I have two Orange 4200mAh 5S lipo batteries
1) 2* Orange 4200mAh 5S 35C/70C Lithium polymer battery Pack (LiPo)
(Initially it was 6s but i have removed one cell from each battery as it was dead)

2) Charger: ToolkitRC M8S 400W 18A
https://www.banggood.in/ToolkitRC-M8S-400W-18A-Color-Screen-Balance-Charger-Discharger-for-1-8S-Lipo-LiHV-Life-Lion-NiMh-Pb-Battery-p-1552170.html

3) Parallel charging Board
https://hobbyking.com/en_us/hobbyking-parallel-charging-board-for-6-packs-2-6s-xt-60.html

For battery recommended Max. Charge Rate is 5C, I have never charged battery more than 2A.

My question is
1) Should i charge battery with minimum 4.2 A (1C) or is it ok to charge 8.4A(2C)?
2) When i connect battery to parallel charging board then, should i charge with minimum 8.4(1C considering two batteries) or use 16.8A(2C considering two batteries)?

Which is good for battery life?

If you are charging it for the first time after repair then do not use parallel charge.
If it is not really necessary it is always good to charge at low charging rates and 1C is very safe in this matter.
Higher charging rates reduces battery life and you can choose 2C if you still choose to do it.

So for my 4200mAh 5S lipo, should i choose 8.4A charging current?

Quote from: MrNams on January 10, 2021, 06:56:20 PM
So for my 4200mAh 5S lipo, should i choose 8.4A charging current?

Mr Reddy already answered this in the previous post...

Regards

Quote from: MrNams on January 10, 2021, 06:56:20 PM
So for my 4200mAh 5S lipo, should i choose 8.4A charging current?

For your battery, 1C is 4.2A and 2C is 8.4A.
As experts said, if you are in hurry, it's ok to charge in 2C. But on long run, it may reduce battery life span.

Personally, I never charged above 1C.

thanks all