Healthy Volts trumps total mah - Or the other way around? What is your choice and why?

[Modular Hippo]

Hi Forum,

Hope all is well!!

Building a battery pack of recycled 18650 Li-Ion batteries and have a question that someone might be able to shed some light on

If I have to pick one of two batteries for my pack, then would max voltage trump higher watts? Let me explain, lets say you have the two batteries below:

A: 4.20 v 2226 mah = 9,349 watts

B: 4.19 v 2376 mah = 9,955 watts

If I was aiming for the highest watts I would pick battery B, saying that it only holds 4.19 Volts...
If aiming for a healthy battery then maybe go for battery A that display 4.20 Volts....

What is more important, a healthy reading of Volts of the battery, or the total watts?

Is there a cut-of point where a fully charged 18650 has a voltage so low that it should not be used regardless how many mah it stores?

In a scenario where you can only pick one of them then what is your view and why?

Thanks
Modular Hippo

 

[LydMekk]

Why 18650 instead of LIFEPO4?
The fire hazard level pulled you to it?

 

[efficientPV]

To most people here, volts and amps are interchangeable. For those in electronics, lower voltage always means higher IR loss and lower electronics efficiency. What you have isn't a choice,

 

[Q-Dog]

I suppose I would want to know how far off from factory spec the cells are to make a decision on their health, but honestly, you couldn't pay me to mess with used batteries at this point

 

[Modular Hippo]

Why 18650 instead of LIFEPO4?
The fire hazard level pulled you to it?

I had access to 18650 and found it a good way to get my head around Volt, Amps & Watts, BMS (risks and basics etc.) in a fun way. I am fully aware of the fires etc. and trying my best not to burn the house down - My next project is LIFEPO4 but will have to save up for that one as a bit mote expensive

 

[Modular Hippo]

To most people here, volts and amps are interchangeable. For those in electronics, lower voltage always means higher IR loss and lower electronics efficiency. What you have isn't a choice,

So are you saying that going for highest possible mah is the way forward and ignore the 0.01 drop in voltage (from 4.20 to 4.19) as irrelevant in my usage case?

 

[Modular Hippo]

I suppose I would want to know how far off from factory spec the cells are to make a decision on their health, but honestly, you couldn't pay me to mess with used batteries at this point

I guess drop in mah is one thing but wonder what the implications are in relation to voltage drop... Th search will continue

 

[efficientPV]

I'm saying you are splitting hairs on numbers that aren't that accurate and won't reflect what is actually sent. It is still the same chemistry.