, and ABSORPTION is stage 2, then what does the following mean? (It is a quote lifted from another thread on this forum)

""When talking about charge voltage: Boost = Absorption = Bulk
The three are used interchangeably to mean the voltage at which the charge transitions from constant current to constant voltage.""

I am misunderstanding something because I can't see how both statements can be true :-(

 

[Supervstech]

No wonder I am confused. If BULK is stage one, and ABSORPTION is stage 2, then what does the following mean? (It is a quote lifted from another thread on this forum)

""When talking about charge voltage: Boost = Absorption = Bulk
The three are used interchangeably to mean the voltage at which the charge transitions from constant current to constant voltage.""

I am misunderstanding something because I can't see how both statements can be true :-(

Usually, charge controllers use the term constant current as the max current output figure. Controllers are rated at a current value. Say, 30A or whatever. Once the voltage limit is reached at the max current setting, it transitions to only output that voltage and only outputs what the load draws at the max voltage setting.

 

[timselectric]

The "Bulk" of the charge is forced in at a high current.
Then the remainder of the charge is "absorbed" at a lower current. (Similar to batteries in parallel equaling with each other)