So, I just gotta know...

When making a "48V" battery out of 18650 cells, why do we use a 14S configuration rather than a 13S configuration?
I never thought about it when I was making my pack, I just excepted what folks did and did it. But, I can never just except something, I am cursed with always wanting to know why. And in doing a video a few weeks back I started to think, why 14when 13 fits the bill?
The 13S configuration would be 52 V top (with a cell voltage of 4.0 V) and 45.5 V bottom (with a 3.5 cell voltage). That is right in the sweet spot for my (and I think most) inverter.
Is it just the result for folks preferring even numbers to odd--which I find odd, or the old superstition of unlucky number 13???

I just like the number 14 more than 13.
14 is an even number, which i like more. It can also be devided with the number 2, which results in 7 which is a commonly used config aswell.
Makes my monkey brain happy.

Most 48 volt inverters, also allow for voltages up to 60v, And i can run a little bit more power, trough the same cables.
13s - 3.6v per cell - 2.5mm² 16A cable -> 749 watts
14s - 3.6v per cell - 2.5mm² 16A cable -> 806 watts
Thats about 7% more power i could push trough the same cable.

I usually build 52V packs and they are always 14s. I always associate 13s with 48V packs. I guess I've never heard of a 14s pack referred to as 48V.

DiggsUt said:

I usually build 52V packs and they are always 14s. I always associate 13s with 48V packs. I guess I've never heard of a 14s pack referred to as 48V.

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Well, I have never seen a 52 V inverter, so the battery it "sees" is a 48V battery. So, I thought most folks (or maybe it is just me) referred to them as a 48 V battery.
Just like we call a car battery 12V, but really is is more like 13 V.

Oberfail said:

I just like the number 14 more than 13.
14 is an even number, which i like more. It can also be devided with the number 2, which results in 7 which is a commonly used config aswell.
Makes my monkey brain happy.

Most 48 volt inverters, also allow for voltages up to 60v, And i can run a little bit more power, trough the same cables.
13s - 3.6v per cell - 2.5mm² 16A cable -> 749 watts
14s - 3.6v per cell - 2.5mm² 16A cable -> 806 watts
Thats about 7% more power i could push trough the same cable.

Click to expand...

They did a study I saw years ago, where folks like even numbers better than odd numbers. Something in the human brain that wires us that way.
Of course me being odd in many, many ways, I prefer prime numbers (13 is one of them) and they are all odd, except for two; which in an of itself is rather odd.

Nothing stops you from using 13s for your battery, if you prefer it more, just use it ^^

Its a matter of voltage range vs available equipment. I find that there are more options for 14s than 13s - e.g. more to choose from which leads to less $, especially if you're original choice dies and you need to look for new/alternate equipment.

Oberfail said:

Most 48 volt inverters, also allow for voltages up to 60v, And i can run a little bit more power, trough the same cables.
13s - 3.6v per cell - 2.5mm² 16A cable -> 749 watts
14s - 3.6v per cell - 2.5mm² 16A cable -> 806 watts
Thats about 7% more power i could push trough the same cable.

Click to expand...

+1 to above.
Higher voltages would help efficiency too as higher currents (ie w lower voltage systems) mean more IxR losses.
But if your inverter & other gear doesn't like the higher end, you've got to do what suits....

Redpacket said:

+1 to above.
Higher voltages would help efficiency too as higher currents (ie w lower voltage systems) mean more IxR losses.
But if your inverter & other gear doesn't like the higher end, you've got to do what suits....

Click to expand...

No, no, the inverter has no issues,
I have a 14s 240P battery already done and running for over half a year. I was just curious as to why when you look at 18650 cell configuration to make a "48 V" battery, they give a 14s configuration.
Just curious, not looking to change anything,. I an cursed (and it is a curse, trust me) with having to know the "why" of everything I do, if even after the fact
Not sure about less loss, we are talking about a small voltage difference over a short run.
I got the sneaking suspicion that not being 13 was probably the origin of it.

I suppose the lower voltage makes the difference, because under a certain voltage the inverter goes off:

13S @ 3.2V = 41.6V
13S @ 4.2V = 54.6V

That's a 13V range for a 13S.

14S @ 3.2V = 44.8V
14S @ 4.2V = 58.8V

And this is a 14V range for a 14S. So you have a wider range for 14S... well, at least that's what I always thought...

For me I like 14s because I also do a lot of 24vdc with 7s so I can easily combine multiple of my 7s AmmoBatts together to get the higher 48vdc or 72vdc system standards. I have a lot of GreenWorks 82v(20s) tools that I am wanting to be able to run on my AmmoBats, I also have a lot of DeWalt 60v tools so those don't fit so well. But overall when I have looked at motors for electrifying things 72vdc is pretty common for higher efficiency.

I have noticed that that my 48vdc electric bike is 13s but there is an upgraded "extra power" battery that is 14s that I could have gotten. I wish I had gotten it since currently with the voltage drop I am only able to get go juice for about half the battery capacity. It still works after that but less power from the motor to go really fast

Well there is my rambling.