## hpr3816 :: Post Apocalyptic 4s5 Battery Pack  

 HR000000000
H Hybrid: Denotes some prepurchased or hard to find components
R Robotics: suitable for robots
buy: 4s 40A BMS
https://www.aliexpress.com/item/4000025857655.html
(can't specifically vouch for this vendor, just chose the first that
came up)
make sure to choose 4s and balance

find or buy materials: duct or gorilla tape, trashed computer dvd
or cd drive, 20 18650 cells, molex connectors(you can also use barrel
jacks or whatever you want to transfer power), wire and maybe 'tab wire'
https://nl.aliexpress.com/item/32650006768.html
solder everything together as per schematic and pictures (there
is theoretically a danger in soldering cells, but I have never had a
problem. Have a pair of pliers and a nearby window handy to throw them
out of if anything goes wrong)
wrap in cardboard and tape as per pictures
add the cd/dvd drive lids(if you taped well you won't short
anything and burn your house down
tape dvd lids to battery

Getting into the battery for maintenance just requires a utility
knife.
Watt Hour does a great job describing the 3s BMS, which is very
similar to the 4s used in my case: https://yewtu.be/watch?v=QNENyu97w2A
Battery Schematic
 Click the
thumbnail to see the full-sized image
Cut through tape to reveal battery

Click the thumbnail to see the full-sized
image
Flat metal holds cells together

Click the thumbnail to see the full-sized
image
Detail of 4.2v
 Click the thumbnail
to see the full-sized image
Only have to desolder one side
 Click
the thumbnail to see the full-sized image
New cells in
 Click the thumbnail to
see the full-sized image
Make sure there is thick tape covering battery

Click the thumbnail to see the full-sized
image
DVD drive case for stability
 Click
the thumbnail to see the full-sized image
Tape the DVE case to battery
 Click
the thumbnail to see the full-sized image
Charge board with Molex connector

Click the thumbnail to see the full-sized
image
Outdoors 1
 Click the thumbnail to
see the full-sized image
Outdoors 2
 Click the thumbnail to
see the full-sized image
