2-Stage Battery Dischargers and Auto-Cutoff Modules - Home Page
Our Products
  · Overview
  · Pack Dischargers
  · Auto-Cutoff Modules
  · Load Modules
  · Accessories & Parts
  · Custom Products
Why Discharge?
  · Why do it?
  · How does it help?
  · Over-discharging
  · When to discharge?
  · Fast vs. slow
  · Heat is the enemy
  · Maximizing life
Tech Tips
Discharging FAQs
  · The Basics
  · Pack Dischargers
  · Auto-Cutoff Modules
Downloads
Price List & Ordering
Recycling
About CamLight
Contact Us     Terms of Use     Privacy     Copyright     Legal    

Why Discharge? — Heat is the enemy


All of the Why Discharge? topics can be found together in our Why Discharge? white paper. (PDF, 35KB)


Fast discharging has a lot of benefits but it can cause damage to your packs if you're not careful. Simply put, heat is bad. You might have seen packs get so hot that their heat shrink melted (or worse) and they appeared OK, but they're not. While high-quality cells are more resistant to damage from heat than ever before, they're not invulnerable. The cell can leak gasses formed during fast discharging and plate or separator warping or damage can occur. It might not be obvious at first, but over time the damage will lower the pack's capacity and voltage under load, eventually leading to the failure of one or more cells.

But, a lot of times we don't have much of a choice while using the pack. The discharge current level often needs to be high to get the performance we need out of the device using the pack. Just be aware that the temperature of the cells is much, much higher inside that pack than it is outside of the shrink wrap and do whatever you can to cool them quickly. But, do not refrigerate your packs before using them or cool them with anything other than air! A cold cell will not perform well and can very easily be damaged by localized heating inside the cell as it's used. In addition, cooling them too fast (e.g., using water or carbon-dioxide, etc.) will just cause warping or other physical damage to the cell as the inside of the cell is still very hot.

To help maximize the life of your packs:
  • Keep the discharge current level low enough to prevent overheating whenever you can. Let the temperature of the cells tell you how high a discharge current level they can safely handle. Most manufacturers set the safe temperature limit during discharge to 130ºF. (55ºC.) or so, with a maximum of 150ºF. (66ºC.) set by manufacturers of some cells. This doesn't mean that the outside surface of the shrink wrap should stay below this temperature. The cell itself needs to stay below this level to maximize its life.
  • As much as possible, cool them with fast moving air as they are being used. Add space between the cells to allow for better air flow.
  • Don't store them above 85ºF. (30ºC.) or below 32ºF. (0ºC.).
Can you exceed the rated maximum temperatures and have the cell survive? Of course. Just be aware that a little bit of the pack's performance might be lost, and its life expectancy shortened, each time you do.


«Previous Topic«                 »Next Topic»