| ??? 03/08/07 15:16 Read: times |
#134586 - Very simple! Responding to: ???'s previous message |
Jeroen said:
I has to keep running an entire weekend (some 50-55h)
I want to make a 3.6V or 4.8V stack of batteries. 3.6V has is preferred since this uses 1 battery less ($$ and space), the power consumption is 20mA. What should the capacity be? This is very simple: 55h x 20mA = 1100mAh Due to imperfect discharge/charge cycles you will loose some of the capacity and nominal voltage. You should take into your calculation a nominal voltage down to 1.1...1.0V per cell and at least 20% loss of capacity. So, the absolute minimum capacity you need is 1300mAh and your worst case nominal voltage of three such cells goes down to 3.0V. With this data we can conlude: You cannot use AA (Mignon) NiCd but only AA NiMh. Good ones have 1700mAh, but be careful and have a good look into the datasheet!! Kai |
| Topic | Author | Date |
| Calculate battery lifetime | 01/01/70 00:00 | |
| Well .. | 01/01/70 00:00 | |
| calculator | 01/01/70 00:00 | |
| Calculation | 01/01/70 00:00 | |
| Aging | 01/01/70 00:00 | |
| use a buck-boost | 01/01/70 00:00 | |
| Sucking dry | 01/01/70 00:00 | |
| depends on battery type | 01/01/70 00:00 | |
| what's a buck boost? | 01/01/70 00:00 | |
| a Buck/Boost is a switcher that will make the outp | 01/01/70 00:00 | |
| Battery Life | 01/01/70 00:00 | |
| Very simple! | 01/01/70 00:00 | |
| Remember, though: | 01/01/70 00:00 | |
| So what? | 01/01/70 00:00 | |
| 1.2V | 01/01/70 00:00 | |
| Ah sorry. | 01/01/70 00:00 | |
| Confusing the numbers... | 01/01/70 00:00 | |
| Lithium Ion | 01/01/70 00:00 | |
| and 3.7V | 01/01/70 00:00 | |
| Not for beginner | 01/01/70 00:00 | |
| combine AA & AAA | 01/01/70 00:00 | |
| So, you intend to use NiCd? | 01/01/70 00:00 | |
| Not a good Idea | 01/01/70 00:00 | |
Minimum capacitiy per cell must be 1300mAh! | 01/01/70 00:00 |