I have been learning more about how battery packs work and are made. I have been playing around with this one: https://www.batteryspace.com/li-ion-18650-battery-18v-2900-mah-52wh-7a-rate-5s-s-ncr18650pf.aspx
It has built in protection (I suppose this would be called a BMS or battery monitor?). Though I would to estimate the battery life the battery has at any given moment. I understand that it can be estimated with voltage monitoring or using a BMS IC that can give this info. But if I have a built battery pack already, and it already has an IC inside, what are my options for monitoring the pack externally?
I looked through Digikey and found that most ICs want to be embedded into the pack itself. I am looking for something external to monitor the pack state of charge (SOC). Closest thing I found was this: https://www.analog.com/en/products/ltc2943.html
I believe it would have worked great with an external pack but the voltage limit is 20V.
Any hints for this battery monitoring newbie?
EDIT: I did find this part: https://www.analog.com/en/products/ltc2944.html#product-overview and it looks to work fine but are there better alternatives to what I am trying to acheive?