Ready to bite the bullet

Batteries, Chargers, and Battery Management Systems.
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Teeach   100 µW

100 µW
Posts: 8
Joined: Apr 14 2020 6:32pm

Ready to bite the bullet

Post by Teeach » Apr 24 2020 11:10am

Hi

I put a thread up little while ago but now have done some more research and singled some bits out.

scoot is a generic chaos.

start at the beginning i guess
battery pack I will build myself

18s4p = 64.8v
64.8v motor @ 2000w = 36a
max current per p cell (a/p*) = 9a (36a/4p cells)

This however this is above the values in a chart I seen here where 7a is acceptable for 7mm 0.15, obviously the 9 is max so i'm not too concerned about this however I guess the connections from one 'p' cell to the next, need to be uniform otherwise current will take the path of least resistance and overheat that particular nickel strip?? i'm seriously considering soldering.

I haven't yet found a suitable BMS with Bluetooth. haven't looked n into it that much but i know i need a minimum of 18s, would a 20s work and disable them?


motor/controller, any recommendation on this? price seems good etc../. and a direct fit.

https://www.ebay.co.uk/itm/Brushless-Mo ... Swl05eoCZi

at full charge this will over volt quite a bit but at nominal it will be 4.8v over, dont think that's any problem?

any input is appreciated and will get some pics up aqs and when i start building the different components.

oh nearly forgot the fancy finger throttle with lcd screen i guess is dependent on the controller or are these generic that have the ability to power the screen and display info and obviously control the speed

chers

Balmorhea   10 kW

10 kW
Posts: 714
Joined: Oct 01 2019 8:30pm

Re: Ready to bite the bullet

Post by Balmorhea » Apr 24 2020 12:51pm

The display is almost always specific to the controller. Throttle is usually generic, except for the plug.

goatman   1 MW

1 MW
Posts: 1567
Joined: Jun 23 2019 6:50pm
Location: Surrey, B.C.

Re: Ready to bite the bullet

Post by goatman » Apr 24 2020 2:14pm

I would just ask to make sure the caps aren't 63v in the controller. 18s is 75.6v.
I solder with 16 gauge copper wire for serial and I don't think parallel carries any amps really, I use light gauge wire like what your throttle uses 18/20? gauge for parallel and run 10 amp burst. then I usually cruise at 1600 watts which is 5 to 7amp constant depending on the voltage of the pack. I run 70v down to 51v (17s).

I had bad volt sag on my packs and soldered copper on top of the nickel serial connections to fix the sag. its in this link

viewtopic.php?f=6&t=104027&p=1527424&hi ... n#p1526264

I use a 60 watt solder iron with a 1/4 inch wide chisel tip. 60/40 solder a pre tin flux and it takes a count of three to make the solder joint and ill have a cool damp rag to touch the solder to help cool the joint but the battery doesn't really get hot, if you use a 40watt soldering iron you have to spend too much time trying to solder like 6 seconds and the battery gets hot. ive soldered about 7 packs so far. its frowned upon but ive been lucky. my cells were used. im looking at doing magnet battery connections because im about to buy new cells but at $10 each I don't really want to risk damaging new cells by soldering.

Teeach   100 µW

100 µW
Posts: 8
Joined: Apr 14 2020 6:32pm

Re: Ready to bite the bullet

Post by Teeach » Apr 24 2020 2:49pm

Thanks...

Ah I can't check that until it arrived it which point it would be too late. Surely they allow for fresh charge voltage?

That said I'm starting with the batteries and going o o we only the standard until it pops I will dig the controller out now and see what rated caps are in there.

Cheers

999zip999   100 GW

100 GW
Posts: 9466
Joined: Jan 10 2010 1:40pm
Location: Dana Point So. Cal

Re: Ready to bite the bullet

Post by 999zip999 » Apr 24 2020 3:37pm

1 Esther parallel cell will always help the longevity of your battery

john61ct   100 GW

100 GW
Posts: 5482
Joined: Dec 18 2018 2:06pm

Re: Ready to bite the bullet

Post by john61ct » Apr 25 2020 3:26pm

Esther?

Balmorhea   10 kW

10 kW
Posts: 714
Joined: Oct 01 2019 8:30pm

Re: Ready to bite the bullet

Post by Balmorhea » Apr 25 2020 11:42pm

john61ct wrote:
Apr 25 2020 3:26pm
Esther?
Extra? As interpreted by stoopid fone?

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