Hey, hardware engineer but I'm interested in doing a repair shop for dead drill batteries, there doesn't seem to be anyone doing it where I live. I have a basic understanding on cells, but not so much on the Circuits Ryobi uses, I'm going to ask a lot of questions, even some that are basic, but hearing it from others help me learn better. I'm currently working on 6 Ryobi packs, different sizes. 5 are 18v different amp hours, and 1 40V. I've been watching youtube videos on re-starting low cells and that is what I did, I think I fixed my first. I don't have a ryobi tool with me to test, but charger is now showing full charge and battery pack does show 20V on multimeter. 1 pack is completely dead, so I'm thinking on tossing that, unless it makes sense I spend $25 CAD on 5 new cells labor

​

1. What specific voltage does the charger need to start charging battery pakcs?
2. At what voltage would you toss or replace a cell.
3. I have a pack that has a button that if pressed shows light showing battery life, but the pack itself has the 18V and marks as full on charger (6 amp ahs) how do I reset the light
4. What do people usually charge for fixing drill batteries. I'm assuming most of you are in the states what do battery cells costs over there
5. What type of battery cells should I be replacing the packs with.
6. what does the extra pins on the battery charger do? besides positive and negative, I'm assuming one is a sensor, but what is the other one exactly?
7. What kind of nickel strips for spot welding should I be using?
8. What else should I be considering?
9. any tips or tools you guys like to use for the job, do share with me, link preferred!
10. Safety precautions, what type of things do you all prepare in case of emergency, what are some common risks when fixing battery packs, etc...

Thank you! I do know some of these but sometimes I'm second guessing myself as I don't have any friends that do this that I could talk shop with. In hearing you all I will have a better insight into this!