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  #21  
Old 03-05-2020, 10:21 AM
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Default Battery Basics

FYI:
Battery - is usually used to refer to an individual "battery" cell (like AAA or a 9V)
...but, sometimes a group up of "individual" cells is also referred to as a "battery" (like a 12V car battery)

Battery Module - a group of individual cells connected together make up a "battery module"

Battery Pack - several battery modules, grouped together, are usually referred to as a "battery pack".

In-series- is when (2) or more battery cells/modules are connected together (+) to (-). The positive (+) terminal of a battery cell/module is connected to the negative (-) terminal of another battery cell/module.
(connecting battery cells/modules "in series" will double the voltage but, not the capacity)

In-parallel- is when (2) or more battery cells/modules are connected together (+) to (+) & (-) to (-). The positive (+) terminal of a battery cell/module is connected to the positive (+) terminal of another battery cell/module & the negative (-) terminal of the battery cell/module is also, connected to the negative (-) terminal of the other battery cell/module.
(connecting battery cells/modules "in parallel" will double the capacity but, not the voltage)

Now, lets move on to/with the basics/specifications of Lead (batteries)

A standard 12V Lead (chemistry) battery (module) is comprised of (6) (individual) cells.

These "individual" Lead cells have a:
... (low) voltage threshold of ~1.75V
...a (nominal) voltage of ~2V
...the (high or max) voltage is ~2.21V
…with a (usable) voltage range of only ~0.46V

So, the voltage limits for a (standard) 12V Lead battery "module" would be:
...(low) ~10.5V
…(nominal) ~12V
...the (max) is ~13.3V
…with a (usable) voltage range of ~2.8V

Takin' it a step further, if (2) 12V battery "modules" are connected together "in series" you would have a 24V "battery pack"
…(3) 12V "modules" would make up a 36V "pack"
…& (4) of them would make up a 48V "pack" etc.

Lead Battery Module/Pack Voltage Ranges

Voltage___Low____Nominal___High____Usable

12V______~10.5V____~12V____~13.3V___~2.8V
24V______~21V_____~24V_____~26.6V___~5.6V
36V______~31.5V___~36V_____~39.9V___~8.4V
48V______~42V_____~48V_____~53.2V___~11.2V
60V______~52.5V___~60V_____~66.5V___~14V
72V______~63V_____~72V_____~79.8V___~16.8V
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  #22  
Old 03-08-2020, 10:46 AM
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Ok now, let's discuss the parameters of small DCV (Direct Current Voltage) systems

It seems that the voltage specs for most of these small DCV systems, that were working with, is based on the voltage specs of Lead Acid batteries
(I guess, mainly, because they were mostly the only type of battery that was commercially available for many years)

Something like this:

DC System Voltage Ranges

Voltage___Low____Max

12V______~10.5V____~20V
24V______~21V_____~32V
36V______~31.5V____~44V
48V______~42V_____~56V
60V______~52.5V___~68V
72V______~63V_____~80V

We have a pretty good idea of the low V specs, from the Lead Battery Module/Pack Voltage Ranges chart
…& the Max is kind of a "guestimate" of what these small DCV systems should be able to safely handle

Why is this important?

It's important because a lot more of us/we/folks want to use Lithium battery packs on our DIY karts
...or when converting a "gas" kart to electric
...&/or even when upgrading an electric kart/minibikes etc. from Lead battery packs upto lithium packs

But, there are a lot of different battery chemistry types (as discussed above)
…with (sometimes) large voltage differences between those different battery chemistry types
…plus, the battery cells can be set up in many different configurations (14S, 15S, 16S etc.)
…& (usually) there are other variables (differences in dis-charge & charging rates) that really need/must be "factored in" to use these "super powerful batteries" SAFELY
...especially when "posting" info that others may try/follow
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  #23  
Old 03-09-2020, 07:25 AM
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I think we can sum your entire thread into 3 lines.

Google the battery you would like to use.
Read it's datasheet and find the appropriate charger and safety equipment
Treat the battery like your first born kid regardless of chemistry.
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  #24  
Old 03-13-2020, 10:18 AM
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Quote:
Originally Posted by Tpdingo View Post
I think we can sum your entire thread into 3 lines.

Google the battery you would like to use.
Read it's datasheet and find the appropriate charger and safety equipment
Treat the battery like your first born kid regardless of chemistry.
Simple as "Google the battery you would like to use" huh ?
..but, there's a ba-zillion different types & other variables too
...& it seems like that's where most folks get stuck
...or start heading down the wrong path
...or at least not the best path

So, where does "one" start?

Example:
OK Um... I want to use a 48V 1,000W system on my kart
...so, I'll just Google "What battery to use on a go kart with a 48V 1,000W motor?"

The first thing that came up was:

"Unit Pack Power Electric Bike Battery
- 48V Ebike Battery for 1500W/1000W/500W Bicycle DIY
- Best Lithium ion Battery for Bafang Motor(48V 20Ah/ 52V 14Ah)

This triangle Ebike battery is 52V 20AH, suitable for 1000W/500W motor.
Max constant discharge current:30A.
Size:10.3×6.3×2.8 in.
Charger: 54.6V 2.5A US Plug"

https://www.amazon.com/UnitPackPower...304003878&th=1

But, in the same ad it shows a 48V 20AH bat pack w/30A BMS $335.50
…a 48V 20AH bat pack w/50A BMS $355.50
…& a 52V 20AH bat pack w/30A BMS $358.00 (probably a typo & it's really 14AH)

So, do we know what the voltage is, of the cells, that this pack is constructed of? No
...what about the materials those cells are constructed from No, again
...or how those cells are configured? (12S, 6S2P etc.) Nope, no clue

Does it come with the appropriate charger? (the ad mentions: "Charger: 54.6V 2.5A US Plug")
...but, it doesn't specify "if" that charger is included

Nope, that's NOT confusing, at all
…& that's just the first one

Now, what happens after the average Jo, reads thru a few of those "Google" results (ad's, videos etc.)

Um...help

Yup, their way more confused than when they started

That why I started this thread
...to help me & others understand this stuff better

IMO
"Don't just hand someone a fish, show them how to fish"
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  #25  
Old 03-17-2020, 12:47 PM
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I've been thinkin' about it
...& I think I figured out how/why I had that Lithium battery stuff all wrong

First, keep in mind that forever & ever, the main "big" battery type was based upon Lead Acid chemistry
…& they were almost always configured in 12V packages (packs)

There were also Industrial batteries available, configured into 6V packages, for like fork lifts & golf carts
…they were of the Lead Acid type too
…& they were usually connected in series to form higher voltage packs (multiples of 12V like 36V, 48V etc.)

But, there was NOT a lot of other variations to deal with
...mainly, just match-up the voltages

So basically, you could just use (1) 12V battery to power a 12V system & then, a 12V charger to charge it back up (like automobiles)
…or use (2) 12V batteries wired "in series" to power a 24V system & a 24V charger, to charge them up
…or (4) 6V battery "modules" "in series" could also be used to power 24V systems etc.,etc.


So, when I was researching, to learn more about Lithium batteries, it looked like with this "new" technology, there were (2) "main" but, very different types, LiPo & LiMag

To me, it seemed like the LiPo cells,
...were made with Lithium & Potassium
...packaged in round containers
...& had a 3.2V (Nominal) voltage rating
...like the famous 18650's

& then, there were these LiMag cells
...that were made with Lithium & Magnesium
...packaged in Pouch type containers
...with a 3.7V (Nominal) voltage rating
...like used in the Chevy Volt & Nissan Leaf automotive battery packs

* So, I guess that, I figured it was kinda like, back when VCR's (video cassette recorders) first came out
...& there was (2) "main" but, very different competing types available, VHS & Beta

But, that's NOT the end of the story because there are so many more variables (chemistries, voltages, packaging etc.)

So, now I (& hopefully anyone who reads this) understands that the most important things to know, when working with lithium batteries
...is to "BE AWARE" of, learn & understand what the specifications are for the specific type of lithium cells, that you want to use
…& follow those specifications, to the letter
..."Treat the battery like your first born kid" as Tpdingo has suggested
…& always remember, as Sid had made clear "LiIon cells are NOT LiIon cells!!!"
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  #26  
Old 03-24-2020, 12:58 PM
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Default DIY battery packs

Now, lets look into some of the details that are involved, with building a DIY battery pack

First, keep in mind, "factory made" battery cells (AA, AAA, 9V, 18650's etc.)
…& battery packs (12V automotive, 36V E-bike batteries etc.) have been designed & manufactured by professionals

Which means that a trained professional has "done the math" & contemplated many factors that need to be incorporated into the mix like:
... pack voltage
...amp ratings (dis-charging & charging)
...pack capacity
...& even resistance

Next, materials are thoughtfully chosen
...then, those materials are professionally assembled
...& finally, the "end product" gets thoroughly tested, before being "released" for public use

So, "if" these factory made battery/packs are treated & used "as directed" there's usually not a lot, for the end user, to "think" or worry about


Now, to build a DIY batt pack yourself, "you" have to be the "trained professional" (so to speak)
...& wear all of the different "hats"

The designer
...& "do the math" to account for all of the factors involved, with "your" specific situation

The parts chooser
…& pick compatible parts that match "your" specific system's specs
(don't forget that ya gotta factor in some of the other important details like weight, size & even the total cost)

The assembler
...to arrange & assemble the components

& the tester
...put 'er on your kart & try 'er out (the best part)
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