Ok I get you now… is there a way for you to read how much power u consume while riding?
U probably would need a bluetooth module and an app for that but yeah…
If u had lipos there might be a difference you will feel in power delivery… lipos might be a bit more quicker when delivering power compared to li-ions…
what else…
yeh, if you just need a spare pack to get along and are worried about lipos, u might get that 36v pack and still sqeeze out similar range u are having now with 9s system… at least that is what I think…
You see, with higher power load, there will probably be less capacity… I calculated some ‘reserve’ but by not knowing the actual cells used in the pack it is hard to estimate… though I think it should be close to 10miles for sure of riding… which might be just enough for you.
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If you do get it, report the results back… All what I did was calculating theoretical values and typical load you see on flats. For more info go and check @Ackmaniac works and Metr.At app and similar Data logging options for Vesc.
After u have done that u should be able to judge is your next battery pack able to put out enough watts for your daily use. Keep safe!
My boards are completed and i have volt meters on both, my son and I ride them almost every day. Check out my pics on "NO WORDS JUST PICS TOPIC. I just want to find batteries that are good and safer than lipos so i dont have to worry about lipo puff and how dangerous that can be.
yeh, if you gonna give the ‘new battery’ board to your son, I think you should be okay. If they speak english (at the site) just give them a call and explain the situation and then lets see what they are going to say.
Just say you are going to need 800-900W of power at times from the battery.
Will this bms work for a 36 volt battery, im also thinking of building my own since i have access to some 3.7 volt 18650 laptop batteries? It says its good upto 48 volts.
You might need a lot of laptop batteries to build proper pack. How many do you have?
Also… it might not be a that easy task, it is recommended to check each cell, before you are going to use. For that you need a ‘test rig’ to find out each cell’s capacity and so on.
Otherwise, that bms might work but im no expert.
@Namasaki can comment bms choice I think but otherwise I think he wont agree on using laptop cells either.
3A - 5A per cell is not a lot. Best case scenario - About 40cells to make a pack and also then the board might even feel a bit weak maybe. People usually do 6-8P packs I think, when going with laptop cells.
Some ebikes even use 20P packs. (their maximum discharge 20A, so only 1A per cell).
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Battery you showed with 30A discharge and integrated Bms looked okay.
It might be even better to build your own pack now.
Where are you located?
Some cells can be had for about 3-4$ a piece.
Multiply by 20 to get at least a somewhat usable pack.
80$ + work and you got your pack.
He pondered idea about laptop cells… I imagine he would need maybe 50cells (6cells in laptop pack = 10packs at least, if only 10cells are bad total), then each cell could output 4A and he would get there.
20A x 42V =840 W of power (full)
20A x 36V = 720 W of power. (middle / nominal)
20A x 30V = 600W of power. (low)
For a kid and not going up hills would be enough.
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I tried 400w scooter with 4s, believe me, it works but the difference can be felt between 1.3kw setup and 400w setup.
I have access to alot of laptop batteries at my job that are not being used.
I also have all the tools to build a battery pack except spot welder but my friend has one i can use.
The following statements are solely my own opinion.
Using laptop cells is a joke unless your building a laptop.
Dirt cheap low current BMS’s are unreliable and simply a waist of money.
If your gonna build with a BMS, spend the money and get a name brand BMS.
The only brands I know of that are proven is Bestech and Battery Supports also known as Supower
Thanks for the info. I did check out battery supports and they are popular. I was thinking of purchasing this battery pack from battery supports. Can I have your opinion on it? I know you know your stuff. I read alot in this forum.
In my opinion, a 30a battery is no where near enough for an E-board.
But then neither is a 60a battery in my opinion.
The reason is Voltage sag which robs you of power and range.
Some say that voltage sag is normal and acceptable. I disagree.
I like to keep voltage sag as minimal as possible.
To achieve this, I built a 300a battery pack with 60C lipos.
I have found that more headroom=less voltage sag.
