Hard to grasp info on many different capacities of Lithium battery packs

Thread Starter

abdulbadii

Joined Aug 30, 2017
84
The below is info on many different capacities of Lithium battery packs as a PS to most, if not all, of cordless heavy-duty equipments today
But while they have a voltage value info also they have very confusing, hard to grasp info on:

48Vf, 88Vf, 98Vf and 268Vf

So what's actually the Vf all about ?

Please whom I thank sincerely help clarify its true meaning
 

Irving

Joined Jan 30, 2016
3,810
Capacity is measured in Amp-hours (Ah) or Watt-hours (Wh). Vf is rare, usually relates to Voltage-force as a poor description/mis-translation of what is better known as Potential Difference.

48V and 96V are common nominal voltages for Li-Ion EV-bike battery packs. Never seen 88,used but might relate to a 24cell * 3.7v = 88.8v which would more commonly be designated a 96v pack. No idea on 268!

Can you post a link to these examples so we can see them in context, which will help us to understand your confusion.
 

crutschow

Joined Mar 14, 2008
34,062
They are usually measured in nominal Volts and ampere-hours.
The total battery energy (Wh) is somewhat less than the Volts * Ah, since the voltage drops as the battery discharges.
 

aston79

Joined May 23, 2023
2
The below is info on many different capacities of Lithium battery packs as a PS to most, if not all, of cordless heavy-duty equipments today
But while they have a voltage value info also they have very confusing, hard to grasp info on:

48Vf, 88Vf, 98Vf and 268Vf

So what's actually the Vf all about ?

Please whom I thank sincerely help clarify its true meaning
Short answer divide Vf by 3.6 to get mAh. 288Vf divided by 3.6 is 80mAh.
We know that the quantity of charge, Q (in coulombs or C) that flows in an electric current (in amperes or A) is given by the product of current and time (in seconds or s) for which the current is flowing
C = A x s
A battery can be likened to a capacitor as both of these are storage of charge. For a capacitor, the product of voltage (in volts or V) and capacitance (in farads or f) is actually the charge stored.
C = Vf
Hence Vf is actually C. For example 288 Vf is 288 C which by definition is 288 As. To convert 288 As to mAh we first multiply by 1000 and then divide by 3600 (1hour is 3600s). Hence 288Vf is equivalent to 80 mAh.
It is necessary to check the replacement battery voltage one is purchasing because the individual 18650 cells can be configured to give different output voltages irregardless of its Vf capacity.
 

WBahn

Joined Mar 31, 2012
29,883
Short answer divide Vf by 3.6 to get mAh. 288Vf divided by 3.6 is 80mAh.
We know that the quantity of charge, Q (in coulombs or C) that flows in an electric current (in amperes or A) is given by the product of current and time (in seconds or s) for which the current is flowing
C = A x s
A battery can be likened to a capacitor as both of these are storage of charge. For a capacitor, the product of voltage (in volts or V) and capacitance (in farads or f) is actually the charge stored.
C = Vf
Hence Vf is actually C. For example 288 Vf is 288 C which by definition is 288 As. To convert 288 As to mAh we first multiply by 1000 and then divide by 3600 (1hour is 3600s). Hence 288Vf is equivalent to 80 mAh.
It is necessary to check the replacement battery voltage one is purchasing because the individual 18650 cells can be configured to give different output voltages irregardless of its Vf capacity.
So, according to this, that 48 Vf battery pack has a capacity of 13 mAh?

Despite the TS specifically saying that these are for heavy-duty equipment?

Despite even the smallest button cell batteries generally having at least twice that capacity?

Despite the 18650 cells mentioned having between 100x and 300x that capacity?

Perhaps it is time to stop just spewing whatever ChatGPT spits out at you.
 

aston79

Joined May 23, 2023
2
So, according to this, that 48 Vf battery pack has a capacity of 13 mAh?

Despite the TS specifically saying that these are for heavy-duty equipment?

Despite even the smallest button cell batteries generally having at least twice that capacity?

Despite the 18650 cells mentioned having between 100x and 300x that capacity?

Perhaps it is time to stop just spewing whatever ChatGPT spits out at you.
You may be right I might have made an error. But do you see any thing wrong with my working. Must assuredly I must confess I am a mere human and nowhere near as knowledgeable as any ChatGPT. Is it possible to delete my original post?
 

WBahn

Joined Mar 31, 2012
29,883
You may be right I might have made an error. But do you see any thing wrong with my working. Must assuredly I must confess I am a mere human and nowhere near as knowledgeable as any ChatGPT. Is it possible to delete my original post?
The problem is that ChatGPT is not knowledgeable at all. That is merely an illusion. All it does is, in essence, is run the probabilities to decide which word should come next in the sentence it is generating based on all the strings of words it had in it's training set. It has zero concept regarding whether those words, taken as an abstract concept, make any sense at all. The big problem with these tools is that they are really good at making well-worded gibberish that superficially sounds plausible and reasonable, but, especially in technical discussions, is patently absurd when you look past that well-worded shimmer.
 

bassbindevil

Joined Jan 23, 2014
818
Those are plausible voltages if you're talking very small EVs, but not for cordless tools. The Makita pack I rescued from the roadside says 18V 4.0Ah 72Wh. Guessing from the magnitude of the numbers, maybe Vf is just Wh in another language.
 
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